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Predicted radiation dose and risk associated with pediatric diagnostic x-ray procedures

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Predicted radiation dose and risk associated with pediatric diagnostic x-ray procedures
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Hintenlang, Kathleen M., 1964-
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xv, 232 leaves : ill. ; 29 cm.

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Bone marrow ( jstor )
Bones ( jstor )
Breasts ( jstor )
Dosage ( jstor )
Leukemia ( jstor )
Lungs ( jstor )
Manuals ( jstor )
Ovaries ( jstor )
Pediatrics ( jstor )
Skin ( jstor )
Dissertations, Academic -- Environmental Engineering Sciences -- UF ( lcsh )
Environmental Engineering Sciences thesis, Ph.D ( lcsh )
City of Starke ( local )
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bibliography ( marcgt )
non-fiction ( marcgt )

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Thesis:
Thesis (Ph.D.)--University of Florida, 1998.
Bibliography:
Includes bibliographical references (leaves 223-231).
General Note:
Typescript.
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Vita.
Statement of Responsibility:
by Kathleen M. Hintenlang.

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PREDICTED RADIATION DOSE AND RISK ASSOCIATED
WITH PEDIATRIC DIAGNOSTIC X-RAY PROCEDURES













By


KATHLEEN M. HINTENLANG


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY



UNIVERSITY OF FLORIDA


























Copyright 1998

by

Kathleen M. Hintenlang



























This dissertation is dedicated to my daughter, Lauren Lea Hintenlang, and my son,

Hunter Austin Hintenlang, for bringing the goals of this research that much closer to

home. To my husband David, je t'aime.














ACKNOWLEDGMENTS


The undertaking of this dissertation reminded me of the following koan:
When the mouth wants to speak about it, words fail.

When the mind seeks affinity with it, thought vanishes.

I would like to express my deepest appreciation and gratitutde to the following

people who made the thoughts and words come together: to Drs. Larry Fitzgerald and

Tom Crisman at the University of Florida for their unending support, to Dr. Randy Carter

in Statistics, without whom statistics would be numbers with no physical meaning, and to

Drs. Emmett Bolch and Jon Williams for their continual guidance. Again and always,

immortalis ago gratias vobis agamque. I would also like to thank the Shands at UF

radiology staff for their encouragement and assistance. Additional recognition is due Drs.

Wes Bolch and David Hintenlang; with their assistance, my idea germinated into a seed

and then sprouted many branches. I would like to acknowledge the support I received

from the Children's Miracle Network and the Shands Medical Guild. Sincere appreciation

is extended to my director in the EH&S Division, Dr. Bill Properzio, and to my assistant

director, Don Munroe, not only for the professional development but also for the growth

of a fast friendship. Heartfelt thanks go to my own staff in the Health Center office.

I would like to extend my greatest thanks to my family: Mom and Dad, Tom and

Rachael, Rob and Terry, and Mike and Venessa, for their continued love and support.

Finally, my most sincere and personal thanks go to my husband, David, for his

loving patience, understanding and staunch encouragement.

To quote the words written on a monastery wall in the Middle Ages: "The book is

finished. Let the writer play."















TABLE OF CONTENTS




page


ACKNOWLEDGMENTS ................................. ................................iv

LIST O F TA BLE S ....... .................... ................................................. ........... viii

L IST O F FIG U R E S ............................................................ ............ ............ ....... xi

ABSTRACT................ ............. ............... ........................... xiv

CHAPTERS

1 INTRODUCTION AND BACKGROUND............ ......... ............ ........... 1

G general ...................... ............. .... ............ ......................... 1
Pediatric Radiology as a Subspeciality ........................... ................. ..... ........3
R atio n ale .................. .... ..... .......... .......................................................... ..... .... ..6
Adult Organ Doses in Plain Film Radiography ........................ ........ ...... 8
Pediatric Organ Doses in Plain Film Radiography ........................................... 9
Calculation of Energy Imparted in Diagnostic Radiology............................ .. 11
P h an to m s ........... .... .. .... ........ .................. ............ .................. ....... ... 13
Mathematical ....... ................................... ...................... .... 13
Anthropomorphic............................................................. ... 14
Radiation D election Instrum entation ............................................... ................. 16
G as Filled Ionization C ham bers .............................................. ......... ........ 16
Sem iconductors............................. ................ 16
D term nation of R isk ............................................................ .. ....... 18
Significance and Objectives...................... ............................ ............... ........... 19

2 PATIENT AND EXAMINATION TRENDS OF PEDIATRIC X-RAY
P R A C T IC E S ....................................... .. .. .. .. ...... ..... .. .. .. ...... ................ ..... 2 2

Shands at the U university of Florida................................................ .... ......... ...... 22
Ten Florida Facilities................. ..... ....................................... ............ 26
E xam Sim ulations........................................................................ ..................... 28









A P sk u ll ............................................. ..... ..... 3 0
L ateral skull ......... ....... .. ............... ... .. 31
T ow nes skull ............................ .. ............ .. ......... ...... ................ 32
W aters sinu s .......... ............ .. .. .. .. ... .. .. ... .. ..... .. .. ..... ..... .. 3 3
A P cervical spine .......... ................... ... .. .. ..... .... 33
Lateral cervical spine............. ................ ........................................... 33
AP thoracic spine .................................. ....................... .. ....... .. 34
Lateral thoracic spine ........................................... ................................ .. 34
AP lumbar spine ..... .. .... ... ............ ........................ 35
Lateral lumbar spine ....................................................... ......... .......... .... 35
A P abdom en ............................... .. .. .. .......... ..... .. .. ..... .. ..... .. ... 36
A P p e lv is .................................................................................. ...... ... 3 6
A P bilateral hip.................................. ................... .. ..... .. 36
AP, PA and lateral chest .................................... .............. 37
Survey Data ............... .... ..................... ....... ...40

3 RADIATION MEASUREMENT EQUIPMENT AND TECHNIQUES............ 42

One-Year-Old Anthropomorphic Phantom ......................................... ......... ..42
Metal Oxide Semiconductor Field Effect Transistor (MOSFET) Dosimetry
S y ste m .................................. ...................................................... 4 6
Theory of O peration.................................. ................ ... ..................... 46
Characterization of High Sensitivity MOSFET Dosimeter...................... .......48
M O SFET Placem ent .......................................... ....................................... 50
Measurement of Absorbed Dose........................ .... ............. 55
Sensitivity A nalysis.......................... .................................................................. 56
C alculation of E effective D ose ............................................................................. 58

4 R ISK A SSE SSM E N T ............................................................................................. 60

G e n e ra l ...................... ................. ......................... ....................................... 6 0
Com ponents of a Risk M odel ................................................................... ..... 60
BEIR V M ethodology................................................... ................ 62
Populations for Determining Cancer Risk ...........................................................62
H um an Populations ........................................ ............................... 62
Anim al Populations .................................... .............. 63
Populations for Determining Genetic Risk ..................... ............................. 63
H um an P populations ..................................................................................... 64
Anim al Populations ........................................................... .................... 64
Dose-Response Curves...... .............................. .... ..... 65
D o se-R ate E effects ............................................................................................. 66
Population Transfer Coefficients................................................ ....... ............ 68
BEIR V Cancer Risk Projection M ethod ................................... ....................... 69
Specific C ause of D eath............................................................ ................. 72
A ge of Population ....... .................... ............... .... ..... ......... ...... 72
BEIR V Genetic Risk Projection Method .............................. .......... 73









Calculating the Relative Cancer Risk from Pediatric Diagnostic X-Ray
P ro cedures ........................ ......................... ...... .. ...... .................73

5 RESULTS AND DISCUSSIONS............. .. ...................................... 79

Facility Approach to Handling Special Concerns of Pediatric Patients...................... 79
Patient and Examination Trends........................................ ......... ................. 85
G enerators ............ ...... ................ ..... ...... ........ 93
Exposure Time......................................94
F ocal Spot Size ............................................................. ............... .. 95
A additional Filtration ...................................................... .. ............ 95
G rids ................................. .. .. .. .. .. ....... .......... ............. ... 96
C assettes ........................................ ... ..... .......... ............... 97
Film-Screen Combination ........................ ....... .... ......... 98
Source-Image Distance (SID).................................. ....... ............ ... 98
Automatic Exposure Control......................................................... 98
Field Size and Collim ation ............................................... ......... ..... 99
Radiographic Film Quality ............................................. 100
Repeat Analysis... ...................................................... ................. 100
R radiation Protection................................................................... 102
Organ Doses per Entrance Skin Exposure and Effective Doses............................... 103
Relative Risk..... ......................... .......... ....................... .... ..... ........... 111

6 CON CLU SION S .......................... .... ............ ................ 115

Site Surveys............................................ ................. 115
Phantom M easurements ........................................ ............................ 118
Effective Dose and Risk Predictions .. ......................................... ...................... 120

APPENDICES

A NUMBER OF EXAMS FOR PEDIATRIC PATIENTS UNDER 16 YEARS
O F A G E .. ............................ ............. ... ..... ............ .................... ................. 12 1

B EXAM FREQUENCY FOR PEDIATRIC PATIENTS UNDER 16 YEARS
O F A G E ....................................................... ...................... ...................... 130

C EXAM CHARACTERISTICS DETERMINED FROM FACILITY SITE
SURVEYS ... ................. .......... .................. 136

D AVERAGE MASS ENERGY ABSORPTION COEFFICIENTS........................... 147

E EFFECTIVE DOSE AND RISK CALCULATIONS ............................................ 150

LIST OF REFERENCES............................... ................. 223

BIOGRAPHICAL SKETCH ........................................ 232















LIST OF TABLES


Table page

2-1. Age Group Corresponding to Phantom ................................... ..................... 23

2-2. Annual Number of Plain Film Chest X-Rays by Age Group ..............................24

2-3. Percent Frequency of Plain Film Chest X-Rays ........................................ ........24

2-4. Surveyed Examinations .................................... .. ...................................26

2-5. Defined Locations of Anatomical Landmarks on Phantom Vertical Axis
with the Origin at the Base of the Trunk (cm) ......................................... 30

3-1. Tissue Weighting Factors for Calculation of Effective Dose...............................51

3-2. Position of the MOSFET Dosimeters Within the One-Year-Old Phantom.......... 53

3-3. Percentage Active Bone Marrow and Bone Surface Associated with the
Skeletal M O SFET Locations ................................................... ............... 54

3-4. Sensitivity Calibration Factors (R/mV) at 70 kVp ...................................... 56

3-5. Conversion Factors Converting Exposure to Absorbed Dose............................ 57

4-1. Lifetable Analysis of a Standard Mortality Table..................... ..................... 70

5-1. Effective Doses for Male and Female One-Year-Olds at Shands at UF............. 106

5-2. Comparison of Effective Doses for Male and Female One-Year-Olds
Among Facilities for Chest Exams ............... .................... ................. 107

5-3. Comparison of Shands at UF and FDA Absorbed Dose/ESE........................ 109

5-4. Comparison Among All Facilities and NRPB Effective Dose/ESD.................. 111

5-5. Relative Risk for Shands at UF Examinations ................................................. 112

5-6. Relative Risk for Chest Examinations Among All Facilities............................. 113









C -1. A P Skull .. ................ .. ............ ....... ....................... ........... 137

C -2. T ow nes Skull ................. ........... ........................... .................. 137

C -3 L ateral Sk ull..................................................................................................... 13 8

C -4. A P C ervical Spine .................. ......... .... ........................................... 139

C -5. L ateral C ervical Spine ........................................ ........................ ................ 139

C-6. AP Thoracic Spine ............................................................... 140

C -7. L ateral Thoracic Spine .......................................... .......................... ...... 140

C-8. AP Lumbar Spine............................................ ........... .......... 141

C-9. Lateral Lumbar Spine................................................... 141

C -10. A P A bdom en ...................................................... ....... ............................... 142

C-l A P Pelvis ........................................ 142

C -12 A P H ip ............................................ .. ..... ....... ................... 143

C-13. Waters Sinus... ........................................... 144

C -14. L ateral Sinus..................................... ............ .... ............. 144

C-15. Lateral Chest... .......................... ........... 145

C -16. A P Chest ...................................................... ................ .... ..... ....... 145

C -17. PA C hest........................ .... .. .. ............. ..... .......... .. 146

C-18. Non-Exam Specific Operational Data................................................. ......... 146

E -1. A P Skull ....... .............. ........ .... ........ 151

E-2. A P Skull w ith Thyroid Shield ........................................................................... 153

E -3 P A Skull ............... .. ... ........ .................... ...... .. ............... 155

E-4. PA Skull with Thyroid Shield ............................. ............... ............ 157

E -5 L ateral Skull........... ... ...................... .................................. ................ 159











E-6.

E-7.

E-8.

E-9.

E-10.

E-11.

E-12.

E-13.

E-14.

E-15.

E-16.

E-17.

E-18.

E-19.

E-20.

E-21.

E-22.

E-23.

E-24.

E-25.

E-26.

E-27.


T ow nes Skull ................................... .......................

A P C ervical Spine ...........................................................

Lateral Cervical Spine .......................................................

A P T horacic Spine ................................ .... ...................

Lateral Thoracic Spine ......................................................

AP Lumbar Spine.......................................................

L ateral L um bar Spine........................................................

AP Abdomen Supine........................................................

PA Abdomen Supine...................................

AP Abdomen Upright........................................................

A P P elvis ................ ... ...... .. .. ... .....

A P H ip ........................ ........................................

W aters Sinus ................................ .. .. .............

Lateral Sinus.................

AP Sinus.... ...............................................................

A P C h est................... ...... .. ..... .. .. ..... .. .. .. .. .. .. ..... ..

AP Chest with Thyroid Shield ................................

P A C hest.......... .. ... ..... .. .. .. .. .. .. .. .. .. .. .. ......

L ateral C hest .............. ..... .. .. .. .. .. .. .. ..... .. .. .. .....

L A O C hest.................. ............................

R PO C hest .......................................... ............

R A O C hest ............................................. ................


............................. 161

............................. 163

................ .. 16 6

...................... ....... 169

.................. ......... 172

...................... ........ 17 5

................... ........ 178

.... ........ .............. 181

................. ......... 184

..................... 18 7

........ ....... ....... 19 0

...... ..................... 193

.................... ....... 196

............................... 198

......... .. .. .. ... .. 2 0 0

..... ................ .. 202

.................. ........... 205

....... .. .. ... .. .... .... 2 0 8

S............... ........... 211

.............................. 214

.............................. 217

.. .. .... .. ..... ....... 2 2 0














LIST OF FIGURES


Figure page

2-1. Items frequently used for immobilization. .................................................... 31

2-2. Infant immobilized and supported by the Pigg-o-stat device for an upright
chest film ........ .................... ................ .............38

2-3. Toddler immobilized for an AP chest radiograph on the Tame-Em
im m obilizer................................... .................. ... ................. 39

2-4. Infant immobilized for a left lateral chest radiograph on a Plexiglas
im m obilizer............................... ....... .... .... .......... ................ 39

2-5. Octagon board for immobilization ........................................ ................. 40

3-1. One-year-old pediatric phantom ........................................ ................. 45

3-2. Thomson and Nielsen Electronics Ltd. MOSFET Patient Dose Verification
System ................................. ... .............. ...... ................... 47

3-3. MOSFET dosimeters placed in position in prototype one-year-old phantom...... 52

4-1. Various models used to extrapolate high-dose data on cancer incidence to
the low-dose region, so that risk estimates can be performed ..................... 68

4-2. The risk of leukemia due to low LET radiation as a function of attained age....... 71

4-3. Time dependent risk for exposure at age equal to one year for both male
and female leukemia models................... .......... .......... ................ 75

4-4. Time dependent risk for exposure at age equal to one year for male
respiratory cancer model.......................... .. .. ............... 76

4-5. Time dependent risk for exposure at age equal to one year for female
respiratory cancer model...................... ...... .................... 76

4-6. Time dependent risk for exposure at age equal to one year for male
digestive cancer model................. .. ...........................77









4-7. Time dependent risk for exposure at age equal to one year for female
digestive cancer model......................................................... 77

4-8. Time dependent risk for exposure at age equal to one year for both male
and fem ale other cancer m models ........................................ ...... .. .... ... 77

4-9. Time dependent risk for exposure at age equal to one year for female
breast cancer m odel ....................................... ..................... ....... ......... .. 78

5 -1 A P S ku ll ...................... ............... .. .. .. .. ... .... .. ......... ........ .. .. .. 8 6

5-2 L ateral S kull. ... .. ........ .... ..... .. .. ..... .... .. ..... .. .. ..... ..... ..... .. .. ... 86

5-3. Townes Skull ....... .... ....................... 87

5-4 A P C ervical Spine ................................................................................ ........ 87

5-5. L ateral C ervical Spine .................................................................... ............. 88

5-6 A P T horacic Spine ................................... ........................................................ 88

5-7. L ateral T horacic Spine .................... .............................. ...................... 89

5-8. A P L um bar Spine .................................................................. ........................ 89

5-9. L ateral L um bar Spine................. ................................... ............................... 90

5-10. A P A bdom en ........................................ ........................................ 90

5-11. A P Pelvis .. ..... ........ ... ........ ........................................... 91

5-12 A P L eft H ip ...................................................................................................... 9 1

5-13. W waters Sinus... .............................. 92

5-14. L ateral Sinus ............. ........... ........... ............ ............... 92

5-15. A P C hest................................. .. ....... .. .. .. ........... ... .. .. .. ...... .. .. .. 9 3

5-16. Lateral Chest..... ........ .. ................ 93

5-17. Range of kVp used for the 17 surveyed exams................. ............. ........ 94

5-18. Range of mAs used for the 17 surveyed exams ................. ......................... 95




xii









5-19. R ange of H V L ...................................... ........................................ 96

5-20. Net lung optical densities for AP chest, PA chest and lateral chest films............ 100

5-21. R epeat percentages per facility ............................................ ...................... 101




















Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy


PREDICTED RADIATION DOSE AND RISK ASSOCIATED
WITH PEDIATRIC DIAGNOSTIC X-RAY PROCEDURES

By

Kathleen M. Hintenlang

December 1998

Chairman: W. Emmett Bolch Jr.
Major Department: Environmental Engineering Sciences


The most effective method of assessing the risks from exposure to radiation is by

calculating the individual tissue absorbed doses and subsequently determining the effective

dose. The absorbed dose to a specific tissue has traditionally been difficult and time

consuming to measure. The effective dose and overall risk are therefore difficult to

calculate directly. The problem is compounded in pediatric radiology, where the patient is

particularly sensitive to radiation effects, and the body and organ sizes differ greatly from

the common adult reference man.

This research developed and applied a new methodology that permitted rapid

measurement of the effective dose from x-ray radiation, and the associated risks, to

pediatric patients for a variety of plain film diagnostic examinations. The methodology










utilizes an anthropomorphic phantom incorporating direct reading MOSFET dosimetry,

allowing the rapid and simple determination of absorbed dose to individual organs. The

research integrated clinical examinations, dosimetry measurements and BEIR V risk

assessment calculations using a prototype, anthropomorphic phantom of a one-year-old to

quantify radiation doses delivered to pediatric patients in clinical radiology exams. Site

surveys were performed in ten facilities using several standard exams to determine

variations in effective dose related to clinical practice. Recommendations resulting from

the site surveys were provided for the optimization of pediatric radiography procedures.

Quantitative studies for a variety of examinations were performed at Shands at UF. The

effective dose for these procedures ranged from 0.1 mrem for an AP skull exam that

utilized thyroid shielding, to 9.2 mrem for an AP upright abdomen exam. The relative

leukemia carcinogenic risk ranged from 1.000041 for the skull exam, to 1.002732 for the

abdomen exam, with corresponding excess risks from 106 exams of 0.005 and 0.3

leukemias per year, respectively. Effective doses and risks for various cancers from all

surveyed exams were quantified. These individual examinations provided a significant

benefit to the patient with minimal risk. This provided the basis for continuing research to

quantify long-term risk assessment to pediatric patients, as well as providing a clinical tool

to evaluate the effective dose delivered to these patients from other current and emerging

radiology imaging modalities.














CHAPTER 1
INTRODUCTION AND BACKGROUND


General

It is well established that diagnostic x-rays constitute the largest and most widely

distributed source of man-made radiation exposure to the general population (NCRP

1987, 1989). While infants and children constitute only about 10% of the total number of

radiographic examinations (NCRP 1989), they are the segment of that population at

higher risk from potential radiation effects. First, their growing tissues are more

susceptible to radiation effects than mature adult tissues (BEIR 1990). Second, their

skeletons encompass a greater fractional distribution of active bone marrow, an organ of

high radiation sensitivity (ICRP 1995). Third, the greater post-exposure lifetimes of

infants and children increase the possibility for any radiation-induced effects to manifest.

Fourth, children are known to have short attention spans and can be non-cooperative; as a

result, they are subject to a greater number and/or longer exposures than adult patients.

Finally, pediatric patients frequently have a larger portion of their anatomies located within

the x-ray beam than adults in similar exams and projections.
In the course of their care, these young patients may be exposed to a wide variety

of x-ray examinations. Conventional radiographs make up three quarters of pediatric

radiological examinations performed (Griscom 1996). These examinations yield medical
benefits and diagnostic information which must be balanced against potential risks from

patient radiation exposure. With ever increasing improvements in clinical care, survival

rates for prematurely born infants have risen over the past decade. As these individuals

age, they frequently experience additional complications requiring a large number of x-ray










examinations from a variety of imaging modalities. Consequently, these patients may

accumulate large radiation doses, the effects of which have not been evaluated since few

survived in earlier years. Technological improvements that permit these newborn infants

and young children to survive increase the need for clinical decision-making based on

4quantitative assessments of radiation risk.

The fundamental quantity of interest from these examinations is the cumulative

absorbed dose to exposed organs. Several studies have focused on average organ doses in

adult patients undergoing radiographic procedures, either through computer simulation

(Rosenstein 1976a, 1976b, 1988; Jones and Wall 1985; Rosenstein et al. 1992; Stern et al.

1995) or physical measurement (Shleien 1973; Ellis et al. 1975; Chen et al. 1978).

Nevertheless, very little current information exists on organ doses from pediatric

radiographic projections, particularly for technique factors common to U.S. practice (Beck

1978, 1979; Rosenstein et al. 1979; Zankl et al. 1989; Hart et al. 1996).

The desire to perform a study of the current patient and examination trends in

pediatric x-ray practices in the State of Florida and incorporate a direct and simple method

to measure organ and effective doses in a pediatric phantom in order to perform a risk

assessment was the basis for this research. An epoxy resin based anthropomorphic

phantom of a one-year-old child constructed in companion research to this dissertation

was utilized (Bower 1997). Site visits were performed at ten hospitals in the State of

Florida. Simulated examinations of a series of plain film radiographs were performed by

pediatric x-ray technologists on the phantom. Real-time Metal Oxide Semiconductor

Field Effect Transistor (MOSFET) dosimeters were inserted into various organ locations

in the phantom to obtain point dose measurements of the organ absorbed dose and

effective dose measurements in real-time. Subsequent risk assessment calculations were

performed utilizing BEIR V methodologies.

In order to facilitate the development and transfer of scientific information for the

improvement in the radiologic care of children, the methods developed in this research can









then be utilized to integrate the computational and advanced experimental components and

determine organ doses and assess risks to various ages of pediatric patients undergoing a

variety of modern diagnostic examinations to include fluoroscopy, computed tomography,

cardiac catheterization, computed radiography and digital radiography.


Pediatric Radiology as a Subspeciality

The history of pediatric radiology is the story of the emergence of pediatrics and

radiology as individual medical specialties, the growth of each of these specialties, and

finally the fusion of these two specialties into the new subspecialty of pediatric radiology,

or Roentgenology, as it was called in the early days.

Roentgen's discovery of x-rays in November and December 1895 was announced

to the world in January 1896. On February 3, 1896, a fourteen-year-old boy who was

thought to have broken his wrist two weeks earlier while skating on the Connecticut

River, was brought to Dartmouth College in Hanover, New Hampshire, because they

supposedly had one of the best collections of vacuum tubes in the western hemisphere at

that time (Spiegel 1995). His wrist was radiographed, with an exposure time of twenty

minutes, and the resulting image on the emulsion-coated glass plate "showed the fracture

in the ulna very distinctly." In addition to what is considered to be the first clinical

radiograph in America, it was also the beginning of pediatric radiology in this hemisphere.

In March of 1896, Dr. E. P. Davis of New York City reported visualizing the trunk

of a living infant and the skull of a dead fetus and also recorded images of a fetus

examined in utero (Davis 1896). Shortly thereafter, the first recorded observation of

disease in children probably belonged to Professor Cox of McGill University, Montreal,

Canada, who used a thirty-minute exposure to find a needle embedded in the wrist of a girl

of unstated age (Cox 1896). William G. Morton, at a meeting of the County of New York

Medical Society held on April 27, 1986, reported that he had already seen the fetal head in










utero and predicted that the time was not far distant when the sex of the fetus in utero

would be disclosed Roentgenographically (Caffey 1956). At this meeting, Morton showed

lantern slides of an entire fetal skeleton and used the terms "inside-seeing or esography"

for Roentgen visualization. In July, a publication listed conditions that the author had

successfully shown by x-ray, including pediatric cases of dactylitis and absence of the radii

(Codmam 1896).

Radiation injury to children apparently was recognized within a few weeks after

the Roentgenology method was instituted, as Dr. W. V. Gage (1896, page 307) of

McCook, Nebraska, reported "erythema and finally sloughing of the region penetrated by

the rays, which at present is the size of the hand" in a child who was being studied for a

foreign body in the stomach. Although this episode was reported in the Medical Record

of August 29, 1896, Caffey stated that it is obvious that the actual Roentgen injury must

have occurred many weeks earlier during the first months of 1896 (Caffey 1956). It is

interesting to note that the spread of Roentgen's discovery was not just limited to large

cities, but was also utilized within months of his publication in a community as medically

remote as McCook, Nebraska, on the prairie which was still "frontier country" at that time

(population 2,346 by the 1890 census). In many of the early reports, there appeared to be

a disproportionate prevalence of pediatric cases, probably because x-rays from the

available tubes at that time could not penetrate larger subjects. In addition, a majority of

the researchers in the initial trial period were not physicians. Sosman (1951, page 552)

observed that "by 1900, the x-ray method was being used by physicists, engineers,

photographers, some charlatans and a few honest physicians". Caffey added bicycle repair

men and the entrepreneurs of circus sideshows to this observation.

After this initial burst of enthusiasm after Roentgen's discovery, Caffey reports

that American pediatric radiology lagged significantly behind the growth of both radiology

and pediatrics and failed to progress until the 1930s, as demonstrated by the limited

number of publications. In the Transactions of the American Roentgen Ray Society,










number of publications. In the Transactions of the American Roentgen Ray Society,

established in 1901, no pediatric subject was discussed until 1904, when Preston M.

Hickey of Detroit reported his Roentgenologic study of skeletal maturation (Hickey 1904,

1906). In addition to the decreased number of studies being reported, the majority of the

case studies published represented superficial subjects. Caffey reported that in 1903,

Volume 20 of the Archives of Pediatrics published a total of only four papers on

Roentgenologic subjects. The most interesting one, Caffey felt, presented Roentgenologic

data by A. C. Cotton purporting to show that wadding of thick diapers between the thighs

produced lateral bowing of the femurs. Caffey also reported that in the first volume of the

American Journal of Diseases of Children in 1911, a study by Long and Caldwell on the

relationship between carpal ossification and mental development was performed with

Roentgen prints of the paired hands of twenty-nine subjects, in which the authors

concluded that "we can find no relation between the carpal development and the quality of

mind" (Caffey 1956, page 440). Caffey noted, with some sarcasm, that this conclusion

has stood the test of time. Griscom indicated that the focus was more on techniques and

equipment at that time than on the medical components of the radiology of children

(Griscom and Jaramillo 1995).

The 1930s, 40s and 50s showed a drastic increase in the number of x-ray studies of

large numbers of healthy children from birth through adolescence. Due to the lack of

normal standards, Dr. Arial George (1908, page 381) explained that "A thorough

knowledge of the normal human anatomy is absolutely necessary, as are its variants. The

whole study of disease in children by the Roentgen method rests on this one point. The

mistakes in diagnosis by the Roentgen ray method will not be the fault of the Roentgen

ray, but the fault of those who are ignorant, and who from lack of training are unable to

interpret its findings ." As a result, Boyd performed studies of the normal thymus (1927).

Lincoln, Hodges, and Josephi investigated cardiac size in healthy infants (Lincoln and

Stillman 1928; Hodges 1933; Josephi 1935). Bouslog and Henderson studied the normal









infantile gastrointestinal tract (Bouslog 1935; Henderson 1942). The normal neonatal

skull was studied Roentgenographically by Henderson and Sherman (1946). Rotch called

attention to the epiphyses, as studied by x-rays, to indicate the state of bodily maturity in

normal standards of growth and development for various age groups (Smith 1951).

Caffey published several norms of the skeleton (Caffey 1956).

All of these early attempts to establish normal values were open to criticism as they

were based on studies of groups of infants and children. It was felt that more accurate

values could be obtained by longitudinal studies in which the same groups of children were

investigated as they progressed from birth to maturity. So, from 1925 through 1940,

Maresh and Washburn performed serial Roentgenographic observations on one hundred

normal infants and children to demonstrate the variation in the size and shape of the

respiratory track (Maresh and Washburn 1940). Griscom indicated that at the second

meeting of the Society of Pediatric Radiology in 1959, sixteen case studies were presented

(Griscom 1995). About half dealt with plain films, the remainder with intravenous

urography, barium studies, nuclear medicine and dosimetry. This was the first instance

where dosimetry for pediatric x-rays is mentioned in the literature. Dr. Donald Darling,

from the Children's Hospital in Pittsburgh, presented a progress report entitled

"Measurement of Gonadal Dose in Routine Pediatric Radiological Practice." Dr. Darling

indicated that results were never published from this study (personal communication,

1998).


Rationale

The organs to be considered in radiologic risk assessment were standardized by the

International Commission on Radiological Protection in 1977 with the introduction of the

effective dose equivalent (EDE) (ICRP 1977). Calculations of the EDE require

knowledge of the absorbed dose (total energy deposited per unit mass) to the following









tissues: breasts, lungs, reproductive tissues (ovaries or testes), thyroid, active bone

marrow, skeletal endosteum and unspecified remainder tissues. These absorbed doses, or

more specifically, dose equivalents,1 are then multiplied by tissue weighting factors (wr)

which represent the fraction of total radiation risk (cancer mortality and severe genetic

damage) attributed to irradiation of that tissue. The EDE is calculated as a summation of

these weighted doses and thus represents a single radiation dose proportional to the total

radiation risk of the exposure, regardless of whether the irradiation is uniformly or

nonuniformly delivered.

This dosimetry concept was further expanded in 1990 with the introduction of the

effective dose (E) in which tissue weighting factors were reassessed based on a more

recent analysis ofradiobiological effects (ICRP 1991). Additional weighting factors were

also given for the esophagus, stomach wall, colon, liver, skin and urinary bladder wall.

While originally defined for radiation protection purposes, these quantities of EDE and E

have been widely reported in the medical literature for both nuclear medicine procedures

and for diagnostic radiology examinations. Their intended use in medicine is to provide

physicians with a unified quantity for risk communication and a quantitive means for

procedure optimization. As defined in ICRP Publications 26 and 60, the tissue weighting

factors are specific only to populations of adults and should not be applied in the

estimation of radiation risk to individual patients (Poston 1993). For use in risk

communication and/or procedure optimization, tissue weighting factors specific for

children have been proposed by Almen and Mattsson (1996).

The determination of organ doses in diagnostic radiology is typically a two-step

process. First, an indicator dosimetry quantity is measured in the clinical setting.

Examples include the entrance skin exposure (ESE), the entrance skin dose (ESD) or the

dose-area product (DAP). Second, these indicator quantities must be multiplied by an

1 Dose equivalent is defined as the product of an absorbed dose and a radiation weighting
factor which for photons is set to unity.









organ dose coefficient to obtain individual organ doses (i.e. mrad per R) (Rosenstein

1988). These conversion factors are obtained either through experimental measurement

within physical phantoms or through computer simulations within mathematical models of

the patient. The specific procedures involved in obtaining the conversion factors utilized

in this research are discussed in Chapter 3, Radiation Measurement Equipment and

Techniques.


Adult Organ Doses in Plain Film Radiography

The first systematic study of organ dose coefficients was published by Rosenstein

in 1976 in Food and Drug Administration (FDA) Reports 76-8030 (Rosenstein 1976b)

and 76-8031 (Rosenstein 1976a). In this study, the Fisher-Snyder mathematical model of

the adult male was modified for use in determining organ doses for a variety of diagnostic

x-ray projections. This model was previously developed for estimates of internal photon

absorbed fractions needed for nuclear medicine dosimetry (Snyder et al. 1978). The

model consisted of geometrical descriptions of eighteen internal organs of the adult and

included three distinct tissue compositions: soft tissue, skeleton (a homogenized mixture

of bone and marrow) and lung (a homogenized mixture of soft tissue and air). While the

model was developed as a description of Reference Man defined in ICRP Publication 23

(1975), it was a hermaphrodite in that it included both testes and a uterus and ovaries.

In order to reduce computational requirements, the following approach was

utilized. Organ doses were first determined for parallel, collimated beams of

monoenergetic photons incident on the surface of the mathematical model. Each photon

beam was situated on one grid of a system of 4 cm x 4 cm grid elements superimposed

upon the front surface of the model (AP projection), back surface of the model (PA

projection), or on a plane just inside the arm bones (lateral projection) to simulate the

actual conditions of exposure in which the arm is generally moved out of the primary









beam. Organ doses for a given examination (e.g. AP chest) were determined by first

summing the individual dose contributions from each grid element contained within the

field-of-view, and then energy weighting these results for the x-ray spectrum of interest.

By using this procedure, beam divergence and air scattering effects were ignored and

oblique views were not accommodated. These data were subsequently used to produce a

handbook providing organ doses per unit entrance skin exposure free-in-air (mrad/R) to

the testes, ovaries, thyroid and active bone marrow for sixteen projections and six beam

qualities (HVLs of 1.5 to 4.0 mm Al). The field size was assumed to equal the film size in

this study. Limited experimental data were collected as part of the study using lithium

fluoride thermoluminescent dosimeter's (LiF TLDs) in anthropomorphic phantoms.

A revision to this handbook was published in 1988 which expanded the number of

projections considered to fifty-four. In addition, Cancer Detriment Indices were also

reported for each exam based upon risk data contained in ICRP Publication 45 (1985). In

the early 1980s, Gesellschaft fir Strahlen und Umweltforschung (GSF) in Germany

(Kramer et al. 1982; Drexler et al. 1984) developed their own male and female adult

phantoms and the British National Radiological Protection Board (NRPB) (Jones and

Wall 1985) further developed the Cristy (1980) modified versions of the original Snyder

Medical Internal Radiation Dosimetry (MIRD) mathematical model (Snyder et al. 1969) to

assess organ doses to adults in diagnostic radiology.


Pediatric Organ Doses in Plain Film Radiography

A comprehensive and systematic investigation of organ dose coefficients for

pediatric radiographic projections was published by Beck and Rosenstein in 1979 as FDA

Reports 79-8078 (Beck 1978, 1979) and 79-8079 (Rosenstein et al. 1979). This study

included a survey of five hospitals in the Baltimore-Washington area to determine the

frequency and types of pediatric radiographic examinations performed and the various










technique factors employed in those exams such as kVp, mAs, field size, SID and beam

quality. The survey data were subsequently used to perform computer simulations of the

more common projections following methods similar to those employed in the adult

report.

Three mathematical models developed at Oak Ridge National Laboratory by

Hwang et al. were utilized representing a newborn, a one-year-old, and a five-year-old

individual (1976a, 1976b, 1976c). Twenty examinations were considered, each

representing at least one percent of the total number of exams in a given age group. For

each exam, organ dose coefficients (mrad/R) were determined for testes, ovaries, thyroid,

active bone marrow, lungs and total body at one representative source-to-image receptor

distance, two field sizes (age dependent) and four beam qualities (HVLs of 2.0, 2.5, 3.0,

and 3.5 mm Al). As with the adult report, limited experimental data were collected as part

of the study using LiF TLDs in anthropomorphic phantoms representing a head and neck,

and two phantoms corresponding to the Monte Carlo mathematical design: a one-year-

old and a five-year-old. Given the experimental uncertainties in the TLD measurements

and the limited number of photon histories transported (60,000), the authors concluded

that good agreement was seen between the two data sets.

To date, no revisions have been made to FDA Reports 79-8078 and 79-8079, and

these data are still widely used for dose estimation in pediatric radiology. Several

arguments can be made for revising and expanding the research of Beck and Rosenstein.

First, while mathematical models did exist for a representative ten-year-old and fifteen-

year-old patient, these two groups were notably absent in the final handbook. Second, the

input photon spectra used in these reports were for single phase generators, while current

radiology practice employs primarily three-phase, constant potential, and high-frequency

x-ray units. Third, while the pediatric models of Hwang et al. included twenty-six internal

organs, dose estimates were given only for the six organs listed above, thus making

calculations of EDE or E impossible. Fourth, substantial revisions and improvements have










been made to the ORNL pediatric model series over the past eighteen years, thus making

the dosimetry of FDA reports 79-3030 and 79-3031 obsolete and somewhat inconsistent

with current practice in radiology and in radiation protection (Cristy 1980, 1987).

In the Hwang et al. 1976 series of pediatric models, a large number of internal

organs were simply scaled downward from the Fisher-Snyder adult model. In 1980, Cristy

reported that this procedure resulted in "shifting and crowding" of various internal organs

in a manner which did not reflect actual anatomical growth trends (Cristy 1980). As a

result, a complete redesign of the ORNL pediatric model series was initiated, resulting in

the publication of new pediatric models by Cristy and Eckerman in 1987. These models

were subsequently adopted for radiation protection dosimetry by the ICRP in 1989 (ICRP

1989) and for nuclear medicine dosimetry in 1988 by the MIRDOSE computer code

maintained by the Radiation Dosimetry Information Center in Oak Ridge, Tennessee

(Stabin 1996). These models were the basis upon which a new MIRD family of

mathematical models are being developed at the University of Florida in companion

research to this dissertation.

Finally, no new pediatric anthropomorphic phantoms have been developed that

correspond to the changes made in the MIRD mathematical models. The only other

comprehensive source of organ doses for pediatric plain film exams is that produced by

the NRPB in 1996 for technique factors specific to the United Kingdom and European

Community utilizing the older 1987 version of the Cristy and Eckerman mathematical

models (Hart et al. 1996).


Calculation of Energy Imparted in Diagnostic Radiolovg

One may also estimate radiation risk for diagnostic procedures by measuring the

total energy imparted to the patient for a given diagnostic exam (the integral dose).

Extensive studies of energy imparted in diagnostic radiology have been performed by










Huda and colleagues (Huda et al. 1989; Huda and Bissessur 1990; Atherton and Huda

1995, 1996; Huda and Atherton 1995; Gkanatsios and Huda 1997; Huda and Gkanatsios

1997). Values of energy imparted, however, in and of themselves do not provide

important information on individual organ doses for a given projection or exam. In his

publications, Huda proposed the use of approximate ratios of effective dose per unit

energy imparted which, in combination with energy imparted on homogeneous phantoms,

can be used to derive an estimate of the effective dose. These ratios must also be obtained

from previous Monte Carlo studies such as those performed by the NRPB (Shrimpton et

al. 1991; Hart et al. 1994, 1996) which use heterogeneous anthropomorphic models of

patients. Huda has recently proposed a simple mass scaling of these ratios to yield

effective doses to children undergoing CT exams (Huda et al. 1997). An important

limitation of this approach is that individual organ doses can never be recovered from a

single value of effective dose and the risk from different diagnostic procedures cannot be

compared when different organs are exposed.

It must be remembered that the effective dose is a weighted average of the

individual organ doses where the tissue weighting factors are chosen based on the current

knowledge of radiation cancer risk and other detriment. This knowledge base changes

with time and with changes in cancer mortality; thus the tissue weighting factors are

influenced by changing success rates in cancer treatment. Consequently, the tissue

weighting factors are always subject to change, whereas the individual organ dose for a

specific diagnostic procedure is not. It is for these very reasons that the MIRD

committee of the Society of Nuclear Medicine has always maintained a focus on individual

organ absorbed dose.









Phantoms


Mathematical

In 1994, companion research to this dissertation was initiated by Dr. Wesley Bolch

to couple the complete series of pediatric mathematical models of Cristy and Eckerman to
the EGS4 radiation transport code (Nelson et al. 1985) for external sources of radiation.
This was additionally performed as a task group effort of the Society of Nuclear

Medicine's MIRD Committee to consider, for the first time, detailed transport of electrons

and beta particles within internal organs for internal sources of radiation. At ORNL, the

Cristy and Eckerman pediatric model series have been used extensively with ALGAM, a

radiation code limited only to the consideration of photon transport (Cristy and Eckerman
1987). EGS4 allows for explicit treatment of coupled photon and electron transport

(including bremsstrahlung production) and has been extensively utilized in both high

energy physics and medical physics research. To verify the coding of the pediatric

mathematical models within the framework of the EGS4 code system, several comparisons

of specific absorbed fractions of energy were performed with the 1987 data published by

Cristy and Eckerman (Kodimer 1995). Excellent agreement was seen over a wide range

of photon energies, confirming the transport of photons in the Cristy and Eckerman
models using EGS4.

A new mathematical model of the adult head and brain has been published

(Bouchet et al. 1996). The model includes a detailed description of the skeletal system

including the maxilla, teeth, mandible, cranium and cervical vertebrae. New regions in the

brain model include the caudate nucleus, cerebellum, cerebral cortex, lateral ventricles,
third ventricle, lentiform nucleus, thalamus and white matter. Other features include eyes

and the thyroid enclosed within an explicit neck region (the original head region was

modeled simply as an elliptical cylinder topped by half an ellipsoid, with no representation










photon transport, its exclusion artificially attenuates external photon sources depositing

dose to the thyroid gland.

Work was initiated in late 1996 to produce a pediatric series of head and brain

models based on modification of the adult model and data published on neural tissue

growth trends. In June of 1997, the MIRD committee also adopted a series of revisions to

the Cristy and Eckerman family of phantoms (Bolch, personal communication, 1997).

These revisions included the addition of an esophagus, a prostate gland, a four-region

kidney (to include a medulla, cortex, papillary, and pelvic region), a mucosal layer within

walled organs (GI tract, gall bladder, and urinary bladder) and the inclusion of a rectum

separate from the sigmoid colon within the current models. It is anticipated that upon

completion of these revisions, future work will include the Monte Carlo-generated doses

being experimentally verified against the MOSFET dosimeter measurements within the

various pediatric anthropomorphic phantoms.


Anthropomorphic


ICRU Report 48 defines a phantom as a "structure that contains one or more

tissue substitutes and is used to simulate radiation interactions in the body" (ICRU 1993,

page 1). They are commonly used to investigate radiographic equipment image quality

and dosimetric evaluations. The complexity of phantoms ranges from very simple

geometries representing singles tissues such as a slab of water simulating soft tissue or a

sheet of copper simulating a chest, to complex geometries with multiple realistic tissue

substitutes for soft tissue, lungs and bones. Such complex phantoms are referred to as

"anthropomorphic" because they simulate the size, shape and composition of a human

body to provide the same attenuation and scattering characteristics.

The majority of anthropomorphic dosimetric phantoms represent an adult man

(Conway et al. 1984; Constantinou et al. 1986; Conway et al. 1990; ICRU 1993). As










previously indicated in the discussion of the mathematical models, a scaled-down adult

phantom is inappropriate to simulate a child, since the organ growth of a child is a

complex process which cannot be described by simply scaling the anatomy of an adult.

The anatomical geometry of a child varies greatly from that of an adult. The weight of

the head with respect to the total body weight is greater for a child than an adult, the trunk

of a child is more cylindrical compared to the elliptical adult trunk, and certain internal

organs such as the thymus gland are larger (Hwang et al. 1976a). The percentage of

extracellular water in children is larger and represents a higher percentage of the total

body weight than in adults (Haschke et al. 1981), and the concentration of certain minerals

is lower in the skeleton of children (Haschke et al. 1981; ICRP 1995). In addition, the

skeleton of a child has more water and less fat than an adult skeleton (Cristy and

Eckerman 1987). Furthermore, the distinction between cortical and trabecular bone and

the percent distribution between yellow and red bone marrow change greatly as children

age (Cristy and Eckerman 1987). The anthropomorphic pediatric phantoms developed by

Chen (Chen et al. 1978) were constructed to represent identically the mathematical models

of the one-year-old and the five-year old, which again, were scaled-down versions of adult

models.

Due to the lack of pediatric anthropomorphic phantoms in the research community

and on the commercial market, research was initiated to construct a prototype one-year-

old phantom at the University of Florida (Bower 1997). The one-year-old representation

was chosen because a review of the examination frequency data provided by Shands at the

University of Florida from the period 1990-present indicated that the majority of pediatric

diagnostic x-ray examinations are of children in their first few years of life; therefore, a

phantom of a one-year-old would be fairly representative of a large class of examinations.

In addition, an anthropomorphic one-year-old phantom has a mass of approximately 10 kg

(21 Ibs), which is easily manageable for construction and its ultimate use in field testing.

The prototype one-year-old anthropomorphic phantom developed by Bower (1997)









utilized in this research is reviewed in detail in Chapter 3, Radiation Measurement

Equipment and Techniques.


Radiation Detection Instrumentation

A variety of detection instrumentation has been used to measure radiation

exposure or absorbed dose. These include gas filled ionization chambers, radiographic

film, semiconductors and thermoluminescent detectors.


Gas Filled Ionization Chambers

Ionization chambers have a response that is proportional to absorbed energy, and,

therefore, they are widely used in performing dosimetry measurements. Most ionization

chambers are cylindrical with an air-equivalent wall and measure exposure. When

radiation interacts with the air in the detector, ion pairs are created and collected

generating a small current. Since the Roentgen is defined as the amount of ionization in

air, measurement of this ionization current will indicate exposure.

The Keithley TRIADM Field Service Kit2 was used in this research to perform

free-in-air exposure measurements in order to calculate entrance skin exposure (ESE) at

the location where the x-rays are expected to enter the patient and characterize beam

quality for the simulated x-ray examinations.


Semiconductors

A semiconductor detector acts as a solid state ionization chamber, whereby the

ionizing particle interacts with atoms in the sensitive volume of the detector to produce

electrons by ionization. The elements in semiconductor materials form crystals that


2 Radiation Measurements Division of Keithley Instruments, Inc., 28775 Aurora Road,
Cleveland, Ohio, 44139, TRIADTM Field Service Kit Model 10100A









consist of a lattice of atoms that are joined together by covalent bonds. Absorption of

energy by the crystal leads to disruption of these bonds which results in a free electron and

a "hole" in the position formerly occupied by the valence electron. This free electron can

move about the crystal with ease. The hole can also move about in the crystal, e.g. an

electron adjacent to the hole can jump into the hole and therefore leave another hole

behind. Connecting the semiconductor in a closed electric circuit results in a current

through the semiconductor as the electrons flow towards the positive terminal and the

holes flow toward the negative terminal. The operation of a semiconductor radiation

detector depends on its having either an excess of electrons or an excess of holes. A

semiconductor with an excess of electrons is called an n-type semiconductor, while one

with an excess of holes is called ap-type semiconductor (Cember 1996).

In order to assess point estimates of organ doses in the one-year-old phantom, the

Patient Dose Verification System designed by Thompson & Nielsen Electronics3 was

utilized. This system is composed of Metal Oxide Semiconductor Field Effect Transistor

(MOSFET) dosimeter arrays. The MOSFET is a common microelectronic device. It is a

layered device consisting of a p-type semiconductor separated from a metal gate by an

insulating oxide layer. Ionizing radiation forms electron-hole pairs in the oxide-insulating

layer of the MOSFET. The applied bias then causes the electrons to travel to the gate,

while the holes migrate to the oxide silicon interface where they are trapped. The trapped

positive charges cause a negative shift in the voltage required to allow conduction through

the MOSFET. The shift in voltage is proportional to the radiation dose deposited, thus

allowing the MOSFET to be used as a dosimeter (Hughes et al. 1988; Gladstone and Chin

1991; Vettese et al. 1996).

This system was originally designed using standard sensitivity dosimeters to

measure skin doses during radiation therapy treatments. Characterization of high

3 Thompson & Nielsen Electronics Ltd., 25E Northside Road, Nepean, Ontario, Canada,
K2H 8S1, Patient Dose Verification System Model TN-RD-50









sensitivity dosimeters by Bower and Hintenlang (1998) for use in diagnostic radiological

applications is detailed in Chapter 3, Radiation Measurement Equipment and Techniques.


Determination of Risk

Radiation risks of diagnostic radiology in the pediatric patient are either

deterministic or stochastic in nature. Deterministic radiation injuries, such as tissue injury

or cataract production, occur when a number of cells are involved and a threshold dose is

required. Above the threshold, the severity of the injury is proportional to the dose.

There is no evidence that deterministic injuries occur as a result of low-dose plain film

procedures. Stochastic radiation injuries, such as genetic effects and carcinogenesis, are

believed to be caused by injury to a single cell and typically a threshold dose is not

required. The probability of the injury is proportional to the dose, but the severity of the

injury is independent of the dose. If one assumes a linear relation without a threshold for

such effects, then any amount of radiation, including low-dose plain film procedures, may

potentially have an effect. A more detailed discussion of the linear, no-threshold (LNT)

theory is presented in Chapter 4, Risk Asssessment.

Risk models were developed to provide a method of predicting the risk of

radiation induced genetic effects and carcinogenesis in relation to the natural incidence in

an unirradiated population. The epidemiological ideal of following several populations

over time was not practical; therefore, statistical models were used to derive risk

estimates. Radiological risk assessments and resulting risk estimates have been developed

by numerous organizations, including the National Academy of Science/National Research
Council's Fifth Committee on the Biological Effects of Ionizing Radiations (BEIR V,

1990), the United Nations Scientific Committee on the Effects of Atomic Radiation
(UNSCEAR, 1988), the International Commission on Radiological Protection (ICRP 60,










1990) and the National Council on Radiation Protection and Measurements (NCRP 115,

1993).

The most recent reassessment of radiation-induced cancer risks from exposure to

low levels of ionizing radiation was performed by the BEIR V committee, and this

methodology was utilized in performing the calculation of the risk estimate from plain film

procedures performed in Chapter 4, Risk Assessment. The BEIR V Report provided

mathematical models to estimate risks for breast cancer, respiratory tract cancer, digestive

tract cancer, leukemia, and other nonleukemia cancers. These equations include terms for

dose, age at exposure, time after exposure and interaction effects. The dose term utilized

in these equations is the effective dose calculated from the MOSFET organ dose

determinations upon applying the dose conversion factors.


Significance and Objectives

Pediatric radiographic examinations are widely thought to yield medical benefits

and/or diagnostic information which greatly exceed any potential risk from patient

radiation exposure. Nevertheless, quantification of that risk is important for a number of

reasons. First, it allows radiographic procedures to be optimized to maximize the medical

benefit while minimizing patient risk. Second, it gives the radiologist a basis for

communicating that risk to concerned patients and/or parents. Third, it allows for

reconstruction of total risk for individuals who have developed radiation-associated

diseases (e.g., leukemia) and who were known to have undergone high-dose or multiple

radiographic procedures at an earlier age (i.e., dose reconstruction). In each case, the

fundamental quantity of interest is the cumulative absorbed dose to the radiosensitive

organs.

As previously discussed, several studies have focused on quantifying average

organ doses in adult patients undergoing radiographic procedures, either through









computer simulation or physical measurement. Nevertheless, very little information exists

on pediatric organ doses from plain film examinations, and no systematic techniques have

been developed to obtain this information for pediatric dynamic procedures such as

fluoroscopy, CT or cardiac catheterization. Consequently, the first objective of this

research project was to establish a baseline and develop a method for assessing pediatric

organ doses for the most frequent plain film procedures used in clinical practice. The

second objective was to verify this method for plain film exams through the use of an

anthropomorphic phantom representing a one-year-old pediatric patient and coupled to a

real-time radiation dosimetry system. The third objective was to utilize the organ doses

determined from the anthropomorphic phantom and calculate an effective dose for each

plain film procedure. The fourth objective was to utilize the effective dose in the BEIR V

methodology to calculate the risk from the procedure. The following specific aims were

designed to accomplish these objectives:

1. To determine, via site survey often facilities, the current examination trends

for one-year-old patients in pediatric x-ray practices in the State of Florida.

2. To determine, utilizing a one-year-old anthropomorphic model providing real-

time radiation dosimetry, organ doses to pediatric patients undergoing the most

common plain film procedures and calculate corresponding effective doses.

3. To estimate, utilizing BEIR V risk model methodology, the risk to pediatric

patients of carcinogenesis from the plain film procedures.

To facilitate specific aim 1, detailed examinations were simulated at Shands at UF

in order to focus the site surveys on the most prevalent examinations currently performed

in pediatric practices. Technique information for these examinations were collected from

all facilities. Due to the time constraint of room downtime, dosimetry data were collected

at the ten facilities for the single most prevalent exam; dosimetry data were collected for

all examinations simulated at Shands at UF. In specific aim 2, point estimates of organ

doses were assessed by selective placement of an array of Metal Oxide Semiconductor









Field Effect Transistors (MOSFET) detectors within the phantom. These measurements

for the x-ray procedures utilized the prototype one-year-old anthropomorphic phantom

developed by Bower (1997). Specific aim 2 also involved the determination of dose

conversions factors (organ absorbed dose per unit entrance skin exposure) for a range of

radiographic projections and radiation beam qualities and the calculation of effective doses

as defined by the ICRP (1977). The task associated with specific aim 3 used equations

developed by BEIR V (1990) to utilize the effective dose calculated in specific aim 2 in

order to predict the risk of radiation induced carcinogenesis from the simulated plain film

procedures.

These tasks not only update and expand obsolete data on pediatric organ doses

from plain film examinations, but establish the method to benchmark experimentally the

mathematical models previously discussed and provide a baseline for the organ dose

estimation computational and experimental techniques necessary to simulate dynamic

pediatric exams. This research provides vital information to the pediatric radiology

community in their efforts to assess organ doses and procedure risk from plain film exams

both prospectively and retrospectively.














CHAPTER 2
PATIENT AND EXAMINATION TRENDS OF PEDIATRIC X-RAY PRACTICES

A general overview of the range of pediatric x-ray practices was obtained through

a site survey of selected facilities within the State of Florida. Ten facilities were selected

to represent their cohorts throughout the rest of the State: six facilities represented

Children's Hospitals and/or Radiology Departments with dedicated pediatric radiologists,

two hospitals represented community patient populations and two hospitals represented

rural patient populations. Selection of the number of facilities was not based on statistical

considerations, as the purpose of this survey was only to identify and characterize the

examinations that are most commonly employed and not establish their precise frequencies

in the U.S. population. Private practices were not included in this survey. In addition,

more specific information was obtained on a single pediatric radiologic practice during in-

depth investigations carried out in the Pediatric section of the Radiology Department at

Shands at the University of Florida.


Shands at the University of Florida


Shands at the University of Florida is a 576-bed not-for-profit tertiary care facility.

The Children's Hospital at Shands at the University of Florida is a 169-bed hospital-

within-a-hospital. The Radiology Department at Shands at UF has a workload of 163,000

examinations per year, approximately six percent of which are for patients under sixteen

years of age. In order to determine which examinations to include in the site surveys,

examination frequency data specific for pediatrics were extracted from the Radiology

Information System (RIS). The RIS provides a computerized patient record from which

physicians can call up all the clinical data that they need about a given patient in










alphanumeric text. The review of the RIS ascertained, retrospectively, the frequency and

types of x-ray procedures performed as a function of age, and simulations were then

performed to determine the important technical parameters of each procedure.

Since the data were to be adapted to five anthropomorphic phantoms and

mathematical models, five age groups were defined for the frequency data. These age

groups were determined from formulae utilized for approximate average height and weight

of normal infants and children that are commonly found in pediatric textbooks (Behrman

and Vaughan 1987). These categories are defined in Table 2-1.

Table 2-1. Age Group Corresponding to Phantom
Phantom Age Group
Newborn 0 to 3 months
One-Year-Old 3 months to 12 months
Five-Year-Old 1 year to 6 years
Ten-Year-Old 7 years to 12 years
Fifteen-Year-Old 13 years to 16 years

The first piece of information extracted from the RIS data was the determination

of the types and frequencies of examinations as a function of age. The RIS data file listed

all the pediatric radiological examinations performed at Shands at the University of Florida

from January 1990 through December 1997. An additional computer program was

written to extract the number of examinations performed in a given year, broken out by

the age group defined in Table 2-1 from the RIS data file. The file encompassed general

radiology (including ultrasound), fluoroscopy, CT, and nuclear medicine examinations.

No exam technique information was contained in this file. An example of the file is

presented in Table 2-2 illustrating the number of pediatric chest x-rays performed in 1997.

The 1997 file in its entirety is located in Appendix A. Prior years were not included as a

trend analysis indicated similar distributions of exams.










Table 2-2. Annual Number of Plain Film Chest X-Rays by Age Group
Year Modality Exam & Projection Newborn 1-Year 5-Year 10-Year 15-Year
97 GENERAL CHEST PA &LATERAL 477 474 1524 665 546
97 GENERAL CHEST 1 VIEW 3763 797 1713 875 973
97 GENERAL BABYORAM (hest & abdomae) 730 30 17 0 0
97 GENERAL CHEST DECUBITUS LEFT 31 3 18 3 9
97 GENERAL CHEST DECUBITUS RIGHT 24 3 11 2 8

The frequency of exams was also determined from this file. The frequency is

defined as the ratio of a specific exam and projection falling within a modality to the total

number of examinations classified for that modality, and is expressed as a percentage. An

example of the data is presented in Table 2-3 demonstrating the percent frequency of

pediatric chest x-rays performed in 1997. The 1997 percent frequency file in its entirety is

located in Appendix B and is tabulated from most to least frequent exam.


Table 2-3. Percent Frequency of Plain Film Chest X-Rays
Year Modality Exam & Projection Newborn 1-Year 5-Year 10-Year 15-Year
97 GENERAL CHEST PA& LATERAL 8 26 26 16 12
97 GENERAL CHEST 1 VIEW 65 44 30 21 22
97 GENERAL BABYGRAM (chet & abdonen) 13 1.7 0.3 0 0
97 GENERAL CHEST DECUBITUS LEFT 0.5 0.2 0.3 007 0.2
97 GENERAL CHEST DECUBITUS RIGHT 0.4 0.2 0.2 0.05 02

The frequency data were further segregated by the principal body region exposed

in the examination: head and neck; thorax and shoulder (excluding humerus); abdomen,

pelvis and hips; and extremities. The most frequent plain film exams per principal body

region were chosen to be included in the dosimetry study. Table 2-4 lists the plain film

exams that were surveyed at each facility based on the data for the one-year-old.

Extremity examinations were not included in the dosimetry survey for the one-year-old

phantom. As demonstrated in Appendix B, the frequency of these exams does not

increase until the older age groups when a child has learned to walk and run, and falls

occur, with subsequent damage to extremities,. Limitations of phantom design with

respect to limb movement also restricted the realism with which such examinations could

be simulated. Radiographic components offluoroscopy examinations were not considered

in this research, as it would be more appropriate to include such dose considerations in a









study of the overall fluoroscopic exam dose. Several additional examinations were

performed at Shands at UF to investigate the effect of shielding on the resultant dose.
The RIS data file also included the projections used in the examinations. The

nomenclature for projections follows that commonly used in radiology (Ballinger 1995).

When referring to a radiograph of a body part as seen from the aspect of the x-ray film,

this is termed a "view," in which case one refers to the side of the body, or body part,

which is closest to the film. For example, in an anterior view of the chest, the patient faces

the film; in a left lateral view, the patient's left side is toward the film. A left posterior

oblique view is performed with the patient turned with his left back toward the film and his

right front away from the film. Generally when the x-ray beam is not incident normally on

the patient's front or back, "view" terminology is used, as opposed to "projection"
terminology. A "projection" defines the path of the x-ray beam through the body or body

part. Thus, in an Anterior-Posterior projection of the chest, the beam enters the front and

exits through the back, producing what could correctly be termed a posterior view. In this

research, projection orientation is used whenever the beam is normally incident on the

front or back ((Anterior-Posterior (AP) or Posterior-Anterior (PA)); view orientation is

used for all others, although the term projection is used for uniformity throughout.
Projections are additionally defined in terms of rotation of the patient or part,

clockwise from the superior aspect beginning with the patient facing the tube. Thus an AP

projection has 0 degree rotation, facing the tube; PA projection has 180 degree rotation,

facing the film; LAT projection (lateral projection) has two possibilities: RLAT (right

lateral) has 90 degree rotation, with the right side towards the film; and LLAT (left lateral)

has 90 degree rotation, with the left side towards the film. The term decubitus is used if

the patient is lying down rather than standing up. Obliques are not included in this data

set, as the majority of oblique projections are associated with fluoroscopy exams.

Additional nomenclature specific for skull and sinus examinations includes "Townes" and

"Waters" projections, respectively. The Townes method for radiographing the skull










involves angling the x-ray tube 20 to 25 degrees caudad (beam penetration through the

top of the head). The Waters method for radiographing the sinuses involves extending the

patient's neck with their chin on the cassette stand.


Table 2-4. Surveyed Examinations
Exam Projection
Skull AP
Skull LAT
Skull Townes
Sinus Waters
Sinus LAT
Cervical spine AP
Cervical spine LAT
Thoracic spine AP
Thoracic spine LAT
Lumbar spine AP
Lumbar spine LAT
Abdomen AP
Pelvis AP
Hip AP
Chest LAT
Chest AP
Chest PA


Ten Florida Facilities


The exposure to pediatric patients during x-ray procedures would be expected to

vary from facility to facility. Factors such as equipment setup and operational

characteristics, patient classification and procedural techniques are of key importance. To

investigate the variation that exists among facilities, a site survey of pediatric x-ray

practices in ten Florida hospitals was conducted. The surveys were conducted in

cooperation with the radiologist, the administrative director and the pediatric x-ray

technologist of the participating facility. One or more of these personnel were present

during each site visit and data collection. In addition to Shands at the University of

Florida, the following facilities participated in this research:









* Tallahassee Memorial HealthCare

Tallahassee Memorial HealthCare is located in Tallahassee, Florida and has 736 beds,

with a radiology workload of 31,200 procedures per year, approximately one and a

half percent of which are estimated to be pediatric.

University Medical Center, Jacksonville

University Medical Center is a 528-bed medical center located in Jacksonville, Florida
with a radiology workload of 190,000 procedures per year, approximately eight

percent of which are estimated to be pediatric.
Shands at AGH

Shands at AGH is located in midtown Gainesville, Florida and has 410 beds, with a

radiology workload of 72,000 procedures per year, approximately four percent of

which are estimated to be pediatric.

Arnold Palmer Hospital for Children & Women

Arnold Palmer Hospital for Children & Women is located on the downtown Orlando

Regional Healthcare System campus in Orlando, Florida and has 267 beds, with a

radiology workload of 33,420 procedures per year, all of which are pediatric.

* All Children's Hospital

All Children's Hospital is located in St. Petersburg, Florida and has 236 beds, with a

radiology workload of 35,930 procedures per year, all of which are pediatric.

* Wolfson Children's Hospital

Wolfson Children's Hospital is part of the Baptist/St. Vincent's Health System located

in Jacksonville, Florida and has 190 beds, with a radiology workload of 41,000

procedures per year, all of which are pediatric.
* Shands at Lake Shore

Shands at Lake Shore is a 128-bed acute care community hospital located in Lake

City, Florida with a radiology workload of 36,000 procedures per year, approximately

eight percent of which are estimated to be pediatric.










* Shands at Starke

Shands at Starke is a 49-bed acute care rural hospital located in Starke, Florida with a

radiology workload of 14,780 procedures per year, approximately six percent of which

are estimated to be pediatric.

* Shands at Live Oak

Shands at Live Oak is a 30-bed acute care rural hospital located in Live Oak, Florida

with a radiology workload of 18,000 procedures per year, approximately three percent

of which are estimated to be pediatric.

The six facilities representing Children's Hospitals and/or Radiology Departments

with dedicated pediatric radiologists were Shands at UF, Tallahassee Memorial

HealthCare, University Medical Center, Arnold Palmer Hospital for Children & Women,

All Children's Hospital and Wolfson Children's Hospital. The two hospitals representing

community patient populations were Shands at AGH and Shands at Lake Shore. The two

hospitals representing rural patient populations were Shands at Starke and Shands at Live

Oak.


Exam Simulations


Per a scheduled appointment approved by the radiologist, initial contact was made

with the director of radiology upon arrival at each facility. The purpose and objectives of

the research were reiterated and the phantom and dosimetry system demonstrated. Copies

of recent news publications about the research were also distributed. The director then

assigned a x-ray room and technologist to the research project for 2.5 hours on average.

The designated time was requested during appointment scheduling and was approximated

based on the time required to carry out the initial characterizations performed at Shands at

UF.









After initial set-up of the phantom to perform real-time dosimetry readings as

described in Chapter 3, the phantom was turned over to the pediatric x-ray technologist to

simulate, as close to clinical practice as possible, the exams listed in Table 2-4 for a one-

year old patient. In order for the pediatric x-ray technologist to simulate the x-ray field

size, shape and location on the phantom, it was necessary to indicate the locations of

certain anatomical landmarks on the phantom that approximated those of an actual one-

year-old patient. The anatomical landmarks, which were defined and placed on the

phantom during the initial simulations at Shands at UF by Dr. J. Williams, a staff pediatric

radiologist, were as follows:

1. Vertex The top or highest part of the phantom head.

2. External acoustic meatus (EAM) Defined to be at the horizontal level of the floor of

the phantom skull.

3. Sternal Notch Defined as the point midway between the anterior medial ends of the

phantom clavicles.

4. Nipples Defined to be located on the level midway between the top of the phantom

trunk and the inferior margin of the twelfth rib; considered to be the midpoint of the

thorax.

5. Xiphoid Process Defined as the inferior margin of the sternum at the level of the

seventeenth rib.

6. Umbilicus Defined as located at the level midway between the phantom diaphragm

and the bottom of the trunk. The umbilicus is considered to be at the midpoint of the

abdomen and at the level of the iliac crests.

7. Symphysis Pubis Defined as located on a level 0.086 times the vertical height of the

trunk above the inferior margin of the trunk, whose relative position is taken from the

vertex. This point is considered to be located at the superior margin of the pubis.

8. Hip Joint Defined as lying on a vertical line, originating at the center of the base of

the leg bone, one-third of the vertical height of the pelvis, above the floor of the trunk.










The distances of these landmarks from the base of the trunk are listed for the one-

year-old phantom in Table 2-5.


Table 2-5. Defined Locations of Anatomical Landmarks on Phantom Vertical Axis with
the Origin at the Base of the Trunk (cm)
Landmark
Vertex 48.5
EAM 39.4
Sternal notch 27.5
Nipples 22.6
Xiphoid process 19.2
Umbilicus 10.6
Hip joint 1.1
Symphysis pubis 0.7

The next section of this chapter describes each exam simulation setup of the

phantom patient in detail. The descriptions are based on technologist interviews and

visual observations obtained of the best practices at each site for actual patient

examinations, supported with the textbook by Kirks and Griscom (1998). Additional

descriptions are provided by Ballinger (1995), Bontrager (1997) and Wilmot and Sharko

(1987). The left lateral projection was chosen for all lateral examinations for ease in

positioning. Images of these examinations are provided in Chapter 5, along with

corresponding phantom images.

AP skull

The patient is positioned supine. The midsaggital plane (divides the body into

right and left halves) of the skull is kept perpendicular to the tabletop. The orbitomeatal

baseline is kept 15 to 20 degrees cephalad from the perpendicular by using a small sponge

wedge or roll of diapers behind the patient's neck to provide some support to maintain this

position. The orbitomeatal line is a frequently used positioning line located between the

outer crease of the eye and the EAM. Several immobilization methods were observed,

ranging from Velcro and tape to foam-backed lead "bookends" placed at both sides of the

head, as shown in Figure 2-1. Typically, one-year olds are also immobilized using the









"bunny" or "mummy" technique, which consists of tightly wrapping the patient in a
blanket to immobilize arms and legs. The thyroid was protected by a shadow shield,
which is a piece of lead attached to the tube head with an adjustable arm. Note that PA
projections are not routinely obtained for this age group, as young children tend to be
frightened of being face down.


Figure 2-1. Items frequently used for immobilization. A: Sandbags, tape, clear Plexiglas
strip. B: Sponges of various shapes and sizes, Velcro strap. C: "Bookends"; patient
"mummified". Figures A and B reproduced with permission from Lippincott-Raven
Publishers. Figure C reproduced with permission from Mosby-Year Book Publishers,
Textbook of Radiographic Positioning and Related Anatomy, K. L. Bontrager (1997).

Lateral skull
The patient is positioned either semiprone or supine. If using a grid, the head is
rotated so that the affected side is closest to the film. If a grid is not used, a cross table
lateral is performed with a film holder. The unaffected side of the body is elevated from
the tabletop using sponges under the neck and shoulders so that the coronal plane (divides


WWO- i
9L









the body into anterior and posterior parts) of the body creates an angle of 45 degrees with

the tabletop. The head is positioned in such a way that the midsaggital plane of the skull is

parallel to the tabletop, and the interorbital line is perpendicular to the film. The

interorbital line is a frequently used positioning line that connects either the pupils or the

outer creases of the patient's eyes. The central ray is perpendicular to the midsaggital

plane and passes midway between the glabella (the smooth raised prominence between the

eyebrows just above the bridge of the nose) and the occipital protuberance (the prominent

"bump" at the inferoposterior portion of the skull). Immobilization and shielding

techniques were similar to those used in the AP projection, except the foam-backed lead

"bookends" were not placed in the field of view.

Townes skull

The patient lies supine on the table so that the orbitomeatal baseline is

perpendicular to the tabletop. Visualization of the foramen magnum (the large opening at

the base of the occipital bone through which the spinal cord passes as it leaves the brain)

may be improved by placing a 20 degree-angled sponge under the skull. For this age

group, an additional angled sponge placed under the lower extremities may also assist in

positioning by depressing the shoulders and encouraging further flexion of the neck. With

the x-ray tube angled 30 to 35 degrees caudal (away from the head end of the body,

toward the feet), the central ray enters the frontal bone in the midsagittal plane at the

hairline passing through a line connecting both external auditory meatuses and exits

through the foramen magnum. An angle of 30 degrees between the orbitomeatal line and

the central ray should be achieved. Immobilization and shielding techniques were similar

to those used in the AP projection. Due to the inability of the phantom's head to

articulate for this method, the pediatric technologist compensated by angling the x-ray

tube to produce the same projection.









Waters sinus

The patient is examined sitting or standing with the chin and the nose in contact

with the film cassette. The patient's mouth is opened during the radiographic procedure.

The neck is extended in such a way so that the orbitomeatal baseline forms a 40 to 45

degree angle with the plane of the film so that the midsaggital plane is perpendicular to the

cassette. The central ray enters at the posterior sagittal suture (the joint connecting the

two parietal bones) just above the occipital protuberance in the midline and runs parallel to

the mentomeatle line and exits at the level where the nose and upper lip meet. The

mentomeatle line is a frequently used positioning line that connects the midpoint of the

chin with the EAM. Again, due to the inability of the phantom's head and jaw to

articulate for this method, the pediatric technologist compensated by angling the x-ray

tube to produce the same projection.

AP cervical spine

As the patient lies supine on the table, the neck is extended to bring the

orbitomeatal baseline to 20 degrees cephalad (toward head end of body) to the vertical.

An angled sponge under the patient's shoulders may be used in order to achieve greater

extension of the neck. The central ray is kept between 10 to 20 degrees cephalad. The

central ray enters at the level ofC-4 or at the thyroid cartilage. The field size is adjusted

so that the view includes the base of the skull as well as the T-l vertebrae. A lead lap

apron was utilized as shielding.

Lateral cervical spine

If using a grid, the patient is positioned supine. The head is in a true lateral

position with the chin raised slightly. The central ray enters the C-4 vertebrae

perpendicular to the film cassette. This procedure may be performed either with extension

or flexion of the neck depending on the kind of functional study. The field is collimated to

include the C-l to T-2 vertebrae. If a grid is not used, a cross table lateral is performed

with a film holder. The patient is placed in a reclined supine position with a sponge placed










under the shoulders. The neck is in a slightly extended position so that the inferior border

of the mandible is vertical. The central ray enters approximately 2.5 cm posterior to the

angle of the mandible. The field is collimated to include C-1 to T-2 vertebrae. Shielding

techniques are similar to those used in the AP projection.

AP thoracic spine

The patient is placed in the supine position. The patient's head rests directly on

the table without the support of a pillow. The patient's chin should be slightly raised. The

hips and knees should be slightly flexed and the knees supported on a pillow so that the

cervical spine will become nearly parallel to the tabletop. Additional restraint is provided

by placing sandbags over the elbows and knees, and by placing Velcro restraining bands

across the chest, hips, and knees. Additional sandbags may be placed along the sides of

the chest and abdomen to further limit movement. The central ray enters at the level ofT-

6 or approximately 10 cm below the sternal notch. The field is collimated to include C-7

to L- vertebrae.

Lateral thoracic spine

The patient is positioned in a true lateral position with the arm closest to the table

flexed to bring the hand up under the head The upper arm also rests on the side of the

head. Note that the arms in the phantom are encased in the trunk and cannot be moved.

When positioning the patient for the lateral view, the head should be placed on a firm

pillow to raise the head and bring the cervical spine into alignment with the thoracic spine.

The hips and knees are flexed to provide stability. In order to reduce the lateral curvature

and ensure that the thoracic spine is parallel to the tabletop, a sponge should be placed

under the patient at the level of the lumbar spine, but above the iliac crests. The arms and

legs should be restrained with sandbags and Velcro restraining bands. A bookend support

should be placed against the back and against the anterior chest wall to discourage arching

of the back. The central ray enters at the level of T-6 just below the inferior angle of the










scapulae. The field is collimated to include C-7 to L-1 vertebrae. The upper 2 or 3

thoracic vertebrae are not well visualized on the standard lateral view.

If upper thoracic vertebrae are of particular interest, a "swimmers" lateral view is

performed. The patient is positioned as described above, but the upper arm is brought to

rest behind the patient's buttocks and the shoulder is rotated slightly posteriorly. This

positioning ensures that neither shoulder will be superimposed on the upper thoracic spine.

The central ray enters at the level ofT-2 and the field is collimated to include C-7 to T-2

vertebrae. Since the arms in the phantom are encased in the trunk and cannot be moved,

this view was not performed.

A "breathing" technique was commonly employed by technologists for lateral

thoracic spine radiographs. Rather than waiting for the time of expiration to take an

exposure, technologists would routinely have the patient breathe normally, so that the

movement would blur the lungs and ribs out.

AP lumbar spine

The patient lies supine with knees and hips flexed and the arms placed to the side.

It was unnecessary for the phantom to perform this flexion, as the posterior aspect of the

phantom lies immediately adjacent to the tabletop. The midsaggital plane of the body is

aligned to the midline of the table. The central ray enters perpendicularly at the level of

the iliac crest or at the L-4 to L-5 interspace. The techniques of immobilization already

described under the discussion for positioning of the thoracic spine are equally applied in

examinations of the lumbar spine.

Lateral lumbar spine

If a cross table lateral is not performed, the patient lies in a lateral recumbent

position with a pillow under the head and the knees and hips flexed with support between

the knees and ankles. The pelvis and the torso are in a true lateral position. The coronal










plane of the patient is aligned to the midline of the table. The central ray enters

perpendicularly at the level of the iliac crest or at the level of the L-4 vertebrae.

AP abdomen

The patient lies supine on the table. The midsaggital plane of the patient is aligned

with the center of the table or the film cassette. Immobilization methods that have been

previously discussed were utilized, such as Velcro or tape, and foam wedges or sandbags

on both sides of the abdomen. The central ray is perpendicular to the film and enters

about one inch above the umbilicus for a one-year-old. The exposure should be made at

the end of expiration. Upright projections of the abdomen may be clinically required and

are performed with immobilization techniques similar to those utilized for upright chest

radiography.

AP pelvis

The patient lies supine with legs extended and separated. The legs are internally

rotated 15 to 20 degrees. Since the phantom's legs are not attached to the trunk of the

body, this positioning does not change the internal anatomy of the phantom. The patient

midsagittal plane is aligned with the central ray which enters a point midway between the

level of the anterior superior iliac spine (prominent anterior border of the iliac crest) and

the superior border of the symphysis pubis. The central ray is perpendicular to the film,

and a gonad shield is utilized. It should be mentioned that a "frog-leg" pelvis view is also

routinely performed for this age group. In a frog-leg view, the knees and hips are flexed

as far as comfortable. Both thighs are abducted as far as possible, and plantar surfaces of

the feet are placed together. This view was not performed with the phantom due to the

inability of the phantom's joints to articulate.

AP bilateral hip

The patient lies supine with their arms immobilized at their sides or crossed at the

chest with the pelvis as symmetrically positioned as possible. The legs are extended and









rotated internally 15 to 20 degrees when a non-trauma patient is being examined. The

central ray enters the midline at a point halfway between the anterior superior iliac spine

and the symphysis pubis. Both hips are always examined in the same projection on the

same film.

A lateral frog-leg hip is routinely performed for this age group. The patient is laid

partially oblique with a support under the affected area. The knee on the affected side is

flexed, and the thigh is drawn up to a 45 degree angle position. The affected femoral neck

is centered to the midpoint of the film cassette. The central ray is perpendicular to the film

and enters at the level of the mid-femoral neck. This view was not performed with the

phantom, due to the inability of the phantom's joints to articulate.

AP. PA and lateral chest

Pediatric chest radiographs are routinely performed upright without a grid. The

challenge of performing upright imaging includes preventing motion and rotation, freeing

the lung fields of superimposition of chin, humeri and scapulae, and obtaining a good

inspiratory radiograph. Various methods of immobilization are used, however, the most

common pediatric positioner and immobilization tool utilized is the Pigg-o-stat. The Pigg-

o-stat is composed of a large support base on wheels, a small adjustable seat and Plexiglas

support sleeves, which come in two sizes. The seat, sleeves, and "turntable" base rotate

as a unit to facilitate quick positioning from the PA to the lateral projection.

As shown in Figure 2-2, the child sits on the little bicycle type seat. The plastic

support sleeves fit snugly around the sides and keeps the arms raised. The child usually

cries with frustration at being confined, but the crying actually helps to obtain a good x-

ray image because, at the end of a cry, the child will take a big gasp of air, and at that

moment the exposure is taken. The orientation of the room, i.e., where the chest stand or

film holder is located relative to the control panel, determines how well the technologist

can see the child's thorax to ensure the exposure is made during inspiration. Inspiration









can also be detected by watching the child's abdomen as it extends on inspiration,

watching the chest wall as the ribs will be outlined on inspiration and watching the rise and

fall of the sternum. The central ray for both PA and lateral projections enters

perpendicular to the film at the level of the midthorax T-6/T-7 vertebrae or mammillary

(nipple) line. The collimation is adjusted so that all of the ribs are included in the
radiograph and should extend from, and include, the mastoid tips to just above the iliac

crests. A lead lap apron was utilized as shielding.




















Figure 2-2. Infant immobilized and supported by the Pigg-o-stat device for an upright
chest film. The device is then rotated 90' for a lateral projection. Note the presence of
shielding for the pelvis. Figure reproduced with permission from Lippincott-Raven
Publishers, Practical Pediatric Imaging: Diagnostic Radiology of Infants and Children
D. R. Kirks and N. T. Griscom (1998).

Radiologists that did not favor the use of the Pigg-o-stat for aesthetic reasons or

because of the potential for sleeve artifacts, frequently used a supine pediatric immobilizer

referred to as a Tam-em board. This one step immobilization device positions the child

with the arms, head and legs immobilized with foam lined Velcro straps to a Plexiglas

frame for both an AP projection (with the film located on the tabletop under the frame as









shown in Figure 2-3) and a cross table lateral projection (with the film in a holder as

shown in Figure 2-4). This immobilization device was also used when upright positioning

was contraindicated.


Figure 2-3. Toddler immobilized for an AP chest radiograph on the Tame-Em
immobilizer. Velcro bands are placed around the arms and legs; a vinyl sheet of lead
covers the lower abdomen and gonads. Figure reproduced with permission from
Lippincott-Raven Publishers, Practical Pediatric Imaging: Diagnostic Radiology of Infants
and Children, D. R. Kirks and N. T. Griscom (1998).


Figure 2-4. Infant immobilized for a left lateral chest radiograph on a Plexiglas
immobilizer. Velcro bands are placed around the arms and head; a vinyl sheet of lead
covers the lower abdomen and gonads. Figure reproduced with permission from Mosby-
Year Book Publishers, Merrill's Atlas of Radiographic Positions and Radiologic
Procedures, P. W. Ballinger (1995).
A variation of this device is an octagonal immobilizer, shown in Figure 2-5, which

is an eight-sided immobilization tool that permits visualization in a variety of positions.























Figure 2-5. Octagon board for immobilization. Figure reproduced with permission from
Lippincott-Raven Publishers, Practical Pediatric Imaging: Diagnostic Radiology of Infants
and Children, D. R. Kirks and N. T. Griscom (1998).


Survey Data

For future comparison of the measured and simulated effective doses, several

parameters from the survey data would need to be correlated. The most important

descriptors collected during the exam simulations at each facility included the type of

generator, e.g. single phase, three phase, constant potential or high frequency; the

collimated size of the x-ray field; the distance from the tube focal spot to the beam

entrance point on the skin or surface of the phantom (SSD); the direction of the x-ray

beam with respect to the long axis of the phantom (projection); and the quality of the x-

ray beam as described by the kVp and half value layer (HVL).

For comparison of technique factors among hospitals, additional parameters were

collected from each facility. These parameters included the mode of operation, e.g.

manual or automatic exposure controlled (AEC, also called phototiming or amplimatting);

the detector configuration of ion chambers that were utilized for AEC-right (R), center

(C) and/or left (L) and the density setting ((-3, -2, -1, Normal (N), +1, +2, or +3)); if

scatter suppression was used; film size; film/screen speed; the distance from the tube focal

spot to the image receptor distance (SID); the output of the x-ray beam as defined by the









milliamperage and time applied (mAs); the focal spot size-large (LFS) or small (SFS); and

shielding used. Repeat and reject rate percentages were also collected.

In addition to recording technique parameters during the simulations, several

measurements were performed. Higher than normal exposures were taken to ensure

reasonable accuracy in the absorbed dose data. After the clinical exam was performed,

exposures from an output of 80 mAs were performed. The accuracy of the kVp was

verified prior to measuring the HVL. The exposure per mAs was measured at a variety of

kVp settings at a given distance in order to compute the entrance skin exposure (ESE),

which was subsequently used in the effective dose calculation. X-ray films were obtained

for all the chest examinations, and the optical density of the middle of the lung fields on

the chest x-rays were quantified with a densitometer and averaged to provide a measure of

image quality. All measurements were performed in accordance with procedures

recommended by the American Association of Physicists in Medicine (Seibert et al. 1994).

The survey data in their entirety are reviewed in Chapter 5 and are tabulated for each

exam and projection in Appendix C.

During the initial survey performed at Shands at UF, x-ray films and dosimetry

measurements were performed for each examination listed in Table 2-4. During the

subsequent site surveys, x-ray films and dosimetry measurements were only performed for

the chest examinations in order to decrease room downtime. The chest examinations were

chosen for comparison, as they were the most frequently performed examination at each

facility.














CHAPTER 3
RADIATION MEASUREMENT EQUIPMENT AND TECHNIQUES


One-Year-Old Anthropomorphic Phantom

Bower successfully constructed a full-scale prototype of a physical heterogeneous

phantom to represent the new MIRD one-year-old mathematical model, which included a

revised head and neck (1997). This prototype was the phantom utilized for the

measurements in the site survey study. The construction entailed several steps. First,

processing techniques were developed to produce tissue equivalent materials

approximating soft, lung and bone tissues which required the addition of a particulate filler

with a moderately high effective atomic number, such as magnesium oxide, to an unfilled

liquid resin with a low effective atomic number. The theoretical interaction coefficients

(mass attenuation and mass energy-absorption coefficients) were matched between these

tissue-equivalent materials and the tissue media used in the 1987 Cristy and Eckerman and

MIRD models over the photon energy range 1.5 keV to 150 keV using the computer

program XCOM written by Berger and Hubbell at the Center for Radiation Research,

National Bureau of Standards (Hubbell 1982). The mass density was adjusted by adding a

small quantity of low-density microballoons (hollow gas-filled spheres). This basic

process followed that published by White (1977) and further developed by White et al.

(1977, 1986) and Herman et al. (1985, 1986).

The soft tissue substitutes were made of materials providing a final elemental

composition of 59.2% carbon, 20.6% oxygen, 10.5% magnesium, 7.5% hydrogen, 2.0%

nitrogen and 0.10% chlorine by weight. The attenuation and mass energy-absorption

coefficients of the tissue-equivalent substitutes were modeled after the atomic










compositions of soft tissue defined in the 1987 models of Cristy and Eckerman and ICRP

Publication 23 (1975). These two sets of photon interaction coefficients were in

agreement within + 3% and were considerably closer at most energies. The soft tissue

substitute's photon interaction coefficients were also favorably compared to those given

for individual tissues given in ICRU Publication 44 (1989). The soft tissue substitute was

modeled to provide the appropriate soft tissue density of 1.04 g/cm3.

Lung-equivalent materials were manufactured using a foaming agent and a

surfactant, similar to the method presented by White et al. (1986). The lung tissue

substitutes were made of materials giving an elemental composition of 59.42% carbon,

17.65% oxygen, 12.06% magnesium, 8.24% hydrogen, 1.64% nitrogen, 0.84% silicon and

0.15% chlorine. The lung tissue substitute density was 0.360 g/cm3, which approximated

the lung tissue density of 0.296 g/cm3 for the mathematical model.

A bone tissue substitute approximating the skeletal tissue of a one-year-old was

also produced. Cristy and Eckerman made the following observations concerning the

skeleton of the newborn: "The skeleton of the newborn contains more water, less fat, and

less mineral than the adult skeleton. Furthermore, the distinction of two bone types,

cortical and trabecular bone, is not evident in the newborn skeleton, and the marrow of the

skeleton is all active. Thus it is clear that the elemental composition of the adult skeleton

cannot be used when evaluating radiation transport in the newborn." [1987, page 42]

Consequently, the authors proposed a different skeletal tissue medium for their newborn

model, but utilized the adult skeletal tissue medium for all other models in the series

including the one-year-old. New data on average skeletal atomic composition as a

function of age available in ICRP Publication 70 (1995) were used to manufacture age-

specific skeletal-equivalent materials incorporated into the one-year-old phantom. The

skeleton composition (in terms of water, protein, mineral and fat by percent weight) was

used to calculate an appropriate elemental composition of the bone-equivalent substitute

for the one-year-old skeleton consisting of 52.98% carbon, 24.54% oxygen, 5.86%









hydrogen, 2.03% nitrogen, 5.79% chlorine and 8.81% calcium. The mineral percent by

weight for a one-year-old skeleton was provided explicitly in ICRP Publication 70. The

water and fat percentages were obtained from the 1995 document's data tables and the

percentage of protein was obtained by subtraction. However, Bower had difficulty in

producing a bone substitute that matched the density for a one-year-old, but could

produce a bone substitute mixture of 1.18 g/cm3 in 1997, which approximated Cristy and

Eckerman's density of 1.22 g/cm3 for the newborn in 1987. Since the new elemental bone

composition for the one-year-old developed by Bower in 1997 was close to the newborn,

and the difference in densities between the newborn and the one-year-old in ICRP

Publication 70 was only 0.01 g/cm3, he decided to use the newborn bone density of 1.18

g/cm3 for the one-year-old.

Molds were then created for the lungs and individual skeleton components

consisting of two leg bones, two arm bones, a pelvis, a spine, twelve ribs, two scapula and

two clavicles. The molds were filled with the respective lung or bone liquid resin tissue

substitutes and allowed to cure. The cured components were milled to final shape. Once

the internal components were completed, molds were created for the external parts

consisting of the trunk, legs and skull. The soft tissue substitute material was then poured

into the external cylindrical trunk mold in a layered method which facilitated the correct

placement of the skeletal and lung components. The legs were frustums of two soft tissue

cones surrounding the leg bones. The head consisted of a skull enclosing the mandible,

teeth, cranium and upper face region, as well as a neck. Guide holes were drilled into the

phantom to allow placement of the dosimeters. Figure 3.1 shows the mathematical model

of the one-year-old, a portion of the internal skeleton with the head model, and an external

view of the completed physical prototype phantom.



































A B C

Figure 3-1. One-year-old pediatric phantom. A: Mathematical model. B: Skeletal model
with 4 ribs. C: External view of physical prototype phantom.

The total mass of the one-year-old prototype is 10.2 kilograms. The length of the

head, trunk and legs, respectively, is 16 cm, 32.5 cm, and 26.5 cm, for a total height of 75

cm. Several aberrations should be noted regarding the prototype phantom. The

mathematical model has soft tissue eyes with a volume of 6.25 cm3, whereas the physical

prototype phantom does not have soft tissue eyes. The space for the eyes is composed of

bone tissue substitute; therefore the mass of the upper face region for the physical

phantom is slightly higher than the mathematical model. The upper portion of the

mandible is slightly thinner in the physical phantom, however, this portion abuts against

the upper face region. Therefore, when averaged together, the two regions are

approximately correct in comparison with the mathematical model. The teeth are also










slightly more massive in the physical phantom, however, the total mass of the teeth is only

22 grams, and the teeth are not a chosen dosimetry monitoring location. Some of the ribs

in the prototype were heavier than the theoretical masses; however, the individual ribs are

thin (volume 7.28 cm3) and are not used as a measurement location.


Metal Oxide Semiconductor Field Effect Transistor (MOSFET) Dosimetrv System



Theory of Operation


The basic structure of a metal oxide semiconductor field effect transistor

(MOSFET) is a sandwich-type device consisting of a p-type channel built on a n-type

silicon semiconductor substrate separated from a metal gate by an insulating oxide layer.

The source and the drain are on top of the positively doped silicon region. When

sufficient negative bias is applied to the gate with reference to the substrate, a significant

number of holes will be attracted to the oxide silicon surface. A sufficient hole population

permits current to flow between the source and the drain. The gate voltage necessary to

allow conduction through the MOSFET is referred to as the threshold voltage (Soubra

1994; Ramani 1997).

When the MOSFET is exposed to ionizing radiation, electron-hole pairs are

formed in the oxide insulation layer. The applied positive potential to the gate causes the

electrons to travel to the gate, while the holes migrate to the oxide silicon interface, where

they are trapped. These trapped positive charges cause a shift in the threshold voltage.

The voltage shift is proportional to the radiation dose deposited in the oxide layer. This is

the basis of the MOSFET as a dosimeter. The Thomson and Nielsen Patient Dose

Verification System used in this research utilizes a dual bias, dual MOSFET device design,

which consists of two MOSFETs fabricated on the same chip. The threshold voltage shift

magnitude is increased when the positive gate bias is raised. Since the MOSFETs are










irradiated simultaneously, the measured difference in the threshold shifts in the two

sensors is representative of the absorbed dose (Soubra 1994).

Each detector of the Patient Dose Verification System consists of the matched pair

of MOSFET dosimeters operated at two different positive gate biases. Each MOSFET

dosimeter has an active area of 0.04 mm2. The pair is mounted under a 1-mm layer of

epoxy to a 20-cm long thin semi-opaque polyamide laminate cable encasing two gold

wires. The extremely thin (0.2 mm), flexible laminate cable is attached to a sturdy 1.4-m

long cable that is connected to a bias supply. The reader can accommodate up to 20

dosimeters. To facilitate monitoring of the lower absorbed doses associated with

diagnostic x-rays, the model TN-RD-19 high-sensitivity bias supply is used. Grouped in

sets of five, each MOSFET set is connected to a bias supply labeled "A" through "D". In

this research, there were two sets of five dosimeters labeled "A" and "D", for a total often

dosimeters. The entire dosimetry system is shown in Figure 3-2 including the reader,

power supply, bias supply, a MOSFET dosimeter and the associated cabling.


Figure 3-2. Thomson and Nielsen Electronics Ltd. MOSFET Patient Dose Verification
System









Characterization of High Sensitivity MOSFET Dosimeter


The commercial Patient Dose Verification System manufactured by Thomson and

Nielsen was originally designed for radiation therapy dose verification. To measure doses

to organs that were outside of the primary therapy beam, Thomson and Nielsen developed

high sensitivity dosimeters to measure the lower doses. Bower and Hintenlang

characterized these high sensitivity dosimeters for diagnostic energies (1998). Bower

measured the sensitivity, linearity, rotational angular response, multiple query response

and post-exposure response of the high sensitivity MOSFETs. He determined that the

high sensitivity MOSFET dosimeters had a nearly uniform angular response, good

linearity, and precise sensitivities at the lower energy ranges that resulted in a standard

error of+ 5% for a typical x-ray exposure. He also determined that the energy

dependence of the sensitivity, the post-exposure drift and the multiple query responses

were not significant limitations. Johnson performed three additional characterization tests,

including a comparison of the MOSFET to TLD, a determination to see if the small air

gap that surrounds the MOSFET when inserted into the phantom influences the dose

measurement, and a determination of the axial angular dependence of the MOSFET

(1998). She determined that the dose reported by the MOSFET is equivalent to the dose

reported by the TLD inside the tissue phantoms and that the small air gap that surrounds

the MOSFET when it is inserted in the holes in the phantom does not affect the reported

dose. Consequently, there is no need to fill the air gap with other tissue equivalent

material. She also determined that angular dependence in the axial (saggital would be a

more appropriate definition) orientation of the MOSFET when placed in the phantom does

not influence the measured absorbed dose. An extrapolation of these determinations for

the rotational and saggital planes is that the angular dependence from a coronal orientation

would also not influence the measured absorbed dose.










The MOSFET is a consumable detector. While the detector is not annealed or

cleared after reading, as is the case for thermoluminescent dosimeters, the system can

provide a reset between desired readings. The reset process consists of measuring the mV

response and using this response as a reference value for the following measurement. The

response is not completely stable over long periods of time post-exposure. Bower

performed a fading study in 1997 to measure the response of the high sensitivity

MOSFETs as a function of time post-exposure out to 500 hours. The dual-bias, dual-

MOSFET system utilizes the stable difference in response from the two detectors for

measuring absorbed dose. This method eliminates temperature and high-dose

dependencies, but does not control post-exposure drift. The drift is a complicated

function attributed to an array of causes. The drift is reproducible, and mathematical

models and deconvolution methods have been proposed and employed (Gladstone and

Chin 1995). In using this dosimeter system to monitor organ doses within the one-year-

old phantom in real-time, delay times between exposure and dosimeter readout are on the

order of minutes, therefore, another fading study was performed to measure the response

of the MOSFET as a function of time post exposure for an immediate read, a one-minute

delay, a two-minute delay and a three-minute delay. The exposure between the four

reading times varied by less than 2%, so a delay time of one minute was utilized in this

research to decrease the room downtime associated with the data collection, and no

correction factors were necessary.

The dosimeters inserted within the physical phantom are required to have good

angular response characteristics since there is no way to adjust the orientation of the

detectors towards the x-ray source when simulating different views of x-ray examinations.

In 1997, Bower demonstrated there is a marked angular dependence of the MOSFET

dosimetry system when it is used free-in-air without an attenuating medium. The

packaging of the MOSFET appears to be the main source of this angular dependence,

providing different responses when exposing the flat surface (60% lower) as opposed to










the epoxy bubble side of the dosimeter. It was initially thought this difference might be

attributed to insufficient material on the flat surface of the dosimeter for the establishment

of electronic equilibrium. It was subsequently demonstrated that this response is not

simply due to scattering from the 1-mm bubble of epoxy, since the angular response

remained after material was added to the flat side of the detector to make it more

symmetrical. The effect is actually due to the inherent asymmetric structure of the

MOSFET itself, specifically resulting from attenuation in the silicon substrate layer. The

angular dependence is much less pronounced when the dosimeter is surrounded by

attenuating media. This was verified by using a tissue equivalent cylinder and measuring

the angular response for the high sensitivity MOSFET dosimeter. The cylinder, with a

detector inserted in the center, was irradiated in 15* increments over 3600 at a tube

potential of 90 kVp, 150 mAs, and a source-to-detector distance of 75 cm. The

procedure was repeated for each MOSFET to obtain an average dose measurement at

each increment. The response was very symmetrical, indicating excellent angular response

when using this dosimeter within a phantom. The nearly uniform angular response and its

small size were primary reasons the MOSFET dosimeter was chosen for the real-time

dosimetry applications within the one-year-old phantom.


MOSFET Placement


The effective dose concept presented in the 1990 recommendations of the ICRP

(1991) identified twelve specific tissues at risk from radiation detriment and supplied

tissue weighting factors for these tissues. Several other tissues were addressed in a

"remainder" term. The specific tissues and their associated weighting factors are shown in

Table 3-1. The MOSFET dosimeters were placed in locations to estimate the absorbed

dose in these tissues for the one-year-old phantom. For localized organs, the MOSFET

was placed at the centroid of the organ to determine the dose. For distributed organs, the










dose was determined from a fractional weighting scheme applied to a specific array of

MOSFET dosimeters. Standard dosimetric allowances were made for measuring the

absorbed dose in both the testes and the ovaries in the hermaphrodite phantom since an

actual patient would not have both types of gonads. The effective dose estimates

performed in Chapter 5 are shown with the testes absorbed dose being used as the gonadal

dose component for the male estimate, and the ovaries absorbed dose being used as the

gonadal dose component for the female estimate. All other tissues and their

corresponding tissue weighting factors were the same. A skin dose estimate was obtained

by measuring the entrance and exit absorbed doses and using an average value of the two

measurements. The organs defined in the remainder term were as follows: muscle,

stomach wall, small intestine wall, upper large intestine wall, lower large intestine wall,

kidneys, pancreas, spleen, thymus, uterus, adrenals, and bladder wall. A remainder dose

estimate was calculated by averaging the measurements in the arms and the trunk of the

body as representative of the overall location of the remainder organs.

Table 3-1. Tissue Weighting Factors for Calculation of Effective Dose (ICRP, 1991)

Tissue or organ Tissue Weighting Factor (wT)
Gonads 0.20
Bone Marrow (red) 0.12
Colon 0.12
Lung 0.12
Stomach 0.12
Bladder 0.05
Breast 0.05
Liver 0.05
Esophagus 0.05
Thyroid 0.05
Skin 0.01
Bone surface 0.01
Remainder 0.05


The MOSFET locations in the one-year-old phantom are shown in Figure 3-2 and

detailed in Table 3-2. The MOSFET locations for the soft tissue organs, including the









lungs, were generally placed at the centroid of the organ. A single MOSFET location was

chosen for the testes and breasts for the following reasons. In the mathematical model

representing a one-year-old, the testes are outside of the trunk and are very small (1.16

cm3). The testes are close together, and great differences were not expected between the

individual testes, therefore, a single monitoring location was chosen at the point where the

two legs and the trunk join. Additional soft tissue material was not added to the phantom

at this representative location. The mathematical model has breasts that are again very

small for the one-year-old (1.06 cm3 including skin), so breasts were not explicitly created

for the anthropomorphic phantom. The dose to the breasts is estimated with the

anthropomorphic phantom by measuring the absorbed dose to the surface midway

between the two breasts. The centroids of the soft tissue organs in the anthropomorphic

phantom were adopted from those supplied by Cristy and Eckerman (1987; Eckerman et

al. 1996) for their mathematical model with the exception of the colon and the esophagus.

Representative monitoring locations were chosen for the colon and the esophagus based

on the equations provided for the colon (ICRP 1995) and the esophagus (Eckerman et al.

1996). The skeletal locations were chosen using three criteria: 1) the bones selected were

larger bones able to accept the MOSFET without loss of a significant percentage of the

bone material, 2) the bones selected represented high concentrations of active bone

marrow and 3) locations were selected to cover a major portion of the skeleton.













Figure 3-2. MOSFET dosimeters placed in position in prototype one-year-old phantom.











Table 3-2. Position of the MOSFET Dosimeters Within the One-Year-Old Phantom
gonads: testes-general (left & right)
ovaries-left
ovaries-right
colon
lung-left
lung-right
stomach
bladder
breasts-general (left & right)
esophagus
liver
thyroid
skeleton: skull & facial
spine (in head)
spine (middle of back)
pelvis
leg-lower left
leg-lower right
arm-left
arm-right

The MOSFETs were placed in the phantom with the epoxy bubble facing toward

the x-ray tube, and the leads were taped down to prevent any movement. Initially, ten

dosimeters were available for measurements. Two of the original compliment often failed

early in the measurement series. One failed mechanically; the reason for the other failure

could not be determined by the manufacturer. The simulations had to be repeated two and

a half times since there are 20 different organ sites and only eight dosimeters were

available. In each successive simulation, the dosimeters were placed in the 10

measurement sites that could be accessed on the top half of the phantom, and the

simulation was repeated in order to measure the 10 remaining sites that were accessed on

the bottom half of the patient. A full complement of dosimeters were not purchased until

data collection was close to completion.

ICRP Publication 70 (1995) provides tables of the active bone marrow found in

various bones as a function of age. These tables are based on work presented by Cristy










(1981) who relates the active marrow in individual bones, parts of bones, or bone groups

expressed as a percentage of active marrow in the body. Weightings of the active marrow

for the different phantom skeletal regions were assigned to the skeletal MOSFET locations

given in Table 3-2. New active marrow percentages associated with the MOSFET

location were assigned by Bower and are presented in Table 3-3.

Table 3-3 has been updated to include new bone surface percentages introduced in

this research. Cristy (1981) also provides the skeletal volume for each region, from which

a percentage of the total bone was calculated. Using an analagous technique, weightings

of the total bone for the different skeletal regions were assigned to the same skeletal

MOSFET locations, and new bone surface percentages associated with the MOSFET

location were assigned.


Table 3-3. Percentage Active Bone Marrow and Bone Surface Associated with the
Skeletal MOSFET Locations
Phantom Skeletal Region % % MOSFET % Active % Bone
Active Bone Location Marrow Surface
Marrow Assigned Assigned
to to
MOSFET MOSFET
Skull (cranium & facial skeleton) 24.74 19.9 Skull & facial 14.7 11.6
Spine (upper portion) 1.88 3.2 Spine head 14.7 11.6
Arm bones upper portion 2.41 5.0 Arm bone left 7.79 9.8
Scapulae 2.73 3.2 Arm bone right 7.79 9.8
Clavicles 0.83 0.8
Ribs 9.61 10.7
Spine (middle portion) 9.27 8.5 Spine middle 15.88 18.5
Ann bones middle portion 2.25 5.0
Arm bones lower portion 4.36 5.0
Spine (lower portion) 3.37 4.1 Pelvis 21.91 21.9
Pelvis 16.47 9.3
Leg bones upper portion 2.07 8.5
Leg bones middle portion 3.88 8.5 Leg lower left 8.64 8.5
Leg bones lower portion 13.4 8.5 Leg lower right 8.64 8.5








Measurement of Absorbed Dose

Sensitivity has been defined as the MOSFET response per unit of exposure (mV

per C kg1 or mV/R) at a given tube potential; consequently the absorbed dose (rad) in the
tissue may be derived as follows. The ion chamber measures exposure in air in units of
roentgen (R); therefore, this unit was used in measuring the sensitivity. The exposure in
air, as measured by the MOSFET dosimetry system is therefore the MOSFET dose
measurement (mV) divided by the sensitivity (mV/R). Expressed symbolically in Equation
1, where X is the exposure, M is the MOSFET dose measurement and S is the sensitivity.
X=M*() (Eq. 1)

One roentgen produces an absorbed dose of 0.876 rad in air; therefore,
D,, =X*0.876 (Eq 2)

The absorbed dose in tissue may be then be calculated with the following equation:

D,_ = D.,Z _1)_, (Eq. 3)

where p,, / p is the average mass energy-absorption coefficient associated with the mean

energy of the x-ray spectrum. Equations 1-3 may be combined into one useful equation as

follows.


D, 0.876* M (Eq. 4)


The value of p, / p for the oxide could be removed from the equation without

error; however, its inclusion indicates that the absorbed dose in the MOSFET device is an
integral part of the corresponding dose value in tissue. The average mass energy-
absorption coefficient ratios are effectively 1.0 for soft tissue, but increase to 3.5 for
skeletal tissue at 30 keV.










The mean energy of the x-ray spectrum was estimated by utilizing the computer

program XCOM5R (Nowotny and Hifer 1985). The program is a spectrum generating

program which accounts for parameters such as the tube potential, the inherent filtration,

and the target materials. The program provides detailed information about the x-ray

spectrum, including the mean photon energy of the spectrum. The determination of the

exact mean spectrum energy is not critical for soft tissue or lungs, since the ratio of mass

energy absorption coefficients is relatively constant and nearly 1.0 over the diagnostic

energy range. The determination is more critical for the bones since that ratio is a rapidly

changing with photon energy and peaks around 30 keV.


Sensitivity Analysis


MOSFET sensitivity, defined as the mV response per R exposure, is shown in

Table 3-4 below for the ten high sensitivity dosimeters initially used in this research. Just

prior to the completion of data collection, an additional ten dosimeters were added to the

system, so during the calibration of the new dosimeters, the old dosimeters were

recalibrated, as shown in column three. Exposure measurements were simultaneously

made with a Keithley calibrated ion chamber. The data points were fit to obtain entrance

skin exposures as a linear function of tube potential; only the most commonly used tube

potential determined from the site surveys is reported.


Table 3-4. Sensitivity Calibration Factors (R/mV) at 70 kVp
MOSFET # Calibration Factor (R/mV)
1 0.028
2 0.031
3 0.029
4 0.029
5 0.030
6 0.030
7 0.031
8 0.031
9 0.029
10 0026


Calibration Factor (R/mV)
0.030
0.035
0.031
0.030
0.029
0.037
0.034
0.036
0.032
0.033









Table 3-4, continued.
11 0.031
12 0.029
13 0.029
14 0.030
15 0.030
16 0.030
17 0.033
18 0.030
19 0.032
20 0.033

Calibration factors needed for subsequent determination of tissue absorbed dose

(R/mV) were determined from these sensitivity data and through the application of the

Bragg-Gray cavity theory, as previously described. The conversion factors given in Table

3-5 contain the ratio of average mass energy absorption coefficients detailed in Appendix

D and a constant for converting exposure to the absorbed dose in air, as described in

Equation 4. Utilization of these conversion factors convert the exposure, obtained by

multiplying the MOSFET measurement by the appropriate value in Table 3-4 to absorbed

dose.


Table 3-5. Conversion Factors Converting Exposure to Absorbed Dose
Tube Potential Soft Tissue Lung Tissue Bone Tissue
70 1.009 1.046 3.316

The following technique was used to assign a dose to the active bone marrow

using a weighted fraction of bone marrow assigned to the MOSFET locations in the

skeleton reported in Table 3-3. The active bone marrow dose was calculated by utilizing

the conversion factor for soft tissue in Table 3-5 to calculate the absorbed dose of each of

the skeletal components, multiplying by the fraction of active bone marrow assigned to the

MOSFET (Fi) reported in Table 3-3, and then summed to get the total absorbed dose to

the active marrow. Equation 5 illustrates how the dose to the active marrow is calculated.









D =0.876*.* *- I *M,* ~F, (Eq. 5)


A similar technique was used to assign a dose to the bone surface using a weighted
fraction of bone surface assigned to the MOSFET locations in the skeleton reported in
Table 3-3. The bone surface dose was calculated by utilizing the conversion factor for
bone in Table 3-5 to calculate the absorbed dose of each of the skeletal, multiplying by the
fraction of bone surface assigned to the MOSFET (Fi) reported in Table 3-3, and then
summed to get the total absorbed dose to the bone surface. Equation 6 illustrates how the
dose to the bone surface is calculated.


D =0.876* *L b *M* F (Eq.6)




Calculation of Effective Dose

Effective dose (E) as presented by the ICRP in 1991 is the most current and
comprehensive measure of radiation detriment. Effective dose equivalent (HE) was a
measure presented earlier by the ICRP in 1976. The effective dose was chosen to be
calculated in this research as it evaluates the absorbed dose from more tissues than the
effective dose equivalent and applies updated tissue weighting factors which are
numerically different from those used with the effective dose equivalent. Various sets of
tissue weighting factors were derived for children ages 0 to 9 and 10 to 19 years by Almen
et al. and tested for use in the calculation of effective dose (1996). They concluded that
the ICRP tissue weighting factors were applicable to children and adolescents; therefore,
the ICRP tissue weighting factors were utilized in this research. The effective dose was
calculated by multiplying the absorbed dose for each organ described in the previous
section by its respective tissue weighting factor reported in Table 3-1. To summarize,






59


organ doses were determined with the MOSFET at the centroid of the organ, the active

marrow and bone surface doses were determined via fractional weightings assigned to

individual MOSFET locations, and the remainder dose was determined from an averaged

measurement over MOSFETs located in the torso region. Since the effective dose

calculation is a weighted average of the MOSFET measurement, the uncertainty in the

effective dose caclulation is determined to be a maximum of+ 5%. Appendix E presents

the measured organ doses and calculated effective doses utilizing the MOSFET dosimetry

system and the one-year-old physical prototype phantom. The results are reviewed in

Chapter 5.














CHAPTER 4
RISK ASSESSMENT


General

Risk assessment has been defined by the National Research Council (NRC) as "the

characterization of the potential adverse health effects of human exposures to

environmental hazards"(NRC 1983, page 18). An assessment of the risks from all types of

hazards, including radiological hazards, requires all or some of the following components:

i) hazard identification, which is investigated to determine whether a particular hazard has

a corresponding health effect; ii) dose-response assessment, in which the relation between

the magnitude of the dose and the probability that the health effect will occur is

determined; iii) exposure or dose assessment, which is the determination of the extent to

which humans will be exposed to the hazard; and iv) risk characterization, which describes

the nature and magnitude of the human risk, including uncertainties surrounding that risk

[NRC, 1983 #2254]. It is the last component of risk characterization that integrates the

results of the previous three components into a risk model that includes one or more

quantitative estimates (Cohrssen and Covello 1989).


Components of a Risk Model

The model used to perform a risk assessment is a function of several parameters,

including populations from which data are obtained, relationships between doses and

effects and methods used to project risks into the future. Due to the limited knowledge of

radiation effects, there is diverse discussion about the interpretation of dose-response data

and the choice of values for the other parameters










Populations used in epidemiological studies vary among risk assessment models.

Some studies provide better data than others do because some populations better

represent the population of concern. In addition, differences in population characteristics

such as lifestyles, cancer rates and types of exposures must be considered in transferring

the results obtained from one population to another population, which is defined in a risk

model as the population transfer coefficient.

The dose-response curve and dose-rate effect applied can differ. Among the

possible risk models, the risk analysis techniques most commonly applied are a linear-

quadratic or a linear relationship.

Risk projection models used to predict the mortality from, or incidence of, cancer

and genetic disease that will occur within a given population can be of several types.

Cancer risk projections use additive or multiplicative methods; genetic risk projections

may use direct or indirect methods. Each method requires choices from among several

additional parameters including death rates, specific causes of death, population statistics,

and dose calculations.

Radiological risk assessments and resulting risk estimates have been developed by

numerous organizations. Organizations such as the National Research Council's fifth

committee on the Biological Effects of Ionizing Radiations (BEIR V), the United Nations

Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), and the

International Commission on Radiological Protection (ICRP) have summarized the

complex data previously discussed that are available on the effects of radiation in a form

that is easily applicable. The BEIR V methodology is considered the most recent consent

document for risk analysis and was utilized in this research.









BEIR V Methodolovg



Populations for Determining Cancer Risk

In the risk assessment by the BEIR V Committee in 1987, cancer risks were based

mainly on epidemiological studies and, in large part, on the population of residents from

Hiroshima and Nagasaki in 1950 (the Life Span Study). The data from this population

were based on dose estimates made in 1986 (the Dosimetry System 1986 {DS86})

(Shimizu et al. 1987). To validate these assessments, additional human and animal

populations were reviewed. For example, thirty-four additional studies were cited in

support of the risk assessment for breast cancer.

Human Populations

The BEIR V Report estimated risks for breast cancer, respiratory tract cancer,

digestive tract cancer, leukemia and other nonleukemia cancers. The human populations

used in the risk assessment were chosen based on the type of cancer. For breast cancer,

four populations were used: residents of Hiroshima and Nagaski in 1950 (the Life Span

Study), most of whom were exposed to the atomic bomb; women examined by

fluoroscopy in Canada for tuberculosis from 1930 to 1952; women examined by

fluoroscopy in Massachusetts from 1930 to 1956; and women treated with radiotherapy

for postpartum mastitis in New York during the 1940s and 1950s. For respiratory and

digestive tract cancers, the population comprised residents of Hiroshima and Nagaski in

1950 (the Life Span Study). For leukemia, two populations were used: residents of

Hiroshima and Nagaski in 1950 (the Life Span Study); and people treated with

radiotherapy for ankylosing spondylitis in the United Kingdom from 1935 to 1954. A

third population, women treated with radiotherapy in several countries for cervical cancer,

may have been used in the leukemia risk calculations, however, the BEIR V report is










unclear on this point. For all other cancers (except leukemia), the study population was

comprised of residents of Hiroshima and Nagaski in 1950 (the Life Span Study).

Animal Populations

In general, the BEIR V report cancer risk assessments considered animal

populations only when necessary to validate or understand data from human populations.

Animal studies raise numerous problems, including extrapolation of results obtained under

experimental conditions to the conditions relevant to population exposure, such as dose

rates, fractionation, and other variables; and extrapolation from an experimental organism

in which radiation effects may be estimated with some confidence, to humans, because

organisms differ in radiation sensitivity.


Populations for Determining Genetic Risk


The assessment for genetic risk relied on animal (especially mouse) data to

supplement human data. To determine human genetic risk by extrapolating from animal

data, three assumptions were made: the amount of genetic damage induced by a given

type of radiation under given conditions in the animal species was the same in human germ

cells; biological factors such as sex, germ cell stage, and age, and physical factors such as

quality of radiation and dose rate, similarly affected genetic damage in the animal species

and in humans; and the relationship between low- linear energy transfer (LET) radiation

and frequency of genetic effects was linear at low doses and low dose rates. Genetic

effects, by definition, require that at least one generation pass before they are expressed,

and their expression is affected by the exposed population's sex, age, and probability of

having children. Genetic risks determined from human data are based on the assumption

that all of the exposed population was of reproductive age and wanted to have children.

In the irradiation of an entire population, the reproducing people are a fraction of the total,

and damage to the germ cells of the nonreproducing people in the population does not









pose a genetic risk. When the irradiation is neither random nor uniform, as is true of the

available human populations utilized in the risk assessment, a reduction factor is required

to adjust the genetic risk estimates.

Human Populations

The BEIR V report used several human populations, divided into three sets, to

assess genetic risk. The first set consisted of people with genetic disorders resulting from

spontaneous mutations. These disorders included dominant autosomal disorders, sex-

linked recessive disorders, recessive autosomal disorders, chromosomal abnormalities,

congenital abnormalities and other multifactorial traits. Multifactorial traits are a group of

disorders about which the exact mode of inheritance is unknown and include such diseases

as diabetes mellitus, gout, schizophrenia, affective psychoses, epilepsy, glaucoma,

hypertension, varicose veins, asthma, psoriasis, ankylosing spondylitis and juvenile

osteochondrosis of the spine. The second set consisted of people with genetic disorders

resulting from several specific spontaneous mutations that were used to calculate mutation

rates. The disorders included dominant autosomal disorders and recessive sex-linked

disorders. The third set was the Hiroshima and Nagasaki survivors and their children,

including members of a pregnancy termination study, a cytogenetic study of the children of

exposed parents, an investigation of rare electrophoretic variants in children of exposed

parents, and doubling dose studies.

Animal Populations

In general, mouse populations were used to assess genetic risk when human data

were unavailable or inappropriate. A few data points were taken from monkey and

marmoset studies. The animals in these studies displayed a specific endpoint, such as

dominant and recessive lethal and visible mutations, reciprocal and heritable

translocations, congenital malformations and aneuploidy.









Dose-Response Curves

A dose-response relationship, or curve, is determined by the change in effect

(response, the dependent variable) with increasing amounts of radiation (dose, the

independent variable). The relationship between dose and response is the primary problem

in predicting the health risks of radiation (Cohrssen and Covello 1989). Determining the

radiation dose has been detailed in Chapter 3. Determining the response to radiation is

difficult, and the details of the process are beyond the scope of this research. Although

somatic effects (such as cancer) and genetic effects are the major responses to radiation,

many intermediate conditions or specific endpoints may be used as measurements. Among

the many endpoints that are considered in nonhuman studies are clonogenic survival of

cultured cells and formation of tumors and death in test animals. In human studies, effects

such as chromosome abnormalities, enzyme aberrations, tumorigenesis and leukemia are

considered.

The effects of cancer and genetic damage are presumed to be stochastic; that is,

any level of irradiation increases the likelihood of inducing genetic damage or cancer (no

threshold relationship). Thus, the dose-response relationship of interest presumably begins

at the level of background radiation, which varies from place to place. This presumption

is currently under great controversy, as a threshold relationship is becoming more

frequently used. As these methodologies evolve, the quantitative risk predictions of this

research may need to be revisited.

Most experimental studies are conducted using high doses, because the effects of

low doses of experimentally applied radiation are indistinguishable from those of natural

background radiation in small experimental populations (UNSCEAR 1986)1. These high

doses are plotted against the responses to obtain a piece of the dose-response curve, and a

mathematical relationship is used to determine the shape of the curve in the low-dose


1 The UNSCEAR defines low dose as less than 0.2 Gy (20 rad).










region. Mathematical relationships explain the two differently shaped dose-response

curves most commonly applied to radiation data: linear and linear-quadratic., as shown in

Equations 1 and 2, respectively, where R is response, D is dose and a and (i are constants.
LINEAR: R=aD (Eq. 1)

LINEAR-QUADRATIC: R = a D + / D (Eq. 2)

The linear relationship extrapolates high-dose data along a straight line into the

low-dose region where response is directly proportional to dose. The linear-quadratic

relationship is effectively linear at low doses but begins to rise more steeply with

increasing dose because of a squared term in the mathematical expression. Thus, at high

doses, response is proportional to the square of the dose. At low doses, the linear

relationship predicts a greater response than does the linear-quadratic relationship and is

often considered as an upper limit. Thus, the linear relationship provides a conservative

estimate of dose useful for radiation protection purposes.

The BEIR V committee chose a linear dose-response curve for quantifying genetic

risk and most cancer risks from low doses of radiation because the epidemiological data

they reviewed were best described by this model. For leukemia, however, the BEIR V

committee used a linear-quadratic dose-response curve, which better fit the DS86

dosimetry data from the residents of Hiroshima and Nagasaki.


Dose-Rate Effects

Since most of the data on radiation effects come from high doses, they must be

extrapolated to low doses, which describe most human irradiation, and the plain film

examinations reviewed in this research. Evidence from medicine and biology suggests that

as dose and dose rate decrease, the effect per unit dose also decreases for low-LET

radiation (NCRP 1980). Thus, high doses and dose rates are more effective at causing










damage than low doses and dose rates. This difference is quantified by the dose-rate

effectiveness factor (DREF) or dose and dose-rate effectiveness factor (DDREF).

The effect of dose rate has been studied for numerous years. For low-LET

radiation, the effect depends on several factors, including repair of sublethal damage,

redistribution of cells in the mitotic cycle, and compensatory proliferation of cells during

protracted irradiation. For high-LET radiation, the dose-rate effect is much reduced. The

effect seems to apply both to cancer and genetic endpoints, although the effect is not

necessarily equal for either endpoint (BEIR 1990)

The dose rate effectiveness factor is estimated using mouse or human data. To

reiterate, with a linear-quadratic relationship, the dose response curve is approximately

linear at low doses at the low end of the curve. With a linear relationship, the dose-

response curve continues to be linear at low doses. Since it is extrapolated from high-

dose data along a straight line, it predicts greater response at a given dose than does the

linear-quadratic relationship. The ratio of these two responses at low doses, which is in

effect the linear extrapolation overestimation factor, approximates the dose-rate

effectiveness factor (Fabrikant 1990). These two models are shown in Figure 4-1. The

solid circles represent hypothetical data for an excess incidence of cancer observed at

relatively high doses. Curve A represents a linear extrapolation; curve B represents a

quadratic relationship between incidence and dose; curve C illustrates a threshold type of

response, which was previously discussed. While all three models fit the high-dose data

equally well, the risk estimates pertinent to this research in the low-dose region are quite

different according to which model is chosen for the extrapolation.











t
z


C-)
z


U,



X-RAY DOSE ~
LOW-DOSE HIGH-DOSE
REGION REGION


Figure 4-1. Various models used to extrapolate high-dose data on cancer incidence to the
low-dose region, so that risk estimates can be performed. Redrawn from: Radiation
Carcinogenesis in Man, United Nations Scientific Committee on the Effects of Atomic
Radiation (1977).

The most commonly cited range for dose-rate effectiveness factor is two to ten;

that is, radiation at high doses and dose rates is from two to ten times more effective at

causing damage than radiation at low doses and dose rates (NCRP 1980). Dose rate

effectiveness factors are applied with care. For example, as previously discussed, BEIR V

used a linear-quadratic relationship to model leukemia, which would already predict

reduced numbers of cases of leukemia at low doses and dose rates (BEIR 1990). The

BEIR V committee also chose to fit separate dose-response curves for each cancer

(Fabrikant 1990) and therefore did not use a dose-rate effectiveness factor. The factor

used in assessing genetic risk, which was based on the ratio of genetic risk from high to

low dose-rate irradiation of mice, was approximately three.


Population Transfer Coefficients


A number of uncertainties are involved in a risk assessment. Some sources of

uncertainty can be evaluated using conventional statistical theory and are incorporated into

risk assessment parameters such as dose-response relationships and risk projection










methods. Other sources of uncertainties cannot be captured by the usual statistical

techniques. One important uncertainty addressed by the BEIR V report was that inherent

in applying risks determined in one population to another population. Referenced in a risk

model as the population transfer coefficient, this issue was of major concern because the

BEIR V methodology's risk assessment was primarily based on results from the Hiroshima

and Nagasaki survivors applied to U.S. populations. The extrapolation required

assumptions about diets, industrial exposures, cancer rates and lifestyles in general. The

BEIR V committee recognized the population transfer issue to be a fundamental problem

and considerable source of uncertainty in estimating risks. The report chose to evaluate

this issue by "a consensus of expert opinion as to the uncertainty, expressed in a number

on a scale commensurate with ordinary statistical measures of variability" (BEIR 1990,

page 220).

The committee obtained this number by judging the range within which it was

believed to lie with 95 percent confidence. In this way, all types of uncertainty, both

statistically calculated and estimated by consensus, were evaluated together to obtain

combined measurements of standard error and confidence intervals. The committee thus

estimated the uncertainty in population transfer to be 20%.


BEIR V Cancer Risk Projection Method


Lifetable analyses using standard mortality tables that were modified to include an

additional incremental risk from radiation were used by the BEIR V committee to

calculate lifetime cancer risks from specific irradiation. Input data for the lifetable analyses

included radiation doses and parameters used in the assumed dose-response relationship

(Bunger et al. 1981).

To comprehend a lifetable analysis of a standard mortality table, consider a lifetime

irradiation at a constant annual rate. A lifetable analysis starts with a hypothetical










population of one million newborns, and the columns of the table provide the following

information shown in Table 4-1.


Table 4-1. Lifetable Analysis of a Standard Mortality Table
Number of Cancer Number of Number of deaths
surviving infants death rate cancer cases from other causes

The first column gives the number of infants expected to survive each age; the

second column gives the cancer death rate predicted by the dose-response curve; the third

column gives the number of cases of cancer deaths (which is the product of the first and

second columns); and the fourth column gives the number of deaths from causes other

than radiation based on mortality rates. The number of infants surviving to each age (first

column) less the number of radiogenic and nonradiogenic cancer deaths (sum of third and

fourth columns) is the number of survivors at the beginning of the next age interval. This

process continues with increasing age until the entire population is dead or until age one

hundred (BEIR 1990).

Quantifying excess cancer deaths from radiation is the key to projecting risks.

When the risk to exposed people exceeds the risk to unexposed people by the same

amount at all ages, the effect of the radiation is additive, and the mathematical expression

for this risk is thus an additive one. This is often called the absolute risk because at all

ages the excess risk is constant. When the risk to exposed people exceeds the risk to

unexposed people by a constant fraction, the effect of radiation is multiplicative. Also

known as relative risk because at all ages after irradiation, the relative risk or risk ratio is

constant, the multiplicative relationship is the mathematical expression of this risk

(Muirhead and Darby 1987). These two models are overly simplistic in projecting risk.

The BEIR V Committee permits the risk to vary as complex functions of time after

exposure throughout the individual's lifetime. This is demonstrated in Figure 4-2, which

illustrates the Committee's preferred risk model for leukemia.










t









ATTAINED AGE -+


Figure 4-2. The risk of leukemia due to low LET radiation as a function of attained age.

Cancer risk projection requires knowledge of several parameters, including the

relationship between excess cancer risk and relative risk, the latency period or the time

from irradiation to the first expression of excess cancer risk, the plateau period or the time

from the first expression of excess risk until the excess cancer risk disappears, the age

distribution of the exposed population and the baseline pattern of age-specific mortality

rates from all causes and from the cancers under consideration, the age at irradiation and

the dose-response function. These parameters are brought together in the cancer risk

projection model used by the BEIR V Committee. The report used cancer risk projection

to provide several measures of risk, i.e., estimating the probability of radiation-induced

cancer death expressed as a percentage, the number of projected cancer deaths expressed

as deaths per thousand or million exposed people per unit dose, and the number of years

of life lost in an exposed population because of radiation-induced cancers. All of these

estimates, however, derive from a single measure of excess lifetime cancer risk chosen by

BEIR V, as discussed in the next section.
The BEIR V Committee chose to use only multiplicative methods to project

cancer risk. The measure chosen by this committee was excess lifetime cancer risk, which

is the increase in the lifetime probability that a person will die from a specific cancer as a










result of a specific irradiation. The method of lifetime excess risk estimation used in the

BEIR V report differs slightly from those previously used. In the BEIR V Report,

separate lifetime risks are estimated for an exposed population and for an unexposed

population. The unexposed population is assumed to be exposed to the same background

radiation as the exposed population. The excess cancer risk is simply the difference

between the two lifetime risks (BEIR 1990). The parameter estimates used for the BEIR

V cancer risk projections were obtained using AMFIT, a program developed for the

analysis of survival data. Further discussion of some of these parameters provides more

insight into the assumptions made by the BEIR V report and are reviewed in the next

sections.

Specific Cause of Death

As previously noted in the discussion on populations, the BEIR V report projected

risks separately for leukemia, breast cancer, respiratory tract cancer, digestive tract cancer

and other nonleukemia cancers. For leukemia deaths, the BEIR V report assumed a two-

year latency period. For deaths from other cancers, a ten-year latency period was

assumed.

Age of Population

The age distribution of a population at the time of irradiation must be specified in

order to predict the effect of that irradiation because some of the cancers used as

endpoints depend strongly on age at irradiation. For example, leukemia risks for people

exposed before age 20 are much greater than leukemia risks for people exposed later in

life (Vaeth and Pierce 1990) and risk varies as a complex function of age and time since

irradiation (Thomas, Darby et al. 1992). For the cancers with the longer latency periods,

there is more uncertainty in the application of the BEIR V risk models. Since there is

nothing available that is more advanced than BEIR V, the BEIR V methodology was










utilized, recognizing that these results may need to be revised if the BEIR V models are

revised.


BEIR V Genetic Risk Projection Method

The BEIR V report did not provide a direct estimate of the risk of total genetic

damage, stating that these estimates were highly uncertain because they did not include

allowance for genetic diseases of complex etiology that may be caused by multiple factors.

The report suggested that these diseases make up the largest category of genetically

related diseases and that further research was required before these probabilities could be

estimated accurately. The report did provide estimates of genetic effects for other types

of genetic disorders, however, the performance of these calculations are beyond the scope

of this research. This research will only utilize the BEIR V methodology to estimate the

risk of radiation induced cancer utilizing the equations detailed in the following section.


Calculating the Relative Cancer Risk from Pediatric Diagnostic X-Ray Procedures

The BEIR V report's general expression for calculating the total cancer risk,

including natural and radiation-induced, to a population is given in Equation 3 (BEIR

1990).


A (d)= [ + f(d)g(fl)] or A (d) = + f(d)g(fl)A (Eq. 3)


where X0 is the individual's age and gender-specific mortality rate for a given type of

cancer in the absence of a radiation exposure other than natural background (or absolute

age specific cancer risk to the unexposed population);f(d) is a function of dose equivalent

in Sievert; g(P) is the excess risk function for a specific cancer that depends upon gender,

age of the individual, age at exposure, and time since exposure; and X(d) represents total









fatal cancer risk. The second term on the right of Equation 3, [1 +Ad) g(f)], therefore,

represents the radiation-induced fatal cancer risk.

The dose-response function,fd), depends upon the type of cancer involved. The

equations forAd), taken from BEIR V (BEIR 1990), are:


Leukemia:


Ad) = 0.243d+ 0.271d'


Respiratory cancer: Ad) = 0.636d

Digestive cancer: Ad) = 0.809d

Other cancer: fd) = 1.22d

Female Breast Cancer: Ad) = 1.22d

Similarly, the radiation -induced cancer risk depends upon a number of factors that

are incorporated into the excess risk function that has been discussed previously. In the

following equations for the excess risk function g(f), E represents the age at exposure,

and T represents the number of years following exposure. Only the equations applicable

to a one-year-old patient simulated in this research are presented.

For males:

A. Leukemia (latent period = two years)

E < 20; T < 15: g(f) = exp(4.885) = 132.3

B. Respiratory cancer (latent period = ten years)

g(3)= exp[-1.437 ln(T/20)]
C. Digestive cancers (latent period = ten years)

E <25: g() = exp(0) = 1.0

D. Other cancers (latent period = ten years)

E < 10: g() = 1.0

For females:

A. Leukemia (latent period = two years)

E < 20; T < 15: g() = exp(4.885) = 132.3










B. Respiratory cancer (latent period = ten years)

g(P) = exp[-1.437 ln(T/20) + 0.711]
C. Digestive cancers (latent period = ten years)

E < 25: g(p) = exp(0.553)= 1.74

D. Other cancers (latent period = ten years)

E < 10: g() = 1.0

E. Breast cancers (latent period = ten years)

E < 15: g() = exp[1.385 0.104 In(T/20)- 2.21 n2(T/20)]

The values ofg(P) were determined for each gender for an exposure that occurs at

an age of one year and the time post-exposure was chosen to be five years past the latency

period for each different type of cancer. The five year post-latent time period was chosen

by plotting g(B) as a function of time for each cancer and gender, as shown in Figures 4-3

through 4-9. These illustrations only extend to 25 years, but the elevated risk continues

further into the future. The five year post-latent time period was chosen as representative

of all the cancer models but was initially based on the leukemia cancer model because that

is approximately in the middle of the time interval of maximum risk for leukemia, as shown

in Figure 4-3.



150

100

50


0 5 10 15 20 25 30
Time (years)

Figure 4-3. Time dependent risk for exposure at age equal to one year for both male and
female leukemia models.













2.5
2
1.5


0.5
0
0 5 10 15 20 25 30
Time (years)

Figure 4-4. Time dependent risk for exposure at age equal to one year for male respiratory
cancer model.


0.8

0.6

| 0.4

0.2
0
0 10 20 30
Time (years)


Figure 4-5. Time dependent risk for exposure at age equal to one year for female
respiratory cancer model.











1.2

0.8
0.6
0.4
0.2
0
0 5 10 15 20 25 30
Time (years)

Figure 4-6. Time dependent risk for exposure at age equal to one year for male digestive
cancer model.


1.5


0.5
0
0 5 10 15 20 25 30
Time (years)


Figure 4-7. Time dependent risk for exposure at age equal to one year for female digestive
cancer model.





1.2

0.8
9 0.6
S0.4
0.2
0
0 5 10 15 20 25 30
Time (years)

Figure 4-8. Time dependent risk for exposure at age equal to one year for both male and
female other cancer models.












3
2.5
2
1.5

0.5
0
0 5 10 15 20 25 30
Time (years)

Figure 4-9. Time dependent risk for exposure at age equal to one year for female breast
cancer model.

The values offtd) were determined utilizing the effective doses calculated in

Chapter 3, rather than dose equivalent, since effective dose is the most current and

comprehensive measure. The values ofg(P) were then multiplied by the appropriate value

offd) and the relative risk predicted by the [1 +f(d) g(p)] term in Equation 1 was

determined using these variables for each procedure simulated. The calculation of the

relative risk for specific pediatric exams are performed in Chapter 5.














CHAPTER 5
RESULTS AND DISCUSSIONS


Facility Approach to Handling Special Concerns of Pediatric Patients

The child is not a small adult. This aphorism is a mantra for any discussion of

pediatric radiology; it is particularly pertinent to the specifics of technique. Most general

diagnostic radiologists and radiologic technologists are uncomfortable examining an infant

or young child. Unfortunately, this uneasiness may be transmitted to the pediatric patient

and frequently to the parent. The result is often an inadequate examination that is either

confusing or uninterpretable and requires retakes, ultimately yielding an increase in

radiation dose to the patient (Kirks and Griscom 1998). Pediatric imaging is no better

than its techniques and technologists. Thus, special approaches are required to handle

pediatric patients.
Children are frequently apprehensive in the hospital setting. These feelings are

compounded by fear of the unknown and the pain so often associated with doctors and

hospitals. As a result, not all technologists enjoy working with children; many become

frustrated by the lack of cooperation of infants and by the time required for pediatric

examinations, and there are, therefore, dedicated pediatric technologists. All of the

pediatric technologists involved in the site surveys appeared to be conscientious and

dedicated individuals who enjoyed working with children and had sufficient patience but
firmness to develop the rapport to handle pediatric patients. Reducing the child's fright

and obtaining his or her trust is of great benefit to the patient psyche and adds to the
technologist's ability to carry out high-quality examinations.









There are many different ways of successfully approaching a child, and certain

basic guidelines were observed during the site surveys that appeared to be adapted to

individual technologist styles and personalities. Of greatest importance is obtaining the

pediatric patient's trust. Obtaining trust can be difficult with any child but is especially

difficult with a child who is ill and suddenly finds herself, or himself, in a strange

environment. Creating an environment in which a child feels unthreatened and

comfortable is a challenge to hospital designers. Children enjoy stimulating surroundings

and require something to occupy their time while waiting for a procedure to be performed.

The environment must accommodate the parent's needs in addition to those of the child.

Since the first area encountered in a radiology department is usually the waiting room,

furniture appropriate to both parents and children should be available. For the

departments in the site survey that had dedicated pediatric facilities, an area equipped with

tables and chairs to accommodate children's activities was commonly found. Unbreakable

toys, puzzles, games, coloring books, crayons and storybooks were observed in all of the

surveyed facilities. In the majority of surveyed facilities, the room commonly used for

pediatric examinations had a mural painted on the wall or a myriad of stuffed animals on

the shelves to provide a soothing, entertaining atmosphere for the child. One of the

facilities visited had the x-ray equipment itself painted in a jungle motif and the table and

lift decorated to resemble a boat; patients were told to relax and enjoy the jungle boat ride.

Most pediatric rooms also carefully kept all medical paraphernalia out of sight but had

accessory equipment such as sponges, sandbags, and restraining devices readily accessible

from the tableside.

All of the pediatric technologists interviewed indicated that the key to establishing

rapport with a child is truth and honesty. As children are not only inquisitive, but very

perceptive, they should never be lied to. All of the technologists attempted to establish a

good cooperative relationship with the child by initiating a conversation with the child

about things that interested him or her. Chatting often enables the child to relax and









increases their willingness to help with the study. The technologists always explained the

procedure fully to the patient no matter how young the child was, in words that could be

understood. The technologists felt this knowledge not only helped to lower the patient's

anxiety, but also increased their credibility. Children like to be talked to and feel reassured

and comforted by participating in an interesting conversation. This technique also worked

with infants, who seemed to feel more secure when they heard a friendly voice.

A major aid utilized by all the surveyed facilities to decrease parent and patient

anxiety was to furnish them with a simple, printed explanation of the procedure when the

appointment is initially made. The technologists felt this proved to be a great help in

getting the patient to relax and be cooperative. Scheduling the appointment to coincide

with the child's routine was also important, although obviously not always practical. All

technologists expressed the preference to not x-ray children under the age of five between

noon and 4:00 P.M., as that is when most children are eating lunch and taking naps. The

technologists preferred to perform the procedures in the morning when the children were

rested, refreshed, not a lot of doctors had poked at them, and nothing really overwhelming

had happened to them yet. Children cannot handle the procedure as well later in the

afternoon because they are tired, stressed out and they have reached their limit for the day.
In obtaining the child's cooperation, it is often helpful to give him/her a small

degree of control over the circumstances. For example, a teddy bear or a security blanket

may be placed as the child wishes, or the choice of a particular Band-Aid or color of

hospital gown may give the child the feeling that he/she can still influence this new

environment. Another method of helping children feel in control of the situation is to tell

them what they're going to do during the exam. The most successful technologists

observed would say "You're going to stand up here and do this, then you're going to turn

around and do that, I'm going to do this, and then you're finished!" rather than "Come on
in here and let's take some pictures." Another example often recalled by the technologists

included emphasizing what's positive, e.g. asking a child to show them how long they










could hold still rather than telling the child "Don't move." It is worthwhile for the child to

understand that he/she is an active participant in this important procedure that is being

performed on his/her behalf. Children often want to help adults, and the sick child is no

exception. The phrase "Now I need you to help me" was heard frequently during the site

surveys.

Parent involvement in the procedure varied from site to site and appeared to be a

controversial issue. At most of the facilities, parents were invited to be present in the

radiography suite for all plain film examinations, as most young children are more

cooperative during radiographic procedures when a parent is present. Separation from

parents can be very stressful for young children and the presence of the parent may make

the child more cooperative by diminishing the fear of being deserted in a strange place.

During the explanation of the exam, the technologist can determine the child's response to

the new environment and decide which parent will make the most effective assistant. It

was common to invite only one parent to accompany the patient into the radiographic

suite. A careful explanation of the procedure enhances the ability of the parent to assist

the technologist and provides reassurance to the child. Parents sometimes feel guilty that

their child has suffered an accident or illness and allowing them to assist may help to ease

their anxiety as well. The technologists also made it clear that if the parent became upset

with the procedure or were disruptive to the achievement of good rapport with the child,

they would not hesitate to ask them to leave the room. The technologists indicated that

the possibility that a parent may be asked to leave is often sufficient encouragement for the

child to cooperate in the study, as is the thought of having to repeat the procedure. The

technologist also made it clear to the child that the examination he/she is undergoing is

necessary and inevitable and that he/she has no choice in the matter. The idea that the

technologist is "the boss" was also made clear to the child. The technologists routinely

stressed the importance of immobilization to the parent. If immobilization devices are

used, the parent can assist in placing the child in the device, although most technologists









seemed to prefer to do this themselves so that the parent just provided moral support and

could "come to the rescue" when the procedure was over. Parents can also demonstrate

to the child what will take place during the exam. The technologists indicated that many

children balk at instructions from an instinct of self-preservation, as children will not turn

their backs to complete strangers in complete medical settings, especially if they have had

rectal exams, lumbar punctures or shots Getting the child into the appropriate position

was often accomplished with the use of stickers on the wall at the point where children of

differing heights would be looking. The children were then told to look at and count the

stickers appropriate to their height. Often, animal stickers would be scattered about the

mural previously discussed. The children are then instructed to try and spot as many

stickers as possible and choose a favorite, they are then told to hold very still because if

they move, the animal sticker will run away. Bargaining with lollipops and stickers is a

common technique (however, many children possess uncanny negotiating skills). Many

such games were observed. Of additional benefit to the technologist, the parent can serve

as an extra set of hands and eyes to ensure the child's safety while on a radiography table

or in a restraining device, since toddlers are very active.

Finally, the child needs to be rewarded for good behavior and for contributing to

the success of the exam. The technologists felt this was important for symbolic value and

hopefully left the child with a relatively good feeling about a potentially negative

experience. Verbal praise was observed to be administered copiously throughout the

procedure and subsequently in the parent's presence at the completion of the exam. To

quote Mary Francis Sheppard, Supervisor of Pediatric Radiology at Shands at UF and lead

pediatric radiologist, "It's of great benefit and costs nothing." All facilities also distributed

a variety of stickers, lollipops, coupons, or small toys.

Younger children are sometimes inconsolable and will cry or struggle even under

optimal circumstances. In these situations, it was observed that performing the exam

quickly and efficiently is the best thing that can be done. Pacifiers appeared to be helpful,










as was a soothing continuously talking voice. It was observed that the technologist would

always talk to the child, even if he/she was screaming, crying, looking away, or pretending

to talk to someone else. Frequently, the children who seemed to be ignoring the

technologist were actually paying close attention. A common ploy used by the

technologist would be to keep asking the child questions during all the screaming and slide

in the question if they wanted to go home and if they answered, then the technologist

knew they were listening. Although most parents would tell their child to not cry, the

technologist would tell them that crying is preferable to biting, kicking or spitting as a

method to relieve their stress.

To consistently obtain high-quality radiographs in agitated children is a technically

demanding task, but the overall observation from the site surveys was that success was

possible with thought, care, time and patience. The following poem by pediatric

radiologist Leonard E. Swischuk, M.D. (1997), was posted in a majority of the surveyed

facilities and accurately depicts the approach a facility should follow with pediatric

patients.
A bundle of movement so awkward to hold,
Crying and crying for minutes untold.
Perpetual motion, so hard to contain,
Your charisma and patience, it truly can strain

Your very first thought may prompt a retreat,
You'll want to give up and concede to defeat.
But before you pack up and go screaming away,
Just think for a moment, this babe needs you today.

Hold him awhile, help him adjust,
Restrain his momentum, it's almost a must.
You'll not really hurt him, if his arms you must bind,
Just stay in command, be gentle and kind.

There is nothing so fine as to take a babe home,
And nothing so hard as to leave him alone.
So help little Jack, and somebody's Jill,
Their mothers and fathers sure hope that you will.









Patient and Examination Trends


Although the workload distribution of examinations were significantly different

between hospitals, the same examinations tended to predominate in each hospital. As

shown by the survey data in Appendix C, the numerical workload was dominated by the

data for the hospitals with the most beds and any statistical comparison among the

hospitals would be of little value. Looking only at the examinations identified from the

initial survey at Shands at UF, it was seen that these examinations listed in Table 2-4 were

represented in each hospital sample. The purpose of this survey was only to characterize

the examinations that were most commonly employed and not to establish their precise

frequencies.

In adult examinations, the assumption that the field size equals the film size is

usually made for organ dose calculations. This assumption is not representative of

pediatric radiography, where an unexposed margin was seen on the majority of films in the

various hospitals surveyed. The field sizes used on the phantom in this survey represent

the fields used in actual clinical practice

This section illustrates the exams included in the site survey in each of the figures.

The left hand illustration is an actual patient x-ray obtained from Dr. Jonathan Williams'

teaching and case file and the right hand illustration is the comparable view of the one-

year-old anthropomorphic phantom. Note that the dosimeters, leads and drill holes are

frequently visible in the phantom images.

The anatomical features shown in the projection in Figure 5-1 demonstrate the

petrous ridges that are projected through the lower third of the orbits. The organs of

hearing and balance are housed in the petrous pyramids. The petrous ridges are the upper

border of these pyramids.




Full Text

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PREDICTED RADIATION DOSE AND RISK ASSOCIATED WITH PEDIATRIC DIAGNOSTIC X-RAY PROCEDURES By KATHLEEN M HINTENLANG A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1998

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Copyright 1998 by Kathleen M Hintenlang

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This dissertation is dedicated to my daughter Lauren Lea Hintenlang and my son, Hunter Austin Hintenlang for bringing the goals of this research that much closer to home To my husband David je t aime

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ACKNOWLEDGMENTS The undertaking of this dissertation reminded me of the following koan : When the mouth wants to speak about it words fail When the mind seeks affinity with it thought vanishes I would like to express my deepest appreciation and gratitutde to the following people who made the thoughts and words come together : to Drs Larry Fitzgerald and Tom Crisman at the University of Florida for their unending support to Dr Randy Carter in Statistics without whom statistics would be numbers with no physical meaning and to Drs Emmett Bolch and Jon Williams for their continual guidance Again and always immortalis ago gratias vobis agamque I would also like to thank the Shands at UF radiology staff for their encouragement and assistance Additional recognition is due Drs Wes Bolch and David Hintenlang ; with their assistance my idea germinated into a seed and then sprouted many branches I would like to acknowledge the support I received from the Children s Miracle Network and the Shands Medical Guild Sincere appreciation is extended to my director in the EH&S Division, Dr Bill Properzio and to my assistant director, Don Munroe not only for the professional development but also for the growth of a fast friendship Heartfelt thanks go to my own staff in the Health Center office I would like to extend my greatest thanks to my family : Mom and Dad Tom and Rachael Rob and Terry and Mike and Venessa, for their continued love and support Finally my most sincere and personal thanks go to my husband David for his loving patience understanding and staunch encouragement To quote the words written on a monastery wall in the Middle Ages : 'The book is finished Let the writer play .'' l V

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TABLE OF CONTENTS page A CKN" 0 WLEDGMENT S .............................................................................................. iv LIST OF TABLES ................................................................................. ......... ................... 'Vl.11 LIST OF FIGURES ........................................................................................................ xi ABSTRACT ................................................................................................................. xiv CHAPTERS 1 INTRODUCTION AND BACKGROUND .. .......................................... .................. 1 General ................. .................................................................................................... 1 Pediatric Radiology as a Subspeciality ......................................................... ............... 3 Rationale ................................................................................................................... 6 Adult Organ Doses in Plain Film Radiography ...................................................... 8 Pediatric Organ Doses in Plain Film Radiography ................................................. 9 Calculation of Energy Imparted in Diagnostic Radiology .................................... 11 Phantoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Mathematical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Anthropomorphic .. ............................................................................................ 14 Radiation Detection Instrumentation ........................................................................ 16 Gas Filled Ionization Chambers .......................................................................... 16 Semiconductors .................................................................................................. 16 Determination of Risk .............................................................................................. 18 Significance and Objectives ...................................................................................... 19 2 PATIENT AND EXAMINATION TRENDS OF PEDIATRIC X-RAY PRACTICES ........................................................................................................... 22 Shands at the University of Florida ........................................................................... 22 Ten Florida F acili ti es ................................................................................................. 2 6 Exam Simulations ................................................................................................ 28 V

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AP skull ....................................................................................................... 3 0 Lateral skull ... ............................................................................................. 31 Tow nes skull ................................................................................................ 3 2 Waters sinus ................................................................................................. 3 3 AP ce-rvical spine ........... ... .. .. ................... .. ......... ........ .. ... .. ..... .......... 3 3 Lateral ce-rvical spine ............... .................................................................... 3 3 AP thoracic spine ............................................. ........................................... 34 Lateral thoracic spine ................................................................................... 3 4 AP lumbar spine ........................................................................................... 3 5 Lateral lumbar spine ..................................................................................... 3 5 AP abdomen ................................................................................................. 36 AP pelvis ...................................................................................................... 3 6 AP bilateral hip ............................................................................................. 3 6 AP PA and lateral chest ............................................................................... 3 7 Survey Data ...... .. ..... ..... .. .. .. .. . ... ..... ...... ..... .. .. ... .. ........................ .. .. ...... 40 3 RADIATION :MEASUREMENT EQUIPMENT AND TECHNIQUES ................... 42 One-Year-Old Anthropomorphic Phantom ... .. .. .. ............... .. .. ...... ....................... 42 Metal Oxide Semiconductor Field Effect Transistor (MOSFET) Dosimetry System ................................ .. .. ...... ........ .. .. .. .. ......... ......... .. .. ..... ..... .. ..... 46 Theory of Operation ................... . .. ................... ........................ .. . ... ..... . ...... 46 Characterization of High Sensitivity MOSFET Dosimeter .. ............................... 48 MOSFET Placement .................................................... .................. .................. 50 Measurement of Absorbed Dose ......................................................... ........ ...... 5 5 Sensitivity An.alysis ............................................................................... ............. 5 6 Calculation of Effective Dose ............................................................... ............. 5 8 4 RISK ASSESSME.NT ................... .. .. ...................... .. .......................................... 60 General ............................ ............ ..... .. .. ..... ... .................. ..... .............................. 60 Components of a Risk Model ................. ..... .. ............ ............... ........................... 60 BEIR.. V Methodology ........................................... .................. ... .. .. ........ .. ........ 62 Populations for Determining Cancer Risk .............................. ... . .. .. .. .. ..... ...... 62 Human Populations ............... ................................. .................................... 62 Animal Populations ........ .. ...... ................................................................... 63 Populations for Determining Genetic Risk ..... ................................. .................. 63 Human Populat ions .................................... ......... ........ .. ............................. 64 .Animal Populations ........................................................................... ..... ..... 64 Dose-Response Cu-rves ............................... ........................ ........ .. ......... .. ..... 65 Dose-Rate Effects ........................................ . ...................................... ............ 66 Population Transfer Coefficients ............................................ ............................ 68 BEIR.. V Cancer Risk Projection Method ............................................................ 69 Specific Cause of Death ............................... .. ..... ....................................... 72 Age of Population ..... ............................................. ... .. .. ........................... 72 BEIR.. V Genetic Risk Projection Method ..................................... ........... ........ 73 VI

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Calculating the Relative Cancer Risk from Pediatric Diagnostic X-Ray Proc edures ......................................................................................................... 73 5 RESULTS AND DISCUSSIONS ............................................................................ 79 Facility Approach to Handling Special Concerns of Pediatric Patients ....................... 79 Patient and Examination Trends ....... ....................................................................... 8 5 Generators .................................................................. ................................. 93 Exposure Time .......................................................... .. ................................. 94 Focal Spot Size .............................................................................................................................. .......... .......... 95 Additional Filtration ........................................................................... ......... 95 Gt-ids ...................................................................................................... ...... 96 Cassettes ......................................................... ............................... ............. 97 Film-Screen Combination ..... ................ .. : ..... .. ......................................... 98 SourceImage Distance (SID) ....................................................................... 9 8 Automatic Exposure Control ........................................................................ 98 Field Size and Collimation ............................................................................ 99 Radiographic Film Quality .......... ............................................................... 100 Repeat .Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I 00 Radiation Protection ................................................................................... 102 Organ Doses per Entrance Skin Exposure and Effective Doses ............................... 103 Relative 'Risk .................................................. ....................................................... 111 6 CONCLUSIONS ............................ ........... ... ......................... ............... ............ 115 Site Surv-eys ........................................................................................................... 115 Phantom Measurements ......................................................................................... 118 Effective Dose and Risk Predictions ....................................................................... 120 APPENDICES A NUMBER OF EXAMS FOR PEDIATRIC PATIENTS UNDER 16 YEARS OF AGE ................................................................................................................ 121 B EXAMFREQUENCYFORPEDIATRICPATIENTS UNDER 16 YEARS 0 F A GE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 13 0 D FROM FACILITY SITE S"UR.'VEYS ................................................................................................................ 136 D AVERAGE MASS ENERGY ABSORPTION COEFFICIENTS ........................... 147 E EFF ECTIVE DOSE AND RISK CALCULATIONS ..... ....................................... 150 LIST OF REFERENCES ............................................................................................. 223 BIOGRAPIIICAL SKETCH ............. ................................. ....................................... 232 vu

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LIST OF TABLES Table page 2-1 Age Group Corresponding to Phantom ............................................................... 23 2-2 Annual Number of Plain Film Chest X-Rays by Age Group ................................ 24 2-3 Percent Frequency of Plain Film Chest X-Rays ................................................... 24 2-4 Surveyed Examinations ...................................................................................... 26 2-5 Defined Locations of Anatomical Landmarks on Phantom Vertical Axis with the Origin at the Base of the Trunk ( cm) ............................. .................. 3 0 3-1 Tissue Weighting Factors for Calculation of Effective Dose ................................ 51 3-2 Position of the MOSFET Dosimeters Within the One-Year-Old Phantom ........... 53 3 -3 Percentage Active Bone Marrow and Bone Surface Associated with the Skeletal MOSFET Locations .... .. ......... ......................................................... 54 3-4 Sensitivity Calibration Factors (R/m V) at 70 kVp ............................................... 56 3-5 Conversion Factors Converting Exposure to Absorbed Dose .............................. 57 4-1 Lifetable Analysis of a Standard Mortality Table ................................................. 70 5-1 Effective Doses for Male and Female One-Year-Olds at Shands at UF .............. 106 5-2 Comparison of Effective Doses for Male and Female One-Year-Olds Among Facilities for Chest Exams .... .. .. ...................................................... 107 5-3 Comparison of Shands at UF and FDA Absorbed Dose / ESE ............................ 109 5-4 Comparison Among All Facilities and NRPB Effective Dose/ESD .................... 111 5-5 Relative Risk for Shands at UF Examinations ................................................ .. 112 5-6 Relative Risk for Chest Examinations Among All Facilities ............................... 113 Vlll

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C-1 AP Skull ...... ................... .............. ............................................................... 137 C-2 Townes Skull ................................................... ............................................. 137 C-3 Lateral Skull ..... ...................................................... ......................................... 138 C-4 AP Cervical Spine ........................... ..... ........................................................ 139 C-5 Lateral Cervical Spine 139 C-6 AP Thoracic Spine 140 C-7 Lateral Thoracic Spine ...................................................................................... 140 C-8 AP Lumbar Spine . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 C-9 Lateral Lumbar Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 C-10 AP Abdomen .................................... ......... ......... ................................. ..... . 142 C-11 AP Pelvis ............................. .. .. ... ............ .. ........................................ ....... 142 C-12 AP I-lip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. . . . . . . . . . . 14 3 C-13 Waters Sinus .......... .. ............................... ...................................................... 144 C-14 Lateral Sinus ............................................... ............ ..................... .. .............. 144 C-15 Lateral. Chest . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5 C-16 AP Chest ............................................................................................................ 145 C-17 PA Chest .. ..................................................... . .. .. ...... .. ... ................ ...... ................ 146 C-18 Non-Exam Specific Operational Data ............................................................. . 146 E-1. AP Skull .......................... .... .. .......................... ............... ............... ............... 151 E-2 AP Skull with Thyroid Shield ............................................................................ 153 E-3 PA Skull .......... ..................... .......... ..... ........................................................ 155 E-4 PA Skull with Thyroid Shield ................ ......... ................................................... 157 E-5 Lateral Skull ...... .................................................................... .......................... 159 lX

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E-6 Townes Skull ......................................................................................................................................... 161 E-7 AP Cervical Spine ............................................................................................ 163 E-8 Lateral Cervical Spine .. .................................................................................................................. ....................... 166 E-9 AP Thoracic Spine .. ............................................................................................................................ 169 E-10 Lateral Thoracic Spine .. .................................................................................................................... 172 E-11 AP Lumbar Spine ............................................................................................. 1 7 5 E-12 Lateral Lumbar Spine ....................................................................................... 1 78 E-13 AP Abdomen Supine ........................................................................................ 181 E-14 PA Abdomen Supine ........................................................................................ 184 E-15 AP Abdomen Upright ....................................................................................... 187 E-16 AP Pelvis ............................................. 190 E 17 AP flip ............................................................................................................. 193 E-18 Waters Sinus .................................................................................................... 196 E-19 Lateral Sinu s ........................................................................................... .. ..... 198 E-20 AP Sinus .................................................................... ..................................... 200 E-21 AP Chest .......................................................................................................... 202 E-22 AP Chest with Thyroid Shield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..... 205 E-23 PA Chest .................................................................................................. ........ 208 E-24 Lateral Chest ................................................................................................... 211 E-25 LAO Chest ........................................................................................................ 214 E-26 ~O Chest ........................................................................................................ 217 E-27 RAO Che s t 220 X

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LIST OF FIGURES 2-1 Items frequently used for immobilization ........ .... .............................................. 31 2-2 Infant immobilized and supported by the Pigg-o-stat device for an upright chest film ............... ....................................................................................... 3 8 2-3 Toddler immobilized for an AP chest racliograph on the Tame-Em immobilizer ..................................... . ............. ................................................. 39 2-4 Infant immobilized for a left lateral chest radio graph on a Plexiglas immobilizer ...................................... ...................................................... ....... 3 9 2-5 Octagon board for immobilization ...................................................................... 40 3-1 One-year-old pediatric phantom ......................................................................... 4 5 3-2 Thomson and Nielsen Electronics Ltd MOSFET Patient Dose Verification System ............................................. ............................................................ 47 3-3 MOSFET dosimeters placed in position in prototype one-year-old phantom . ..... 52 4-1 Various models used to extrapolate high-dose data on cancer incidence to the low-dose region, so that risk estimates can be perfortned ......................... 68 4-2 The risk of leukemia due to low LET radiation as a function of attained age ....... 71 4-3 Time dependent risk for exposure at age equal to one year for both male and female leukemia models ......... .......................... ...................................... 7 5 4-4 Time dependent risk for exposure at age equal to one year for male respiratory cancer model ..................................... .......................................... 7 6 4-5 Time dependent risk for exposure at age equal to one year for female respiratory cancer mod el . .............................................................................. 7 6 4-6 Time dependent risk for exposure at age equal to one year for male digestive cancer model .............. .................................................................... 77 X1

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47 Time dependent risk for exposure at age equal to one year for female digestive cancer model ..................................................................... ............. 77 4-8 Time dependent risk for e x posure at age equal to one year for both male and female other cancer models ..................................................................... 77 4-9 Time dependent risk for exposure at age equal to one year for female breast cancer model ....................................................................................... 78 5-1 AP Skull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6 5-2 Lateral Skull ..... ........................ ................................................................... ..... 86 5-3 Townes Skull ................................ ............................................................. ....... 87 5-4 AP Cervical Spine .......................................................... .. .......... ..................... 87 5-5 Lateral Cervical Spine .............................................. ......................................... 88 5-6 AP Thoracic Spine ............................................................................................. 88 57 Lateral Thoracic Spine ....................................................................................... 89 5-8 AP Lumbar Spine ........................................................................................... ... 8 9 5-9 Lateral Lumbar Spine ...................................................................................... ... 90 5-10 AP Abdomen ...... .................................................. ............ .............................. 90 5-11 APPelvis ......... .. .................................................. ......................................... .. 91 5-12 AP Left llip .................................... ... .............................................................. 91 5-13 Waters Sinus .... .. ............................ .. .. ... ..................................... ... ............. 92 5-14 Lateral Sinus ................ .......................................................... .......................... 92 5-15 APChest ............................................................................................................ 93 5-16 Lateral Chest ...................................................................................................... 93 5-17 Range of kV p used for the 17 surveyed exams ........ ........... ............................... 94 5-18 Range of mAs used for the 17 surveyed exams : ..... ........................................... 95 Xll

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5-19 Range ofHVL ...................................................................................................... 96 5-20 Net lung optical densities for AP chest, PA chest and lateral chest films ............ 100 5-21 Repeat percentages per facility ......................................................................... 101 X11l

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Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy PREDICTED RADIATION DOSE AND RISK ASSOCIATED WITH PEDIATRIC DIAGNOSTIC X-RAY PROCEDURES By Kathleen M Hintenlang December 1998 Chairman : W Emmett Bolch Jr Major Department : Environmental Engineering Sciences The most effective method of assessing the risks from exposure to radiation is b y calculating the individual tissue absorbed doses and subsequently determining the effective dose The absorbed dose to a specific tissue has traditionally been difficult and time consuming to measure. The effective dose and overall risk are therefore difficult to calculate directly The problem is compounded in pediatric radiology where the patient is particularly sensitive to radiation effects and the body and organ sizes differ greatly from the common adult reference man This research developed and applied a new methodology that permitted rapid measurement of the effective dose from x-ray radiation, and the associated risks to pediatric patients for a variety of plain film diagnostic examinations The methodology XIV

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utilizes an anthropomorphic phantom incorporating direct reading MOSFET dosimetry allowing the rapid and simple determination of absorbed dose to individual organs The research integrated clinical examinations dosimetry measurements and BEIR V risk assessment calculations using a prototype anthropomorphic phantom of a one-year-old to quantify radiation doses delivered to pediatric patients in clinical radiology exams Site surveys were perfor1ned in ten facilities using several standard exams to determine variations in effective dose related to clinical practice Recommendations resulting from the site surveys were provided for the optimization of pediatric radiography procedures Quantitative studies for a variety of examinations were perfor1ned at Shands at UF The effective dose for these procedures ranged from O 1 mrem for an AP skull exam that utilized thyroid shielding to 9 2 mrem for an AP upright abdomen exam The relative leukemia carcinogenic risk ranged from 1 000041 for the skull exam, to 1 002732 for the abdomen exam, with corresponding excess risks from 10 6 exams of 0 005 and 0 3 leukemias per year respectively Effective doses and risks for various cancers from all surveyed exams were quantified These individual examinations provided a significant benefit to the patient with minimal risk This provided the basis for continuing research to quantify long-term risk assessment to pediatric patients as well as providing a clinical tool to evaluate the effective dose delivered to these patients from other current and emerging radiology imaging modalities xv

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CHAPTER 1 INTRODUCTION AND BACKGROUND General It is well established that diagnostic x-rays constitute the largest and most widely distributed source of man-made radiation exposure to the general population (NCRP 1987 1989) While infants and children constitute only about 10% of the total number of radiographic examinations (NCRP 1989) they are the segment of that population at higher risk from potential radiation effects First, their growing tissues are more susceptible to radiation effects than mature adult tissues (BEIR 1990) Second their skeletons encompass a greater fractional distribution of active bone marrow an organ of high radiation sensitivity (ICRP 1995) Third the greater post-exposure lifetimes of infants and children increase the possibility for any radiation-induced effects to manifest Fourth, children are known to have short attention spans and can be non-cooperative ; as a result they are subject to a greater number and/or longer exposures than adult patients Finally pediatric patients frequently have a larger portion of their anatomies located within the x-ray beam than adults in similar exams and projections In the course of their care these young patients may be exposed to a wide variety of x-ray examinations Conventional radiographs make up three quarters of pediatric radiological examinations perfonned (Griscom 1996) These examinations yield medical benefits and diagnostic inf ox 1nation which must be balanced against potential risks from patient radiation exposure With ever increasing improvements in clinical care survival rates for prematurely born infants have risen over the past decade As these individuals age, they frequently experience additional complications requiring a large number ofx-ray 1

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2 examinations from a variety of imaging modalities Consequently these patients may accumulate large radiation doses the effects of which have not been evaluated since few survived in earlier years Technological improvements that permit these newborn infants and young children to survive increase the need for clinical decision-making based on 4quantitative assessments of radiation risk The fundamental quantity of interest from these examinations is the cumulative absorbed dose to exposed organs Several studies have focused on average organ doses in adult patients undergoing radiographic procedures, either through computer simulation (Rosenstein 1976a 1976b, 1988 ; Jones and Wall 1985 ; Rosenstein et al 1992 ; Stem et al 1995) or physical measurement (Shleien 1973 ; Ellis et al 1975 ; Chen et al 1978) Nevertheless very little current information exists on organ doses from pediatric radiographic projections, particularly for technique factors common to U S practice (Beck 1978 1979 ; Rosenstein et al 1979 ; Zankl et al 1989 ; Hart et al 1996) The desire to perforrn a study of the current patient and examination trends in pediatric x-ray practices in the State of Florida and incorporate a direct and simple method to measure organ and effective doses in a pediatric phantom in order to perfo11n a risk assessment was the basis for this research An epoxy resin based anthropomorphic phantom of a one-year-old child constructed in companion research to this dissertation was utilized (Bower 1997) Site visits were perfor1ned at ten hospitals in the State of Florida Simulated examinations of a series of plain film radiographs were perfor1ned by pediatric x-ray technologists on the phantom Real-time Metal Oxide Semiconductor Field Effect Transistor (MOSFET) dosimeters were inserted into various organ locations in the phantom to obtain point dose measurements of the organ absorbed dose and effective dose measurements in real-time Subsequent risk assessment calculations were performed utilizing BEIR V methodologies In order to facilitate the development and transfer of scientific information for the improvement in the radiologic care of children the methods developed in this research can

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3 then be utilized to integrate the computational and advanced experimental components and determine organ doses and assess risks to various ages of pediatric patients undergoing a variety of modern diagnostic examinations to include fluoroscopy, computed tomography cardiac catheterization, computed radiography and digital radiography Pediatric Radiology as a Subspeciality The history of pediatric radiology is the story of the emergence of pediatrics and radiology as individual medical specialties the growth of each of these specialties and finally the fusion of these two specialties into the new subspecialty of pediatric radiology, or Roentgenology as it was called in the early days. Roentgen s discovery ofx-rays in November and December 1895 was announced to the world in January 1896 On February 3 1896 a fourteen-year-old boy who was thought to have broken his wrist two weeks earlier while skating on the Connecticut River was brought to Dartmouth College in Hanover, New Hampshire because they supposedly had one ofthe best collections of vacuum tubes in the western hemisphere at that time (Spiegel 1995) His wrist was radiographed with an exposure time of twenty minutes and the resulting image on the emulsion-coated glass plate '' showed the fracture in the ulna very distinctly ' In addition to what is considered to be the first clinical radiograph in America, it was also the beginning of pediatric radiology in this hemisphere In March of 1896 Dr E P Davis ofNew York City reported visualizing the trunk of a living infant and the skull of a dead fetus and also recorded images of a fetus examined in utero (Davis 1896) Shortly thereafter the first recorded observation of disease in children probably belonged to Professor Cox of McGill University Montreal Canada who used a thirty-minute exposure to find a needle embedded in the wrist of a girl of unstated age (Cox 1896) William G Morton at a meeting of the County ofNew York Medical Society held on April 27 1986 reported that he had already seen the fetal head in

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4 utero and predicted that the time was not far distant when the sex of the fetus in utero would be disclosed Roentgenographically (Caffey 1956) At this meeting Morton showed lantern slides of an entire fetal skeleton and used the terms ''inside-seeing or esography '' for Roentgen visualization In July, a publication listed conditions that the author had successfully shown by x-ray including pediatric cases of dactylitis and absence of the radii (Codmam 1896) Radiation injury to children apparently was recognized within a few weeks after the Roentgenology method was instituted, as Dr W V Gage (1896, page 307) of McCook Nebraska, reported '' erythema and finally sloughing of the region penetrated by the rays, which at present is the size of the hand '' in a child who was being studied for a foreign body in the stomach Although this episode was reported in the Medical Record of August 29 1896 Caffey stated that it is obvious that the actual Roentgen injury must have occurred many weeks earlier during the first months of 1896 (Caffey 1956) It is interesting to note that the spread of Roentgen's discovery was not just limited to large cities but was also utilized within months of his publication in a community as medically remote as McCook, Nebraska on the prairie which was still '' frontier country' at that time (population 2 346 by the 1890 census) In many of the early reports there appeared to be a disproportionate prevalence of pediatric cases probably because x-rays from the available tubes at that time could not penetrate larger subjects In addition a majority of the researchers in the initial trial period were not physicians Sosman (1951, page 552) observed that '' by 1900, the x-ray method was being used by physicists, engineers photographers some charlatans and a few honest physicians ''. Caffey added bicycle repair men and the entrepreneurs of circus sideshows to this observation After this initial burst of enthusiasm after Roentgen's discovery Caffey reports that American pediatric radiology lagged significantly behind the growth of both radiology and pediatrics and failed to progress until the 193 Os as demonstrated by the limited number of publications. In the Transactions of the American Roentgen Ray Society,

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5 number of publications In the Transactions of the American Roentgen Ray Society established in 1901 no pediatric subject was discussed until 1904 when Preston M Hickey of Detroit reported his Roentgenologic study of skeletal maturation (Hickey 1 9 04 1906) In addition to the decreased number of studies being reported, the majority of the case studies published represented superficial subjects Caffey reported that in 1903 Volume 20 of the Archives of Pediatrics published a total of only four papers on Roentgenologic subjects The most interesting one Caffey felt presented Roentgenologic data by A C Cotton purporting to show that wadding of thick diapers between the thighs produced lateral bowing of the femurs Caffey also reported that in the first volume of the American Journal of Diseases of Children in 1911 a study by Long and Caldwell on the relationship between carpal ossification and mental development was perfor1ned with Roentgen prints of the paired hands of twenty-nine subjects in which the authors concluded that 'we can find no relation between the carpal development and the quality of mind '' (Caffey 1956 page 440) Caffey noted with some sarcasm, that this conclusion has stood the test of time Griscom indicated that the focus was more on techniques and equipment at that time than on the medical components of the radiology of children (Griscom and Jaramillo 1995) The 1930s 40s and 50s showed a drastic increase in the number ofx-ray studies of large numbers of healthy children from birth through adolescence Due to the lack of normal standards Dr Arial George (1908 page 3 81) explained that '' A thorough knowledge of the normal human anatomy is absolutely necessary as are its variants The whole study of disease in children by the Roentgen method rests on this one point The mistakes in diagnosis by the Roentgen ray method will not be the fault of the Roentgen ray but the fault of those who are ignorant and who from lack of training are unable to interpret its findings .'' As a result Boyd perfor111ed studies of the normal thymus (1927) Lincoln, Hodges, and Josephi investigated cardiac size in healthy infants (Lincoln and Stillman 1928 ; Hodges 1933 ; Josephi 1935) Bouslog and Henderson studied the normal

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6 infantile gastrointestinal tract (Bouslog 193 5 ; Henderson 194 2) The nor1nal neonatal skull was studied Roentgenographically by Henderson and She1man (1946) Rotch called attention to the epiphyses as studied by x-rays to indicate the state of bodily maturity in no11nal standards of growth and development for various age groups (Smith 195 1 ) Caffey published several no1ms of the skeleton (Caffey 1956) All of these early attempts to establish no1 rnal values were open to criticism as they were based on studies of groups of infants and children It was felt that more accurate values could be obtained by longitudinal studies in which the same groups of children were investigated as they progressed from birth to maturity So, from 1925 through 1940 Maresh and Washburn perfor1ned serial Roentgenographic observations on one hundred normal infants and children to demonstrate the variation in the size and shape of the respiratory track (Maresh and Washburn 1940) Griscom indicated that at the second meeting of the Society of Pediatric Radiology in 1959 sixteen case studies were presented (Gri_scom 1995) About half dealt with plain films the remainder with intravenous urography barium studies, nuclear medicine and dosimetry This was the first instance where dosimetry for pediatric x-rays is mentioned in the literature. Dr Donald Darling from the Children s Hospital in Pittsburgh, presented a progress report entitled 'Measurement of Gonadal Dose in Routine Pediatric Radiological Practice .' Dr Darling indicated that results were never published from this study (personal communication, 1998) Rationale The organs to be considered in radiologic risk assessment were standardized by the International Commission on Radiological Protection in 1977 with the introduction of the effective dose equivalent (EDE) (ICRP 1977) Calculations of the EDE require knowledge of the absorbed dose ( total energy deposited per t1nit mass) to the following

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7 tissues : breasts lungs reproductive tissues ( ovaries or testes) thyroid active bone marrow skeletal endosteum and unspecified remainder tissues These absorbed doses or more specifically, dose equivalents 1 are then multiplied by tissue weighting factors (w T) which represent the fraction of total radiation risk ( cancer mortalit y and severe genetic damage) attributed to irradiation of that tissue The EDE is calculated as a summation of these weighted doses and thus represents a single radiation dose proportional to the total radiation risk of the exposure regardless of whether the irradiation is uniformly or nonunif ormly delivered This dosimetry concept was further expanded in 1990 with the introduction of the effective dose (E) in which tissue weighting factors were reassessed based on a more recent analysis of radiobiological effects (ICRP 1991) Additional weighting factors were also given for the esophagus stomach wall colon, liver skin and urinary bladder wall While originally defined for radiation protection purposes these quantities of EDE and E have been widely reported in the medical literature for both nuclear medicine procedures and for diagnostic radiology examinations Their intended use in medicine is to provide physicians with a unified quantity for risk communication and a quantitive means for procedure optimization As defined in ICRP Publications 26 and 60 the tissue weighting factors are specific only to populations of adults and should not be applied in the estimation of radiation risk to individual patients (Poston 1993) For use in risk communication and/or procedure optimization tissue weighting factors specific for children have been proposed by Almen and Mattsson ( 1996) The determination of organ doses in diagnostic radiology is typically a two-step process First an indicator dosimetry quantity is measured in the clinical setting Examples include the entrance skin exposure (ESE) the entrance skin dose (ESD) or the dose-area product (DAP) Second these indicator quantities must be multiplied by an 1 Dose equivalent is defined as the product of an absorbed dose and a radiation weighting factor which for photons is set to unity

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8 organ dose coefficient to obtain individual organ doses (i e mrad per R) (Rosenstein 1988) These conversion factors are obtained either through experimental measurement within physical phantoms or through computer simulations within mathematical models of the patient The specific procedures involved in obtaining the conversion factors utilized in this research are discussed in Chapter 3, Radiation Measurement Equipment and Techniques Adult Organ Doses in Plain Film Radiography The first systematic study of organ dose coefficients was published by Rosenstein in 1976 in Food and Drug Administration (FDA) Reports 76-8030 (Rosenstein 1976b) and 76-8031 (Rosenstein 1976a) In this study, the Fisher-Snyder mathematical model of the adult male was modified for use in determining organ doses for a variety of diagnostic x-ray projections This model was previously developed for estimates of internal photon absorbed fractions needed for nuclear medicine dosimetry (Snyder et al 1978) The model consisted of geometrical descriptions of eighteen internal organ s of the adult and included three distinct tissue compositions : soft tissue skeleton ( a homogenized mixture of bone and marrow) and lung (a homogenized mixture of soft tissue and air) While the model was developed as a description of Reference Man defined in ICRP Publication 23 (1975), it was a hermaphrodite in that it included both testes and a uterus and ovaries In order to reduce computational requirements, the following approach was utilized Organ doses were first deter1nined for parallel collimated beams of monoenergetic photons incident on the surface of the mathematical model Each photon beam was situated on one grid of a system of 4 cm x 4 cm grid elements superimposed upon the front surface of the model (AP projection) back surface of the model (PA projection) or on a plane just inside the arm bones (lateral projection) to simulate the actual conditions of exposure in which the arm is generally moved out of the primary

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9 beam Organ doses for a given examination (e.g AP chest) were determined by first summing the individual dose contributions from each grid element contained within the field-of-view, and then energy weighting these results for the x-ray spectrum of interest By using this procedure, beam divergence and air scattering effects were ignored and oblique views were not accommodated These data were subsequently used to produce a handbook providing organ doses per unit entrance skin exposure free-in-air (mrad/R) to the testes, ovaries thyroid and active bone marrow for sixteen projections and six beam qualities (HVLs of 1 5 to 4 0 mm Al) The field size was assumed to equal the film size in this study Limited experimental data were collected as part of the study using lithium fluoride thermoluminescent dosimeter's (LiF TLDs) in anthropomorphic phantoms A revision to this handbook was published in 1988 which expanded the number of projections considered to fifty-four In addition Cancer Detriment Indices were also reported for each exam based upon risk data contained in ICRP Publication 45 (1985) In the early 1980s, Gesellschaft fur Strahlen und Umweltforschung (GSF) in Germany (Kramer et al. 1982 ; Drexler et al 1984) developed their own male and female adult phantoms and the British National Radiological Protection Board (NRPB) (Jones and Wall 1985) further developed the Cristy (1980) modified versions of the original Snyder Medical Internal Radiation Dosimetry (MIRD) mathematical model (Snyder et al 1969) to assess organ doses to adults in diagnostic radiology Pediatric Organ Doses in Plain Film Radiography A comprehensive and systematic investigation of organ dose coefficients for pediatric radiographic projections was published by Beck and Rosenstein in 1979 as FDA Reports 79-8078 (Beck 1978 1979) and 79-8079 (Rosenstein et al. 1979) This study included a survey of five hospitals in the Baltimore-Washington area to determine the frequency and types of pediatric radiographic examinations perfot 1ned and the various

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10 technique factors employed in those exams such as kVp mAs field size SID and beam quality The survey data were subsequently used to perform computer simulations of the more common projections following methods similar to those employed in the adult report Three mathematical models developed at Oak Ridge National Laboratory by Hwang et al were utilized representing a newborn a one-year-old and a five-year-old individual (1976a 1976b 1976c) Twenty examinations were considered each representing at least one percent of the total number of exams in a given age group For each exam, organ dose coefficients (mrad/R) were determined for testes ovaries thyroid active bone marrow lungs and total body at one representative source-to-image receptor distance two field sizes (age dependent) and four beam qualities (HVLs of 2 0 2 5 3 .0, and 3 5 mm Al) As with the adult report limited experimental data were collected as part of the study using LiF TLDs in anthropomorphic phantoms representing a head and neck, and two phantoms corresponding to the Monte Carlo mathematical design : a one-year old and a five-year-old. Given the experimental uncertainties in the TLD measurements and the limited number of photon histories transported (60 000) the authors concluded that good agreement was seen between the two data sets To date no revisions have been made to FDA Reports 79-8078 and 79-8079 and these data are still widely used for dose estimation in pediatric radiology Several arguments can be made for revising and expanding the research of Beck and Rosenstein First while mathematical models did exist for a representative ten-year-old and fifteen year-old patient these two groups were notably absent in the final handbook Second, the input photon spectra used in these reports were for single phase generators while current radiology practice employs primarily three-phase constant potential and high-frequenc y x-ray units Third while the pediatric models of Hwang et al included twenty-six internal organs dose estimates were given onl y for the six organs listed above thus making calculations of EDE or E impossible Fourth, substantial revisions and improvements have

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11 been made to the ORNL pediatric model series over the past eighteen years, thus making the dosimetry of FDA reports 79-3030 and 79-3031 obsolete and somewhat inconsistent with current practice in radiology and in radiation protection (Cristy 1980 1987) In the Hwang et al 1976 series of pediatric models a large number of internal organs were simply scaled downward from the Fisher-Snyder adult model In 1980 Cristy reported that this procedure resulted in ' shifting and crowding'' of various internal organs in a manner which did not reflect actual anatomical growth trends (Cristy 1980) As a result a complete redesign of the ORNL pediatric model series was initiated resulting in the publication of new pediatric models by Cristy and Eckerman in 1987 These models were subsequently adopted for radiation protection dosimetry by the ICRP in 1989 (ICRP 1989) and for nuclear medicine dosimetry in 1988 by the MIRDOSE computer code maintained by the Radiation Dosimetry Infor1nation Center in Oak Ridge Tennessee (Stabin 1996) These models were the basis upon which a new MIRD family of mathematical models are being developed at the University of Florida in companion research to this dissertation Finally no new pediatric anthropomorphic phantoms have been developed that correspond to the changes made in the MIRD mathematical models The only other comprehensive source of organ doses for pediatric plain film exams is that produced by the NRPB in 1996 for technique factors specific to the United Kingdom and European Community utilizing the older 1987 version of the Cristy and Eckerman mathematical models (Hart et al 1996) Calculation of Energy Imparted in Diagnostic Radiology One may also estimate radiation risk for diagnostic procedures by measuring the total energy imparted to the patient for a given diagnostic exam (the integral dose) Extensive studies of energy imparted in diagnostic radiology have been performed by

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12 Huda and colleagues (Huda et al 1989 ; Huda and Bissessur 1990 ; Atherton and Huda 1995 1996 ; Huda and Atherton 1995 ; Gkanatsios and Huda 1997 ; Huda and Gkanatsios 1997) Values of energy imparted however in and of themselves do not provide important information on individual organ doses for a given projection or exam In hi s publications Huda proposed the use of approximate ratios of effective dose per unit energy imparted which in combination with energy imparted on homogeneous phantoms can be used to derive an estimate of the effective dose These ratios must also be obtained from previous Monte Carlo studies such as those perfo11ned by the NRPB (Shrimpton et al 1991 ; Hart et al 1994 1996) which use h e t e rogeneous anthropomorphic models of patients Huda has recently proposed a simple mass scaling of these ratios to yield effective doses to children undergoing CT exams (Huda et al 1997) An important limitation of this approach is that individual organ doses can never be recovered from a single value of effective dose and the risk from different diagnostic procedures cannot be compared when different organs are exposed It must be remembered that the effective dose is a weighted average of the individual organ doses where the tissue weighting factors are chosen based on the current knowledge of radiation cancer risk and other detriment This knowledge base changes with time and with changes in cancer mortality ; thus the tissue weighting factors are influenced by changing success rates in cancer treatment Consequently the tissue weighting factors are always subject to change whereas the individual organ dose for a specific diagnostic procedure is not It is for these very reasons that the l\1IRD committee of the Society of Nuclear Medicine has always maintained a focus on individual organ absorbed dose

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13 Phantoms Mathematical In 1994, companion research to this dissertation was initiated by Dr Wesley Bolch to couple the complete series of pediatric mathematical models of Cristy and Ecke11nan to the EGS4 radiation transport code (Nelson et al 1985) for external sources of radiation This was additionally performed as a task group effort of the Society of Nuclear Medicine s MIRD Committee to consider, for the first time, detailed transport of electrons and beta particles within internal organs for internal sources of radiation At ORNL the Cristy and Eckerman pediatric model series have been used extensively with ALGAM, a radiation code limited only to the consideration of photon transport (Cristy and Eckerman 1987). EGS4 allows for explicit treatment of coupled photon and electron transport (including bremsstrahlung production) and has been extensively utilized in both high energy physics and medical physics research To verify the coding of the pediatric mathematical models within the framework of the EGS4 code system several comparisons of specific absorbed fractions of energy were perfor1r1ed with the 1987 data published by Cristy and Eckertnan (Kodimer 1995) Excellent agreement was seen over a wide range of photon energies confirming the transport of photons in the Cristy and Ecker1nan models using EGS4 A new mathematical model of the adult head and brain has been published (Bouchet et al 1996) The model includes a detailed description of the skeletal system including the maxilla teeth mandible cranium and cervical vertebrae New regions in the brain model include the caudate nucleus, cerebellum cerebral cortex lateral ventricles third ventricle, lentifortn nucleus thalamus and white matter Other features include eyes and the thyroid enclosed within an explicit neck region (the original head region was modeled simply as an elliptical cylinder topped by half an ellipsoid with no representation

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14 photon transport, its exclusion artificially attenuates external photon sources depositing dose to the thyroid gland Work was initiated in late 1996 to produce a pediatric series of head and brain models based on modification of the adult model and data published on neural tissue growth trends In June of 1997 the MIRD committee also adopted a series of revisions to the Cristy and Eckerman family of phantoms (Bole~ personal communication 1997) These revisions included the addition of an esophagus a prostate gland a four-region kidney (to include a medulla, corte x, papillary and pelvic region) a mucosal layer within walled organs (GI tract gall bladder and urinary bladder) and the inclusion of a rectum separate from the sigmoid colon within the current models It is anticipated that upon completion of these revisions future work will include the Monte Carlo-generated doses being experimentally verified against the MOSFET dosimeter measurements within the various pediatric anthropomorphic phantoms Anthropomorphic ICRU Report 48 defines a phantom as a '' structure that contains one or more tissue substitutes and is used to simulate radiation interactions in the body '' ( ICRU 19 9 3 page 1 ) They are commonly used to investigate radiographic equipment image quality and dosimetric evaluations The complexity of phantoms ranges from very simple geometries representing singles tissues such as a slab of water simulating soft tissue or a sheet of copper simulating a chest to complex geometries with multiple realistic tissue substitutes for soft tissue lungs and bones Such complex phantoms are referred to as '' anthropomorphic '' because they simulate the size shape and composition of a human body to provide the same attenuation and scattering characteristics The majority of anthropomorphic dosimetric phantoms represent an adult man (Conway et al 1984 ; Constantinou et al 1986 ; Conway et al 1990 ; ICRU 1993) As

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15 previously indicated in the discussion of the mathematical models, a scaled-down adult phantom is inappropriate to simulate a child, since the organ growth of a child is a complex process which cannot be described by simply scaling the anatomy of an adult The anatomical geometry of a child varies greatly from that of an adult The weight of the head with respect to the total body weight is greater for a child than an adult, the trunk of a child is more cylindrical compared to the elliptical adult trunk, and certain internal organs such as the thymus gland are larger (Hwang et al 1976a) The percentage of extracellular water in children is larger and represents a higher percentage of the total body weight than in adults (Haschke et al 1981 ), and the concentration of certain minerals is lower in the skeleton of children (Haschke et al 1981; ICRP 1995) In addition, the skeleton of a child has more water and less fat than an adult skeleton (Cristy and Eckerman 1987) Furthermore the distinction between cortical and trabecular bone and the percent distnbution between yellow and red bone marrow change greatly as children age (Cristy and Eckertnan 1987) The anthropomorphic pediatric phantoms developed by Chen (Chen et al 1978) were constructed to represent identically the mathematical models of the one-year-old and the five-year old which again, were scaled-down versions of adult models Due to the lack of pediatric anthropomorphic phantoms in the research community and on the commercial market research was initiated to construct a prototype one-year old phantom at the University of Florida (Bower 1997) The one-year-old representation was chosen because a review of the examination frequency data provided by Shands at the University of Florida from the period 1990-present indicated that the majority of pediatric diagnostic x-ray examinations are of children in their first few years of life ; therefore a phantom of a one-year-old would be fairly representative of a large class of examinations In addition, an anthropomorphic one-year-old phantom has a mass of approximately 10 kg (21 lbs) which is easily manageable for construction and its ultimate use in field testing The prototype one-year-old anthropomorphic phantom developed by Bower (1997)

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16 utilized in this research is reviewed in detail in Chapter 3 Radiation Measurement Equipment and Techniques Radiation Detection Instrumentation A variety of detection instrumentation has been used to measure radiation exposure or absorbed dose These include gas filled ionization chambers radiographic film semiconductors and thermoluminescent detectors Gas Filled Ionization Chambers Ionization chambers have a response that is proportional to absorbed energy and therefore, they are widely used in performing dosimetry measurements Most ionization chambers are cylindrical with an air-equivalent wall and measure exposure When radiation interacts with the air in the detector ion pairs are created and collected generating a small current Since the Roentgen is defined as the amount of ionization in air measurement of this ionization current will indicate exposure The Keithley TRIAD Field Service Kit2 was used in this research to perform free-in-air exposure measurements in order to calculate entrance skin exposure (ESE) at the location where the x-rays are expected to enter the patient and characterize beam quality for the simulated x-ray examinations Semiconductors A semiconductor detector acts as a solid state ionization chamber whereby the ionizing particle interacts with atoms in the sensitive volume of the detector to produce electrons by ionization The elements in semiconductor materials fortn crystals that 2 Radiation Measurements Division of Keithley Instruments Inc ., 28775 Aurora Road Cleveland Ohio 44139 TRIAD Field Service Kit Model 10100A

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17 consist of a lattice of atoms that are joined together by covalent bonds Absorption of energy by the crystal leads to disruption of these bonds which results in a free electron and a '' hole' in the position formerly occupied by the valence electron This free electron can move about the crystal with ease The hole can also move about in the crystal e g an electron adjacent to the hole can jump into the hole and therefore leave another hole behind Connecting the semiconductor in a closed electric circuit results in a current through the semiconductor as the electrons flow towards the positive terminal and the holes flow toward the negative terminal. The operation of a semiconductor radiation detector depends on its having either an excess of electrons or an excess of holes A semiconductor with an excess of electrons is called an n-type semiconductor while one with an excess of holes is called ap-type semiconductor (Cember 1996) In order to assess point estimates of organ doses in the one-year-old phantom the Patient Dose Verification System designed by Thompson & Nielsen Electronics3 was utilized This system is composed of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) dosimeter arrays The MOSFET is a common microelectronic device It i s a layered device consisting of a p-type semiconductor separated from a metal gate by an insulating oxide layer Ionizing radiation forrns electron-hole pairs in the oxide-insulating layer of the MOSFET The applied bias then causes the electrons to travel to the gate while the holes migrate to the oxide silicon interface where they are trapped The trapped positive charges cause a negative shift in the voltage required to allow conduction through the MOSFET The shift in voltage is proportional to the radiation dose deposited, thus allowing the MOSFET to be used as a dosimeter (Hughes et al 1988 ; Gladstone and Chin 1991 ; V ettese et al 1996) This system was originally designed using standard sensitivity dosimeters to measure skin doses during radiation therapy treatments Characterization of high 3 Thompson & Nielsen Electronics Ltd ., 25E Northside Road Nepean, Ontario Canada K2H 8S1 Patient Dose Verification System Model TN-RD-50

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18 sensitivity dosimeters by Bower and Hintenlang (1998) for use in diagnostic radiological applications is detailed in Chapter 3 Radiation Measurement Equipment and Techniques Determination of Risk Radiation risks of diagnostic radiology in the pediatric patient are either deterministic or stochastic in nature Deterministic radiation injuries such as tissue injury or cataract production, occur when a number of cells are involved and a threshold dose is required Above the threshold the severity of the injury is proportional to the dose There is no evidence that deterministic injuries occur as a result of low-dose plain film procedures. Stochastic radiation injuries such as genetic effects and carcinogenesis are believed to be caused by injury to a single cell and typically a threshold dose is not required The probability of the injury is proportional to the dose, but the severity of the injury is independent of the dose If one assumes a linear relation without a threshold for such effects then any amount of radiation, including low-dose plain film procedures may potentially have an effect A more detailed discussion of the linear no-threshold (LNT ) theory is presented in Chapter 4 Risk Asssessment Risk models were developed to provide a method of predicting the risk of radiation induced genetic effects and carcinogenesis in relation to the natural incidence in an unirradiated population The epidemiological ideal of following several populations over time was not practical ; therefore statistical models were used to derive risk estimates Radiological risk assessments and resulting risk estimates have been developed by numerous organizations including the National Academy of Science/National Research Council's Fifth Committee on the Biological Effects of Ionizing Radiations (BEIR V 1990), the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 1988) the International Commission on Radiological Protection (ICRP 60

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19 1990) and the National Council on Radiation Protection and Measurements (NCRP 115 1993) The most recent reassessment of radiation-induced cancer risks from exposure to low levels of ionizing radiation was performed by the BEIR V committee and this methodology was utilized in perf orrning the calculation of the risk estimate from plain film procedures performed in Chapter 4 Risk Assessment The BEIR V Report provided mathematical models to estimate risks for breast cancer respiratory tract cancer, digestive tract cancer, leukemia, and other nonleukemia cancers These equations include tertns for dose age at exposure time after exposure and interaction effects The dose term utilized in these equations is the effective dose calculated from the MOSFET organ dose deter1ninations upon applying the dose conversion factors. Significance and Objectives Pediatric radiographic examinations are widely thought to yield medical benefits and/or diagnostic infotmation which greatly exceed any potential risk from patient radiation exposure Nevertheless quantification of that risk is important for a number of reasons First, it allows radiographic procedures to be optimized to maximize the medical benefit while minimizing patient risk Second it gives the radiologist a basis for communicating that risk to concerned patients and / or parents Third it allows for reconstruction of total risk for individuals who have developed radiation-associated diseases (e g leukemia) and who were known to have undergone high-dose or multiple radiographic procedures at an earlier age (i e ., dose reconstruction) In each case, the fundamental quantity of interest is the cumulative absorbed dose to the radiosensitive organs As previously discussed, several studies have focused on quantifying average organ doses in adult patients undergoing radiographic procedures either through

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20 computer simulation or physical measurement Nevertheless very little information exists on pediatric organ doses from plain film examinations, and no systematic techniques have been developed to obtain this information for pediatric dynamic procedures such as fluoroscopy CT or cardiac catheterization Consequently the first objective of this research project was to establish a baseline and develop a method for assessing pediatric organ doses for the most frequent plain film procedures used in clinical practice The second objective was to verify this method for plain film exams through the use of an anthropomorphic phantom representing a one-year-old pediatric patient and coupled to a real-time radiation dosimetry system The third objective was to utilize the organ doses detertnined from the anthropomorphic phantom and calculate an effective dose for each plain film procedure The fourth objective was to utilize the effective dose in the BEIR V methodology to calculate the risk from the procedure The following specific aims were designed to accomplish these objectives : 1 To determine, via site survey of ten facilities, the current examination trends for one-year-old patients in pediatric x-ray practices in the State of Florida 2 To determine utilizing a one-year-old anthropomorphic model providing real time radiation dosimetry organ doses to pediatric patients undergoing the most common plain film procedures and calculate corresponding effective doses 3 To estimate, utilizing BEIR V risk model methodology, the risk to pediatric patients of carcinogenesis from the plain film procedures To facilitate specific aim 1 detailed examinations were simulated at Shands at UF in order to focus the site surveys on the most prevalent examinations currently perfonned in pediatric practices Technique info1111ation for these examinations were collected from all facilities Due to the time constraint of room downtime dosimetry data were collected at the ten facilities for the single most prevalent exam ; dosimetry data were collected for all examinations simulated at Shands at UF In specific aim 2, point estimates of organ doses were assessed by selective placement of an array of Metal Oxide Semiconductor

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21 Field Effect Transistors (MOSFET) detectors within the phantom These measurements for the x-ray procedures utilized the prototype one-year-old anthropomorphic phantom developed by Bower (1997) Specific aim 2 also involved the determination of dose conversions factors ( organ absorbed dose per unit entrance skin exposure) for a range of radiographic projections and radiation beam qualities and the calculation of effective doses as defined by the ICRP (1977) The task associated with specific aim 3 used equations developed by BEIR V (1990) to utilize the effective dose calculated in specific aim 2 in order to predict the risk of radiation induced carcinogenesis from the simulated plain film procedures These tasks not only update and expand obsolete data on pediatric organ doses from plain film examinations but establish the method to benchmark experimentally the mathematical models previously discussed and provide a baseline for the organ dose estimation computational and experimental techniques necessary to simulate dynamic pediatric exams This research provides vital infor1nation to the pediatric radiology community in their efforts to assess organ doses and procedure risk from plain film exams both prospectively and retrospectively

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CHAPTER2 PATIENT AND EXAMINATION TRENDS OF PEDIATRIC X-RAY PRACTICES A general overview of the range of pediatric x-ray practices was obtained through a site survey of selected facilities within the State of Florida Ten facilities were selected to represent their cohorts throughout the rest of the State : six facilities represented Children s Hospitals and / or Radiology Departments with dedicated pediatric radiologists two hospitals represented community patient populations and two hospitals represented rural patient popula t ions Selection of the number of facilities was not based on statistical considerations as the purpose of this survey was only to identify and characterize the examinations that are most commonly employed and not establish their precise frequencies in the U S population Private practices were not included in this survey In addition, more specific information was obtained on a single pediatric radiologic practice during in depth investigations carried out in the Pediatric section of the Radiology Department at Shands at the University of Florida Shands at the University of Florida Shands at the University of Florida is a 576-bed not-for-profit tertiary care facility The Children,s Hospital at Shands at the University of Florida is a 169-bed hospital within-a-hospital The Radiology Department at Shands at UF has a workload of 163,000 examinations per year approximately six percent of which are for patients under sixteen years of age In order to determine which examinations to include in the site surveys examination frequency data specific for pediatrics were extracted from the Radiology Infotmation System (RIS) The RIS provides a computerized patient record from which physicians can call up all the clinical data that they need about a given patient in 22

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23 alphanumeric text The review of the RIS ascertained retrospectively the frequency and types of x-ray procedures performed as a function of age and simulations were then perforn1ed to determine the important technical parameters of each procedure Since the data were to be adapted to five anthropomorphic phantoms and mathematical models five age groups were defined for the frequency data These age groups were determined from formulae utilized for approximate average height and weight of normal infants and children that are commonly found in pediatric textbooks (Behrman and Vaughan 1987) These categories are defined in Table 2-1 Table 2-1 Age Group Corresponding to Phantom Phantom Age Group Newborn O to 3 months One-Year-Old 3 months to 12 months Five-Year-Old 1 year to 6 years Ten-Year-Old 7 years to 12 years Fifteen-Year-Old 13 years to 16 years The first piece of information extracted from the RIS data was the dete11nination of the types and frequencies of examinations as a function of age The RIS data file listed all the pediatric radiological examinations perfo1med at Shands at the University of Florida from January 1990 through December 1997. An additional computer program was written to extract the number of examinations performed in a given year broken out by the age group defined in Table 2-1 from the RIS data file The file encompassed general radiology (including ultrasound) fluoroscopy CT and nuclear medicine examinations No exam technique information was contained in this file An example of the file is presented in Table 2-2 illustrating the number of pediatric chest x-rays performed in 1997 The 1997 file in its entirety is located in Appendix A Prior years were not included as a trend analysis indicated similar distributions of exams

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24 Table 2-2 Annual Number of Plain Film Chest X-Rays by Age Group Y ear M o dali ty Ex am & P ro jec ti o n New born 1-Year 5 Year 1 0 Year 15 Year 97 GENERAL CHEST P A & LATERAL 4 77 4 74 1 5 2 4 665 546 97 GENERAL CHEST l VIEW 376 3 797 1 713 875 973 97 GENERAL BABYGRAM ( dl esl & a bdomen ) 7 3 0 3 0 17 0 0 97 GENERAL CHES T D EC U B I TUS LEFT 31 3 1 8 3 9 97 GENERAL C HE S T DECUBITUS RIG HT 2 4 3 11 2 8 The frequency of exams was also deter 11iined from this file The frequency is defined as the ratio of a specific exam and projection falling within a modality to the total number of examinations classified for that modality and is expressed as a percentage An example of the data is presented in Table 2-3 demonstrating the percent frequency of pediatric chest x-rays perforn1ed in 1997 The 1997 percent frequency file in its entirety is located in Appendix B and is tabulated from most to least frequent exam Table 2-3 Percent Frequency of Plain Film Chest X-Rays Year Modalit y Ex am & Projecti o n New born I-Year 5 -Year I OYear 1 5-Year 97 GENE RAL C HE ST P A & LATERAL 8 2 6 97 GENERAL C HE S T 1 VIEW 65 44 2 6 16 12 3 0 2 1 22 97 GENE RAL B ABYGRAM ( dl est & abdomen ) 1 3 1 7 97 GENE RAL C HE ST D ECUBITUS LEFT 0 5 0 2 0 3 0 0 0 3 0.07 0 2 97 GENE RAL C HE ST D ECUBITUS RI G HT 0 4 0 2 0 2 0 05 0. 2 The frequenc y data were further segregated by the principal body region exposed in the examination : head and neck ; thorax and shoulder ( excluding humerus) ; abdomen pelvis and hips ; and extremities The most frequent plain film exams per principal body region were chosen to be included in the dosimetry study Table 2-4 lists the plain film exams that were surveyed at each facility based on the data for the one-year-old Extremity examinations were not included in the dosimetry survey for the one-year-old phantom As demonstrated in Appendix B the frequency of these exams does not increase until the older age groups when a child has learned to walk and run, and falls occur with subsequent damage to extremities ,. Limitations of phantom design with respect to limb movement also restricted the realism with which such examinations could be simulated Radiographic components of fluoroscopy examinations were not considered in this research, as it would be more appropriate to include such dose considerations in a

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25 study of the overall fluoroscopic exam dose Several additional examinations were performed at Shands at UF to investigate the effect of shielding on the resultant dose The RIS data file also included the projections used in the examinations The nomenclature for projections follows that commonly used in radiology (Ballinger 1995 ). When referring to a radiograph of a body part as seen from the aspect of the x ray film this is termed a 'view ," in which case one refers to the side of the body or body part which is closest to the film For example in an anterior view of the chest the patient faces the film ; in a left lateral view the patient s left side is toward the film A left posterior oblique view is performed with the patient turned with his left back toward the film and his right front away from the film Generally when the x-ray beam is not incident normally on the patient s front or back, 'view' te11ninology is used as opposed to '' projection '' terminology A '' projection '' defines the path of the x-ray beam through the body or body part Thus in an Anterior-Posterior projection of the chest the beam enters the front and exits through the back, producing what could correctly be tet 1ned a posterior view In this research, projection orientation is used whenever the beam is not 1nally incident on the front or back ((Anterior-Posterior (AP) or Posterior-Anterior (PA)) ; view orientation is used for all others although the term projection is used for uniformity throughout Projections are additionally defined in terms of rotation of the patient or part clockwise from the superior aspect beginning with the patient facing the tube Thus an AP projection has O degree rotation, facing the tube ; PA projection has 180 degree rotation, facing the film ; LAT projection (lateral projection) has two possibilities : RLAT (right lateral) has 90 degree rotation, with the right side towards the film ; and LLAT (left lateral) has 90 degree rotation, with the left side towards the film The term decubitus is used if the patient is lying down rather than standing up Obliques are not included in this data set as the majority of oblique projections are associated with fluoroscopy exams Additional nomenclature specific for skull and sinus examinations includes 'Townes '' and Waters '' projections respectively The Townes method for radiographing the skull

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26 involves angling the x-ray tube 20 to 25 degrees caudad (beam penetration through the top of the head) The Waters method for radiographing the sinuses involves extending the patient s neck with their chin on the cassette stand Table 2-4 Surveyed Examinations Exam Pro '. ection Skull AP Skull LAT Skull Townes Sinus Waters Sinus LAT Cervical spine AP Cervical spine LAT Thoracic spine AP Thoracic spine LAT Lumbar spine AP Lumbar spine LAT Abdomen AP Pelvis AP Hip AP Chest LAT Chest AP Chest PA Ten Florida Facilities The exposure to pediatric patients during x-ray procedures would be expected to vary from facility to facility Factors such as equipment setup and operational characteristics patient classification and procedural techniques are of key importance To investigate the variation that exists among facilities a site survey of pediatric x-ray practices in ten Florida hospitals was conducted The surveys were conducted in cooperation with the radiologist, the administrative director and the pediatric x-ray technologist of the participating facility One or more of these personnel were present during each site visit and data collection In addition to Shands at the University of Florida the following facilities participated in this research :

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27 Tallahassee Memorial HealthCare Tallahassee Memorial HealthCare is located in Tallahassee Florida and has 736 beds with a radiology workload of 31 200 procedures per year, approximately one and a half percent of which are estimated to be pediatric University Medical Center Jacksonville University Medical Center is a 528-bed medical center located in Jacksonville Florida with a radiology workload of 190 000 procedures per year approximately eight percent of which are estimated to be pediatric Shands at AGH Shands at AGH is located in midtown Gainesville Florida and has 410 beds with a radiology workload of 72 000 procedures per year approximately four percent of which are estimated to be pediatric Arnold Palmer Hospital for Children & Women Arnold Palmer Hospital for Children & Women is located on the downtown Orlando Regional Healthcare System campus in Orlando Florida and has 267 beds with a radiology workload of 33 420 procedures per year all of which are pediatric All Children s Hospital All Children s Hospital is located in St Petersburg Florida and has 236 beds with a radiology workload of 35 930 procedures per year all of which are pediatric Wolfson Children s Hospital Wolfson Children s Hospital is part of the Baptist/St Vincent s Health System located in Jacksonville Florida and has 190 beds with a radiology workload of 41 000 procedures per year all of which are pediatric Shands at Lake Shore Shands at Lake Shore is a 128-bed acute care community hospital located in Lake City Florida with a radiology workload of 36 000 procedures per year approximately eight percent of which are estimated to be pediatric

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28 Shands at Starke Shands at Starke is a 49-bed acute care rural hospital located in Starke Florida with a radiology workload of 14 780 procedures per year approximately six percent of which are estimated to be pediatric Shands at Live Oak Shands at Live Oak is a 30-bed acute care rural hospital located in Live Oak, Florida with a radiology workload of 18 000 procedures per year approximately three percent of which are estimated to be pediatric The six facilities representing Children s Hospitals and/or Radiology Departments with dedicated pediatric radiologists were Shands at UF Tallahassee Memorial HealthCare University Medical Center Arnold Palmer Hospital for Children & Women All Children s Hospital and Wolfson Children s Hospital The two hospitals representing community patient populations were Shands at AGH and Shands at Lake Shore The two hospitals representing rural patient populations were Shands at Starke and Shands at Live Oak Exam Simulations Per a scheduled appointment approved by the radiologist initial contact was made with the director of radiology upon arrival at each facility The purpose and objectives of the research were reiterated and the phantom and dosimetry system demonstrated Copies of recent news publications about the research were also distributed The director then assigned ax-ray room and technologist to the research project for 2 5 hours on a v erage The designated time was requested during appointment scheduling and was approximated based on the time required to carry out the initial characterizations perfot med at Shands at UF

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29 After initial set-up of the phantom to perform real-time dosimetry readings as described in Chapter 3 the phantom was turned over to the pediatric x-ray technologist to simulate as close to clinical practice as possible the exams listed in Table 2-4 for a one year old patient In order for the pediatric x-ray technologist to simulate the x-ray field size shape and location on the phantom it was necessary to indicate the locations of certain anatomical landmarks on the phantom that approximated those of an actual one year-old patient The anatomical landmarks which were defined and placed on the phantom during the initial simulations at Shands at UF by Dr J Williams a staff pediatric radiologist were as follows : 1 Vertex The top or highest part of the phantom head 2 External acoustic meatus (EAM) Defined to be at the horizontal level of the floor of the phantom skull 3 Sternal Notch Defined as the point midway between the anterior medial ends of the phantom clavicles 4 Nipples Defined to be located on the level midway between the top of the phantom trunk and the inferior margin of the twelfth rib ; considered to be the midpoint of the thorax 5 Xiphoid Process Defined as the inferior margin of the sternum at the level of the seventeenth rib 6 Umbilicus Defined as located at the level midway between the phantom diaphragm and the bottom of the trunk The umbilicus is considered to be at the midpoint of the abdomen and at the level of the iliac crests 7 Symphysis Pubis Defined as located on a level O 086 times the vertical height of the trunk above the inferior margin of the trunk whose relative position is taken from the vertex This point is considered to be located at the superior margin of the pubis. 8 Hip Joint Defined as lying on a vertical line originating at the center of the base of the leg bone one-third of the vertical height of the pelvis above the floor of the trunk

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30 The distances of these landmarks from the base of the trunk are listed for the one year-old phantom in Table 2-5 Table 2-5 Defined Locations of Anatomical Landmarks on Phantom Vertical Axis with the Origin at the Base of the Trunk ( cm) Landmark Vertex BAM Sternal notch Nipples Xiphoid process Umbilicus Hip joint Symphysis pubis 48 5 39 4 27 5 22 6 19 2 10 6 1 1 0 7 The next section of this chapter describes each exam simulation setup of the phantom patient in detail The descriptions are based on technologist interviews and visual observations obtained of the best practices at each site for actual patient examinations supported with the textbook by Kirks and Griscom (1998) Additional descriptions are provided by Ballinger (1995) Bontrager (1997) and Wilmot and Sharko (1987) The left lateral projection was chosen for all lateral examinations for ease in positioning Images of these examinations are provided in Chapter 5, along with corresponding phantom images AP skull The patient is positioned supine The midsaggital plane ( divides the body into right and left halves) of the skull is kept perpendicular to the tabletop The orbitomeatal baseline is kept 15 to 20 degrees cephalad from the perpendicular by using a small sponge wedge or roll of diapers behind the patient s neck to provide some support to maintain this position The orbitomeatal line is a frequently used positioning line located between the outer crease of the eye and the BAM Several immobilization methods were observed, ranging from Velcro and tape to foam-backed lead ''bookends'' placed at both sides of the head, as shown in Figure 2-1 Typically one-year olds are also immobilized using the

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31 '' bunny '' or "mummy" technique, which consists of tightly wrapping the patient in a blanket to immobilize arms and legs The thyroid was protected by a shadow shiel~ which is a piece of lead attached to the tube head with an adjustable arm Note that PA projections are not routinely obtained for this age group, as young children tend to be frightened of being face down A B C Figure 2-1 Items frequently used for immobili z ation A : Sandbags tape clear Plexiglas strip B : Sponges of various shapes and sizes Velcro strap C : "Bookends" ; patient "mummified" Figures A and B reproduced with pe1nlission from Lippincott-Raven Publishers Figure C reproduced with permission from Mosby-Year Book Publisher s, Textbook of Radiographic Positioning and Related Anatomy K L Bontrager (1997) Lateral skull The patient is positioned either semi prone or supine If using a grid the head is rotated so that the affected side is closest to the film If a grid is not used a cross table lateral is performed with a film holder The unaffected side of the body is elevated from the tabletop using sponges under the neck and shoulders so that the coronal plane ( divides

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32 the body into anterior and posterior parts) of the body creates an angle of 45 degrees with the tabletop The head is positioned in such a way that the midsaggital plane of the skull is parallel to the tabletop and the interorbital line is perpendicular to the film The interorbital line is a frequently used positioning line that connects either the pupils or the outer creases of the patient s eyes The central ray is perpendicular to the midsaggital plane and passes midway between the glabella (the smooth raised prominence between the eyebrows just above the bridge of the nose) and the occipital protuberance ( the prominent 'bump ' at the inferoposterior portion of the skull) Immobilization and shielding techniques were similar to those used in the AP projection except the foam-backed lead 'bookends '' were not placed in the field of view Townes skull The patient lies supine on the table so that the orbitomeatal baseline is perpendicular to the tabletop Visualization of the foramen magnum ( the large opening at the base of the occipital bone through which the spinal cord passes as it leaves the brain ) may be improved by placing a 20 degree-angled sponge under the skull For this age group an additional angled sponge placed under the lower extremities may also assist in positioning by depressing the shoulders and encouraging further flexion of the neck With the x-ray tube angled 30 to 35 degrees caudal (away from the head end of the body toward the feet) the central ray enters the frontal bone in the midsagittal plane at the hairline passing through a line connecting both external auditory meatuses and exits through the foramen magnum An angle of 3 0 degrees between the orbitomeatal line and the central ray should be achieved Immobilization and shielding techniques were similar to those used in the AP projection Due to the inability of the phantom s head to articulate for this method, the pediatric technologist compensated by angling the x-ray tube to produce the same projection

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33 Waters sinus The patient is examined sitting or standing with the chin and the nose in contact with the film cassette The patient s mouth is opened during the radiographic procedure The neck is extended in such a way so that the orbitomeatal baseline for1ns a 40 to 45 degree angle with the plane of the film so that the midsaggital plane is perpendicular to the cassette The central ray enters at the posterior sagittal suture (the joint connecting the two parietal bones) just above the occipital protuberance in the midline and runs parallel to the mentomeatle line and exits at the level where the nose and upper lip meet The mentomeatle line is a frequently used positioning line that connects the midpoint of the chin with the EAM Again, due to the inability of the phantom's head and jaw to articulate for this method the pediatric technologist compensated by angling the x ray tube to produce the same projection AP cervical spine As the patient lies supine on the table the neck is extended to bring the orbitomeatal baseline to 20 degrees cephalad (toward head end ofbody) to the vertical An angled sponge under the patient s shoulders may be used in order to achieve greater extension of the neck The central ray is kept between IO to 20 degrees cephalad The central ray enters at the level of C-4 or at the thyroid cartilage The field size is adjusted so that the view includes the base of the skull as well as the T-1 vertebrae A lead lap apron was utilized as shielding Lateral cervical spine If using a grid the patient is positioned supine The head is in a true lateral position with the chin raised slightly The central ray enters the C-4 vertebrae perpendicular to the film cassette This procedure may be performed either with extension or flexion of the neck depending on the kind of functional study The field is collimated to include the C-1 to T-2 vertebrae If a grid is not used a cross table lateral is performed with a film holder The patient is placed in a reclined supine position with a sponge placed

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34 under the shoulders The neck is in a slightly extended position so that the inferior border of the mandible is vertical The central ray enters approximately 2 5 cm posterior to the angle of the mandible The field is collimated to include C-1 to T-2 vertebrae Shielding techniques are similar to those used in the AP projection. AP thoracic spine The patient is placed in the supine position The patient s head rests directly on the table without the support of a pillow The patient s chin should be slightly raised The hips and knees should be slightly flexed and the knees supported on a pillow so that the cervical spine will become nearly parallel to the tabletop Additional restraint is provided by placing sandbags over the elbows and knees and by placing Velcro restraining bands across the chest hips and knees Additional sandbags may be placed along the sides of the chest and abdomen to further limit movement The central ray enters at the level of T6 or approximately 10 cm below the sternal notch The field is collimated to include C7 to L-1 vertebrae Lateral thoracic spine The patient is positioned in a true lateral position with the arm closest to the table flexed to bring the hand up under the head The upper arm also rests on the side of the head Note that the arms in the phantom are encased in the trunk and cannot be moved When positioning the patient for the lateral view the head should be placed on a firm pillow to raise the head and bring the cervical spine into alignment with the thoracic spine The hips and knees are flexed to provide stability In order to reduce the lateral curvature and ensure that the thoracic spine is parallel to the tabletop a sponge should be placed under the patient at the level of the lumbar spine but above the iliac crests The arms and legs should be restrained with sandbags and Velcro restraining bands A bookend support should be placed against the back and against the anterior chest wall to discourage arching of the back The central ray enters at the level of T -6 just below the inferior angle of the

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35 scapulae The field is collimated to include C7 to L-1 vertebrae The upper 2 or 3 thoracic vertebrae are not well visualized on the standard lateral view If upper thoracic vertebrae are of particular interest a '' swimmers' lateral view is performed The patient is positioned as described above but the upper arm is brought to rest behind the patient s buttocks and the shoulder is rotated slightly posteriorly This positioning ensures that neither shoulder will be superimposed on the upper thoracic spine The central ray enters at the level of T-2 and the field is collimated to include C7 to T-2 vertebrae Since the arms in the phantom are encased in the trunk and cannot be moved this view was not performed A ''breathing'' technique was commonly employed by technologists for lateral thoracic spine radiographs Rather than waiting for the time of expiration to take an exposure, technologists would routinely have the patient breathe normally so that the movement would blur the lungs and ribs out AP lumbar spine The patient lies supine with knees and hips flexed and the arms placed to the side It was unnecessary for the phantom to perform this flexion as the posterior aspect of the phantom lies immediately adjacent to the tabletop The midsaggital plane of the body is aligned to the midline of the table The central ray enters perpendicularly at the level of the iliac crest or at the L-4 to L-5 interspace The techniques of immobilization already described under the discussion for positioning of the thoracic spine are equally applied in examinations of the lumbar spine Lateral lumbar spine If a cross table lateral is not perfor1ned the patient lies in a lateral recumbent position with a pillow under the head and the knees and hips flexed with support between the knees and ankles The pelvis and the torso are in a true lateral position The coronal

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36 plane of the patient is aligned to the midline of the table The central ray enters perpendicularly at the level of the iliac crest or at the level of the L-4 vertebrae AP abdomen The patient lies supine on the table The midsaggital plane of the patient is aligned with the center of the table or the film cassette Immobilization methods that have been previously discussed were utilized such as Velcro or tape and foam wedges or sandbags on both sides of the abdomen The central ray is perpendicular to the film and enters about one inch abo v e the umbilicus for a one-year-old The exposure should be made at the end of expiration Upright projections of the abdomen may be clinically required and are perfortned with immobilization techniques similar to those utilized for upright chest radiography AP pelvis The patient lies supine with legs extended and separated The legs are internally rotated 15 to 20 degrees. Since the phantom's legs are not attached to the trunk of the body this positioning does not change the internal anatomy of the phantom The patient midsagittal plane is aligned with the central ray which enters a point midway between the level of the anterior superior iliac sp i ne (prominent anterior border of the iliac crest) and the superior border of the symphysis pubis The central ray is perpendicular to the film and a gonad shield is utilized It should be mentioned that a '' frog-leg' pelvis view is also routinely performed for this age group In a frog-leg view the knees and hips are flexed as far as comfortable Both thighs are abducted as far as possible and plantar surfaces of the feet are placed together This view was not performed with the phantom due to the inability of the phantom s joints to articulate AP bilateral hip The patient lies supine with their arms immobilized at their sides or crossed at the chest with the pelvis as symmetrically positioned as possible The legs are extended and

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37 rotated internally 15 to 20 degrees when a non-trauma patient is being examined The central ray enters the midline at a point halfway between the anterior superior iliac spine and the symphysis pubis Both hips are always examined in the same projection on the same film A lateral frog-leg hip is routinely perfor1ned for this age group The patient is laid partially oblique with a support under the affected area The knee on the affected side is flexed, and the thigh is drawn up to a 45 degree angle position The affected femoral neck is centered to the midpoint of the film cassette The central ray is perpendicular to the film and enters at the le v el of the mid-femoral neck This view was not performed with the phantom, due to the inability of the phantom s joints to articulate AP) PA and lateral chest Pediatric chest radiographs are routinely performed upright without a grid The challenge of perfornung upright imaging includes preventing motion and rotation, freeing the lung fields of superimposition of chin, humeri and scapulae and obtaining a good inspiratory radiograph Various methods of immobilization are used however the most common pediatric positioner and immobilization tool utilized is the Pigg o-stat The Pigg o-stat is composed of a large support base on wheels a small adjustable seat and Plexiglas support sleeves which come in two sizes The seat sleeves and 'turntable ' base rotate as a unit to facilitate quick positioning from the PA to the lateral projection As shown in Figure 2-2 the child sits on the little bicycle type seat The plastic support sleeves fit snugly around the sides and keeps the arms raised The child usuall y cries with frustration at being confined but the crying actually helps to obtain a good ray image because at the end of a cry the child will take a big gasp of air and at that moment the exposure is taken The orientation of the room, i e ., where the chest stand or film holder is located relative to the control panel determines how well the technologist can see the child s thorax to ensure the exposure is made during inspiration Inspiration

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38 can also be detected by watching the child s abdomen as it extends on inspiration, watching the chest wall as the ribs will be outlined on inspiration and watching the rise and fall of the sternum The central ray for both PA and lateral projections enters perpendicular to the film at the level of the midthorax T-6 / T 7 vertebrae or mammillary (nipple) line The collimation is adjusted so that all of the ribs are included in the radiograph and should extend fro~ and include the mastoid tips to just above the iliac crests A lead lap apron was utilized as shielding Figure 2-2 Infant immobilized and supported by the Pigg-o-stat device for an upright chest film The device is then rotated 90 for a lateral projection Note the presence of shielding for the pelvis Figure reproduced with pennission from Lippincott-Raven Publishers Practical Pediatric Ima ging : Diagnostic Radiology of Infants and Children D R. Kirks and N T Griscom (1998) Radiologists that did not favor the use of the Pigg-o-stat for aesthetic reasons or because of the potential for sleeve artifacts frequently used a supine pediatric immobilizer referred to as a Tam-em board Thi s one step immobilization device positions the child with the arms head and legs immobilized with foam lined Velcro straps to a Plexiglas frame for both an AP projection ( with the film located on the tabletop under the frame as

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39 shown in Figure 2-3) and a cross table lateral projection (with the film in a holder as shown in Figure 2-4) This immobilization device was also used when upright positioning was contraindicated -Figure 2-3 Toddler immobilized for an AP chest radiograph on the Tame-Em immobilizer Velcro bands are placed around the arms and legs ; a vinyl sheet of lead covers the lower abdomen and gonads Figure reproduced with permission from Lippincott-Raven Publishers Practical Pediatric Imaging : Diagnostic Radiology of Infants and Children, D.R Kirks and N T Griscom (1998) Figure 2-4 Infant immobilized for a left lateral chest radio graph on a Plexiglas immobilizer Velcro bands are placed around the ar1ns and head ; a vinyl sheet of lead covers the lower abdomen and gonads Figure reproduced with permission from Mosby Y ear Book Publishers Merrill's Atlas of Radiographic Positions and Radiologic Procedures P W Ballinger (1995) A variation of this device is an octagonal immobilizer shown in Figure 2-5 which is an eight-sided immobilization tool that permits visualization in a variety of positions

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40 Figure 2-5 Octagon board for immobilization Figure reproduced with permission from Lippincott-Raven Publishers Practical Pediatric Imaging : Diagnostic Radiology of Infants and Children:, D R Kirks and N T Griscom (1998) Survey Data For future comparison of the measured and simulated effective doses, several parameters from the survey data would need to be correlated The most important descriptors collected during the exam simulations at each facility included the type of generator e g single phase three phase, constant potential or high frequency ; the collimated size of the x-ray field ; the distance from the tube focal spot to the beam entrance point on the skin or surface of the phantom (SSD) ; the direction of the x-ray beam with respect to the long axis of the phantom (projection) ; and the quality of the ray beam as described by the kVp and half value layer (HVL) For comparison of technique factors among hospitals additional parameters were collected from each facility These parameters included the mode of operation, e g manual or automatic exposure controlled (AEC also called phototiming or amplimatting) ; the detector configuration of ion chambers that were utilized for ABC-right (R) center (C) and/or left (L) and the density setting ((-3 -2 -1 Notmal (N) + 1 + 2 or + 3)) ; if scatter suppression was used ; film size ; film / screen speed ; the distance from the tube focal spot to the image receptor distance (SID) ; the output of the x-ray beam as defined by the

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41 milliamperage and time applied (mAs) ; the focal spot size-large (LFS) or small (SFS) ; and shielding used Repeat and reject rate percentages were also collected In addition to recording technique parameters during the simulations several measurements were perfor1ned Higher than normal exposures were taken to ensure reasonable accuracy in the absorbed dose data After the clinical exam was perfor1ned exposures from an output of 80 mAs were perfo11ned The accuracy of the kVp was verified prior to measuring the HVL The exposure per m.As was measured at a variety of kVp settings at a given distance in order to compute the entrance skin exposure (ESE) which was subsequently used in the effective dose calculation X-ray films were obtained for all the chest examinations and the optical density of the middle of the lung fields on the chest x-rays were quantified with a densitometer and averaged to provide a measure of image quality All measurements were perfor1ned in accordance with procedures recommended by the American Association of Physicists in Medicine (Seibert et al 1994) The survey data in their entirety are reviewed in Chapter 5 and are tabulated for each exam and projection in Appendix C During the initial survey perfonned at Shands at UF x-ray films and dosimetry measurements were performed for each examination listed in Table 2-4 During the subsequent site surveys x-ray films and dosimetry measurements were only perfor1ned for the chest examinations in order to decrease room downtime The chest examinations were chosen for comparison, as they were the most frequently perfor1ned examination at each facility

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CHAPTER3 RADIATION MEASUREMENT EQUIPMENT AND TECHNIQUES One-Year-Old Anthropomorphic Phantom Bower successfully constructed a full-scale prototype of a physical heterogeneous phantom to represent the new MIRD one-year-old mathematical model, which included a revised head and neck (1997) This prototype was the phantom utilized for the measurements in the site survey study The construction entailed several steps First processing techniques were developed to produce tissue equivalent materials approximating soft, lung and bone tissues which required the addition of a particulate filler with a moderately high effective atomic number such as magnesium oxide to an unfilled liquid resin with a low effective atomic number The theoretical interaction coefficients (mass attenuation and mass energy-absorption coefficients) were matched between these tissue-equivalent materials and the tissue media used in the 198 7 Cristy and Eckerman and MIRD models over the photon energy range 1 5 ke V to 150 ke V using the computer program XCOM written by Berger and Hubbell at the Center for Radiation Research, National Bureau of Standards (Hubbell 1982) The mass density was adjusted by adding a small quantity of low-density microballoons (hollow gas-filled spheres) This basic process followed that published by White (1977) and further developed by White et al (1977 1986) and Herman et al (1985 1986) The soft tissue substitutes were made of materials providing a final elemental composition of 59 2 % carbon 20 6% oxygen 10 5 % magnesium, 7 5% hydrogen 2 0 % nitrogen and O 10 % chlorine by weight The attenuation and mass energy-absorption coefficients of the tissue-equivalent substitutes were modeled after the atomic 42

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43 compositions of soft tissue defined in the 1987 models of Cristy and Eckertnan and ICRP Publication 23 (1975 ). These two sets of photon interaction coefficients were in agreement within + 3% and were considerably closer at most energies The soft tissue substitute s photon interaction coefficients were also favorably compared to those given for individual tissues given in ICRU Publication 44 (1989) The soft tissue substitute was modeled to provide the appropriate soft tissue density of 1 04 g/cm 3 Lung-equivalent materials were manufactured using a foaming agent and a surfactant, similar to the method presented by White et al ( 1986) The lung tissue substitutes were made of materials giving an elemental composition of 59 42% carbon, 17.65% oxygen, 12 06% magnesium, 8 24% hydrogen, 1 64% nitrogen 0 84% silicon and 0 15% chlorine The lung tissue substitute density was 0 360 g/cm 3 which approximated the lung tissue density of 0 296 g/cm 3 for the mathematical model A bone tissue substitute approximating the skeletal tissue of a one-year-old was also produced Cristy and Eckerman made the following observations concerning the skeleton of the newborn : 'The skeleton of the newborn contains more water less fat and less mineral than the adult skeleton Further more the distinction of two bone types, cortical and trabecular bone is not evident in the newborn skeleton and the marrow of the skeleton is all active Thus it is clear that the elemental composition of the adult skeleton cannot be used when evaluating radiation transport in the newborn [1987 page 42] Consequently, the authors proposed a different skeletal tissue medium for their newborn model, but utilized the adult skeletal tissue medium for all other models in the series including the one-year-old New data on average skeletal atomic composition as a function of age available in ICRP Publication 70 (1995) were used to manufacture age specific skeletal-equivalent materials incorporated into the one-year-old phantom The skeleton composition (in terms of water protein, mineral and fat by percent weight) was used to calculate an appropriate elemental composition of the bone-equivalent substitute for the one-year-old skeleton consisting of 52 98% carbon, 24 54% oxygen, 5 86%

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44 hydrogen, 2 033/o nitrogen, 5 79% chlorine and 8 81% calcium The mineral percent by weight for a one-year-old skeleton was provided explicitly in ICRP Publication 70 The water and fat percentages were obtained from the 1995 document s data tables and the percentage of protein was obtained by subtraction However Bower had difficulty in producing a bone substitute that matched the density for a one-year-old but could produce a bone substitute mixture of 1 18 g/ cm 3 in 1997 which approximated Cristy and Eckerman s density of 1 22 g/cm 3 for the newborn in 1987 Since the new elemental bone composition for the one-year-old developed by Bower in 1997 was close to the newborn, and the difference in densities between the newborn and the one-year-old in ICRP Publication 70 was only 0 01 g/cm 3 he decided to use the newborn bone density of 1 18 g/cm 3 for the one-year-old Molds were then created for the lungs and individual skeleton components consisting of two leg bones two arm bones a pelvis a spine twelve ribs two scapula and two clavicles The molds were filled with the respective lung or bone liquid resin tissue substitutes and allowed to cure The cured components were milled to final shape Once the internal components were completed molds were created for the external parts consisting of the trunk, legs and skull The soft tissue substitute material was then poured into the external cylindrical trunk mold in a layered method which facilitated the correct placement of the skeletal and lung components The legs were frustums of two soft tissue cones surrounding the leg bones The head consisted of a skull enclosing the mandible teeth cranium and upper face region as well as a neck Guide holes were drilled into the phantom to allow placement of the dosimeters Figure 3 1 shows the mathematical model of the one-year-old a portion of the internal skeleton with the head model and an external view of the completed physical prototype phantom

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A ~1 I I I r c.. I I 45 I r B C Figure 3-1 One-year-old pediatric phantom A : Mathematical model. B : Skeletal model with 4 ribs C : External view of physical prototype phantom The total mass of the one-year-old prototype is 10 2 kilograms The length of the head trunk and legs respectively is 16 cm, 32 5 cm, and 26 5 cm for a total height of 7 5 cm Several aberrations should be noted regarding the prototype phantom The mathematical model has soft tissue eyes with a volume of 6 25 cm 3 whereas the physical prototype phantom does not have soft tissue eyes The space for the eyes is composed of bone tissue substitute ; therefore the mass of the upper face region for the physical phantom is slightly higher than the mathematical model The upper portion of the mandible is slightly thinner in the physical phantom, however this portion abuts against the upper face region Therefore when averaged together the two regions are approximately correct in comparison with the mathematical model The teeth are also

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46 slightly more massive in the physical phantom however the total mass of the teeth is only 22 grams and the teeth are not a chosen dosimetry monitoring location Some of the ribs in the prototype were heavier than the theoretical masses ; however the individual ribs are thin (volume 7 28 cm 3 ) and are not used as a measurement location Metal Oxide Semiconductor Field Effect Transistor (MOSFET) Dosimetry System Theory of Operation The basic structure of a metal oxide semiconductor field effect transistor (MOSFET ) is a sandwich-type device consisting of a p-type channel built on a n-type silicon semiconductor substrate separated from a metal gate by an insulating oxide layer The source and the drain are on top of the positively doped silicon region When sufficient negative bias is applied to the gate with reference to the substrate a significant number of holes will be attracted to the oxide silicon surface A sufficient hole population permits current to flow between the source and the drain The gate voltage necessary to allow conduction through the MOSFET is referred to as the threshold voltage (Soubra 1994 ; Ramani 1997 ). When the MOSFET is exposed to ionizing radiation, electron-hole pairs are formed in the oxide insulation layer The applied positive potential to the gate causes the electrons to travel to the gate while the holes migrate to the oxide silicon interface where they are trapped These trapped positive charges cause a shift in the threshold voltage The voltage shift is proportional to the radiation dose deposited in the oxide layer This is the basis of the MOSFET as a dosimeter The Thomson and Nielsen Patient Dose Verification System used in this research utilizes a dual bias dual MOSFET device design which consists of two MOSFETs fabricated on the same chip The threshold voltage shift magnitude is increased when the positive gate bias is raised Since the MOSFETs are

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47 irradiated simultaneously the measured difference in the threshold shifts in the two sensors is representative of the absorbed dose (Soubra 1994) Each detector of the Patient Dose Verification System consists of the matched pair of MOSFET dosimeters operated at two different positive gate biases Each MOSFET dosimeter has an active area of 0 04 mm 2 The pair is mounted under a 1-mm layer of epoxy to a 20-cm long thin semi-opaque polyamide laminate cable encasing two gold wires The extremely thin (0 2 mm) flexible laminate cable is attached to a sturdy 1 4-m long cable that is connected to a bias supply The reader can accommodate up to 20 dosimeters To facilitate monitoring of the lower absorbed doses associated with diagnostic x-rays the model TN-RD-19 high-sensitivity bias supply is used Grouped in sets of five each MOSFET set is connected to a bias supply labeled '' A '' through 'D ''. In this research there were two sets of five dosimeters labeled '' A '' and ''D '', for a total of ten dosimeters The entire dosimetry system is shown in Figure 3-2 including the reader power supply bias supply a MOSFET dosimeter and the associated cabling Figure 3-2 Thomson and Nielsen Electronics Ltd MOSFET Patient Dose Verification System

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48 Characterization of High Sensitivity MOSFET Dosimeter The commercial Patient Dose Verification System manufactured by Thomson and Nielsen was originally designed for radiation therapy dose verification To measure doses to organs that were outside of the primary therapy beam, Thomson and Nielsen developed high sensitivity dosimeters to measure the lower doses Bower and Hintenlang characterized these high sensitivity dosimeters for diagnostic energies (1998) Bower measured the sensitivity linearity rotational angular response multiple query response and post-exposure response of the high sensitivity MOSFETs He determined that the high sensitivity MOSFET dosimeters had a nearly uniform angular response, good linearity and precise sensitivities at the lower energy ranges that resulted in a standard error of 5% for a typical x-ray exposure He also determined that the energy dependence of the sensitivity the post-exposure drift and the multiple query responses were not significant limitations Johnson petfortned three additional characterization tests including a comparison of the MOSFET to TLD a detertnination to see if the small air gap that surrounds the MOSFET when inserted into the phantom influences the dose measurement and a determination of the axial angular dependence of the MOSFET (1998) She deter1nined that the dose reported by the MOSFET is equivalent to the dose reported by the TLD inside the tissue phantoms and that the small air gap that surrounds the MOSFET when it is inserted in the holes in the phantom does not affect the reported dose Consequently there is no need to fill the air gap with other tissue equivalent material She also determined that angular dependence in the axial ( saggital would be a more appropriate definition) orientation of the MOSFET when placed in the phantom does not influence the measured absorbed dose An extrapolation of these determinations for the rotational and saggital planes is that the angular dependence from a coronal orientation would also not influence the measured absorbed dose

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4 9 The MOSFET is a consumable detector While the detector is not annealed or cleared after reading as is the case for thermoluminescent dosimeters the system can provide a reset between desired readings The reset process consists of measuring the m V response and using this response as a reference value for the following measurement The response is not completely stable over long periods of time post-exposure Bower perf 011r1ed a fading study in 199 7 to measure the response of the high sensitivity MOSFETs as a function of time post-exposure out to 500 hours The dual-bias dual MOSFET system utilizes the stable difference in response from the two detectors for measuring absorbed dose This method eliminates temperature and high-dose dependencies but does not control post-exposure drift The drift is a complicated function attributed to an array of causes The drift is reproducible and mathematical models and deconvolution methods have been proposed and employed ( Gladstone and Chin 1995) In using this dosimeter system to monitor organ doses within the one-year old phantom in real-time delay times between exposure and dosimeter readout are on the order of minutes therefore another fading study was perfortned to measure the response of the MOSFET as a function of time post exposure for an immediate read a one-minute delay a two-minute delay and a three-minute delay The exposure between the four reading times varied by less than 2% so a delay time of one minute was utilized in this research to decrease the room downtime associated with the data collection and no correction factors were necessary The dosimeters inserted within the physical phantom are required to have good angular response characteristics since there is no way to adjust the orientation of the detectors towards the x-ray source when simulating different views ofx-ray examinations In 1997 Bower demonstrated there is a marked angular dependence of the MOSFET dosimetry system when it is used free-in-air without an attenuating medium The packaging of the MOSFET appears to be the main source of this angular dependence providing different responses when exposing the flat surface ( 60% lower) as opposed to

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50 the epoxy bubble side of the dosimeter It was initially thought this difference might be attributed to insufficient material on the flat surface of the dosimeter for the establishment of electronic equilibrium It was subsequently demonstrated that this response is not simply due to scattering from the 1-mm bubble of epoxy since the angular response remained after material was added to the flat side of the detector to make it more symmetrical The effect is actually due to the inherent asymmetric structure of the MOSFET itself, specifically resulting from attenuation in the silicon substrate layer The angular dependence is much less pronounced when the dosimeter is surrounded by attenuating media This was verified by using a tissue equivalent cylinder and measuring the angular response for the high sensitivity MOSFET dosimeter The cylinder with a detector inserted in the center was irradiated in 15 increments over 360 at a tube potential of 90 kVp 150 mAs and a source-to-detector distance of 75 cm The procedure was repeated for each MOSFET to obtain an average dose measurement at each increment The response was very symmetrical indicating excellent angular response when using this dosimeter within a phantom The nearly uniform angular response and its small size were primary reasons the MOSFET dosimeter was chosen for the real-time dosimetry applications within the one-year-old phantom MOSFET Placement The effective dose concept presented in the 1990 recommendations of the ICRP (1991) identified twelve specific tissues at risk from radiation detriment and supplied tissue weighting factors for these tissues Several other tissues were addressed in a '' remainder' term The specific tissues and their associated weighting factors are shown in Table 3-1 The MOSFET dosimeters were placed in locations to estimate the absorbed dose in these tissues for the one-year-old phantom For localized organs, the MOSFET was placed at the centroid of the organ to determine the dose For distributed organs the

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51 dose was determined from a fractional weighting scheme applied to a specific array of MOSFET dosimeters Standard dosimetric allowances were made for measuring the absorbed dose in both the testes and the ovaries in the hermaphrodite phantom since an actual patient would not have both types of gonads The effective dose estimates performed in Chapter 5 are shown with the testes absorbed dose being used as the gonadal dose component for the male estimate and the ovaries absorbed dose being used as the gonadal dose component for the female estimate All other tissues and their corresponding tissue weighting factors were the same A skin dose estimate was obtained by measuring the entrance and exit absorbed doses and using an average value of the two measurements The organs defined in the remainder term were as follows : muscle stomach wall, small intestine wall, upper large intestine wall lower large intestine wall kidneys pancreas spleen thymus uterus adrenals and bladder wall A remainder dose estimate was calculated by averaging the measurements in the arms and the trunk of the body as representati v e of the overall location of the remainder organs Table 3-1 Tissue Weighting Factors for Calculation of Effective Dose (ICRP 1991) Tissue or organ Gonads Bone Marrow (red) Colon Lung Stomach Bladder Breast Liver Esophagus Thyroid Skin Bone surface Remainder Tissue Weighting Factor ( wT) 0 20 0 12 0 12 0 12 0 12 0 05 0 05 0 05 0 05 0 05 0 01 0 01 0.05 The MOSFET locations in the one-year-old phantom are shown in Figure 3-2 and detailed in Table 3-2 The MOSFET locations for the soft tissue organs including the

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52 lungs were generally placed at the centroid of the organ A single MOSFET location was chosen for the testes and breasts for the following reasons In the mathematical model representing a one-year-old the testes are outside of the trunk and are very small ( 1 16 cm 3 ) The testes are close together and great differences were not expected between the individual testes therefore, a single monitoring location was chosen at the point where the two legs and the trunk join Additional soft tissue material was not added to the phantom at this representative location The mathematical model has breasts that are again very small for the one-year-old (1 06 cm 3 including skin) so breasts were not explicitly created for the anthropomorphic phantom The dose to the breasts is estimated with the anthropomorphic phantom by measuring the absorbed dose to the sutface midway between the two breasts The centroids of the soft tissue organs in the anthropomorphic phantom were adopted from those supplied by Cristy and Ecke11nan (1987 ; Eckerman et al 1996) for their mathematical model with the exception of the colon and the esophagus Representative monitoring locations were chosen for the colon and the esophagus based on the equations provided for the colon (ICRP 1995) and the esophagus (Eckerman et al 1996) The skeletal locations were chosen using three criteria : 1) the bones selected were larger bones able to accept the MOSFET without loss of a significant percentage of the bone material, 2) the bones selected represented high concentrations of active bone marrow and 3) locations were selected to cover a major portion of the skeleton Figure 3-2. MOSFET dosimeters placed in position in prototype one-year-old phantom

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53 Table 3-2 Position of the MOSFET Dosimeters Within the One-Year-Old Phantom gonads : testes-general (left & right) ovaries-left colon lung-left lung-right stomach bladder ovaries-right breasts-general (left & right) esophagus liver thyroid skeleton : skull & facial spine (in head) spine ( middle of back) pelvis leg-lower left leg-lower right arm-left artn-right The MOSFETs were placed in the phantom with the epoxy bubble facing toward the x-ray tube and the leads were taped down to prevent any movement Initially, ten dosimeters were available for measurements Two of the original compliment of ten failed early in the measurement series One failed mechanically ; the reason for the other failure could not be determined by the manufacturer The simulations had to be repeated two and a half times since there are 20 different organ sites and only eight dosimeters were available In each successive simulation, the dosimeters were placed in the 10 measurement sites that could be accessed on the top half of the phantom, and the simulation was repeated in order to measure the 10 remaining sites that were accessed on the bottom half of the patient A full complement of dosimeters were not purchased until data collection was close to completion ICRP Publication 70 (1995) provides tables of the active bone marrow found in various bones as a function of age These tables are based on work presented by Cristy

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54 (1981) who relates the active marrow in individual bones parts of bones or bone groups expressed as a percentage of active marrow in the body Weightings of the active marrow for the different phantom skeletal regions were assigned to the skeletal MOSFET locations given in Table 3-2. New active marrow percentages associated with the MOSFET location were assigned by Bower and are presented in Table 3-3 Table 3-3 has been updated to include new bone surface percentages introduced in this research Cristy (1981) also provides the skeletal volume for each region, from which a percentage of the total bone was calculated Using an analagous technique weighting s of the total bone for the different skeletal regions were assigned to the same skeletal MOSFET locations and new bone surface percentages associated with the MOSFET location were assigned Table 3-3 Percentage Active Bone Marrow and Bone Surface Associated with the Skeletal MOSFET Locations Phantom Skeletal Region % % MOSFET % Active % Bone Active Bone Location Marrow Surface Marrow Assigned Assigned to to MOSFET MOSFET Skull (cranium & fac i al skeleton) 2 4 74 19 9 Skull & facial 14 7 11 6 Spine (u1.11.1er portion 1 88 3 2 Spine head 14 7 11 6 Arm bones upper portion 2 41 5 0 Arm bone left 7 79 9 8 Scapulae 2. 73 3 .2 Arm bone right 7 79 9 8 Clavicles 0 8 3 0 8 Ribs 9 61 10 7 Spine (middle portion ) 9 .2 7 8 5 Spine middle 15 88 18 5 Arm bones middle portion 2.2 5 5 0 Arm bones lower portion 4 .3 6 5 0 Spine (lower portion ) 3 37 4 1 Pelvis 21 91 21 9 Pelvis 16 47 9 3 Leg bones U}J1.1er portion 2. 07 8 5 Leg bones middle portion 3 88 8 5 Leg lower left 8 64 8 5 Leg bones lower portion 13 4 8 5 Leg lower ri~ht 8 64 8 5

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55 Measurement of Absorbed Dose Sensitivity has been defined as the MOSFET response per unit of exposure (m V per C kg 1 or mV/R) at a given tube potential ; consequently the absorbed dose (rad) in the tissue may be derived as follows The ion chamber measures exposure in air in units of roentgen (R); therefore this unit was used in measuring the sensitivity The exposure in air as measured by the MOSFET dosimetry system is therefore the MOSFET dose measurement (mV) divided by the sensitivity (mV/R) Expressed symbolically in Equation 1, where Xis the exposure, Mis the MOSFET dose measurement and Sis the sensitivity 1 X = M*s (Eq l) One roentgen produces an absorbed dose of O 8 7 6 rad in air ; therefore, D air = X 0 876 (Eq 2) The absorbed dose in tissue may be then be calculated with the following equation : D = D ,. I P) r,,,,,, (Eq 3) Tissue a1r ( / ) en p air where en I p is the average mass energy-absorption coefficient associated with the mean energy of the x-ray spectrum Equations 1-3 may be combined into one useful equation as follows *M (Eq 4) The value of en I p for the oxide could be removed from the equation without error ; however its inclusion indicates that the absorbed dose in the MOSFET device is an integral part of the corresponding dose value in tissue The average mass energy absorption coefficient ratios are effectively 1 0 for soft tissue but increase to 3 5 for skeletal tissue at 30 keV

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56 The mean energy of the x-ray spectrum was estimated by utilizing the computer program XCOM5R (Nowotny and Rifer 1985) The program is a spectrum generating program which accounts for parameters such as the tube potential, the inherent filtration and the target materials The program provides detailed infor1nation about the x-ray spectrum including the mean photon energy of the spectrum The determination of the exact mean spectrum energy is not critical for soft tissue or lungs since the ratio of mass energy absorption coefficients is relatively constant and nearly 1 0 over the diagnostic energy range The determination is more critical for the bones since that ratio is a rapidly changing with photon energy and peaks around 30 keV Sensitivity Analysis MOSFET sensitivity defined as the m V response per R exposure is shown in Table 3-4 below for the ten high sensitivity dosimeters initially used in this research Just prior to the completion of data collection, an additional ten dosimeters were added to the system, so during the calibration of the new dosimeters the old dosimeters were recalibrated as shown in column three Exposure measurements were simultaneously made with a Keithley calibrated ion chamber The data points were fit to obtain entrance skin exposures as a linear function of tube potential ; only the most commonly used tube potential determined from the site surveys is reported Table 3-4 Sensitivity Calibration Factors (R/mV) at 70 kVp MOSFET # Calibration Factor (R/mV) I 0 028 2 0 031 3 4 5 6 7 8 9 10 0 029 0 029 0 030 0 030 0 031 0 031 0 029 0 026 Calibration Factor (Rim V) 0 030 0 035 0 031 0 030 0 029 0 037 0 034 0 036 0 032 0 033

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57 Table 3-4 continued 11 0 031 12 0 029 13 0 029 14 0 030 15 0 030 16 0 030 17 0 033 18 0 030 19 0 032 20 0 033 Calibration factors needed for subsequent determination of tissue absorbed dose (R/mV) were dete11nined from these sensitivity data and through the application of the Bragg-Gray cavity theory as previously described The conversion factors given in Table 3-5 contain the ratio of average mass energy absorption coefficients detailed in Appendix D and a constant for converting exposure to the absorbed dose in air as described in Equation 4 Utilization of these conversion factors convert the exposure obtained by multiplying the MOSFET measurement by the appropriate value in Table 3-4 to absorbed dose Table 3-5 Conversion Factors Converting Exposure to Absorbed Dose Tube Potential Soft Tissue Lung Tissue Bone Tissue 70 1 009 1 046 3 316 The following technique was used to assign a dose to the active bone marrow using a weighted fraction of bone marrow assigned to the MOSFET locations in the skeleton reported in Table 3-3 The active bone marrow dose was calculated by utilizing the conversion factor for soft tissue in Table 3-5 to calculate the absorbed dose of each of the skeletal components, multiplying by the fraction of active bone marrow assigned to the MOSFET (F i ) reported in Table 3-3 and then summed to get the total absorbed dose to the active marrow Equation 5 illustrates how the dose to the active marrow is calculated

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58 D 0 876 en / p ) oxide Active Ma"ow F ) --t:.r == r -\P e n / P air \P en / P oxide i I *M F 1 I s I (Eq 5) A similar technique was used to assign a dose to the bone surface using a weighted fraction of bone surface assigned to the MOSFET locations in the skeleton reported in Table 3-3 The bone surface dose was calculated by utilizing the conversion factor for bone in Table 3-5 to calculate the absorbed dose of each of the skeletal multiplying by the fraction of bone surface assigned to the MOSFET (Fi) reported in Table 3-3 and then summed to get the total absorbed dose to the bone surface Equation 6 illustrates how the dose to the bone surface is calculated D 0 876 en / p ) oxide Bone Surface r ) --rp == J"r-\f/. en/ P air \P en/ P oxide i l M F I I s l (Eq 6) Calculation of Effective Dose Effective dose (E) as presented by the ICRP in 1991 is the most current and comprehensive measure of radiation detriment Effective dose equivalent (H E ) was a measure presented earlier by the ICRP in 1976 The effective dose was chosen to be calculated in this research as it evaluates the absorbed dose from more tissues than the effective dose equivalent and applies updated tissue weighting factors which are numerically different from those used with the effective dose equivalent Various sets of tissue weighting factors were derived for children ages O to 9 and 10 to 19 years by Almen et al and tested for use in the calculation of effective dose (1996) They concluded that the ICRP tissue weighting factors were applicable to children and adolescents ; therefore the ICRP tissue weighting factors were utilized in this research The effective dose was calculated by multiplying the absorbed dose for each organ described in the previous section by its respective tissue weighting factor reported in Table 3 1 To summarize

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59 organ doses were determined with the MOSFET at the centroid of the organ, the active marrow and bone surface doses were determined via fractional weightings assigned to individual MOSFET locations and the remainder dose was dete11nined from an averaged measurement over MOSFETs located in the torso region Since the effective dose calculation is a weighted average of the MOSFET measurement the uncertainty in the effective dose caclulation is determined to be a maximum of + 5% Appendix E presents the measured organ doses and calculated effective doses utilizing the MOSFET dosimetry system and the one-year-old physical prototype phantom The results are reviewed in Chapter 5

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CHAPTER4 RISK ASSESS?vIBNT General Risk assessment has been defined by the National Research Council (NRC) as 1he characterization of the potential adverse health effects of human exposures to environmental hazards '' (NRC 1983 :, page 18) An assessment of the risks from all types of hazards including radiological hazards requires all or some of the following components : i) hazard identificatio0:, which is investigated to determine whether a particular hazard has a corresponding health effect ; ii) dose-response assessment, in which the relation between the magnitude of the dose and the probability that the health effect will occur is determined; iii) exposure or dose assessment which is the determination of the extent to which humans will be exposed to the hazard ; and iv) risk characterizatio0:, which describes the nature and magnitude of the human risk, including uncertainties surrounding that risk [NRC:, 1983 #2254] It is the last component of risk characterization that integrates the results of the previous three components into a risk model that includes one or more quantitative estimates (Cohrssen and Covello 1989) Components of a Risk Model The model used to perfortn a risk assessment is a function of several parameters including populations from which data are obtained relationships between doses and effects and methods used to project risks into the future. Due to the limited knowledge of radiation effects :, there is diverse discussion about the interpretation of dose-response data and the choice of values for the other parameters 60

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61 Populations used in epidemiological studies v ary among risk assessment models Some studies provide better data than others do because some populations better represent the population of concern In addition, differences in population characteristics such as lifestyles cancer rates and types of exposures must be considered in transferring the results obtained from one population to another population which is defined in a risk model as the population transfer coefficient The dose-response curve and dose-rate effect applied can differ Among the possible risk models the risk analysis techniques most commonly applied are a linear quadratic or a linear relationship Risk projection models used to predict the mortality from or incidence of, cancer and genetic disease that will occur within a given population can be of several types Cancer risk projections use additive or multiplicative methods ; genetic risk projections may use direct or indirect methods Each method requires choices from among several additional parameters including death rates specific causes of death, population statistics and dose calculations Radiological risk assessments and resulting risk estimates have been developed b y numerous organizations Organizations such as the National Research Council s fifth committee on the Biological Effects of Ionizing Radiations (BEIR V) the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and the International Commission on Radiological Protection (ICRP) have summarized the complex data previously discussed that are available on the effects of radiation in a form that is easily applicable The BEIR V methodology is considered the most recent consent document for risk analysis and was utilized in this research

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62 BEIR V Methodology Populations for Deterrnining Cancer Risk In the risk assessment by the BEIR V Committee in 1987, cancer risks were based mainly on epidemiological studies and in large part on the population of residents from Hiroshima and Nagasaki in 1950 (the Life Span Study) The data from this population were based on dose estimates made in 1986 (the Dosimetry System 1986 {DS86}) (Shimizu et al 1987) To validate these assessments additional human and animal populations were reviewed. For example, thirty-four additional studies were cited in support of the risk assessment for breast cancer Human Populations The BEIR V Report estimated risks for breast cancer respiratory tract cancer digestive tract cancer leukemia and other nonleukemia cancers The human populations used in the risk assessment were chosen based on the type of cancer For breast cancer four populations were used : residents of Hiroshima and Nagaski in 1950 (the Life Span Study), most of whom were exposed to the atomic bomb ; women examined by fluoroscopy in Canada for tuberculosis from 1930 to 1952; women examined by fluoroscopy in Massachusetts from 1930 to 1956 ; and women treated with radiotherapy for postpartum mastitis in New York during the 1940s and 1950s For respiratory and digestive tract cancers the population comprised residents of Hiroshima and Nagaski in 1950 (the Life Span Study) For leukemia, two populations were used : residents of Hiroshima and Nagaski in 1950 (the Life Span Study) ; and people treated with radiotherapy for ankylosing spondylitis in the United Kingdom from 1935 to 1954 A third population, women treated with radiotherapy in several countries for cervical cancer may have been used in the leukemia risk calculations however the BEIR V report is

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63 unclear on this point For all other cancers ( except leukemia) the study population was comprised of residents of Hiroshima and Nagaski in 1950 (the Life Span Study) Animal Populations In general the BEIR V report cancer risk assessments considered animal populations only when necessary to validate or understand data from human populations Animal studies raise numerous problems including extrapolation of results obtained under experimental conditions to the conditions relevant to population exposure such as dose rates fractionation, and other variables ; and extrapolation from an experimental organism in which radiation effects may be estimated with some confidence, to humans because organisms differ in radiation sensitivity Populations for Dete1 mining Genetic Risk The assessment for genetic risk relied on animal ( especially mouse) data to supplement human data To determine human genetic risk by extrapolating from animal data three assumptions were made : the amount of genetic damage induced by a given type of radiation under given conditions in the animal species was the same in human ge11n cells ; biological factors such as sex ger1n cell stage and age and physical factors such as quality of radiation and dose rate similarly affected genetic damage in the animal species and in humans; and the relationship between lowlinear energy transfer (LET) radiation and frequency of genetic effects was linear at low doses and low dose rates Genetic effects by definition require that at least one generation pass before they are expressed and their expression is affected by the exposed population's sex, age and probability of having children Genetic risks determined from human data are based on the assumption that all of the exposed population was of reproductive age and wanted to have children In the irradiation of an entire population, the reproducing people are a fraction of the total and damage to the ger1n cells of the nonreproducing people in the population does not

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64 pose a genetic risk When the irradiation is neither random nor uniform, as is true of the available human populations utilized in the risk assessment a reduction factor is required to adjust the genetic risk estimates Human Populations The BEIR V report used several human populations divided into three sets to assess genetic risk The first set consisted of people with genetic disorders resulting from spontaneous mutations These disorders included dominant autosomal disorders, sex linked recessive disorders recessive autosomal disorders, chromosomal abnorrnalities, congenital abno1 rnalities and other multifactorial traits Multifactorial traits are a group of disorders about which the exact mode of inheritance is unknown and include such diseases as diabetes mellitus, gout, schizophrenia, affective psychoses epilepsy, glaucoma hypertension varicose veins asthma, psoriasis, ankylosing spondylitis and juvenile osteochondrosis of the spine The second set consisted of people with genetic disorders resulting from several specific spontaneous mutations that were used to calculate mutation rates The disorders included dominant autosomal disorders and recessive sex-linked disorders The third set was the Hiroshima and Nagasaki survivors and their children including members of a pregnancy termination study, a cytogenetic study of the children of exposed parents an investigation of rare electrophoretic variants in children of exposed parents, and doubling dose studies Animal Populations In general, mouse populations were used to assess genetic risk when human data were unavailable or inappropriate A few data points were taken from monkey and marmoset studies The animals in these studies displayed a specific endpoint, such as dominant and recessive lethal and visible mutations reciprocal and heritable translocations congenital malforrnations and aneuploidy

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65 Dose-Response Curves A dose-response relationship or curve is detennined by the change in effect (response, the dependent variable) with increasing amounts of radiation ( dose, the independent variable) The relationship between dose and response is the primary problem in predicting the health risks of radiation (Cohrssen and Covello 1989) Deter1nining the radiation dose has been detailed in Chapter 3 Determining the response to radiation is difficult and the details of the process are beyond the scope of this research Although somatic effects (such as cancer) and genetic effects are the major responses to radiation, many intermediate conditions or specific endpoints may be used as measurements Among the many endpoints that are considered in nonhuman studies are clonogenic survival of cultured cells and for1nation of tumors and death in test animals In human studies effects such as chromosome abnor1nalities enzyme aberrations, tumorigenesis and leukemia are considered The effects of cancer and genetic damage are presumed to be stochastic ; that is, any level of irradiation increases the likelihood of inducing genetic damage or cancer ( no threshold relationship) Thus the dose-response relationship of interest presumably begins at the level of background radiation which varies from place to place This presumption is currently under great controversy as a threshold relationship is becoming more frequently used As these methodologies evolve the quantitative risk predictions of this research may need to be revisited Most experimental studies are conducted using high doses, because the effects of low doses of experimentally applied radiation are indistinguishable from those of natural background radiation in small experimental populations (UNSCEAR 1986) 1 These high doses are plotted against the responses to obtain a piece of the dose-response curve, and a mathematical relationship is used to determine the shape of the curve in the low-dose 1 The UNSCEAR defines low dose as less than 0 2 Gy (20 rad)

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66 region Mathematical relationships explain the two differently shaped dose-response curves most commonly applied to radiation data : linear and linear-quadratic ., as shown in Equations 1 and 2, respectively where R is response, D is dose and a and P are constants UNEAR : R = aD (Eq 1) LINEAR -QU ADRATI C: R = a D + /3 D 2 (Eq 2) The linear relationship extrapolates high-dose data along a straight line into the low-dose region where response is directly proportional to dose The linear-quadratic relationship is effectively linear at low doses but begins to rise more steeply with increasing dose because of a squared term in the mathematical expression Thus at high doses response is proportional to the square of the dose At low doses the linear relationship predicts a greater response than does the linear-quadratic relationship and is often considered as an upper limit Thus, the linear relationship provides a conservative estimate of dose useful for radiation protection purposes The BEIR V committee chose a linear dose-response curve for quantifying genetic risk and most cancer risks from low doses of radiation because the epidemiological data they reviewed were best described by this model For leukemi~ however the BEIR V committee used a linear-quadratic dose-response curve, which better fit the DS86 dosimetry data from the residents of Hiroshima and Nagasaki Dose-Rate Effects Since most of the data on radiation effects come from high doses they must be extrapolated to low doses, which describe most human irradiation, and the plain film examinations reviewed in this research Evidence from medicine and biology suggests that as dose and dose rate decrease, the effect per unit dose also decreases for low-LET radiation (NCRP 1980) Thus high doses and dose rates are more effective at causing

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67 damage than low doses and dose rates This difference is quantified by the dose-rate effectiveness factor (DREF) or dose and dose-rate effectiveness factor (DDREF) The effect of dose rate has been studied for numerous years For low-LET radiation the effect depends on several factors including repair of sublethal damage redistribution of cells in the mitotic cycle and compensatory proliferation of cells during protracted irradiation For high-LET radiation the dose-rate effect is much reduced The effect seems to apply both to cancer and genetic endpoints although the effect is not necessarily equal for either endpoint (BEIR 1990) The dose rate effectiveness factor is estimated using mouse or human data To reiterate with a linear-quadratic relationship, the dose response curve is approximately linear at low doses at the low end of the curve With a linear relationship the dose response curve continues to be linear at low doses Since it is extrapolated from high dose data along a straight line it predicts greater response at a given dose than does the linear-quadratic relationship The ratio of these two responses at low doses which is in effect the linear extrapolation overestimation factor, approximates the dose-rate effectiveness factor (Fabrikant 1990) These two models are shown in Figure 4-1 The solid circles represent hypothetical data for an excess incidence of cancer observed at relatively high doses Curve A represents a linear extrapolation ; curve B represents a quadratic relationship between incidence and dose ; curve C illustrates a threshold type of response which was previously discussed While all three models fit the high-dose data equally well the risk estimates pertinent to this research in the low-dose region are quite different according to which model is chosen for the extrapolation

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t w u z w a u z 0:: w u z <( u er, er, w u X w 68 .(. /. / .,9 / B ,/ / / -,,. / C ,,.. /.,# .. ,, .. .... ,; ___ ,_,,, t L OW-DOSE REGION X RA Y DOSE t HI G H -D O SE REG IO N Figure 4-1 Various models used to extrapolate high-dose data on cancer incidence to the low-dose region, so that risk estimates can be perfo11ned Redrawn from : Radiation Carcinogenesis in Mru1, United Nations Scientific Committee on the Effects of Atomic Radiation ( 1977) The most commonly cited range for dose-rate effectiveness factor is two to ten ; that is radiation at high doses and dose rates is from two to ten times more effective at causing damage than radiation at low doses and dose rates (NCRP 1980) Dose rate effectiveness factors are applied with care For example, as previously discussed BEIR V used a linear-quadratic relationship to model leukemia which would already predict reduced numbers of cases of leukemia at low doses and dose rates (BEIR 1990) The BEIR V committee also chose to fit separate dose-response curves for each cancer (Fabrikant 1990) and therefore did not use a dose-rate effectiveness factor The factor used in assessing genetic risk which was based on the ratio of genetic risk from high to low dose-rate irradiation of mice was approximately three Population Transfer Coefficients A number of uncertainties are involved in a risk assessment Some sources of uncertainty can be evaluated using conventional statistical theory and are incorporated into risk assessment parameters such as dose-response relationships and risk projection

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69 methods Other sources of uncertainties cannot be captured by the usual statistical techniques One important uncertainty addressed by the BEIR V report was that inherent in applying risks determined in one population to another population Referenced in a risk model as the population transfer coefficient, this issue was of major concern because the BEIR V methodology's risk assessment was primarily based on results from the Hiroshima and Nagasaki survivors applied to U S populations The extrapolation required assumptions about diets, industrial exposures, cancer rates and lifestyles in general The BEIR V committee recognized the population transfer issue to be a fundamental problem and considerable source of uncertainty in estimating risks The report chose to evaluate this issue by ''a consensus of expert opinion as to the uncertainty expressed in a number on a scale commensurate with ordinary statistical measures of variability' (BEIR 1990 page 220) The committee obtained this number by judging the range within which it was believed to lie with 95 percent confidence In this way all types of uncertainty both statistically calculated and estimated by consensus were evaluated together to obtain combined measurements of standard error and confidence intervals The committee thus estimated the uncertainty in population transfer to be 20% BEIR V Cancer Risk Projection Method Lifetable analyses using standard mortality tables that were modified to include an additional incremental risk from radiation were used by the BEIR V committee to calculate lifetime cancer risks from specific irradiation Input data for the lifetable analyses included radiation doses and parameters used in the assumed dose-response relationship (Bunger et al 1981) To comprehend a lifetable analysis of a standard mortality table consider a lifetime irradiation at a constant annual rate A lifetable analysis starts with a hypothetical

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70 population of one million newborns and the columns of the table provide the following information shown in Table 4-1 T bl 4 1 Li bl An l f S d d M a1 T bl a e eta e alvs1s o a tan ar ort 1t1 a e Number of Cancer Number of Number of deaths surviving infants death rate cancer cases from other causes The first column gives the number of infants expected to survive each age ; the second column gives the cancer death rate predicted by the dose-response curve ; the third co l umn gives the number of cases of cancer deaths ( which is the product of the first and second columns) ; and the fourth column gives the number of deaths from causes other than radiation based on mortality rates The number of infants surviving to each age (first column) less the number of radiogenic and nonradiogenic cancer deaths (sum of third and fourth columns) is the number of survivors at the beginning of the next age interval Thi s process continues with increasing age until the entire population is dead or until age one hundred (BEIR 1990 ) Quantifying excess cancer deaths from radiation is the key to projecting risks When the risk to ex.posed people exceeds the risk to unexposed people by the same amount at all ages the effect of the radiation is additive and the mathematical expression for this risk is thus an additive one This is often called the absolute risk because at all ages the excess risk is constant When the risk to exposed people exceeds the risk to unexposed people by a constant fraction the effect of radiation is multiplicati v e Also known as relative risk because at all ages after irradiation, the relative risk or risk ratio is constant the multiplicative relationship is the mathematical expression of this risk (Muirhead and Darby 1987 ) These two models are overly simplistic in projecting risk The BEIR V Committee permits the risk to vary as complex functions of time after exposure throughout the individual s lifetime This is demonstrated in Figure 4-2, which illustrates the Committee s preferred risk model for leukemia

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71 ATTAINED Figure 4-2 The risk of leukemia due to low LET radiation as a function of attained age Cancer risk projection requires knowledge of several parameters including the relationship between excess cancer risk and relative risk, the latency period or the time from irradiation to the first expression of excess cancer risk, the plateau period or the time from the first expression of excess risk until the excess cancer risk disappears the age distribution of the exposed population and the baseline pattern of age-specific mortality rates from all causes and from the cancers under consideration the age at irradiation and the dose-response function These parameters are brought together in the cancer risk projection model used by the BEIR V Committee The report used cancer risk projection to provide several measures of risk, i e ., estimating the probability of radiation-induced cancer death expressed as a percentage the number of projected cancer deaths expressed as deaths per thousand or million exposed people per unit dose and the number of years of life lost in an exposed population because of radiation-induced cancers All of these estimates however derive from a single measure of excess lifetime cancer risk chosen b y BEIR V as discussed in the next section The BEIR V Committee chose to use only multiplicative methods to project cancer risk The measure chosen by this committee was excess lifetime cancer risk, which is the increase in the lifetime probability that a person will die from a specific cancer as a

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72 result of a specific irradiation The method of lifetime excess risk estimation used in the BEIR V report differs slightly from those previously used In the BEIR V Report separate lifetime risks are estimated for an exposed population and for an unexposed population The unexposed population is assumed to be exposed to the same background radiation as the exposed population The excess cancer risk is simply the difference between the two lifetime risks (BEIR 1990) The parameter estimates used for the BEIR V cancer risk projections were obtained using AMFIT a program developed for the analysis of survival data Further discussion of some of these parameters provides more insight into the assumptions made by the BEIR V report and are reviewed in the next sections Specific Cause of Death As previously noted in the discussion on populations the BEIR V report projected risks separately for leukemia, breast cancer respiratory tract cancer digestive tract cancer and other nonleukemia cancers For leukemia deaths the BEIR V report assumed a two year latency period For deaths from other cancers a ten-year latency period was assumed Age of Population The age distribution of a population at the time of irradiation must be specified in order to predict the effect of that irradiation because some of the cancers used as endpoints depend strongly on age at irradiation For example, leukemia risks for people exposed before age 20 are much greater than leukemia risks for people exposed later in life (Vaeth and Pierce 1990) and risk varies as a complex function of age and time since irradiation (Thomas Darby et al 1992) For the cancers with the longer latency periods there is more uncertainty in the application of the BEIR V risk models Since there is nothing available that is more advanced than BEIR V the BEIR V methodology was

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73 utilized, recognizing that these results may need to be revised if the BEIR V models are revised. BEIR V Genetic Risk Projection Method The BEIR V report did not provide a direct estimate of the risk of total genetic damage stating that these estimates were highly uncertain because they did not include allowance for genetic diseases of complex etiology that may be caused by multiple factors The report suggested that these diseases make up the largest category of genetically related diseases and that further research was required before these probabilities could be estimated accurately The report did provide estimates of genetic effects for other types of genetic disorders however, the perfo1mance of these calculations are beyond the scope of this research This research will only utilize the BEIR V methodology to estimate the risk of radiation induced cancer utilizing the equations detailed in the following section Calculating the Relative Cancer Risk from Pediatric Diagnostic X-Ray Procedures The BEIR V report s general expression for calculating the total cancer risk, including natural and radiation-induced to a population is given in Equation 3 (BEIR 1990) A (d) =A O [1 + J(d)g(p)] or A (d) =A O + J(d)g(p)J 0 (Eq 3) where Ao is the individual's age and gender-specific mortality rate for a given type of cancer in the absence of a radiation exposure other than natural background ( or absolute age specific cancer risk to the unexposed population);.l{d) is a function of dose equivalent in Sievert ; g(f3) is the excess risk function for a specific cancer that depends upon gender age of the individual age at exposure and time since exposure ; and A(d) represents total

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74 fatal cancer risk The second term on the right of Equation 3, [1 + .f(d) g(f3)] therefore represents the radiation-induced fatal cancer risk The dose-response function,.f(d), depends upon the type of cancer involved The equations for.f(d), taken from BEIR V (BEIR 1990), are : Leukemia : Respiratory cancer : Digestive cancer : Other cancer : Female Breast Cancer : .f(d) = 0 243d + 0 27Id2 j(d) = 0.636d .f(d) = 0 809d .f(d) = 1 22d j{d) = 1 22d Similarly, the radiation induced cancer risk depends upon a number of factors that are incorporated into the excess risk function that has been discussed previously In the following equations for the excess risk function g(f3), E represents the age at exposure and T represents the number of years following exposure. Only the equations applicable to a one-year-old patient simulated in this research are presented For males : A Leukemia (latent period = two years) E 20; T .$ 15 : g(f3) = exp(4 885) = 132 3 B Respiratory cancer (latent period = ten years) g(f3) = exp[-1 437 ln(T / 20)] C. Digestive cancers (latent period = ten years) E 25 : g(f3) = exp(O) = 1 0 D Other cancers (latent period = ten years) E 10 : g(f3) = 1 0 For females : A. Leukemia (latent period = two years) E 20 ; T .$ 15 : g(f3) = exp(4 885) = 132 .3

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75 B Respiratory cancer (latent period = ten years) g(P) = exp[-1 437 ln(T / 20) + 0 711] C Digestive cancers (latent period = ten years) E 25 : g(p) = exp(0 553) = 1 74 D Other cancers (latent period = ten years) E 10 : g(P) = 1 0 E Breast cancers (latent period = ten years) E < 15 : g(p) = exp[l 385 0 104 ln(T / 20) 2 21 ln 2 (T / 20)] The values of g(P) were dete11nined for each gender for an exposure that occurs at an age of one year and the time post-exposure was chosen to be five years past the latency period for each different type of cancer The five year post-latent time period was chosen by plotting g(p) as a function of time for each cancer and gender as shown in Figures 4-3 through 4-9 These illustrations only extend to 25 years, but the elevated risk continues further into the future The five year post-latent time period was chosen as representative of all the cancer models but was initially based on the leukemia cancer model because that is approximately in the middle of the time interval of maximum risk for leukemia as shown in Figure 4-3 m C, 150 100 50 0 '----'-----------0 5 10 15 20 25 30 Time (years) Figure 4-3 Time dependent risk for exposure at age equal to one year for both male and female leukemia models

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2.5 2 m 1 5 C, 1 0 5 76 o ,.__ ____ __._ _________ 0 5 10 15 20 25 30 Time (years) Figure 4-4 Time dependent risk for exposure at age equal to one year for male respiratory cancer model 0 8 0 6 0 4 C, 0 2 0 ,.__ ___ L..__ _____ 0 10 20 30 Time (years) F i gure 4-5 Time dependent risk for exposure at age equal to one year for female respiratory cancer model

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1 2 1 0.8 0 6 C, 0 4 0 2 0 0 5 10 15 Time (years) 20 77 25 30 Figure 4-6 Time dependent risk for exposure at age equal to one year for male digestive cancer model m C, 2 1 5 1 0 5 O L---------'---0 5 10 15 Time (years) 20 25 30 Figure 47 Time dependent risk for exposure at age equal to one year for female digestive cancer model 1 2 1 0 8 0 6 c, 0 4 0 2 0 0 5 10 15 Time (years) 20 25 30 Figure 4-8 Time dependent risk for exposure at age equal to one year for both male and female other cancer models

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3 2.5 2 1 5 en 1 0 5 78 O L--------'-------0 5 10 15 20 25 30 Time (years) Figure 4-9 Time dependent risk for exposure at age equal to one year for female breast cancer model The values of/{ d) were determined utilizing the effective doses calculated in Chapter 3 rather than dose equivalent since effective dose is the most current and comprehensive measure The values of g(p) were then multiplied by the appropriate value of/{d) and the relative risk predicted by the [1 + /{d) g(p)] terrn in Equation 1 was detet rnined using these variables for each procedure simulated The calculation of the relative risk for specific pediatric exams are petformed in Chapter 5

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CHAPTERS RESULTS AND DISCUSSIONS Facility Approach to Handling Special Concerns of Pediatric Patients The child is not a small adult This aphorism is a mantra for any discussion of pediatric radiology ; it is particularly pertinent to the specifics of technique Most general diagnostic radiologists and radiologic technologists are uncomfortable examining an infant or young child Unfortunately this uneasiness may be transmitted to the pediatric patient and frequently to the parent The result is often an inadequate examination that is either confusing or uninterpretable and requires retakes, ultimately yielding an increase in radiation dose to the patient (Kirks and Griscom 1998) Pediatric imaging is no better than its techniques and technologists Thus special approaches are required to handle pediatric patients Children are frequently apprehensive in the hospital setting These feelings are compounded by fear of the unknown and the pain so often associated with doctors and hospitals As a result not all technologists enjoy working with children ; many become frustrated by the lack of cooperation of infants and by the time required for pediatric examinations and there are therefore dedicated pediatric technologists All of the pediatric technologists involved in the site surveys appeared to be conscientious and dedicated individuals who enjoyed working with children and had sufficient patience but firmness to develop the rapport to handle pediatric patients Reducing the child s fright and obtaining his or her trust is of great benefit to the patient psyche and adds to the technologist s ability to carry out high-quality examinations 79

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80 There are many different ways of successfully approaching a child and certain basic guidelines were observed during the site surveys that appeared to be adapted to individual technologist styles and personalities Of greatest importance is obtaining the pediatric patient's trust Obtaining trust can be difficult with any child but is especially difficult with a child who is ill and suddenly finds herself or himself, in a strange environment Creating an environment in which a child feels unthreatened and comfortable is a challenge to hospital designers Children enjoy stimulating surroundings and require something to occupy their time while waiting for a procedure to be performed The environment must accommodate the parent s needs in addition to those of the child Since the first area encountered in a radiology department is usually the waiting room, furniture appropriate to both parents and children should be available For the departments in the site survey that had dedicated pediatric facilities, an area equipped with tables and chairs to accommodate children s activities was commonly found Unbreakable toys puzzles games coloring books crayons and storybooks were observed in all of the surveyed facilities In the majority of surveyed facilities the room commonly used for pediatric examinations had a mural painted on the wall or a myriad of stuffed animals on the shelves to provide a soothing entertaining atmosphere for the child One of the facilities visited had the x-ray equipment itself painted in a jungle motif and the table and lift decorated to resemble a boat ; patients were told to relax and enjoy the jungle boat ride Most pediatric rooms also carefully kept all medical paraphernalia out of sight but had accessory equipment such as sponges sandbags and restraining devices readily accessible from the tableside All of the pediatric technologists interviewed indicated that the key to establishing rapport with a child is truth and honesty As children are not only inquisitive, but very perceptive, they should never be lied to All of the technologists attempted to establish a good cooperative relationship with the child by initiating a conversation with the child about things that interested him or her Chatting often enables the child to relax and

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81 increases their willingness to help with the study The technologists always explained the procedure fully to the patient no matter how young the child was in words that could be understood The technologists felt this knowledge not only helped to lower the patient s anxiety but also increased their credibility. Children like to be talked to and feel reassured and comforted by participating in an interesting conversation This technique also worked with infants who seemed to feel more secure when they heard a friendly voice A major aid utilized by all the surveyed facilities to decrease parent and patient anxiety was to furnish them with a simple printed explanation of the procedure when the appointment is initially made The technologists felt this proved to be a great help in getting the patient to relax and be cooperative Scheduling the appointment to coincide with the child s routine was also important although obviously not always practical All technologists expressed the preference to not x-ray children under the age of five between noon and 4 : 00 P M ., as that is when most children are eating lunch and talcing naps. The technologists preferred to perform the procedures in the morning when the children were rested, refreshed, not a lot of doctors had poked at them, and nothing really overwhelming had happened to them yet Children cannot handle the procedure as well later in the afternoon because they are tired stressed out and they have reached their limit for the day In obtaining the child s cooperation, it is often helpful to give him/her a small degree of control over the circumstances For example, a teddy bear or a security blanket may be placed as the child wishes or the choice of a particular Band-Aid or color of hospital gown may give the child the feeling that he / she can still influence this new environment Another method of helping children feel in control of the situation is to tell them what they re going to do during the exam The most successful technologists observed would say 'You re going to stand up here and do this then you re going to tum around and do that, I m going to do this and then you re finished! '' rather than '' Come on in here and let s take some pictures .'' Another example often recalled by the technologists included emphasizing what s positive e g asking a child to show them how long they

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82 could hold still rather than telling the child 'Don t move .'' It is worthwhile for the child to understand that he / she is an active participant in this important procedure that is being performed on his/her behalf Children often want to help adults and the sick child is no exception The phrase 'Now I need you to help me' was heard frequently during the site surveys Parent in v olvement in the procedure varied from site to site and appeared to be a controversial issue At most of the facilities parents were invited to be present in the radiography suite for all plain film examinations as most young children are more cooperative during radiographic procedures when a parent is present Separation from parents can be very stressful for young children and the presence of the parent may make the child more cooperative by diminishing the fear of being deserted in a strange place During the explanation of the exam, the technologist can determine the child s response to the new environment and decide which parent will make the most effective assistant It was common to invite only one parent to accompany the patient into the radiographic suite A careful explanation of the procedure enhances the ability of the parent to assist the technologist and provides reassurance to the child Parents sometimes feel guilty that their child has suffered an accident or illness and allowing them to assist may help to ea s e their anxiety as well The technologists also made it clear that if the parent became upset with the procedure or were disruptive to the achievement of good rapport with the child they would not hesitate to ask them to leave the room The technologists indicated that the possibility that a parent may be asked to leave is often sufficient encouragement for the child to cooperate in the study as is the thought of having to repeat the procedure The technologist also made it clear to the child that the examination he/she is undergoing is necessary and inevitable and that he / she has no choice in the matter The idea that the technologist is 1:he boss ' was also made clear to the child The technologists routinely stressed the importance of immobilization to the parent If immobilization devices are used the parent can assist in placing the child in the device although most technologists

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83 seemed to prefer to do this themselves so that the parent just provided moral support and could '' come to the rescue '' when the procedure was over Parents can also demonstrate to the child what will take place during the exam The technologists indicated that man y children balk at instructions from an instinct of self-preservation as children will not tum their backs to complete strangers in complete medical settings especially if they have had rectal exams lumbar punctures or shots Getting the child into the appropriate position was often accomplished with the use of stickers on the wall at the point where children of differing heights would be looking The children were then told to look at and count the stickers appropriate to their height Often, animal stickers would be scattered about the mural previously discussed The children are then instructed to try and spot as many stickers as possible and choose a favorite ; they are then told to hold very still because if they move the animal sticker will run away Bargaining with lollipops and stickers is a common technique (however many children possess uncanny negotiating skills) Many such games were observed Of additional benefit to the technologist the parent can serve as an extra set of hands and eyes to ensure the child s safety while on a radiography table or in a restraining device, since toddlers are very active Finally the child needs to be rewarded for good behavior and for contributing to the success of the exam The technologists felt this was important for symbolic value and hopefully left the child with a relatively good feeling about a potentially negative experience Verbal praise was observed to be administered copiously throughout the procedure and subsequently in the parent s presence at the completion of the exam To quote Mary Francis Sheppard Supervisor of Pediatric Radiology at Shands at UF and lead pediatric radiologist 'It s of great benefit and costs nothing ." All facilities also distributed a variety of stickers lollipops coupons or small toys Younger children are sometimes inconsolable and will cry or struggle even under optimal circumstances In these situations it was observed that performing the exam quickly and efficiently is the best thing that can be done Pacifiers appeared to be helpful

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84 as was a soothing continuously talking voice It was observed that the technologist would always talk to the child even if he / she was screaming crying looking away or pretending to talk to someone else Frequently the children who seemed to be ignoring the technologist were actually paying close attention A common ploy used by the technologist would be to keep asking the child questions during all the screaming and slide in the question if they wanted to go home and if they answered then the technologist knew they were listening Although most parents would tell their child to not cry the technologist would tell them that crying is preferable to biting kicking or spitting as a method to relieve their stress To consistently obtain high-quality radiographs in agitated children is a technically demanding task but the overall observation from the site surveys was that success was possible with thought care time and patience The following poem by pediatric radiologist Leonard E Swischuk, M D ( 1997) was posted in a majority of the surveyed facilities and accurately depicts the approach a facility should follow with pediatric patients A bundle of movement so awkward to hold Crying and crying for minutes untold Perpetual motion so hard to contain, Your charisma and patience it truly can strain Your very first thought may prompt a retreat You ll want to give up and concede to defeat But before you pack up and go screaming away Just think for a moment this babe needs you today Hold him awhile help him adjust Restrain his momentum, it s almost a must You 11 not really hurt him, if his arms you must bind Just stay in command be gentle and kind There is nothing so fine as to take a babe home And nothing so hard as to leave him alone So help little Jack, and somebody s Jill Their mothers and fathers sure hope that you will

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85 Patient and Examination Trends Although the workload distribution of examinations were significantly different between hospitals the same examinations tended to predominate in each hospital As shown by the survey data in Appendix C the numerical workload was dominated by the data for the hospitals with the most beds and any statistical comparison among the hospitals would be of little value Looking only at the examinations identified from the initial survey at Shands at UF it was seen that these examinations listed in Table 2-4 were represented in each hospital sample The purpose of this survey was only to characterize the examinations that were most commonly employed and not to establish their precise frequencies In adult examinations, the assumption that the field size equals the film size is usually made for organ dose calculations This assumption is not representative of pediatric radiography where an unexposed margin was seen on the majority of films in the various hospitals surveyed The field sizes used on the phantom in this survey represent the fields used in actual clinical practice This section illustrates the exams included in the site survey in each of the figures The left hand illustration is an actual patient x-ray obtained from Dr Jonathan Williams teaching and case file and the right hand illustration is the comparable view of the one year-old anthropomorphic phantom Note that the dosimeters leads and drill holes are frequently visible in the phantom images The anatomical features shown in the projection in Figure 5-1 demonstrate the petrous ridges that are projected through the lower third of the orbits The organs of hearing and balance are housed in the petrous pyramids The petrous ridges are the upper border of these pyramids

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86 Figure 5-1 AP Skull The anatomical features that are best shown in Figure 5-2 in lateral skull radiographs are cranial bones facial bones nasal sinuses sellae turcica anterior and posterior clinoid process dorsum sellae the mandible and the upper segments of the cervical spine F i gure 5-2 Lateral Skull The anatomical features that are best shown in radiographs utilizing Townes view in Figure 5-3 are the occipital bone the posterior foramen magnum, the dorsum sellae the posterior clinoid processes the petrous bones and the temporomandibular joint

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87 Figure 5-3 Townes Skull Anatomical features best shown with the AP cervical spine projection in Figure 5-4 are C-3 to C-7 vertebral bodies spaces between pedicles intervertebral disc spaces and spmous processes F i gure 5-4 AP Cervical Spine Cervical vertebral bodies intervertebral joint spaces articular pillars spinous processes and zygapophyseal joints are shown with the lateral view in Figure 5-5

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88 Figure 5-5 Lateral Cervical Spine Anatomical features best shown with the AP thoracic spine projection in Figure 56 are thoracic vertebral bodies intervertebral joint spaces distance between pedicles spinous and transverse processes posterior ribs and costovertebral articulations F i gure 5-6 AP Thoracic Spine Thoracic vertebral bodies intervertebral joint spaces and intervertebral foramina are shown with the lateral breathing view in Figure 57

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89 Figure 5-7 Lateral Thoracic Spine Anatomical features best shown with the AP lumbar spine projection in Figure 5-8 are lumbar vertebral bodies, intervertebral joints spinous and transverse processes laminae, and SI joints and sacrum f F i gure 5-8 AP Lumbar Spine Anatomical features best shown with the lateral lumbar spine projection in Figure 5-9 are lumbar vertebral bodies intervertebral joints spinous processes L-5 to S-1 junction, sacrum and first four intervertebral foramina

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90 Figure 5-9 Lateral Lumbar Spine The anatomical structures visualized with the AP abdomen projection in Figure 510 are liver spleen, kidneys abnot tnal masses calcifications or accumulations of gas pelvis lumbar spine and lower ribs Figure 5-10 AP Abdomen The anatomical structures visualized with the AP pelvis projection in Figure 5-11 are the pelvic girdle L-5 sacrum and coccyx, femoral heads, neck and greater trochanter The anatomical structures visualized with the AP frog-leg pelvis projection are the femoral heads neck and greater trochanteric areas

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91 Figure 5-11 AP Pelvis The anatomical structures best shown with the AP hip projection in Figure 5-12 are the acetabulum, femoral head neck, and greater trochanter The lateral view of the acetabulum and femoral head and the neck and trochanteric area are best shown with the frog leg hip projection Figure 5-12 AP Left Hip Anatomical structures best shown with the Waters view in Figure 5-13 include frontal sinuses the maxillary antra the orbits and the petrous bones The lateral sinus view shown in Figure 5-14 demonstrates all the paranasal sinuses and the nasopharynx Imaging the sinuses in patients under the age of two appeared to be a controversial issue as most facilities believed that the views provide very little inf or111ation although they are frequently requested However Swischuk states that such ideas as '' sinuses are not present in patients under two years of age '', '' sinusitis does not occur in patients under two

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92 years of age '' and ''the sinuses can be obliterated in association with crying in the infant '' are all slowly being discarded since it is certain that maxillary and ethmoid sinus cavities are present in infants and when they are opacified they are abnormal ( 1997) Figure 5-13 Waters Sinus Figure 5-14 Lateral Sinus The chest projections shown in Figures 5-15, and 5-16 respectively reveal lungs including apices and trachea, heart and great vessels, diaphragm (including costophrenic angles for the AP projection and the posterior costophrenic angles for the lateral projection) and bony thorax

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93 Figure 5-15 AP Chest Figure 5-16 Lateral Chest The following sections detail the survey results and the techniques summarized in Appendix C As has been previously stated the image quality of a pediatric exam is no better than its radiologic technologist ; however their ability to produce quality films depends upon the equipment they have to use at their disposal Generators The effective radiographic voltage depends on the type and age of the generator Considering the very short exposure times required for pediatric examinations a nearly rectangular radiation waveform and a minimal amount of ripple are desirable for pediatric patients 1, 2and 6-pulse single phase generators cannot generally provide this 12

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94 pulse three phase high frequency or direct current constant potential high voltage generators are required High milliamperage ( 400-600 mA, 800 mA maximum) pennits shorter exposure times so motion is not a problem even in the uncooperative infant or young child yet low milliamperage settings are also required in small infants This means that the smallest patients need the most powerful machines As seen in Appendix C two of the facilities in the site survey have high frequency generators one has a single phase generator and the remainder have three phase systems The range ofkVp utilized by each facility for each exam surveyed is illustrated in Figure 5-17 These facilities were specifically chosen to survey each type of generator available It should be noted that workload and patient flow patterns also dictate the type of equipment needed for general applications if a room is not dedicated for pediatrics 100 9t .. kVp ,o '' ~~~--,....J I 2 I ' I p 10 Facility ID Surveyed Exams 90-100 80-90 D 70-80 60-70 50-60 Figure 5-1 7. Range of kVp used for the 17 surveyed exams Exposure Time In pediatric imaging exposure times must be short which necessitates the high mA stations previously discussed This is only possible with powerful generators and tubes a s well as optimal rectification and accurate time switches The various output mAs employed by each facility for each e x am surveyed is illustrated in Figure 5-18

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IIO 70 60 mAs ,o )0 10 I l 3 s 6 1 Facility ID I !> 10 95 Surveyed Exams Figure 5-18 Range of mAs used for the 17 surveyed exams Focal Spot Size 80-90 D70-80 050-60 D 30-40 D20-30 10-20 00-10 A focal spot size between 0 6 and 1 3 mm edge length was used at all facilities ; all the facilities used the small focal spot for the chest examinations The facilities that didn t use the smaller focal spot for the remainder of the examinations were the non-dedicated pediatric facilities that had bi-focal tubes where the focal spot size that allowed the most appropriate setting of exposure time and voltage at the chosen SID most commonly used was the large Additional Filtration The soft part of the radiation spectrum that is completely absorbed in the patient is useless for the production of the radiographic image and contributes unnecessarily to the patient dose Part of it is eliminated by the inherent filtration of the tube, tube housing and collimator but this is insufficient Most tubes have a minimum inherent filtration of 2 5 mm Al Additional filtration can further reduce unproductive radiation and thus patient dose Pediatric radiation dose should be kept low particularly when high speed film-screen combinations are used As previously discussed not all generators allow the

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96 short exposure times that are required for higher kV technique Consequently very low voltages were frequently observed being used for the pediatric studies surveyed Adequate additional filtration allows the use of higher voltage with the shortest available exposure times, thus overcoming the limited capability of such equipment for short exposures This makes the use of high speed-film combinations possible In all of the facilities surveyed additional filtration of up to 1 mm aluminum or 0 1 mm 0 2 mm of copper equivalent appeared to be present as shown in Figure 5-19 4 c( 3 E E 2 ..J > 1 :c 0 1 2 3 4 5 6 7 8 9 10 Figure 5-19 Range ofHVL Grids Facility ID Grids are composed of alternating strips of lead and interspaces of plastic or aluminum The lead strips are designed to attenuate the scattered radiation and the plastic or aluminum interspaces to allow the passage of the primary radiation Grids are placed between the patient and the film and are an inherent component of either the chestboard or the table bucky The majority of the dedicated pediatric facilities either had grids that were removable from their chestboard or shot cross-table x-rays if the exam was performed on the table and the grid was not preferred Grids are described according to their grid ratio which is the ratio of the height of the lead strips to the distance between them The higher the ratio the more radiation the grid absorbs and hence the more radiation is required to penetrate the patient and the grid to reach the film

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97 In pediatric patients, radiography should be perforrned without grids, as the tissue volume irradiated is small and there is little scatter The radiation dose to the pediatric patient can be significantly reduced by omitting the grid The survey showed that all chest exams were performed without a grid except in facilities where it was impossible to remove the grid The abdomen pelvis spine and skull exams were all performed with a grid Grids with 10 : 1 ratios were found in most of the facilities Facilities that used a general purpose x-ray room for their pediatric studies in which k:ilovoltages of more than 100 kV were commonly used had 12 : I linear grids installed Cassettes The front of a cassette is made of a minimally attenuating material such as carbon fiber The back of a cassette is covered on the inside with a sheet of lead foil to absorb rays and reduce backscatter, which would reduce image quality Cassettes are important for providing proper film-screen contact Poor screen contact resulting from air pockets being trapped between screens and film as the cassette is closed will spread the light emitted from the screen, and blur the recorded radiographic image If the film-screen contact is too tight pressure artifacts are produced and structural screen mottle is accentuated Cassettes should be properly handled and routinely tested for film-screen contact to produce acceptable images and reduce retakes Because pediatric patients range in size from the newborn to the young adult each facility had a spectrum of cassette sizes available The cassettes most commonly used included 20 cm x 25 cm (8 '' x 1 O '' ), 24 cm x 30 cm (1 O' x 12 '' ), 28 cm x 36 cm (11 '' x 14 '' ) and 35 cm x 43 cm (14 '' x 17 '' ) with various other smaller and larger sizes for special applications A variety of cassette manufacturers were utilized in the surveyed faciltities including Kodak, DuPont/Sterling and Fuji

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98 Film-Screen Combination Among the technical parameters the selection of higher speed classes of the film screen combination has the greatest impact on dose reduction In addition it allows shorter exposure times that minimize motion unsharpness which is the most important cause of blurring in pediatric imaging Only one facility utilized a 600 speed system ~ the remainder utilized 400 speed systems The reduced resolution of higher speed screens is the limiting factor in the choice of higher system speed Most facilities also had different sets of cassettes available for special indications with screens of the lower speed and higher resolution Source-linage Distance {SID) There are no differences from adult patients for this item The SID is usually 101 cm ( 40 '' ) for tabletop tubes with grids and 182 cm (72 '' ) for chestboard stands When no grid is used and the cassette is placed upon the table the same tube-table distance as with a grid was usually observed Slight departures from these distances were technologist preferences Automatic Exposure Control Adult patients vary in size but their variation is small compared to the range in pediatric patients Most facilities accomodate this range by utilizing manual techniques yet one would expect that an automatic exposure control (AEC) device would be helpful in this situation However, many of the systems commonly available are not satisfactory for this purpose They have relatively large and fixed ionization chambers Neither their size nor shape or position is able to compensate for the many variations of body size and body proportion in pediatrics patients In addition, the usual ionization chambers of AECs are built in behind the grid Consequently AEC use may be associated with the use of the grid where the grid is not removable Specially designed pediatric AECs have been tested which utilize a small mobile ion chamber for use behind a lead-free cassette The position of the detector can be selected with respect to the most important region of interest This

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99 would need to be perfo1med extremely carefully as even minor patient movement would throw off the detector's reading Since the high speed of modem screens require a minimal dose at the front of the cassette the detector behind the cassette would be required to work in a range at a fraction of the entrance dose It has proven difficult to ensure reproducibility in this range and is an area for future research Manual techniques are the preferred method of radiographing pediatric patients The majority of facilities that utilized manual techniques had generated their technique charts either through experience or through the utilization of a variety of sizes of frozen game birds, for example a game hen would mimic a neonate Field Size and Collimation Inappropriate field size is the most important fault in pediatric radiographic technique A field which is too small will immediately degrade the respective image criteria A field which is too large will not only impair image contrast and resolution by increasing the amount of scattered radiation but also result in unnecessary irradiation of the body outside the area of interest Consequently the anatomical areas specified by the respective image criteria define the minimum and the maximum field sizes although some degree of latitude is necessary to ensure that the entire field of interest is included Correct collimation requires proper knowledge of the external anatomical landmarks by the technologist These differ with the age of the patient according to the varying proportions of the developing body In addition, the size of the field of interest depends more on the nature of the underlying disease in infants and younger children than adults For example the lung fields may be extremely large in congestive heart failure and pulmonary diseases or the position of the diaphragm may be very high in digestive diseases Therefore a basic knowledge of pediatric pathology is required for technologists to ensure proper collimation in these age groups As shown in Appendix C

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100 the facilities that paid strict attention to tight collimation were all dedicated pediatric facilities or conscientious technologists although all facilities had unexposed margins Radiographic Film Quality Film blackening has a major influence on image quality For the same radiographic projection, film blackening depends on many factors : radiation dose, radiation quality, patient size, radiographic technique, image receptor sensitivity and film processing Film blackening determines the optical densities of a radiographic film The optimal range of the optical density (D) is between D = 0 5 and D = 2 0 (net density i e over fog and base) with a mean optical density ofD = 1 2 Films with a mean optical density of less than D = 0 4 or more than D = 2 0 usually possess inferior infortnation content Figure 5-20 illustrates the net lung optical densities for AP chest, PA chest and lateral chest films respectively, perfor1r1ed at each facility The majority of the facilities surveyed were in the optical density range between D = 1 0 and D = 2 0 It should be noted that the degree of film blackening is also subject to the personal preference of the individual radiologist AP PA Lateral 3 2 5 2 1 5 i 1 0 0 5 ~3 Ill C: GI 0 2 1 Q. 0 >, = 2 5 Ill C: 2 1 5 CV 1 Q. o 0 5 .. GI 0 z 0 z 0 z 1 2 3 4 5 6 7 8 9 10 Facility ID 1 2 3 4 5 6 7 8 9 10 Facility ID 1 2 3 4 5 6 7 8 9 10 Facility ID Figure 5-20 Net lung optical densities for AP chest PA chest and lateral chest films Repeat Analysis Repeat analysis involves an assessment of how many and why images are being re taken Most radiology departments save their spent film for silver reclamation which are periodically collected from the waste film bin and evaluated It is important to know the time period over which the films were collected and how much total film was used in the department. The thrown out films are collated into different categories Discarded

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101 radiographic films with patient anatomy on them constitute the repeat category The repeat rate is calculated as the fraction, or percentage, of films that were repeated Repeat films are a technical concern as these films represent repeated radiation exposure to the patient The repeated films can be broken down into subcategories such as overexposed underexposed motion problems and improper positioning Retake rates in excess of 10% are cause for concern Repeat rates for each surveyed facility are shown in Figure 5-21 none of which exceed 10% It should be noted that one facility with a low repeat rate is filmless utilizing a computed radiography (CR) system and generally only uses film when the CR system is nonoperational Computed radiography uses photostimulable phosphor plates to capture x-ray exposure patterns rather than screen/film combinations CR is advantageous because it has a wide dynamic range and can therefore produce diagnostic quality films with suboptimal x-ray techniques resulting in reduced repeats For the purposes of this research the facility agreed to go back to using film-screen combinations 10 8 0 GI ,; 6 a: ,; GI 4 a. 2 0 1 2 3 4 5 6 7 8 9 10 Facility ID Figure 5-21 Repeat percentages per facility It is important to realize that the repeat rate for an institution is not necessarily a good parameter for evaluating the quality between different facilities Radiology services that produce poor images and where the radiologists will read anything will generally have low retake rates, but may not necessarily exhibit high quality Departments with radiologists who demand high quality images from the technologists may exhibit higher retake rates, but yield better diagnostic results

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102 Radiation Protection For all examinations of pediatric patients good radiographic technique includes lead rubber shielding of the body in the immediate proximity of the diagnostic field The body is thus protected from external scattered and extrafocal radiation For exposures of 60-80 kV utilized in this research a dose reduction of about 30-40o/o can be achieved by shielding with O 25 mm lead equivalent rubber 4-6 cm away from the boundary of the primary beam This is only true when the protective device is placed correctly at the field limit Lead-rubber covering further away away from the boundary of the primary beam is less effective and at a distance greater than 6 cm is completely ineffective ; it may have a psychological effect but provides no radiation protection at all For pediatric chest radiography, lead shields that are appropriate to the patient s size are placed over the gonads when the study is perfortned with the patient in the supine position When the child is examined in the upright position, a small lead apron is placed around the waist For abdominal radiography shielding should not be used for either the upright or supine studies in pediatric female patients The gonads are shielded when studies of the abdomen are performed on male patients There is some controversy as to the most appropriate shielding for radiography of the hip of a child Generally only one of the two views of the hips requires gonadal shielding for the first study on female patients ; gonadal shielding is used for both views in all subsequent studies Studies on male patients require gonadal shielding to be used for both views of the hips including those of the first study General studies of the female pelvis as opposed to hip exams, do not require gonadal shielding ; the male gonads are always shielded when the pelvis is radiographed For radiography of the head nee~ cervical and thoracic spines, small lead aprons are placed over the pelvis for all of these studies in pediatric patients No shielding can be employed for the AP lumbosacral spine in pediatric female patients However shielding should be used for both views of male

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103 patients and for the lateral view of female patients The fact that male gonads are always shielded is reflected in the effective dose results detailed in the next section Organ Doses per Entrance Skin Exposure and Effective Doses The one-year-old phantom was used to evaluate the organ doses from several plain film radiographic examinations The radiographic examinations chosen for simulation were those discussed in the previous section for projections common in pediatric radiology and are common projections performed at Shands at the University of Florida Due to the limited time availability at each facility, dosimetry measurements were only perfortned for the chest series of examinations at statewide facilities The x-ray system utilized for the measurements perfo1111ed at Shands at UF was a three phase system with 3 07 mm Al filtration Tube potentials used were typical of what is currently used in practice at Shands at UF and other hospitals which ranged from 60 kVp to 95 kVp The results for the 27 exams at Shands at UF are given in Appendix E There are three data sheets per exam in Appendix E except for the head series which only has two data sheets The first two pages and the top half of the third page of the data sheets are associated with the MOSFET dose measurements and the effective dose information, and the bottom half of the third page of the data sheets contain the risk estimation information Correspondingly for the head series the first page and the top half of the second page of the data sheets are associated with the MOSFET dose measurements and the effective dose infortnation and the bottom half of the second page of the data sheets contain the risk estimates Eight high sensitivity MOSFET dosimeters were available for the majority of the dose measurements The MOSFET locations are shown in the data sheets of Appendix E The one-year-old phantom was loaded with MOSFET dosimeters in areas applicable to

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104 the exam being simulated For example the right arm, left arm, skulVfacial thyroid and spine head positions were loaded first for the skull series The two groupings of MOSFET detectors are shown in the data sheet in the organ/position column The first eight organ/positions correspond to the first group and the next eight organ/positions correspond to the second group Areas on the data sheet without data indicate that the MOSFET measurements were not made at those locations as the dosimeters were located well out of the field of view If a position was monitored and a negative reading was obtained an absorbed dose of zero was assigned The MOSFET measurement is the difference between the voltage measurement of the MOSFET device held at a high bias and the voltage measurement of the MOSFET device held at a low bias ; therefore there is a statistical probability of obtaining small negative readings from the Patient Dose Verification System Negative readings are actually quite common when the device has received no absorbed dose since the MOSFET device with the high bias experiences more ion recombination than the low bias device The last data sheet contains an effective dose calculation for each of the exams The pediatric technologist was asked to simulate each exam as if the phantom were an actual one-year-old ; technique factors specific to the exam were then obtained The absorbed organ dose for this study was obtained by applying a ratio of the actual techniques (m.As) used for the clinical exam to the techniques used to obtain accurate absorbed dose data previously described Tissue weighting factors from Table 3-1 Chapter 3 were then applied The average of the absorbed dose between the two lungs was used multiplied by the lung tissue weighting factor for the lung contribution to the effective dose The same procedure was applied to the left and right ovaries The ovary dose was used for the gonad contribution to the female effective dose calculation and the testes dose was used for the gonad contribution for the male The active marrow bone surface remainder and

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105 skin doses were calculated with the procedure outlined in Chapter 3, and the respective tissue weighting factors given in Table 3-1 were applied The effective dose is gi v en in Table 5-1 for each procedure petfor1ned at Shands at UF and for both males and female s. As expected the exams with higher effective doses reflect the areas of the exposed bod y which contain more radiosensitive organs such as the thoracic and lumbar spine and the abdomen and pelvi s. Female exams also require more attention as their resultant doses were higher than male exams in all cases but one A comparison of the effective doses from the chest examinations among facilities is shown in Table 5-2 Facilities # 3 #4 and # 7 all yielded larger effective doses than the other facilities Some of the possible reasons for the higher effective doses include : Facilities # 3 and #4 are both community hospitals whose patient population is biased towards indigent care ; therefore their protocols are not optimized for pediatric patients Facility # 4 did not utilize a dedicated pediatric technologist The radiologist staff at Facilities # 3 and #4 also prefer a higher degree of film blackening as shown by Figure 520 Facility # 7 utilizes the CR system and demonstrates that although collective doses may be decreased by decreased repeats individual patient doses may be higher since technique factors are not as carefully tracked when CR s post-processing capabilities are available Facilities #4 and # 7 also did not use a manual technique but relied on the AE C system The problems with utilizing AEC units constructed for adult anatomy on pediatric patients has been previously discussed but would only be applicable to Facility #4 as Facility #7 has a dedicated pediatric chest unit Modification of these practices would reduce their doses In general, the facilities that followed the recommended practices discussed for dose reduction, did deliver lower effective doses

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106 Table 5 1 Effective Doses for Male and Female One-Year-Olds at Shands at UF Examination AP Skull Male or Female AP Skull w / thyroid s hield Male or Female PA Skull Male o r Female PA Sk.7lll w / thyroid shiel d Male o r Female LAT Skull Male o r Female Townes Skull Male or Female AP Cervical Spine Male or Female LAT Cervical Spine Male or Female AP Thoracic Spine Male or Female LAT Thoracic Spine Male Fem ale AP Lumbar Spine Male Female LAT Lumbar Spine Male Female AP Abdomen Supine Male Female PA Abdomen Supine Male or Female AP Abdomen Upright Male Female AP Pelvis Male Female AP Hip Male or Female Waters Sinus Male or Female LAT Sinus Male or Female AP Sinus Male or Female LAT Chest Male or Female AP Chest Male o r Female AP Chest w/bladder shield Male or Female PA C he st Male or Female LAO Chest Male or Female RPO Chest Male or Female RAO Chest Male o r Female Effective Dose (mrem) 0 .5 0 1 0.2 0.2 0.2 0.4 1 .0 2 1 4 2 6.6 6.4 4 .3 5.5 3.1 4 .6 6.0 6.9 2.4 7 8 9 2 2 4 3.7 0.7 0. 1 0.2 0.2 0.9 1 2 0 3 0 .4 1 .0 1 3 1 .3

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107 Table 5-2 Comparison of Effecti v e Doses for Male and Female One-Year-Olds Among Facilities for Chest Exams AP Chest PA Chest LAT Chest Facility ID Effective Dose (mrem) Effective Dose (mrem) Effective Dose ( mrem ) Shands at UF # 2 # 3 # 4 # 5 # 6 # 7 # 8 # 9 # 10 0 8 0 7 3 8 5 3 0 8 2 7 5 9 1 2 2 1 2 2 1 2 0 4 3 7 4 1 0 2 0 6 2 4 0 5 0 7 1 3 0 4 I I 4 7 6 1 1 5 1 3 6 1 1 7 6 2 3 1 A comparison was performed between the results of this research and that perfo11ned by the FDA and the NRPB :, as these are the only two entities that have compiled data for this age group as discussed in Chapter 1 The FDA research was performed approximately 20 years ago and the resultant doses reflect the equipment and techniques used in that era The NRPB study reflects European practices that ma y not be directly comparable to U S practices For compari s on between Shands at UF with other dosimetry studies perfo11ned by the FDA, the absorbed dose data were normalized to the clinical exam entrance exposure for the thyroid lung bone marrow ovaries and testes which were the only sites included in the FD A study Comparison of the experimental measurements perfot 1ned at UF and Monte Carlo calculations performed by the FDA are shown in Table 5-3 for 12 of the 27 exams detailed in Appendix E Direct comparison with the experimental TLD measurements performed by the FDA was not possible due to variation between the

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108 phantoms technique factors and equipment specifications for these studies The FDA Handbook of Selected Organ Doses for Projections Common in Pediatric Radiology (Rosenstein et al 1 9 79 ) utilized the notation of enclosing data in parentheses when the coefficient of variation exceeded 50 percent ; this notation is also included in Table 53 The Handbook reports single lung and ovary absorbed dose per unit exposure values ; for comparison purposes these single values were placed either in the a v erage lung or average ovary row as appropriate Additionally the head and neck model utilized b y the FDA is considerably different from the head and neck model utilized in this research ; therefore direct comparisons are not appropriate In general the UF study s estimates of dose are lower than those given in the FDA report The primary reason for the lower v alues are the different organ mass and tissue composition of the phantom and model used For e x ample the total lung mass in the UF anthropomorphic phantom is 150 grams compared to a total lung mass of 129 grams in the FDA mathematical model Consequently it is expected that even for equal values of energy deposition per unit mass to the lungs of both the phantom and the model the UF phantom values would only be 8 6% of the lung doses estimated for the model in the FDA study Additional differences would also be attributed to differences in tissue densities The skeletal lung and soft tissue densities in the UF phantom are 1 18 g/ cm 3 0 2 96 g/ cm 3 and 1 04 g/ cm 3 respectively The skeletal lung and soft tissue densities in the FD A model are 1 4862 g/cm 3 0 2958 g/cm 3 and 0 9896 g/cm 3 respectively This change in tissue density clearl y affects the particle transport and therefore the dose The thyroid dose was appreciabl y higher in the UF study for exams in which the x-ray field was directly projected and the organ was not shielded such as the AP cervical spine This dose differential is directly attributable to the thyroid being placed in a more anatomicall y correct position in the UF phantom than in the FDA model which did not have an explicit neck and included the thyroid as part of the head

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109 Table 5-3 Comparison of Shands at UF and FDA Absorbed Dose/ESE 1998 UF 1979 FDA Absorbed Absorbed Dose/ESE Dose/ESE Organ View and Projection (rad/R) (rad/R) Thyroid Townes Skull 0 171 (0 410 ) AP Skull 0 909 0 585 PA Skull 0 059 0 130 LAT Skull 0 000 0 .3 80 AP C-Spine 1 140 0 585 LAT C-Spine 0 180 (0 370) AP Chest 0 355 0 585 PA Chest 0 089 (0 120 ) LAT Chest 0 253 (0 380) AP Abdomen Supine 0 000 0 000 PA Abdomen 0 000 (0 006) AP Pelvis 0 000 0 000 Average Lung Townes Skull 0 000 0 056 AP Skull 0 000 0 082 PA Skull 0 000 0 078 LAT Skull 0 000 0 029 AP C-Spine 0 000 0 063 LAT C-Spine 0 000 0 045 AP Chest 0 145 0 554 PA Chest 0 195 0 613 LAT Chest 0 105 0 706 AP Abdomen Supine 0 059 0 055 PA Abdomen 0 000 0 056 AP Pelvis 0 000 (0 006) Active Bone Marrow Townes Skull 0 066 0 048 AP Skull 0 064 0 054 PA Skull 0 021 0 072 LAT Skull 0 073 0 051 AP C-Spine 0 000 0 030 LAT C-Spine 0 030 0.035 AP Chest 0 021 0 101 PA Chest 0 061 0 169 LAT Chest 0 045 0 150 AP Abdomen Supine 0 036 0 112 PA Abdomen 0 000 0 214 AP Pelvis 0 000 0 104

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110 Table 5-3 continued 1998 UF 1979 FDA Absorbed Absorbed Dose/ESE Dose/ESE Organ View and Projection (rad/R) (rad/R) Average Ovary Townes Skull 0 000 0 000 AP Skull 0 000 0 000 PA Skull 0 000 0 000 LAT Skull 0 000 0 000 APC-Spine 0 000 0 000 LAT C-Spine 0 000 0 000 AP Chest 0 000 (0 019) PA Chest 0 000 (0 002) LAT Chest 0 000 (0 013) AP Abdomen Supine 0 254 0 400 PA Abdomen 0 000 0 400 AP Pelvis 0 363 0 400 Testes Townes Skull 0 000 0 000 AP Skull 0 000 0 000 PA Skull 0 000 0.000 LAT Skull 0 000 0 000 APC-Spine 0 000 0 000 LAT C-Spine 0 000 0.000 AP Chest 0 000 0 000 PA Chest 0 000 0 000 LAT Chest 0 000 0 000 AP Abdomen Supine 0 000 0 105 PA Abdomen 0 000 0 047 AP Pelvis 0 000 (1 070) In order to compare the doses delivered at the surveyed facilities with dosimetry studies performed by the NRPB the effective dose data were normalized to the clinical exam entrance skin absorbed dose Comparison results between experimental measurements performed at the facilities and Monte Carlo calculations performed by the NRPB are shown in Table 5-4 for the chest exams detailed in Appendix E The NRPB Report of Coefficients for Estimating Effective Doses from Pediatric X-Ray Examinations (Hart et al 1996) utilizes the previous generation Cristy and Ecker111an mathematical pediatric models The NRPB modified these phantoms by adding their own esophagus and neck, and further modified the composition of the breast tissue to reflect a higher fat content These modifications are not published in detail, and the head model utilized by

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111 the NRPB is considerably different from the prototype head model utilized in this research ; therefore direct comparisons are not possible Table 5-4 ComEarison Amons All Facilities and NRPB Effective Dose/ESD AP Chest AP Chest PA Chest PA Chest LAT Chest LAT Chest 1998 UF 1996 NRPB 1998 UF 1996 NRPB 1998 UF 1996 NRPB Effective Effective Effective Effective Effective Effective Dose/ESD Dose/ESD Dose/ESD Dose/ESD Dose/ESD Dose/ESD Facility ID (rem/rad) {rem/rad) (rem/rad) {rem/rad) (rem/rad) {rem/rad) Shands atUF 0 508 0 168 0 162 0 103 0 117 0 113 #2 0 1 33 0 182 0 064 0 109 0 105 0 118 #3 1 .3 48 0 188 1 157 0 115 1 639 0 123 #4 0 24 3 0 200 0 142 0 126 0 202 0 1 33 # 5 0 30 3 0 153 0 076 0 096 0 461 0 107 #6 0 .3 82 0 146 0 088 0 090 0 095 0 101 #7 0 378 0 188 0 186 0 115 0 246 0 123 #8 0 442 0 182 0 187 0 109 0 291 0 118 #9 0 12 3 0 194 0 04 3 0 121 0 102 0 128 #10 0 416 0 210 0 190 0 1 3 7 0 208 0 142 A comparison of the data indicates that the effective doses received from the observed clinical procedures are generally consistent with the effective doses predicted from the Monte Carlo calculations There are however several sites with large discrepancies It is difficult to attribute these discrepancies to any particular features of the exams because the NRPB normalized their doses to entrance skin absorbed dose rather than entrance skin exposure and do not provide a detailed explanation of how they calculate their entrance skin absorbed dose This provides strong motivation for performing the detailed comparison of experimental and computer simulations that will be performed at UF in future work, utilizing a mathematical model that is as identical as possible to the anthropomorphic phantom Relative Risk The BEIR V report s general expression for calculating the total cancer risk, including natural and radiation-induced to a population was utilized to determine relative risks. The values of g(p) were detertnined for each gender for an exposure that occurs at

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112 an age of one year, and the time post-exposure was chosen to be five years past the latency period for each different type of cancer The values of.f{d) were determined utilizing the effective doses calculated in Chapter 3 Numerical values of g(~) and .f{ d) are shown in Appendix E, and were multiplied to detertnine the relative risk predicted by : [ 1 + ft.d) g(~)]. This general expression was evaluated using these variables for each procedure simulated at Shands at UF as shown in Table 5-5 and for the chest examinations at all of the facilities as shown in Table 5-6 Table 5-5 Relative Risk for Shands at UF Examinations Male Female Male Female Female Exam Leukemia Respiratory Respiratory Digestive Digestive Other Breast AP Skull 1 000157 1 000023 1 000046 1.000004 1 000007 1 000006 1 000000 AP Skull w/shield 1 000041 1 000006 1 .0000 12 1 000001 1 000002 1 000002 1 000000 PA Skull 1 000067 1 000010 1 000020 1 000002 1 000003 1 000003 1 000000 PA Skull w / shield 1 000065 1 000009 1 000019 1 000002 1 000003 1 000002 1 000000 LAT Skull 1 .000055 1 .00000 8 1 000016 1 000001 1 000002 1 000002 1 .000000 Townes Skull 1 000131 1 000019 1 .000039 1 000003 1 000006 1. 000005 1 000000 AP C-Spine 1 000308 1 000045 1 000091 1 000008 1.000013 1 000012 1 000001 LAT C-Spine 1 000672 1 000097 1 000198 1 .0000 17 1 000029 1 000025 1 000002 APT-Spine 1 001343 1 000195 1 000397 1 000034 1 000059 1 000051 1 000003 LATT Spine 1 002096 1 000299 1 000628 1 000052 1 000093 1 000080 1 000005 APL-Spine 1 001584 1 000203 1 .000523 1 000035 1 000078 1 000060 1 000003 LATL-Spine 1 001584 1 000146 1 000433 1 000025 1 000064 1 00004 7 1 000003 AP Abdomen Supine 1 002073 1 000279 1 000657 1 .0000 48 1 000097 1 000079 1 000005 PA Abdomen Supine 1 000769 1 000112 1 000227 1 .0000 19 1 000034 1 000029 1 000002 AP Abdomen Upright 1 002732 1 000362 1 000876 1 000063 1 .000 130 1 000104 1 000006 AP Pelvis 1 000970 1 000110 1 000349 1 000019 1 000052 1 000037 1 000002 AP Hip 1 000219 1 000032 1 000065 1 .000006 1 000010 1 000008 1 000001 Waters Sinus 1 000044 1 000006 1 000013 1 000001 1 000002 1 000002 1 000000 LAT Sinus 1 000080 1 000012 1 000024 1 000002 1 .000003 1 000003 1 000000 AP Sinus 1 000050 1 000007 1 000015 1 .00000 1 1 000002 1 000002 1 000000 AP Chest w/shield 1 000107 1 000016 1 000032 1 000003 1 00000 5 1 000004 1 000000 LAO Chest 1 000323 1.000047 1 000096 1 000008 1 000014 1 000012 1 000001 RPO Chest 1 000433 1 000063 1 000128 1 000011 1 000019 1 000016 1 000001 RAO Chest 1 .00 0423 1 000061 1 000125 1 000011 1 000019 1 .0000 16 1 000001

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113 Table 5-6 Relative Risk for Chest Examinations Amons All Facilities AP Chest Male Female Male Female Female Facility ID Leukemia Respiratory Respiratory Digestive Digestive Other Breast Shands at UF 1 000384 1 000056 1 .000 11 3 1 000010 1 000017 1 000015 l 000001 #2 1 000230 1 000034 1 000068 1 000006 1 000010 1 000009 1 000001 #3 1 001237 1 000179 1 000365 1 000031 1 000054 1 000047 1 000003 #4 1 001694 1 000246 1 000499 1 .0000 43 1 000074 1 000064 1 000004 #5 1 000238 1 000034 1 000072 1 000006 1 000011 1 000009 1.000001 #6 1 000832 1 000117 1 000253 1 .000020 1 000038 1 000032 1 000002 #7 1 001895 1 .000276 1 000558 1 000048 1 000083 1 000072 1 000005 #8 1 000382 1 000055 1 000113 1 000010 1 000017 1 000014 1 000001 #9 1 000633 1 000084 1 000204 1 000015 1 000030 1 000024 1 000001 #10 1 000719 1 000104 1 000212 1 000018 1 000031 1 000027 1 000002 PA Chest Male Female Male Female Female Facility ID Leukemia Respiratory Respiratory Digestive Digestive Other Breast Shands at UF 1 .000 123 1 000018 1 000036 1 000003 1 000005 1 000005 1 000000 #2 1 .000138 1 000020 1 000041 1 000003 1 000006 1 000005 1 000000 #3 1 001189 1 .000 17 3 1 000 350 1 000030 1 000052 1 000045 1 000003 #4 1 001314 1 000193 1 000384 1 000033 1 .000057 1 000050 1 000003 #5 1 000062 1 000009 1 000018 1 000002 1 000003 1 000002 1 000000 #6 1 000199 1 000029 1 000059 1 000005 1 000009 1 000008 1 000000 #7 1 000777 1 000113 1 000229 1 000020 1 000034 1 000029 1 000002 #8 1 .000 150 1 000020 1 000048 1 .000003 1 000007 1 000006 1 000000 #9 1 000235 1 000034 1 000069 1 000006 1 000010 1 000009 1 000001 #10 1 000412 1 000060 1 000121 1 000010 1 000018 1 000016 1 000001 LAT Chest Male Female Male Female Female Facility ID Leukemia Respiratory Respiratory Digestive Digestive Other Breast Shands atUF 1 000281 1 000040 1 000084 1 000007 1 000012 1 000011 1 000001 #2 1 000361 1 000052 1 000108 1 000009 1 000016 1 000014 1 000001 #3 1 .00 1500 1 000217 1 .000 444 1 000038 1 000066 1 000057 1 000004 #4 1 001958 1 000284 1 000578 1 000049 1 000086 1 000074 1 000005 #5 1 000495 1 000071 1 .000 147 1 000012 1 000022 1 000019 1 000001 #6 1 000422 1 000061 1 000126 1 000011 1 000019 1 000016 1 000001 #7 1 001945 1 000281 1 000576 1 000049 1 000085 1 000074 1 000005 #8 1 000550 1 000080 1 000162 1 000014 1 000024 1 000021 1 000001 #9 1 001981 1 000287 1 000586 1 000050 1 000087 1 000075 1 000005 #10 1 000900 1 000118 1.000292 1 000020 1 000043 1 000034 1 000002 The values of relative risk show that the examinations that yielded higher effective doses and had the most radiosensitive tissues in the field of view e g the abdomen, thoracic spine and lumbar spine also yielded the highest risk These values of relative risk can also be used to predict excess risks that may be more meaningful to members of the general public For example, from Table 5-5 for an AP abdomen upright exam, the

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114 relative risk for leukemia is 1 002732 Recall from Chapter 4 that Ao is the cancer risk to the unexposed population According to the American Cancer Society (Murphy et al 1995) Ao for leukemia is 28 600 cases in 1994 For the U S population of259 5 x 10 6 as determined by an average of the 1990 1998 U S census (BC 1998) this results in an incidence rate of 1 10 x 10 4 leukemias / person-year For 10 6 individual examinations the excess cancers predicted by BEIR V would be (1 002732 1)( 1 10 x 10 4 leukemias / person-year)(l0 6 persons) = 0.3 leukemias per year The risk from this single examination is quite low and provides a significant benefit to the patient This methodology may be similarly extended to additional cancers and to cases where a patient is subjected to a series of multiple examinations resulting in a significantly greater risk which may be of concern There are several limitations to this approach The first is that the effective dose from the exam perfot 1ned at Shands at UF is not necessarily representative of exams performed in the entire U S It would obviously be better to have a relative risk that is representative of the exams administered throughout the U S The FDA has recently initiated an effort to collect representative data on pediatric exams perfo1med in the U S through their Nationwide Examination ofX-Ray Trends (NEXT) survey which should be available in several years The second is that the BEIR V and American Cancer Society parameters apply to the entire population and do not separate out those specific to pediatric patients The availability of pediatric specific data and models would permit more accurate risk evaluations for this population. The great advantage of this methodology is that it can be readily updated to incorporate future revised data As research into pediatric cancer and radiation exposure continues tissue and radiation weighting factors specific to each age range for pediatric patients may be determined or pediatric specific risk models may be developed These revisions can then be easily combined with the existing organ dose measurements to obtain improved values of effective dose and prediction of risk

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CHAPTER6 CONCLUSIONS Site Surveys Detailed studies in the Shands at UF pediatric section of the radiology department and site surveys in nine other Florida facilities have confirmed that radiation protection is particularly important for the pediatric patient While radiological examinations are indispensable throughout childhood from birth to adolescence the justification and optimization which provide the basis for radiation protection, are of far greater importance in these age groups than in adults Justification of the examination is the most effective radiation protection in pediatric patients Every examination should result in a net benefit for the patient This is only applicable if it is anticipated that the examination will influence the efficacy of the decision of the referring physician with respect to diagnosis patient management and treatment and final outcome for the patient To minimize risks and maximize diagnostic benefit from any imaging examination, the radiologic procedure must be tailored to the specific clinical problem This approach is particularly valid in pediatric radiology because of the radiation dose delivered Radiologists assume responsibility for determining what imaging modalities are indicated for diagnostic evaluation, subsequent therapy and follow-up They must determine if requested examinations are indicated the examination that should be performed, what view s should be obtained what sequence of examinations should be selected and if other imaging modalities are required All of the radiologists who participated in the survey were keenly interested in quantifying the doses they were delivering to their patients and what they could do to improve the quality of their care 115

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116 The radiologic technologist preferably a dedicated pediatric technologist plays the central and critical role in the diagnostic imaging process and is responsible for providing high quality films In order to limit patient exposure as low as practicable without losing its benefits the following recommendations resulting from the site surveys are made for optimization of pediatric diagnostic radiography : Accurate exposure charts should be utilized corresponding to radiographic technique and the patient s weight when x-raying the trunk of the body or the patient s age when x-raying the extremities In the future small computers and utilization of the various ages of anthropomorphic phantoms could incorporate such multifactorial parameters as machine specifics to provide prospectively the dose from a variety of exams to aid the radiologist in his clinical choice This study demonstrated that due to the small body size and volume of young children, a large portion of their total body is exposed to the radiation beam that would cover only a small area in the adult Therefore confining the x-ray beam to the smallest area commensurate with adequate illumination of the field of interest not only improves detailed discrimination of radiographic images but can reduce patient dosage and decrease the scattered radiation dose to attending personnel and technologists Radiography depends on the fact that a small portion of the radiation energy impinging on the patient emerges on the other side of the body and then selectively blackens the x-ray film The difference in energy between the entry and exit radiation, constituting the greater part of the total radiation is either absorbed by the skin and deep tissue structures or scattered to surrounding areas The input radiation may be dramatically reduced without loss of the necessary exit radiation required to produce the film image in the following ways : Increased filtration at the x-ray tube head up to 1 mm Al plus 0 I 0 2 mm Cu or similar materials should be used Since low energy photons generally cannot pass through the patient s body they contribute little to producing an image on the x-ray film The filter will selectively absorb these lower energy photons

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117 Thus the added filtration reduces the entry dose to the patient without sacrificing detail of the film image The use of high-speed intensifying screens and high speed film can also reduce the patient dose without loss of the quality of image on the x-ray film The judicious use of clinical x-ray examinations of pediatric patients, avoiding as far as possible unnecessary repetitive diagnostic radiography and technically nondiagnostic radiography is desirable Technically unsatisfactory x-rays are a waste of time, effort and money Moreover every nondiagnostic film requires a retake and thus a doubling of patient dose and associated risk To this end, proper immobilization techniques improve image quality decrease the length of the examination, and decrease the need for repeat studies When not contraindicated gonadal shielding is always recommended for most diagnostic procedures It is not currently known if genetic damage occurs as a result of low-dose diagnostic radiologic procedures However if one assumes a linear relation without a threshold for genetic effects in which any amount of radiation has a response it would be appropriate to shield the gonads of pediatric patients Thyroid shielding should also be used where applicable Future improvements in x-ray technology such as computed or digital radiography must be used with care As demonstrated with the one facility in the survey that is filmless the potential for abuse is high where post-processing capabilities are available In summary radiation dose and corresponding risk may be decreased by performing only examinations that are clinically indicated, tailoring the examination decreasing exposure with increased filtration and fast film-screen combinations using correct techniques shielding the patient s gonads and thyroid when possible, preventing repeat exposures due to motion with proper immobilization, and using low-dose digital radiography or nonionizing imaging modalities such as ultrasonography or magnetic resonance imaging for definitive diagnosis whenever feasible

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118 Phantom Measurements The organ doses calculated from the point dose measurements excluding the thyroid range from 15% to 143 % of the previously published FDA Monte Carlo data Direct comparison of the data is difficult since the mathematical models have evolved especially with the addition of the head and neck model This is demonstrated by the thyroid organ doses which ranged from 42% to 195 % of the values generated by the FDA The FDA models did not explicitly contain a neck and the head itself was less realistically represented The corresponding effective doses also ranged in agreement with the recently published NRPB Monte Carlo data in some cases by a factor of ten Again, direct comparison of the data is difficult because the NRPB mathematical pediatric models are substantially different from the current mathematical models from which the anthropomorphic phantom was constructed This distinctly points out the need to perform future work at UF utilizing a mathematical model that is as identical as possible to the anthropomorphic phantom The phantom-dosimetry system used in this study has some practical limitations especially in the dete11nination of the dose to the bone marrow First a homogenous bone mixture is used similar to that used in prior Monte Carlo calculations A heterogenous bone and soft tissue mixture would be more realistic of pediatric anatomy both in the anthropomorphic phantom and the mathematical model Second, the system only measures the bone dose in six locations and determines a marrow dose from this limited information The location of the field of view with respect to the MOSFET locations could skew the final marrow dose calculation depending on whether the MOSFET dosimeters were in the primary field or not A similar limitation is seen in the larger organs such as the lungs If the entire lung is either in the primary beam or outside the primary beam then the organ dose estimate calculated from the point dose measurement should be accurate ; however if only the edge of the primary beam intersects the lung the

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119 absorbed dose estimate will either be overestimated if the MOSFET is located within the field of view or underestimated if the MOSFET is located outside the field of view The initial lack of an external funding source limited the full expansion of the system Ideally 20 high sensitivity MOSFET dosimeters would be utilized to measure all the point doses simultaneously and read out immediately into a laptop computer For the majority of this work, only eight high sensitivity dosimeters were available ; therefore multiple exposures were necessary for each view The time required to collect the data was also increased A full complement of dosimeters would reduce the workload and provide instant dose calculations via computer interface making the real-time aspects of the system more evident The phantom-dosimetry system is very simple to use and provides real-time dose estimates It is expected the system could be used for dose reconstruction work dose estimates from typical exams as well as in situations which are difficult to simulate mathematically such as tluoroscopy Since the real-time point dose estimates are a good measure of the organ doses in typical plain film examinations it is expected that they will prove valuable in the verification of the more difficult simulations using oblique views This type of benchmarking for the Monte Carlo simulations is an extremely important step in the ensuring the validity of the results The development of a newborn anthropomorphic phantom is a high priority As shown by the data in Appendix A, thousands of exams are performed on newborns annually Patients born with complications are routinely subjected to a series of multiple examinations resulting in a significantly greater cumulative dose and risk which may be of concern, and where the methodology developed in this research will prove to be most useful

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120 Effective Dose and Risk Predictions The results of this research provide the effective dose and relative carcinogenic risks for several commonly perfortned plain film diagnostic procedures The measured effective doses ranged from a low of O 1 mrem for an AP skull exam that utilized thyroid shielding to a high of 9 2 mrem for an AP upright abdomen exam on a female Correspondingly the relative leukemia carcinogenic risk ranged from 1 000041 for an AP skull exam that utilized thyroid shielding, to a high of 1 002732 for an AP upright abdomen exam, with corresponding estimates of excess risks based on 10 6 exams of O 005 and 0.3 leukemias per year respectively The risk from these individual examinations are quite low and probably provide a significant benefit to the patient Future research into tissue and radiation weighting factors specific to each age range for pediatric patients or pediatric specific risk models is needed in cases where a patient is subjected to a series of multiple examinations such as the newborn patient population previously discussed The methods developed in this research can now be utilized to facilitate the development and transfer of scientific information for the improvement in the radiologic care of children The techniques can be integrated with the computational and advanced experimental interfaces being developed to quickly assess the organ doses and risks to various ages of pediatric patients undergoing a variety of modem diagnostic examinations Such automated systems will pet mit the ready extension of these techniques to advanced radiological procedures including fluoroscopy computed tomography cardiac catheterization, computed radiography and digital radiography

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APPENDIX A NUMBER OF EXAMS FOR PEDIATRIC P A l'IENTS UNDER 16 YEARS OF AGE For the Time Period 01 / 01 /97 -12 /3 1 /9 7 at Shands at the University of Florida Radiology Department The following data indicate number and type of exam for all imaging modalities Year Modality RIS # Exam& View Newborn 151 01 5Year Yea r Year Year 97 CT 1000 ABDOMEN W / OU CONTRAST CT 0 1 1 2 2 97 CT 1001 ABDOMEN W / 0 CONTRAST EXT CT 0 0 0 0 0 97 CT 1 005 ABDOMEN WITH CONTRAST CT 2 2 3 27 98 97 CT 1 006 ABDOMEN W / CONTRAST EXTENDED -C 0 0 0 0 1 97 CT 1 010 ANG IOCT 0 0 0 0 0 97 CT 1015 ABDOMEN W & W / 0 CONTRAST CT 0 0 0 1 8 97 CT 1020 BIOPSY O 30 MINUTES CT 0 0 0 0 0 97 CT 1025 BIOPSY 30 MINUTES 1 HOUR CT 0 0 0 1 0 97 CT 1030 BIOPSY OVER 1 HOUR CT 0 0 0 1 0 97 CT 1035 B RW STEREOTACT LOCAT IO N -CT 0 0 1 1 0 97 CT 1036 BRW STEREOTACTIC LOCATION -EX 0 0 1 5 3 97 CT 1 040 DRAINAGE30MINUTES-1HOUR0 0 0 0 0 97 CT 1045 CHEST W / OlIT CONTRAST CT 0 0 2 1 4 53 97 CT 1046 CHEST W / 0 CONTRAST EXT CT 0 0 0 1 2 97 CT 1050 DRAINAGEOVERlHOUR-CT 0 0 0 0 1 97 CT 1 055 CHEST WITH CONTRAST CT 0 0 3 3 33 97 CT 1 056 CHEST W / CONTRAST EXTENDED CT 0 0 0 0 0 97 CT 1 060 HEAD W / OUT CONTRAST CT 138 87 22 6 173 173 97 CT 1 06 1 HEAD W / 0 CONTRAST EXTENDED CT 2 2 4 1 4 97 CT 1065 CHEST W & W / 0 CONTRAST CT 0 0 0 0 0 97 CT 1070 HEAD WITH CONTRAST CT 1 4 8 10 5 97 CT 1071 HEAD W / CONTRAST E)CrENDED CT 0 0 l 0 0 97 CT 1075 DRAINAGE0 30MINUTES-CT 0 0 0 0 0 97 CT 1 080 HEAD WITH & WITHOlIT CONTRAST C 10 9 53 33 35 97 CT 1 08 1 HEAD W / &W / 0 CONTRAST EXTENDED 0 0 1 4 0 97 CT 1084 CORONAL HEAD CT 2 0 0 0 1 97 CT 1085 MAXILLO FACIAL PR OJ W / 0 CON CT 4 0 5 6 5 97 CT 1086 MAXILLO FACIAL lPROJ W / 0 CON EX l 0 3 4 3 97 CT 1 087 CT MAXILLO FACIAL LIMITED 1 1 4 3 4 97 CT 1 090 ORBITS 1 PROJ W / CONTRAST CT 0 0 0 0 0 97 CT 1 09 1 ORBITS lPROJ W / CONTRAST EXT CT 0 0 0 0 0 97 CT 1 095 MAXILLO FACIAL lPROJ W / CONTRAST 1 0 6 4 1 97 CT 1096 MAXILLO FACIAL lPROJ W / CON EXT 0 1 1 0 0 97 CT 1097 MAXILLO FACIAL lPROJ W / &W / 0 CO 0 0 0 1 0 97 CT 1100 O RBIT S 2 PROJ W / OUT CONTRAST-CT () 0 2 8 6 97 CT 1101 ORBITS 2 PR OJ W / 0 CONTRAST EXT 0 0 0 0 0 97 CT 1105 MAXILLO FACIAL 2 PROJ W / 0 CON 0 0 21 21 16 97 CT 11 06 MAXlLLOFACIAL 2PROJ W / 0 CON EX 1 0 1 1 0 97 CT 1110 ORBITS 2 PR OJ WITH CONTRAST CT 1 0 4 1 0 97 CT 1111 ORBITS 2PR OJ W / CONTRAST EXT CT 0 0 0 0 1 97 CT 111 5 MAXILLO FACIAL 2 PROJ W / CON CT 0 1 11 8 4 97 CT 1116 MAXILLOF AC l AL 2PROJ W / CON EXT 0 0 0 0 0 97 CT 1117 MAXILLO FACIAL 2PR OJ W / &W / 0 CO 0 0 1 0 0 97 CT 1125 ORBITS 1 PROJ W / OUT CONTRAST-CT 0 0 1 0 0 97 CT 1126 ORBITS lPRO J W / 0 CONTRAST EXT 0 0 0 0 0 97 CT 1130 SELLA 1 PROJ W / OUT CONTRAST CT 0 0 0 0 1 97 CT 1 13 5 SELLA 1 PROJ WITH CONTRAST CT 0 0 0 0 1 97 CT 1137 SELLA lPROJ W / &W / 0 CONTRAST CT 0 0 0 0 0 121

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122 Year Modality RlS # Exam& View Newborn 151015Year Year Year Year 97 CT 1140 TEMPORAL BONE 2 PROJ W / 0 CON CT 2 3 36 27 12 97 CT 1141 TEMPORAL BONE 2PROJ W / 0 CON EX 0 0 0 0 1 97 CT 1146 SELLA 2PROJ W / 0 CON EXT CT 0 0 0 0 1 97 CT 1150 TEMPORAL BONE 2 PROJ W / CON CT 0 2 7 3 2 97 CT 1151 TEMPORAL BONE 2PROJ W / CON EXT 0 0 0 0 1 97 CT 1155 SELLA 2 PROJ WITH CONTRAST CT 0 0 0 1 1 97 CT 1157 SELLA 2PROJ W / &W / 0 CON CT 0 1 0 0 2 97 CT 1161 POSTERIOR FOSSA W / 0 CONTRAST CT 1 1 1 0 0 97 CT 1162 POSTERIOR FOSSA W / CONTRAST CT 0 1 2 2 0 97 CT 1163 POSTERIOR FOSSA W / &W / 0 CONTRAS 0 0 1 1 0 97 CT 1165 TEMPORAL BONE 1 PROJ W / 0 CON CT 2 0 8 1 0 97 CT 1166 TEMPORAL BONE lPROJ W / 0 CON EX 0 0 1 0 0 97 CT 1175 TEMPORAL BONE 1 PROJ W / CON CT 0 0 1 1 0 97 CT 1176 TE:MPORAL BONE lPROJ W / CON EXT 0 0 0 0 0 97 CT 1180 LOWER EXTREMITY W / OUT CON -CT 0 0 0 2 10 97 CT 1181 LOWER EXTREMITY W / 0 CON EXT CT 0 0 0 1 2 97 CT 1185 LOWER EXTREMITY WITH CONTRAST-C 0 0 3 2 2 97 CT 1186 LOWER EXTREMITY W / CONTRAST EXT 0 0 0 0 1 97 CT 1190 UPPER EXTREMITY W & W / 0 CON CT 0 0 0 1 0 97 CT 11 95 LOWER EXTREMITY W & W / 0 CON CT 0 0 0 1 6 97 CT 1200 UPPER EXTREMITY WIT2H AIR CT 0 0 0 0 0 97 CT 1205 LOWER EXTREMITY CT WIT2H AIR 0 0 0 0 0 97 CT 1210 UPPER EXTREMITY W / OUT CON CT 0 0 0 3 3 97 CT 1211 UPPER EXTREMITY W / 0 CON EXT CT 0 0 0 0 1 97 CT 1215 PELVIS W / OUT CONTRASTCT 0 0 0 1 3 97 CT 1216 PEL VIS W / 0 CONTRAST EXTENDED CT 0 0 1 0 0 97 CT 1220 UPPER EXTREMITY WITH CONTRAST0 0 0 1 0 97 CT 1225 PEL VIS WITH CONTRAST CT l 1 1 26 83 97 CT 1226 PEL VIS W / CONTRAST EXTENDED CT 0 0 0 0 5 97 CT 1230 PEL VIS W & W / OUT CONTRAST CT 0 0 0 0 0 97 CT 1235 SOFT TISSUE NECK W / CONTRAST CT 1 3 24 16 16 97 CT 1236 SOFT TISSUE NECK W / CON EXT CT 0 0 0 0 0 97 CT 1240 RADIATION THERAPY PLANNING CT 0 0 0 0 0 97 CT 1245 SOFT TISSUE NECK W & W / 0 CON CT 0 0 0 0 1 97 CT 1255 CERVICAL SPINE W / OUT CONTRAST1 0 3 6 10 97 CT 1256 CERVICAL SPINE W / 0 CON EXT CT 0 0 0 0 3 97 CT 1265 CERVICAL SPINE WITH CONTRAST CT 0 0 0 0 0 97 CT 1266 CERVICAL SPINE W / CONTRAST EXT 0 0 0 0 0 97 CT 1267 CERVICAL SPINE W / &W / 0 CON CT 0 0 0 0 0 97 CT 1270 SOFT TISSUE NECK W / 0 CONTRAST1 0 2 0 2 97 CT 1271 SOFT TISSUE NECT W / 0 CON EXT CT 0 0 0 0 0 97 CT 1275 CERVICAL SPINE POST MYELOGRAM0 0 0 0 0 97 CT 1276 CERVICAL SPINE POST MYELO EA'T 0 0 0 0 0 97 CT 1280 LUMBAR SPINE W / OUT CONTRAST-CT 0 0 2 3 4 97 CT 1281 LUMBAR SPINE W / 0 CONTRAST EXT 0 0 1 0 0 97 CT 1285 THORACIC SPINE POST MYELOGRAM0 0 0 0 0 97 CT 1286 THORACIC SPINE POST MYELO EXT 0 0 0 0 0 97 CT 1290 LUMBAR SPINE WITH CONTRAST CT 0 0 1 0 0 97 CT 1291 LUMBAR SPINE W / CONTRAST EXT CT 0 0 0 0 1 97 CT 1300 LUMBAR SPINE POST MYELOGRAM CT 0 0 0 0 0 97 CT 1301 LUMBAR SPINE POST MYELO EXT CT 0 0 0 0 0 97 CT 1310 THORACIC SPINE W / OlIT CONTRAST0 0 0 2 1 97 CT 1311 THORACIC SPINE W / 0 CON &TI CT 0 0 0 1 0 97 CT 1315 3D RECONSTRUCTION CT 1 1 2 2 3 97 CT 1320 TIIORACIC SPINE WITH CONTRAST CT 0 0 0 0 1 97 CT 1321 THORACIC SPINE W / CONTRAST EXT 0 0 0 0 0 97 CT 1322 THORACIC SPINE W / &W / 0 CONTRAST 0 0 0 1 0 97 CT 1325 CT CALLBACK 17 5 48 19 39 97 CT 1330 NON-IONIC CONTRAST 1 UNIT CT 35 27 191 28 1 97 CT 1335 NON-IONIC CONTRAST 3 UNITS CT 0 0 0 10 70 97 CT 1336 NON-IONIC CONTRAST 4 UNITS CT 0 0 0 0 1 97 CT 1340 NON -IONI C CONTRAST 2 UN I TS CT 0 0 10 52 49 97 CT 1345 PEL VIS -LIMITED STUDY CT 0 0 0 0 1 97 CT 1350 L-SPINE WIT2H & W / 0 CONTRAST C 0 0 0 0 0 97 CT 1400 PELVIMETRY-CT 0 0 0 0 0 97 CT 1410 MULTI-PLANAR REFORMATIONS 6 0 22 17 33 97 CT 1411 DENT AL VIEW LIMITED CT 0 0 0 0 1 97 CT 1413 :MPR-DENTAL-CT 0 0 0 0 1

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123 Year Modality RJS # Exam& View Newbo rn 15 101 5Year Year Year Year 97 CT 1490 PARAVERTEBRAL NERVE INJ SING 0 0 0 0 0 97 CT 1491 PARAVERTEBRAL NERVE INJ MULT 0 0 0 0 0 97 CT 1492 FACET INJECTION SINGLE CT 0 0 0 0 0 97 CT 14 9 3 FACET INJECTION ADDITIONAL 0 0 0 0 0 97 CT 1500 ABDOMEN -LIMITED STUDY CT 0 0 0 1 0 97 CT 1505 CHEST -LTh1lTED STUDY CT 0 0 2 0 1 97 CT 1510 NECK-LIMITED STIJDY CT 0 0 0 4 4 97 CT 151 5 HEAD-UMITED STIJDY CT 0 0 0 1 0 97 CT 1520 T-SPINE -LIMITED STIJDY CT 0 0 0 1 0 97 CT 1525 C-SPINE -LIMITED STIJDY CT 0 0 0 1 1 97 CT 1530 I.rSPINE -LIMITED STIJDY CT 0 0 0 0 0 97 CT 1535 LOWER EXTREMITY -LIMITED STIJDY 0 0 0 0 0 97 CT 154 0 UPPER EXTREMITY -LIMITED STIJDY 0 0 0 0 0 97 CT 1600 BIOPSY MUSCLE DEEP CT 0 0 0 0 0 97 CT 1602 BIO NECK/fHORAX SOFI*l'ISSUE CT 0 0 0 1 0 97 CT 1603 BIO BACK OR FLANK SOFT TISSUE 0 0 0 0 0 97 CT 1 60 4 BIO BACK AREA DEEP TISSUE CT 0 0 0 0 0 97 C T 160 5 BIO SHOULDER SUPERFICIAL CT 0 0 0 0 0 97 CT 160 6 BIO SHOULDER DEEP CT 0 0 0 0 0 97 CT 1607 BIO PEL VIS/HIP SUPERFICIAL CT 0 0 0 0 0 97 CT 1608 BIO PEL VIS/HIP DEEP CT 0 0 0 0 0 97 CT 1609 BIO TIBGH/KNEE DEEP CT 0 0 0 0 0 97 CT 1611 BIO PERCUTANEOUS LUNG -CT 0 0 0 1 0 97 CT 1612 BIOL YMP2H NODE DEEP W/NEEDLE C 0 0 0 0 0 97 C T 1613 BIO DEEP AXILLARY NODE CT 0 0 0 0 0 97 CT 1617 BIOPSY LIVER CT 0 0 0 0 0 97 CT 1618 BIO PANCREAS PERCUTANEO US CT 0 0 0 0 0 97 CT 1619 BIOPSY KIDNEY CT 0 0 0 0 0 97 CT 1626 BIOPSY UPPER ARM DEEP CT 0 0 0 0 0 97 CT 1630 BIOPSY LOWER LEG DEEP CT 0 0 0 0 0 97 CT 1632 BIOPSY FEMUR DEEP CT 0 0 0 0 I 97 CT 1634 BIOPSY ABDOMINAIJRETROPERJTONE 0 0 0 0 0 97 CT 1645 DRNG SOFT TISSUE/NECK CT 0 0 0 0 0 97 C T 1 646 DRNG BURSAIKNEEffHIGH CT 0 0 0 0 0 97 CT 1647 DRNGPERITONEAL-CT 0 0 0 0 1 97 CT 1648 DRNG SUBDIAOHRAGMATIC CT 0 0 0 0 0 97 CT 164 9 DRNG RETROPERJTONEAL CT 0 0 0 0 0 97 CT 1650 DRNG PERJTONEOCENTESIS CT 0 0 0 0 0 97 CT 1651 DRNGRE NAUPE RJRENAL-CT 0 0 0 0 0 97 CT 1652 DRAINAGE PANCREATIC PSEUDOCYST 0 0 0 0 0 97 CT 1654 THORA COSTOMY EMPYEMACT 0 0 0 0 0 97 CT 1655 DRAINAGE PANCREAS-CT 0 0 0 0 0 97 CT 1656 DRAINAGE LIVER CT 0 0 0 0 0 97 CT 1700 ASPIRATION 0-30 MIN CT 0 0 0 0 0 97 CT 1701 ASPIRATION 30-60 MIN CT (} 0 0 0 0 97 CT 1702 ASPIRATION OVER 1 HOUR CT 0 0 0 0 1 97 CT 1710 ASPIRATION KIDNEY /PEL VIC CYST 0 0 0 0 0 97 CT 1711 ASPIRATION LUNG CT 0 0 0 0 0 97 CT 1712 ASPIRATIONPLEURALCAVITY-CT 0 0 0 0 0 97 CT 1713 ASPIRATION PNEUMOTHORAXCT 0 0 0 0 0 97 CT 1714 ASPIRATION INTERVERTEBRAL DISK 0 0 0 0 0 97 CT 1900 PEDS ABDOMEN W / 0 CONTRAST CT 1 0 1 2 0 97 CT 1901 PEDS ABDOMEN W / CONTRAST CT 9 5 9 2 30 0 97 CT 1902 PEDS ABDOMEN W / &W / 0 CONTRAST C 5 2 11 4 0 97 CT 1910 PEDS PEL VIS W / 0 CONTRAST CT 0 1 1 0 0 97 CT 1911 PEDS PEL VIS W / CONTRAST CT 7 4 76 25 0 97 CT 1912 PEDS PELVIS W / &W / 0 CONTRAST CT 0 1 2 0 0 97 C T 192 0 PEDS CHEST W / 0 CONTRAST CT 5 5 28 11 1 97 CT 1921 PEDS CHEST W / CONTRAST CT 7 3 36 13 0 97 CT 1922 PEDS CHEST W / &W / 0 CONTRAST CT 2 1 0 1 0 97 CT 8290 MYELOGRAM LUMBOSACRAL 0 0 0 0 0 LUMBAR 97 FLUORO 1275 CERVICAL SPINE POST MYELOGRAM0 0 0 0 0 97 FLUORO 2000 ABDOMEN lVIEW 0 0 0 0 0 97 FLUORO 2010 ABDOMEN SUPINE & UPRIGHT 0 0 0 0 0 97 FLUORO 2020 KUB 1 0 0 0 0 97 FL UORO 2100 CHEST PA & LATERAL 0 0 0 0 0

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124 Year Modality RIS # Exam&View Newborn 151015Year Year Year Year 97 FLUORO 2105 CHEST lVIEW 2 1 0 0 0 97 FLUORO 2115 CHEST DECUBITUS LEFf 0 0 0 0 0 97 FLUORO 2120 CHEST DECUBITUS RIGHT 0 0 0 0 0 97 FLUORO 2200 INfRA VENOUS P YELOGRAM 0 0 0 0 5 97 FLUORO 2205 CYSTOGRAM WITH RADIOLOGIST 0 0 0 0 0 97 FLUORO 2210 INfRA VENOUS PYELOGRAM 0 0 0 0 0 WtrOMOGR 97 FLUORO 2-215 CYS TOGRAM VOIDING 11 2 5 5 4 97 FLUORO 2220 !VP ABBREVIATED 0 0 0 0 1 97 FLUORO 223 0 ANTEGRADEPYELOGRAM 0 0 4 0 3 97 FLUORO 2240 RETROGRADE PYELOGRAM 0 0 0 1 3 97 FLUORO 2245 RETROGRADE URETHROGRAM 0 0 0 0 2 97 FLUORO 2255 LOOPOGRAM 0 0 0 0 0 97 FLUORO 3050 TOMOGRAPHY 0 0 0 0 0 97 FLUORO 3320 SHOULDER RIGHT 0 0 0 0 0 97 FLUORO 3500 CERVICAL SPINE 0 0 0 0 0 97 FLUORO 353 0 C-SPINE FLEXI.ON & EX'TENSION ON 0 0 0 0 1 97 FLUORO 3540 LUMBAR SPINE 0 0 0 0 0 97 FLUORO 4090 ESOPHAGEAL SW ALLOW NUCME D 0 0 0 0 0 97 FLUORO 6160 CATHETE R MANIPULATIONS 0 0 0 0 0 97 FLUORO 6180 CATHETE R PLA CEMENT 0 0 0 0 0 97 FLUORO 6 200 CHOLANGIOGRAM TrrtJBE 0 0 0 0 0 97 FLUORO 6245 PERCUTANEOUSGASTROSTOMY 0 0 0 0 0 97 FLUORO 6500 LUMBAR P UNCTURE 0 0 0 0 0 97 FLUORO 6770 PARA VERTEBRAL NERVE BLOCK 0 0 0 0 0 97 FLUORO 8000 GI SERIES 32 6 18 4 3 97 FWORO 8005 ESOPHOGRAM 6 8 5 2 4 97 FLUORO 8010 GI W / SMALL BOWEL SERIES 1 1 2 2 4 97 FLUO RO 8015 ESOPHOGRAM W/HYPOPHARNYX 0 0 0 0 0 97 FLUORO 8 0 2 5 REHAB BARIUM SW ALLOW 1 0 1 1 2 97 FLUORO 8030 SMALL BOWEL SERIES ONLY 2 0 1 1 3 97 FL UORO 8035 BARIUM ENEMA 11 2 4 3 2 97 FLUORO 8040 ENTEROCLYSIS STUDY 0 0 0 0 0 97 FLUORO 8045 BARIUM ENEMA WITH/ AIR 2 0 3 0 0 97 FLUORO 8050 CHO LANGI OGRAM 0 0 0 0 0 97 FLUORO 8055 HYSTEROSALPINGOGRAM 0 0 0 0 0 97 FLUO RO 8070 ERC P 0 0 1 1 3 97 FLUORO 8085 SINEOGRAM FISTULAGRAM 0 0 0 1 0 97 FLUORO 8090 FLUOROSCOPY 1 1 1 2 0 97 FLUORO 8095 SPEECH CINE EXAM 0 0 0 0 0 97 FLUORO 8100 CHEST FLUORO ONLY 0 1 l 0 1 97 FLUORO 8110 CHEST W/FLUOROSCOPY 0 0 0 0 1 97 FL UO RO 8125 VENOGRAM LEG RIGHT 0 0 0 1 0 97 FLUORO 8140 GI TUBE PLACEMENT 2 0 3 1 0 97 FLUORO 8141 GI TUBE REPOSITION 1 2 1 0 0 97 FLUORO 8145 ARTHROGRAM-WRIST 0 0 0 0 0 97 FLUORO 8146 ARTHROGRAM WRIST LIMITED 0 0 0 0 0 97 FLUORO 8150 ARTHROGRAM SHOULDER 0 0 0 0 1 97 FL U ORO 8151 ARTHROGRAM SHOULDER-LIMITED 0 0 0 0 5 97 FL UO RO 8156 ARTHROGRAM ANKLE LIMITED 0 0 0 0 0 97 FLUORO 8165 ARTHROGRAM ELBOW 0 0 0 0 1 97 FL UORO 8166 ARTHROGRAM ELBOW LIMITED 0 0 0 0 l 97 FLUORO 8175 ARTHROGRAM HIP 0 0 0 0 1 97 FLUORO 8176 ARTHROGRAM HIP LIMITED 0 0 2 2 I 97 FLUO RO 8200 FLUORO W/RADIOLOGIST 3 2 2 3 3 97 FLUORO 8201 FLUORO ER 0 0 3 1 1 97 FLUORO 8210 FOREIGN BODY REMOV AL ESOPHAGE 0 3 7 1 0 97 FLUORO 8224 FACET INJECTION-SINGLE-LUMBAR 0 0 0 0 0 97 FLUORO 8225 FACET INJECTION ADDITIONAL LE 0 0 0 0 0 97 FLUORO 8230 BE INTUSSUSCEPTION 4 2 2 1 0 97 FLUORO 8240 NONIONI C CONTRAST -1 UNIT 0 0 0 1 0 97 FLUORO 8250 DEFECOGRAPHY 0 0 0 0 0 97 FLUORO 8280 MYELOGRAMCERVICAL LUMBAR P U 0 0 0 0 0 97 FLUORO 8283 MYELOGRAM CERVICAL Cl-2 P UNC 0 0 0 0 0 97 FLUORO 8285 MYELOGRAM THORACIC LUMBAR PU 0 0 0 0 0 97 FLUORO 8290 MYELOGRAM LUMBOSACRAL 0 0 0 0 0 LUMBAR

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125 Year Modality RIS # Exam& View Newborn 151015Year Year Year Year 97 FLUORO 8295 MYELOGRAM SPINE CANAL LUMBAR 0 0 0 0 0 97 FLUORO 8304 Cl-2 PUNCTURE DIAGNOSTIC 0 0 1 0 1 97 FLUORO 8305 LUMBAR PUNCTURE DIAGNOSTIC 0 0 0 0 5 97 FLUORO 8306 LUMBAR PUNCTURE THERAPEUTIC 0 0 0 0 14 97 FLUORO 8307 EPIDURAL INJECTION 0 0 0 0 0 97 FLUORO 8310 PARA VERTEBRAL NERVE BLOCK SI 0 0 0 0 0 97 FLUORO 8311 PARA VERTEBRAL NERVE BLOCK RE 0 0 0 0 0 97 FLUORO 9155 FLUOROSCOPY 1 HOUR 0 0 0 0 0 97 FLUORO 9160 FLUOROSCOPY PER HOUR 0 0 0 0 0 97 FLUORO 9626 NO EXAM PERFORMED 0 0 0 0 0 97 FLUORO 9920 INJ EPIDURAL STEROID 0 0 0 0 0 97 GENERAL 2000 ABDOMEN l VIEW 203 82 257 115 83 97 GENERAL 2010 ABDOMEN SUPINE & UPRIGHT 8 7 83 88 51 97 GENERAL 2015 ABDOMEN DECUBITUS LEFT 288 16 40 25 15 97 GENERAL 2020 KUB 491 74 134 69 67 97 GENERAL 2021 KUB FLAT & UPRIGHT 2 0 10 4 4 97 GENERAL 2025 ABDOMEN DECUBITUS RIGHT 3 0 0 0 2 97 GENERAL 2100 CHEST PA & LATERAL 477 474 1 524 665 546 97 GENERAL 2105 CHEST 1 VIEW 3763 797 1713 875 973 97 GENERAL 2106 BABYGRAM CHEST & ABDOMEN 730 30 17 0 0 97 GENERAL 2115 CHEST DECUBITUS LEFT 31 3 1 8 3 9 97 GENERAL 2120 CHEST DECUBITUS RIGHT 24 3 11 2 8 97 GENERAL 2125 CHEST PA & LATERAL WITH BARIUM 0 0 0 0 l 97 GENERAL 2135 CHEST P NLAT & BILATERAL OBLIQ 0 0 0 0 0 97 GENERAL 2140 CHEST OBL IQ UE ONLY 0 0 0 0 0 97 GENERAL 2145 CHEST APICAL LORDOTIC 0 0 0 0 0 97 GENERAL 2150 CHES T 3VIEWS 0 0 0 1 0 97 GENERAL 2200 INTRAVENOUSPYELOGRAM 1 0 2 3 2 97 GENERAL 220 5 CYSTOGRAM WITH RADIOLOGIST 0 2 6 12 3 97 GENERAL 2206 CYSTOGRAM IN CYSTO 0 0 0 0 0 97 GENERAL 2210 INTRAVENOUSPYELOGRAM 0 0 0 l 2 WffOMOGR 97 GENERAL 2215 CYSTOGRAM VOIDING 93 51 269 78 21 97 GENERAL 2220 IVP ABBREVIATED 0 0 0 0 1 97 GENERAL 2225 KIDNEY IN THE OR 0 0 0 0 0 97 GENERAL 223 0 ANTEGRADEPYELOGRAM 10 2 5 4 0 97 GENERAL 2240 RETROGRADE PYELOGRAM 0 0 0 0 I 97 GENERAL 2245 RETROGRADE URETHROGRAM 0 0 0 1 1 97 GENERAL 2250 ABDOMEN W / OBLIQUES 0 0 0 0 6 97 GENERAL 2255 LOOPOGRAM 0 0 0 0 1 97 GENERAL 2400 SKULL SERIES 10 23 17 10 3 97 GENERAL 2405 MANDIBLE 0 0 3 4 15 97 GENERAL 2406 PANOREX 0 0 0 5 6 97 GENERAL 2410 SKULL 2VIEWS FOLLOW UP ONLY 13 6 16 14 11 97 GENERAL 2415 TMJ TEMPORAL MANDIBULAR JOIN 0 0 0 0 2 97 GENERAL 2420 SINUSES 0 0 30 29 20 97 GENERAL 2425 MASTOIDS 0 I 2 3 1 97 GENERAL 2430 FACIAL BONES 0 0 4 10 12 97 GENERAL 2440 NASAL BONES NOSE 0 0 3 5 7 97 GENERAL 2455 EYE FOREIGN BODY 0 0 1 0 0 97 GENERAL 2460 ORBIT EYE 0 0 2 2 4 97 GENERAL 2605 KNEE 4 VIEWS RIGHT 0 0 1 1 9 82 97 GENERAL 2610 FEMUR LEFT 6 0 38 39 20 97 GENERAL 2620 FEMUR RIGHT 9 6 32 41 35 97 GENERAL 2625 KNEE AP & LAT LEIT 1 0 14 43 73 97 GENERAL 2635 KNEE AP & LAT RIGHT I 1 1 6 48 56 97 GENERAL 2640 KNEE 4 VIEWS LEFT 0 0 2 17 84 97 GENERAL 2645 KNEES BILATERAL AP ONLY I 0 0 2 2 97 GENERAL 2655 LOW LEG TIBIA RIGHT 0 4 28 21 73 97 GENERAL 2660 'llBIA LOW LEG LEIT 1 1 4 13 17 97 GENERAL 2665 LEGS AP HIP TO ANKLE BILATER 0 0 19 7 6 97 GENERAL 2670 l'IBIA LOW LEG RIGHT 2 I 5 5 16 97 GENERAL 2675 LEG AP & LAT-HIP TO ANKLE LEF 4 3 15 8 14 97 GENERAL 2685 LEG-AP & LAT HIP TO ANKLE R 5 3 12 11 13 97 GENERAL 2690 LOW LEG 1'IBIALEFT 3 2 34 40 59 97 GENERAL 2695 LEG LENGTH SCANOGRAM 0 0 13 31 17 97 GENERAL 2705 FOOT RIGHT 18 4 38 50 48

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126 Year Modality RIS # Exam& View Newborn 151015Year Year Year Year 97 GENERAL 2710 ANKLE LEFT 0 1 14 67 65 97 GENERAL 2720 ANKLE RIGHT 0 0 25 5 5 12 0 97 GENERAL 2725 HEEL LEFT 0 0 3 2 3 97 GENERAL 2735 HEEI RIGHT 0 0 2 3 2 97 GENERAL 2740 FOOT LEFT 16 1 34 55 46 97 GENERAL 2750 TOES LEFT FOOT 0 0 2 8 1 97 GENERAL 2755 TOES RIGHT FOOT 0 0 3 7 8 97 GENERAL 2900 MAMMOGRAM BILATERAL 0 0 0 0 0 97 GENERAL 2901 MAMMOGRAM BILATERAL LIMITED 0 0 0 0 0 97 GENERAL 2902 MAMMOGRAM BILATERAL 0 0 0 0 0 W / IMPLANfS 97 GENERAL 2906 BREAST LESION LOCALIZATION L 0 0 0 0 0 97 GENERAL 2 907 BREAST LESION LOCAi I ZATION R 0 0 0 0 0 97 GENERAL 2908 BREAST LESION LOCAi J ZATION U 0 0 0 0 0 97 GENERAL 2910 MAMMOGRAM UNILATERAL LEFT 0 0 0 0 0 97 GENERAL 2911 MAMMOGRAM UNILATERAL LEFT LlMI 0 0 0 0 0 97 GENERAL 2912 MAMMOGRAM UNILATERAL LEFT W/IM 0 0 0 0 0 97 GENERAL 2915 MAMMOGRAM SCREENING 0 0 0 0 0 97 GENERAL 2916 MAMMSCREENING PARK A VE 1 0 0 0 0 97 GENERAL 2920 MAMMOGRAM UNILATERAL RIGHT 0 0 0 0 0 97 GENERAL 2921 MAMMOGRAM UNILATERAL RIGHT LIM 0 0 0 0 0 97 GENERAL 2922 MAMMOGRAM UNILATERAL RIGHT W/1 0 0 0 0 0 97 GENERAL 2925 MAMMOGRAPIBC DUCTOGRAM SINGL 0 0 0 0 0 97 GENERAL 2930 BREAST LESION ADDITIONAL LOC 0 0 0 0 0 97 GENERAL 2935 BREAST SURGICAL SPECIMEN 0 0 0 0 0 97 GENERAL 2941 BREAST CYST ASPIRATION LEFT 0 0 0 0 0 97 GENERAL 2942 BREAST CYST ASPIRATION RIGHT 0 0 0 0 0 97 GENERAL 2943 BREAST CYST ASPIRATION US 0 0 0 0 0 97 GENERAL 2944 BREAST CYST ASPIRATION ADD'L 0 0 0 0 0 97 GENERAL 2945 MAMMOGRAM ULTRASOUND 0 0 0 2 4 97 GENERAL 2946 MAMMOGRAMULTRASOUND LIMIT 0 0 0 0 0 97 GENERAL 295 0 MAMMOGRAPHIC DUCTOGRAMMULTI 0 0 0 0 0 97 GENERAL 2955 BREAST CORE BIOPSY LEFT 0 0 0 0 0 97 GENERAL 2956 BREAST CORE BIOPSY RIGHT 0 0 0 0 0 97 GENERAL 2957 BREAST CORE BIOPSY US 0 0 0 0 0 97 GENERAL 2960 BREAST NEEDLE BIOPSY LEFT 0 0 0 0 0 97 GENERAL 2965 STEREOT ACTIC BREAST BIOPSY L 0 0 0 0 0 97 GENERAL 2966 STEREOT ACTIC BREAST BIOPSY R 0 0 0 0 0 97 GENERAL 2975 BREAST ABSCESS DRAINAGE LEFT 0 0 0 0 0 97 GENERAL 2976 BREAST ABSCESS DRAINAGE RIG2H 0 0 0 0 0 97 GENERAL 2999 OUTSIDE READING MAMMS 0 0 0 0 0 97 GENERAL 3000 BONE AGE 5 4 66 126 69 97 GENERAL 3010 CHOLANGIOGRAM OR 2 l 2 0 2 97 GENERAL 3015 NECK SOFT TISSUE 13 14 26 9 9 97 GENERAL 3050 TOMOGRAPHY 0 0 0 0 0 97 GENERAL 3100 PEL VIS AP l VIEW 8 23 72 59 89 97 GENERAL 3101 PEL VIS INLET / OUTLET VIEWS 0 0 0 2 4 97 GENERAL 3102 PEL VIS JUDET VIEWS 0 0 0 1 2 97 GENERAL 3105 HIP AP& LATERAL RIGHT 1 0 4 3 5 97 GENERAL 3110 PEL VIS ORTHO FOR THA 0 0 3 0 3 97 GENERAL 3120 PEL VIS WIT2H LATERAL HIPS 4 4 15 62 50 97 GENERAL 3125 lilP AP ONLY LEFT 0 0 0 0 0 97 GENERAL 3135 HIP AP ONLY RIGHT 0 0 1 1 0 97 GENERAL 3140 HIP AP & LATERAL LEFT 0 0 5 5 3 97 GENERAL 3150 PELVIS -ORTHO W/LAT HIPS FORT 0 0 0 1 1 97 GENERAL 3200 RIBS BILATERAL 0 0 0 1 1 97 GENERAL 3205 RIBS UNILATERAL LEFf 0 0 0 3 3 97 GENERAL 3210 RIBS BILATERAL WITH CHEST 0 0 1 0 0 97 GENERAL 3215 RIBS UNILATERAL RIGHT 0 0 1 2 4 97 GENERAL 3305 SCAPULA RIGHT 0 0 0 1 2 97 GENERAL 3310 SHOULDER LEFT 0 2 7 20 37 97 GENERAL 3320 SHOULDER RIGHT 0 5 6 20 40 97 GENERAL 3325 CLAVICLE LEFT 1 1 7 14 17 97 GENERAL 3335 CLAVICLE RIGHT 2 2 9 10 7 97 GENERAL 3340 SCAPULA LEFT 1 0 0 0 2 97 GENERAL 3345 ACROMIOCLA VICULAR JOINTS 0 0 1 0 3 97 GENERAL 3350 STERNO CLA VICULAR JOINTS 0 0 0 1 0

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127 Year Modality RJS # Exam& View Newbo rn 151015Year Year Year Year 97 GENERAL 335 5 STERNUM 0 1 0 0 0 97 GENERAL 3500 CERVICAL SPINE 7 5 77 90 139 97 GENERAL 3505 LUMBAR SPINE LATERAL ONLY 0 0 0 2 5 97 GENERAL 3510 CERVICAL SPINE LATERAL ONLY 0 l 4 4 1 0 97 GENERAL 3515 LUMBAR SPINE WIT2H OBLIQUES 0 0 0 2 1 6 97 GENERAL 3520 CERVICAL SPINE WIT2H OBLIQUES 0 1 0 3 5 97 GENERAL 3525 L-SPINE FLEXION & EXTENSION ON 0 0 0 0 2 97 GENERAL 3530 C-SPINE FLEXION & EXTENSION ON 0 0 9 27 40 97 GENERAL 3540 LUMBAR SPINE 4 1 23 28 76 97 GENERAL 3545 LUMBAR SPINE BENDING ONLY 0 0 0 0 0 97 GENERAL 3550 THORACIC SPINE 2 0 14 29 48 97 GENERAL 3555 SPINE 1 VIEW ONLY 4 1 2 z 0 97 GENERAL 3560 THORACIC SPINE AP ONLY 0 0 1 z 3 97 GENERAL 3 565 SCOLIOTIC SERIES 0 0 0 1 3 97 GENERAL 3570 SACRUM 1 0 1 1 z 97 GENERAL 3575 SCOLIOTIC AP ONLY 0 0 2 0 l 97 GENERAL 3580 SACROILIAC JOINTS 0 0 0 4 7 97 GENERAL 3585 SCOLIOTlC AP & LAT 0 4 41 125 223 97 GENERAL 35 90 COCCYX 0 0 0 1 1 97 GENERAL 3595 THORACOLUMBARSPINE 0 0 6 6 6 97 GENERAL 3 700 LONG BONE SURVEY 4 0 2 0 0 97 GENERAL 3705 SHUNT SERIES 4 5 28 40 16 97 GENERAL 3710 MET ASTA TIC SUR VEY 0 0 0 0 0 97 GENERAL 3715 SILVERMAN SERIES 14 20 2 6 0 0 97 GENERAL 3720 SKELETAL SURVEY -ADULT 0 0 0 0 0 97 GENERAL 373 0 SKELETAL SURVEY CHILD 3 5 9 1 1 97 GENERAL 3805 ELBOW RIGHT 1 1 42 29 37 97 GENERAL 3806 ELBOW-RIGHT-STRESS VIEWS 0 0 0 0 l 97 GENERAL 3810 HUMERUS UPPER ARM LEFT 1 1 10 20 19 97 GENERAL 3820 HUMERUS UPPER ARM RIGHT 3 3 10 21 21 97 GENERAL 382.5 FOREARM LEFT 5 1 88 111 45 97 GENERAL 3835 FOREARM RIGHT 8 4 73 80 34 97 GENERAL 3840 ELBOW LEFT 0 2 76 46 38 97 GENERAL 3841 ELBOW-LEFT-STRESS VIEWS 0 0 0 0 1 97 GENERAL 3850 WRIST LEFT 2 0 57 131 70 97 GENERAL 3855 HAND LEFT 4 3 24 47 31 97 GENERAL 3860 WRIST RIGHT 4 1 47 96 82 97 GENERAL 386 5 HAND RIGHT 5 3 23 47 87 97 GENERAL 3870 WRIST ORTHO SERIES 7 VIEWS LE 0 0 0 0 0 97 GENERAL 3875 HANDS AP BILATERAL 1 VIEW ] 0 0 0 1 97 GENERAL 3880 WRIST ORTHO SERIES 7 VIEWS RIG 0 0 0 0 0 97 GENERAL 3885 FINGERS LEFT HAND 1 1 17 60 36 97 GENERAL 3895 FINGERS RIGHT HAND 0 0 23 50 39 97 GENERAL 6180 CATHETER PLACEMENT 0 0 0 1 0 97 GENERAL 6545 VENOGRAM UPPER EA'TREMITY LEF 4 0 0 0 0 97 GENERAL 7000 ABDOMEN ULTRASOUND 51 4 10 3 7 97 GENERAL 7015 CHEST-ULTRASOUND 3 0 1 0 0 97 GENERAL 7020 GUIDANCE ONLY ULTRASOUND 0 0 3 3 1 97 GENERAL 7025 DOPPLER ULTRASOUND 6 I 10 0 1 97 GENERAL 7035 BILAT LOWER EXTREMITY DOPPLER 0 0 1 0 1 97 GENERAL 7036 UNILAT LOWER EXTREMITY DOPPLER 2 0 0 0 0 97 GENERAL 7037 BILAT UPPER EXTREMITY DOPPLER 0 0 1 0 0 97 GENERAL 7038 UNILAT UPPER &TIREMITY DOPPLER 0 0 1 1 0 97 GENERAL 7045 HIPS ULTRASOUND 3 0 0 0 0 97 GENERAL 7055 INTRAOPERATIVE ULTRASOUND 0 0 0 1 0 97 GENERAL 7056 ENDOSCOPIC ULTRASOUND 0 0 0 0 0 97 GENERAL 7085 RENAL TRANSPLANT ULTRASOUND 0 0 0 0 0 97 GENERAL 7090 HEAD SCAN ULTRASOUND 305 0 0 0 0 97 GENERAL 7100 SCROTUM-ULTRASOUND 0 l 0 0 0 97 GENERAL 7110 SOFT TISS UE ULTRASOUND 1 0 0 0 1 97 GENERAL 7111 THYROID-US 0 0 0 0 0 97 GENERAL 7115 CALLBACK-ULTRASOUND 9 0 6 0 2 97 GENERAL 7125 LIMITED STUDY-ULTRASOUND 12 4 7 2 5 97 GENERAL 7126 LIMITED R UQ US 3 0 2 2 2 97 GENERAL 7127 LIMITED RENAL US 19 2 5 0 2 97 GENERAL 7128 LIMITED GALLBLADDER US 0 0 1 0 0 97 GENERAL 7136 TRANSREC T AL VOLUME STUDY US 0 0 0 0 0

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128 Year Modality RIS # Exam& View Newborn 151015Year Year Year Year 97 GENERAL 7137 RADIOELEMENT APPLICATION US 0 0 0 0 0 97 GENERAL 7219 BIOPSY KIDNEY US 0 0 0 0 0 97 GENERAL 7247 DRNG PERITONEAL US 0 0 0 0 0 97 GENERAL 7250 DRNG P ARACENTESIS U S 0 0 0 0 0 97 GENERAL 8000 GI SERIES 67 31 51 28 12 97 GENERAL 8005 ESOPHOGRAM 33 13 30 12 10 97 GENERAL 8010 GI W / SMALL BOWEL SERIES 9 6 7 17 11 97 GENERAL 8015 ESOPHOGRAM W/HYPOPHARNYX 0 0 0 1 0 97 GENERAL 8025 REHAB BARIUM SW ALLOW 3 2 18 7 2 97 GENERAL 8035 BARIUM ENEMA 22 3 7 16 2 97 GENERAL 8040 ENTEROCLYSIS STUDY 0 0 1 0 3 97 GENERAL 8045 BARIUM ENEMA WITH/ AIR 1 0 3 1 0 97 GENERAL 8050 CHOLANGIOGRAM 0 0 0 0 0 97 GENERAL 8070 ERCP 0 0 1 3 2 97 GENERAL 8085 SINEOGRAMFISTULAGRAM 0 0 1 4 0 97 GENERAL 8090 FLUORO SCOPY 1 1 2 1 0 97 GENERAL 8095 SPEECH CINE EXAM 0 0 4 4 l 97 GENERAL 8100 CHEST FLUORO ONLY 0 0 1 1 0 97 GENERAL 8140 GI TUBE PLACEMENT 23 13 9 5 4 97 GENERAL 8141 GI TUBE REPOSITTON 4 1 1 0 1 97 GENERAL 8176 ARTHROGRAM HIP LIMITED 0 0 0 0 0 97 GENERAL 8185 FLUOROSCOPY (O R) 47 32 75 55 46 97 GENERAL 8190 FLUOROSCOPY ( 1 HR OR) 2 1 14 12 21 97 GENERAL 8195 FLUOROSCOPY (1.5 HR OR) 0 0 0 1 4 97 GENERAL 8200 FLUORO W/RADIOLOGIST 2 3 5 8 4 97 GENERAL 8201 FLUORO ER 0 0 3 3 3 97 GENERAL 8210 FOREIGN BODY REMOVAL -ESOPHAGE 0 0 5 0 0 97 GENERAL 8230 BE INTUSSUSCEPTION 4 l 1 0 0 97 GENERAL 8305 LUMBAR PUNCTURE DIAGNOSTIC 0 0 0 0 1 97 GENERAL 8306 LUMBAR PUNCTURE THERAPEUTIC 0 0 0 0 2 97 GENERAL 9160 FLUOROSCOPY PER HOUR 0 0 0 0 0 97 GENERAL 9190 OUTSIDE FILM READING 0 0 1 1 0 97 GENERAL 9195 CONSULTATION-OUTPT-EXPANDED 0 2 6 6 6 97 GENERAL 9197 CONSULTATION-INITIAL INPT-MODE 2 0 5 4 2 97 GENERAL 9199 CONSULTATION-FOLLOW UP -INPT 0 1 2 0 3 97 NUCMED 4000 BILIARY SCAN 7 l 0 1 0 97 NUCMED 4005 LIVER HEMANGIOMA / SPECT 0 0 0 0 0 97 NUCMED 4015 SPLEEN SCAN 0 0 1 0 1 97 NUCMED 4030 HEPATIC TUMOR MAA SPECT 0 0 0 0 0 97 NUCMED 4040 LIVER -SPECT l 0 0 0 0 97 NUCMED 4050 GASTRIC/REFLUX & ASPIRATION 0 1 0 0 0 97 NUCMED 4060 GASTRIC EMPTYING 6 7 19 8 1 6 97 NUCMED 4065 RENAL GFR QUANTIFICATION 10 6 31 9 12 97 NUCMED 4070 GI Bl.EEO BLOOD LOSS 0 0 0 0 l 97 NUCMED 4075 RENAL SCAN CAPTOPRIL 1 0 3 1 1 97 NUCMED 4080 GI BLEED MECKEL'$ 1 0 2 1 3 97 NUCMED 4085 RENAL DTPA LASIX 16 5 32 7 8 97 NUCMED 4090 ESOPHAGEAL SW ALLOW NUCMED 0 0 1 0 2 97 NUCMED 4095 RENAL SCAN DTP A 2 2 3 1 5 97 NUCMED 4100 RENOGRAM LASIX 0 0 0 0 1 97 NUCMED 4105 LUNG SCAN VENTILATION XENON 0 0 0 0 0 97 NUCMED 4110 RENOGRAM 1 1 3 2 1 97 NUCMED 4115 LUNG VENTILATION / AER 0 0 0 5 6 97 NUCMED 4120 CYSTOGRAM NUCLEAR MED I CINE 1 2 8 3 0 97 NUCMED 4125 SPLIT LUNG SCAN 0 0 0 0 0 97 NUCMED 4130 LUNG SCAN PERFUSION 1 0 3 5 6 97 NUCMED 4155 BRAIN SCAN 0 0 2 2 2 97 NUCMED 4160 MYOCARDIAL FUNCTION REST IV 0 0 4 6 11 97 NUCMED 4165 BONE IMAGING SPECT 1 1 3 10 19 97 NUCMED 4170 MYOCARDIAL FUNCTION STRESS 0 0 0 0 0 97 NUCMED 4175 BRAIN FUNCTION SCAN SPECT 0 1 17 10 13 97 NUCMED 4180 MYOCARDIAL REST MULTIVIEW 0 0 0 0 0 97 NUCMED 4185 CISTERNOGRAM DTPA 0 0 0 0 0 97 NUCMED 4190 MYOCAR PERFUSION REST & STRE 0 0 0 0 0 97 NUCMED 4195 CISTERNOGRAM CSF LEAK 0 0 0 0 0 97 NUCMED 4205 TUMOR LOCALIZATION -WHOLE BODY 1 2 2 8 8 97 NUCMED 4206 TUMOR LOCALIZATION PROST ASCI 0 0 0 0 0

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129 Year Modality RIS # Exam&View Newborn 151015Year Year Year Year 97 NUCMED 4207 PROSTASCINT-SPECT 0 0 0 0 0 97 NUCMED 4210 BONESCAN 0 1 5 3 1 97 NUCME D 4215 TUMOR LOCALIZATION -SP ECT 0 2 2 8 12 97 NUCMED 4216 ABSCESS LOCALIZATION SPECT z 0 5 6 12 97 NUCMED 4217 ABSCESS LOCALIZATION LIMITED 0 0 0 0 0 97 NUCMED 422 0 BONE SCAN 3PHAS E 6 2 28 30 54 97 NUCMED 4225 ABSCESS LOCALIZATION WHOLE B 4 0 7 5 15 97 NUCMED 4235 TOT AL BODY SCAN 1311 0 0 0 0 1 97 NUCMED 4245 THERAPY STRONTIUM BONE PAIN 0 0 0 0 0 97 NUCMED 4260 PARA THYROID SCAN NUCMED 0 0 0 0 0 97 NUCMED 4270 THYROID SCAN 0 0 0 0 1 97 NUCME D 4275 THER.1131 HYPERTHYROID 10-20 0 0 1 1 4 97 NUCME D 4280 T HYROID UPTAKE 0 0 0 0 0 97 NUCMED 4285 THER.1131 HYPERTHYROID 20-3 0 0 0 0 0 0 97 NUCMED 4290 THYROIDUPT AKE & SCAN 0 0 1 1 5 97 NUCMED 4295 THER 1131 HYPERTHYR0ID50-110 0 0 0 0 0 97 NUCME D 4300 THER.1131 HYPERTHYROIDlll-200 0 0 0 0 0 97 NUCME D 4305 RADIONUCLID E ANGIOGRAPHY 0 0 0 0 0 97 NUCMED 4310 LY~HATIC SCAN 0 0 0 0 0 97 NUCMED 4315 SHUNT PATENCY -NUCLEAR MEDICI 0 0 0 0 0 97 NUCMED 4325 TESTICULAR SCAN NUCMED 0 0 0 1 0 97 NUCME D 4330 VENOGRAM BILATERAL NUCME D 0 0 0 1 0 97 NUCMED 4340 PLA TELETSURVIV AL SC AN I 0 0 0 0 97 NUCMED 4350 ISOTOPES -CATEGORY I 0 0 0 0 0 97 NUCMED 4360 ISOTOPES CATEGORY II 0 0 0 0 0 97 NUCME D 4375 DATA PROCESSING SIMPLE <30 MI 16 9 37 14 24 97 NUCMED 4385 D A TA PROCESSING COMPLEX > 30M 46 27 121 59 50 97 NUCMED 4405 SCHILLINGS ST AGE l 0 0 0 0 97 NUCMED 4410 CALL BACK NUC LEAR MEDICINE 2 3 6 3 3 97 NUCMED 4420 REDBLOOD CELL SURVIVAL 0 0 0 0 0 97 NUCMED 4430 RED BLOOD CELL TECHNETIUM TAG 0 0 1 0 1 97 NUCMED 4435 BRAIN 18-FDG 0 0 1 0 1 97 NUCMED 4436 F-18 FOG TUMOR LOCALIZATION 0 l 7 0 2 97 NUCMED 4440 RED BLOOD CELL VOLUME 0 0 0 0 0 97 NUCMED 4450 KIDNEY STATIC DMSA 43 26 109 41 22 97 NUCMED 4455 BONE MARROW (WHOLE BODY) 0 0 0 0 0 97 NUCMED 4460 STRESS TEST TREADMILL 0 0 0 0 0 97 NUCMED 4465 ADRENAL IMAGING 0 0 0 0 0 97 NUCMED 4466 SOMA TSTATIN 0 0 0 0 0 97 NUCMED 4467 lvfiBG 0 0 0 0 0 97 NUCME D 4481 P32 THERAPY INTRA -ARTI CULAR 0 0 0 0 1 97 NUCMED 4485 MYOCARDIAL PERFUSION REST CAR 0 0 1 0 0 97 NUCMED 4500 MYOCARDIAL 18-FDG 0 0 0 0 0 97 NUCMED 4505 MYOCARDIAL PERFUSION ADENOSIN 0 0 0 0 0 97 NUCMED 4510 RADIONUCLIDE ADMINISTRATION 0 0 0 0 0 97 NUC MED 7025 DOPPLER ULTRASOUND 0 0 0 0 0 97 NUCMED 7085 RENAL TRANSPLANT ULTRASOUND 0 0 0 0 0 97 NUCMED 9625 NOSHOW 0 0 1 0 0 97 NUCMED 9626 NO EXAM PERFORMED 0 0 0 0 0

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APPENDIXB EXAM FREQUENCY FOR PEDIATRIC PATIENTS UNDER 16 YEARS OF AGE For the Time Period Ol/01/97-12/31/97 at Shands at the University of Florida Radiology Department The following data indicate exam frequency for the general radiology modality Examination 0-3 % 3-12 % 1-6 O fo 712 % 13 -16 % months freauen cy months freauencv l vears freauencv ........ uencv l vears l vears "ellC\/ Chest 1 view 3763 54.36 797 43 46 1713 29 46 875 20 59 973 22 26 Babygram 730 1 0 55 474 25 85 1524 26 21 665 15 65 546 12 49 KUB 491 7 09 82 4 47 269 4 63 131 3 08 223 5 10 Chest PA and Lateral 477 6 89 74 4 03 257 4 42 126 2 97 139 3 18 H ead Scan U ltrasound 305 4 41 51 2 78 134 2 30 125 2 94 120 2 75 Abdomen Decubitus Left 288 4 16 32 1 74 88 1 51 115 2 71 89 2 04 Abdomeo 1 View 203 2 93 31 1 69 83 1 43 111 2 61 87 1 99 Cy~ogra m Voiding 93 1 34 30 1.64 77 1 32 96 2 26 84 1.92 GI Series 67 0 97 23 1 25 76 1 31 90 2 12 83 1 90 Abdomen Ultrasound 51 0 74 23 1 25 75 1 29 88 2 07 82 1 88 Fluoro s copy (OR) 47 0 68 20 1 09 75 1 29 80 1 88 82 1 88 E s ophogram 33 0 48 16 0 87 73 1.26 78 1 84 76 1 74 Chest Decubitu s Left 31 0 45 14 0 76 72 1 24 69 1 62 73 1 67 Chest Decubitu s Right 24 0 35 13 0 71 66 1 14 67 1 58 73 1 67 GI T ube Placement 23 0 33 13 0.71 57 0 98 62 1 46 70 1 60 Barium Fnema 22 0 32 7 0 38 5 1 0 88 60 1 41 69 1 58 Foot Right 18 0 26 6 0 33 47 0 81 59 1.39 67 1 53 Foot Left 16 0 23 6 0 33 42 0 72 55 1 29 65 1 49 Silverman Series 14 0 20 6 0 33 41 0 71 55 1 29 59 1 35 Skull 2 Views Follow Up Only 13 0 19 5 0 27 40 0 69 55 1 29 56 1 28 Neck Soft Ti ss ue 13 0 1 9 5 0 27 38 0 65 50 1 18 5 1 1 17 Limited Study Uhrasound 12 0 17 5 0 27 38 0 65 50 1 18 50 1 14 Skull Series 1 0 0 14 5 0 2 7 34 0 58 48 1 13 48 1 10 Antegrade Pyelogram 10 0 14 4 0 22 34 0 58 47 1 11 48 1 10 GI w / Small Bowel Series 9 0 13 4 0 22 32 0 55 47 1 11 46 1 05 Femur Right 9 0 13 4 0 22 30 0 52 46 1 08 46 1 05 Pelvis AP 1 View 8 0.12 4 0 22 30 0 52 43 1 01 45 1 03 Abdomen Supine and Upright 8 0 12 4 0 22 28 0.48 41 0 96 40 0. 92 130

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131 Examination 0-3 % 3-12 % 1-6 % 7-12 % 13-16 % months freciumcy months fr "en cv vears ency vears .. .u ..... uencv vears ~~uen cv Forearm Right 8 0 12 4 0.22 28 0 48 40 0.94 40 0 92 Cervical Spine 7 0.10 4 0.2 2 2 6 0 45 40 0 94 39 0 89 Fem ur Left 6 0 09 4 0 22 26 0 45 39 0 92 38 0 87 Doppler Ultrasound 6 0.09 3 0 16 25 0 43 31 0 73 37 0 85 Leg AP and Lat Hip to Ankle 5 0.07 3 0.16 24 0 41 29 0 68 37 0 85 Right Forearm Left 5 0.07 3 0 16 23 0.40 29 0 68 36 0 82 Hand Right 5 0 07 3 0 16 23 0 40 29 0 68 35 0 80 Bone Age 5 0 07 3 0 16 23 0 40 28 0 66 34 0 78 Shunt Series 4 0.06 3 0 16 19 0 33 28 0 66 31 0. 71 Pelvis w ith Lateral Hips 4 0 06 3 0 1 6 18 0.3 I 27 0 64 21 0.48 Lumbar Spine 4 0.06 3 0 1 6 18 0 31 25 0 59 21 0 48 Hand Left 4 0 06 3 0 16 17 0.29 21 0 49 21 0. 48 GI Tube Reposition 4 0.06 2 0 11 17 0 2 9 21 0 49 20 0 46 Leg AP and Lat Hip to 4 0 06 2 0. 11 17 0 29 20 0 47 20 0.46 Ankle Left Spine l View Only 4 0 06 2 0 11 16 0 28 20 0 47 19 0 43 Long Booe Survey 4 0.06 2 0. 11 16 0 28 20 0 47 17 0 39 Wrist Right 4 0 06 2 0 11 1 5 0.26 19 0 45 17 0 39 BE Intussusception 4 0 06 2 0 11 14 0 24 17 0 40 17 0 39 Low Leg Tibia Left 3 0 04 2 0 11 14 0.24 1 7 0 40 1 6 0 37 Skeletal Survey Child 3 0 04 1 0 05 14 0 24 16 0 38 1 6 0 37 Humerus Upper Ann Right 3 0.04 1 0 05 14 0 24 14 0 33 16 0 37 Abdomen Decubitus Right 3 0.04 1 0.05 13 0 22 14 0 33 15 0 34 Rehab Barium Swallow 3 0 04 1 0 05 12 0 21 13 0 31 15 0 34 Flu oro w/Radiologist 2 0 03 1 0 05 11 0 19 12 0 28 14 0 32 KUBFlat and Upright 2 0 03 1 0 05 1 0 0 1 7 12 0 28 13 0 30 Wrist Left 2 0 03 1 0 05 1 0 0 17 12 0.28 12 0 27 Thoraci c Spine 2 0.03 1 0 05 10 0 17 11 0 2 6 12 0 27 Tibia Low Leg Right 2 0 03 I 0 05 10 0 17 10 0 24 11 0 25 Clav i c le Right 2 0.03 1 0 05 10 0 17 10 0 24 11 0 25 Cholangiogram OR 2 0 03 1 0 05 9 0 1 5 10 0 24 10 0 23 Fluorosoopy (lHR OR) 2 0 03 1 0 05 9 0 1 5 9 0 21 1 0 0 23 SaCnJm 1 0 01 1 0 05 9 0. 15 8 0 1 9 9 0 21 Knee AP and Lat Right 1 0 01 1 0 05 9 0 15 8 0 1 9 9 0 21 C la vi cl e Left 1 0 01 1 0 05 7 0 12 8 0 19 8 0 18 Humerus Upper Ann Left 1 0 01 1 0 05 7 0 12 7 0.16 8 0 18 Knee AP and Lat Left 1 0.01 1 0.05 7 0 12 7 0 16 7 0 16 Barium Enema with Air 1 0 01 1 0 05 7 0 12 7 0 16 7 0 16 Elbow Right 1 0 01 1 0 05 7 0 12 6 0.14 7 0 16 Hands AP Bilateral 1 Viav 1 0 0 1 1 0 05 6 0 1 0 5 0.12 7 0 16

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132 Examination 0 -3 % 3-12 % 1-6 % 7-12 % 13-16 % months months fr..,...mcv fr~encv ucuueocv years Years ... -uency years :fr ~encv Intravenou s Pye)ogram 1 0 01 1 0.05 6 0 10 5 0 12 6 0. 14 Knees Bilateral AP Only 1 0.01 1 0.05 6 0 10 5 0 12 6 0 14 Tibia Low Leg Left 1 0 01 1 0 05 6 0 10 5 0 12 6 0 14 Mammogram Park Avenue 1 0 01 0 0 00 5 0 09 4 0 09 5 0 11 Hip AP and Lateral Rigjlt 1 0 01 0 0 00 5 0 09 4 0 09 5 0 11 Scapula Left l 0 01 0 0.00 5 0.09 4 0 09 5 0. 11 Fingers Left Hand 1 0 01 0 0 00 5 0 09 4 0 09 5 0. 11 Fluorosoopy 1 0 01 0 0 00 5 0 09 4 0.09 4 0 09 Low Leg Tibia RigJit 0 0 00 0 0 00 4 0 07 4 0 09 4 0 09 Shoulder Left 0 0 00 0 0 00 4 0.07 4 0 09 4 0 09 Cystogram with Radiologist 0 0 00 0 0 00 4 0 07 3 0 07 4 0 09 Retrograde Urtthrogram 0 0 00 0 0 00 4 0.07 3 0 07 4 0 09 AP Hip to Ankle 0 0 00 0 0 00 4 0. 07 3 0 07 4 0. 09 Bilateral Ankle Left 0 0 00 0 0 00 3 0 05 3 0 07 4 0. 09 AnkJeRigbt 0 0 00 0 0 00 3 0 05 3 0 07 4 0 09 Toes Rigjlt Foot 0 0 00 0 0 00 3 0 05 3 0 07 3 0.07 Hip AP and Lateral Left 0 0 00 0 0 00 3 0 05 3 0 07 3 0 07 Shoulder Rigjlt 0 0 00 0 0 00 3 0 05 3 0 07 3 0 07 Scoliotic AP and Lat 0 0 00 0 0 00 3 0 05 3 0 07 3 0. 07 Tooracolumbar Spine 0 0.00 0 0 00 3 0 05 3 0 07 3 0 07 Call Back Uhrasound 0 0 00 0 0 .0 0 2 0 03 2 0 05 3 0 07 Abdomen Oecubitus Bilateral 0 0 00 0 0 00 2 0 03 2 0 05 3 0 07 Chest PA/Lat and Bilateral 0 0 00 0 0 00 2 0 03 2 0 05 3 0. 07 Oblique Chest Oblique Only 0 0 00 0 0 00 2 0 03 2 0 05 3 0 07 Chest Apical Lordotic 0 0 00 0 0 00 2 0 03 2 0 .0 5 3 0 07 Chest 3 Views 0 0 00 0 0 00 2 0 03 2 0 05 2 0 05 Cystogram in Cysto 0 0 00 0 0 00 2 0 03 2 0 05 2 0 05 Intravenous Pyelogram 0 0 00 0 0 00 2 0 03 2 0 05 2 0 05 wrromogra IVP Abbreviated 0 0 00 0 0 00 2 0 03 2 0 05 2 0 05 Retrograde Pyelogram 0 0 00 0 0.00 2 0 03 2 0 05 2 0 05 Abdomoo w / Obliques 0 0 00 0 0 00 2 0 03 2 0 05 2 0. 05 Mandible 0 0 00 0 0 00 I 0 02 2 0 05 2 0 05 TMJ Temporal Mandibular 0 0 00 0 0 00 1 0 02 1 0 02 2 0 05 Joint Sinuses 0 0 00 0 0 00 1 0 02 1 0 02 2 0 05 Mastoids 0 0 00 0 0 00 l 0 02 I 0 02 2 0. 05 Facial Bones 0 0 00 0 0 00 1 0 02 1 0 02 2 0. 05 Sella Turcica 0 0 00 0 0 00 1 0 02 1 0 02 2 0 05 Na s al Bones N os e 0 0 00 0 0 00 1 0 02 1 0 02 2 0 05 Eye Foreig Body 0 0 00 0 0 00 1 0 02 1 0 02 2 0 05 Orbit-Eye 0 0 00 0 0 00 1 0 02 1 0 02 2 0 05

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133 Exan1inatioo 0-3 % 3-12 % 1-6 % 7-12 % 13-16 % months fr-~encv months freauencv vears freauwcv l vears frequenc.-v l vears UC21CV Knee 4 View s Right 0 0 00 0 0 00 1 0 02 1 0 02 2 0 05 Knee Left 2V Stress 0 0 00 0 0 00 1 0.0 2 1 0 02 1 0.02 Knee Right2V -Stress 0 0 00 0 0 00 1 0 02 1 0 02 l 0 02 Knee 4 Views Left 0 0.00 0 0 00 l 0.02 1 0 02 1 0 02 Leg Length Scanogram 0 0 00 0 0 00 I 0 02 1 0 02 1 0 02 Ankle Left Stress View s 0 0.00 0 0 00 0 0 00 l 0 02 1 0 02 Ankle Right St.ress View s 0 0 00 0 0 00 0 0 00 l 0 02 1 0 02 Heel Left 0 0 00 0 0 00 0 0 00 I 0 02 1 0 02 Heel Right 0 0 00 0 0 00 0 0 00 1 0 02 1 0 02 Toes Left Foot 0 0.00 0 0 00 0 0 00 l 0 02 1 0 02 Mammogram Bilateral 0 0 00 0 0 00 0 0 00 1 0 02 l 0 02 Mammogram Bilateral 0 0.00 0 0.00 0 0 00 0 0 00 I 0 02 Limited Mammogram Bilateral 0 0.00 0 0.00 0 0.00 0 0 00 1 0 02 w/Implants Breast Lesion Localizatioo L 0 0 00 0 0.00 0 0.00 0 0 00 1 0 02 Breast Lesion Localization R 0 0.00 0 0 00 0 0 00 0 0.00 l 0 02 Breast Lesion Localization U 0 0 00 0 0.00 0 0 00 0 0 00 1 0 0 2 Mammogram Unilateral Left 0 0 00 0 0 00 0 0 00 0 0 00 1 0 02 Mammogram U nilateral Left 0 0.00 0 0 00 0 0 00 0 0 00 0 0 00 Limited Mammogram Screening 0 0 00 0 0 00 0 0.00 0 0 00 0 0. 00 Bone Densitometry 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Mammogram U nilateral Right 0 0.00 0 0 00 0 0 00 0 0.00 0 0. 00 Mammogram Unilatera l Right 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Limited Mammographic Ductogram 0 0 00 0 0.00 0 0 00 0 0 00 0 0 00 Single Breast Lesion Additional Loe 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Breast Surgical Specimen 0 0 00 0 0 00 0 0.00 0 0 00 0 0 00 Breast Cyst Aspiration Left 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Breast Cyst Aspiration Rigbt 0 0 00 0 0.00 0 0 00 0 0 00 0 0 00 Breast Cyst Aspiration US 0 0.00 0 0.00 0 0 00 0 0 00 0 0 00 Brea~'l Cyst Aspiration Add') 0 0.00 0 0 00 0 0 00 0 0 00 0 0 00 Mammogram Ultrasound 0 0 00 0 0.00 0 0 00 0 0 00 0 0 00 Mammogram Ultrasound 0 0 00 0 0 00 0 0.00 0 0 00 0 0 00 Limited Breast Co re Biopsy Left 0 0 00 0 0 00 0 0 00 0 0 00 0 0. 00 Breast Core Biopsy Right 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Breast Core Biopsy US 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Stereotactic Breast Biopsy L 0 0.00 0 0 00 0 0 00 0 0.00 0 0 00 Stereotactic Breast BiopsyR 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Xeroma mmogram 0 0 00 0 0.00 0 0 00 0 0 00 0 0 00 Breast Abscess Drainage Left 0 0 00 0 0.00 0 0 00 0 0 00 0 0 00 Breast Abscess Drainage 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Riehl

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1 3 4 Examination 0-3 % 3-12 % 1-6 % 7-12 % 13-16 % months freauency months freauencv 1years fr .... encv vears frea u eocv 1 vears frea u eo_cy Lymphangiogram Bi l ateral 0 0.00 0 0.00 0 0.00 0 0.00 0 0 00 Pelvis Inl et/Out.let Views 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 Pelvis Judet Views 0 0.00 0 0.00 0 0.00 0 0.00 0 0 00 Pe l vis Ortho For Toa 0 0.00 0 0.00 0 0 00 0 0.00 0 0 00 Hip AP Only Left 0 0.00 0 0.00 0 0 00 0 0 00 0 0.00 Hip AP Only Right 0 0 00 0 0.00 0 0 00 0 0.00 0 0.00 Pelvis Ortho w / Lat Hips for 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 T Ribs Bilatera l 0 0 00 0 0.00 0 0.00 0 0.00 0 0.00 Ribs Unilateral Left 0 0.00 0 0.00 0 0.00 0 0 00 0 0.00 Ri b s B il ateral with Chest 0 0 00 0 0 00 0 0.00 0 0.00 0 0.00 Ribs Unilatera l Rigbt 0 0.00 0 0 00 0 0.00 0 0.00 0 0.00 Scapula Right 0 0.00 0 0.00 0 0.00 0 0.00 0 0 00 Acromioclav i cular Joints 0 0.00 0 0.00 0 0 00 0 0.00 0 0.00 Stemo-C l avicular Jo in ts 0 0.00 0 0.00 0 0 00 0 0 00 0 0.00 Sternum 0 0.00 0 0 00 0 0.00 0 0.00 0 0.00 Lumbar Spine Lateral Only 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 Cervica l Spine Lateral Only 0 0 00 0 0.00 0 0 00 0 0.00 0 0 00 Lumba r S p ine w ith Ob l i qu es 0 0.00 0 0.00 0 0 00 0 0 00 0 0 00 Cerv i ca l S p ine with Ob li q u es 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 L-S p ine F l exioo an d Extt:nsioo 0 0 00 0 0 00 0 0.00 0 0.00 0 0.00 On Cervica l Sp Flexion and 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 Extensioo L um bar S p ine Ben din g Only 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 Th oracic S p ine AP Only 0 0 00 0 0.00 0 0.00 0 0.00 0 0.00 Sco li otic Series 0 0 00 0 0 00 0 0 00 0 0.00 0 0.00 Scoliot i c AP Only 0 0.00 0 0 00 0 0.00 0 0.00 0 0 00 Sacro ili ac Joints 0 0.00 0 0 00 0 0.00 0 0.00 0 0.00 Coccyx 0 0.00 0 0 00 0 0.00 0 0.00 0 0.00 Metastatic Survey 0 0.00 0 0 00 0 0.00 0 0.00 0 0.00 Ske l etal Survey Ad ult 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 E l bow Left 0 0.00 0 0.00 0 0.00 0 0 00 0 0 00 Wrist O rth o Series 7 Views 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 Left Wrist Ortho Series 7 V i ews 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 Right F in gers Right Hand 0 0.00 0 0 00 0 0 00 0 0.00 0 0.00 C h olagiogramTffube 0 0.00 0 0.00 0 0.00 0 0.00 0 0 00 Lumbar Pun cture 0 0.00 0 0 00 0 0.00 0 0 00 0 0.00 G ui dance Only Ultrasound 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 Dop pl er Stu d y/Perip h eral Us 0 0 00 0 0.00 0 0.00 0 0 00 0 0.00 Bloo d Vessels Ultraso un d 0 0.00 0 0.00 0 0 00 0 0.00 0 0.00 Renal T r ansp l ant Ultrasound 0 0 00 0 0.00 0 0 00 0 0.00 0 0.00

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1 3 5 Ex aminat i on 0-3 % 3 12 % 1-6 % 7-12 % 131 6 % mon th s freauencv month s frec 111 encv 1 vears fr.c,. .,,en cv l vears frea u encv vears frea uen cv Tu b e Tho r acosto m y U s 0 0 00 0 0 00 0 0 00 0 0 00 0 0. 00 Dm g So ft Ti ss u e/Neck U s 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Esop h ogra m w/Hyp op harynx 0 0 00 0 0 00 0 0.00 0 0 00 0 0 00 S m a ll Bow e l Series Only 0 0 00 0 0.00 0 0 00 0 0 0 0 0 0 00 Cbo l angiogra m 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 E R C P 0 0.00 0 0 00 0 0 00 0 0 00 0 0 00 Sin eogra m Fistu l agra m 0 0 00 0 0 00 0 0 00 0 0 00 0 0. 00 Speech C in e Exa m 0 0 00 0 0 00 0 0 00 0 0.00 0 0 00 C h est Flu oro Onl y 0 0 00 0 0.00 0 0 00 0 0 00 0 0. 00 F lu o r oscopy ( l 5 HR O R ) 0 0 00 0 0.00 0 0 00 0 0 00 0 0 00 F or eign Bo d y R emoval 0 0 00 0 0 00 0 0 00 0 0 00 0 0.00 Esop h ogus D efecogra ph y 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Myelogra m Cerv i ca l 0 0 00 0 0 00 0 0 00 0 0 00 0 0. 00 Mye l ogram Th oracic 0 0.00 0 0.00 0 0 00 0 0 00 0 0 00 Mye l ogra m Lwnb osacral 0 0.00 0 0 00 0 0 00 0 0 00 0 0 00 F lu oroscopy P er 1 / 2 H o ur 0 0.00 0 0 00 0 0 00 0 0.00 0 0 00 O uts id e F ilm R ead in g 0 0 00 0 0 00 0 0 00 0 0 00 0 0 00 Consultation O utpt Minor 0 0 00 0 0 00 0 0 00 0 0 00 0 0. 00 No Exa m Perform ed 0 0 00 0 0 00 0 0 00 0 0 00 0 0. 00 Ch est Pa and La t era l w ith 0 0.00 0 0.00 0 0.00 0 0.00 0 0 00 Ba rium Chest w/F lu oroscopy 0 0.00 0 0 00 0 0 00 0 0 00 0 0 00 Total 6922 100 1834 100 5814 100 4249 100 43 7 1 100

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APPENDIXC EXAM CHARACTERISTICS DETERMINED FROM FACILITY SITE SURVEYS

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Table C-1 AP Skull Facility ID Relative Generator Mode of Detector AEC Scatter SID FIim Field kVp mA time mAs Focal Shield Speed Type Operation Conflg for Density Suppress Size Size (m sec) Spot Used AEC Settino Size Facility #1 &X) 3 phase manual na na yes 40 18x24 17x24 78 2&) 5 1 25 small yes Facility #2 400 3 phase manual na na yes 40 24x30 16x23 70 100 64 6 40 small yes Facility #3 400 3 phase AE C C N y es 40 24x24 14x23 70 125 136 17 00 large yes Facility #4 400 h i gh frequency AEC C -1 y es 40 2 4x30 19x23 66 ng ng 21 00 large no Facility #5 400 3 phase AEC C N yes 44 24x30 1 7 x23 65 2&) ng 21 70 small no Facility #6 400 3 phase manual na na yes 40 24><3) 19x20 80 400 ng 6 40 small no Facility #7 400 3 phase AEC C N yes 40 24><30 14x19 75 2&) 18 4 50 large no Facility #8 400 high frequency AEC C N yes 40 24><30 18x23 65 500 23 5 11 70 small no Facility #9 400 1 phase AEC C N yes 40 2 4x30 18 X2 4 80 200 ng 10 00 large no Facility #10 400 3 phase AEC C N yes 72 2 4><30 10x15 70 400 36 14 40 large no Table C-2 Townes Skull Facility ID Relative Generator Mode of Detector AEC Scatter SID Film Fleld kVp mA time MAs Focal Shield Speed Type Operation Config for Density Suppress Size Size (msec) Spot Used AEC Settino Size Facility #1 &X) 3 phase manual na na yes 40 18x24 10x10 8 2 250 7 1 75 small yes Facility #2 400 3 phase manual na na yes 40 24><30 17x11 70 100 64 6 40 small yes Facility #3 400 3phase AEC C N yes 40 24x24 23x13 70 125 368 46 00 large yes Facility #4 400 h i gh frequen c y AEC C 1 yes 40 24><3) 23x15 70 ng ng 20 00 large no Facility #5 400 3phase AEC C N yes 38 24><30 25x18 70 2&) ng 11 62 small no Facility #6 400 3phase manual na na yes 40 24x30 20x19 80 400 ng 8 00 small no Facility #7 400 3 phase AEC C N yes 40 2 4x30 20x15 80 250 12 3 00 large no Facility #8 400 high frequency AE C C N yes 40 24x30 23x15 65 500 34 3 1 7 10 small no Facility #9 400 1 phase AE C C N y es 40 2 4x30 22X20 80 200 ng 22 00 large no Fac i lity # 1 o 400 3 phase AE C C N yes 40 24><30 2 4x23 7 5 400 10 4 00 large no

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Table C-3 Lateral Skull FacllltylD Relative Generator Mode of Detector AEC Scatter SID FIim Field kVp mA time mAs Focal Shield Speed Type Operation Config for Density Suppress Size Size (msec) Spot Used AEC Settlna Size Facility #1 6(X) 3 phase manual na na yes 40 18x24 19x22 73 250 7 1 75 small yes Facility #2 400 3 phase manua l na na no 40 24x3J 20x20 00 100 50 5 00 small yes Facility #3 400 3 phase AE C C N y es 40 24x24 18x20 70 125 96 12 00 large yes Facility #4 400 high frequenc y AE C C -1 yes 40 24x30 22x22 65 ng ng 12 40 large no Facility #5 400 3 phase manual na na no 38 24x30 25x23 70 250 10 2 50 small no Facility #6 400 3 phase manual na na yes 40 2 4x30 23x20 70 400 ng 5 00 small no Facility # 7 400 3 phase AE C C N yes 40 2 4x3J 18 x 16 65 250 15 3 75 large no Facility #8 400 high frequency AEC C N yes 40 24><30 20x20 65 500 13 9 6 95 small no Facility #9 400 1 phase AEC C N y es 40 24x30 22X22 75 200 ng 12 00 large no Fa c ility #10 400 3 phase AEC C N y es 72 2 4x30 15 x 10 70 400 33 13 20 large no

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Table C-4 AP Cervical Spine Facility ID Relative Generator Mode of Detector AEC Scatter SID Film Fleld kVp mA time mAs Focal Shield Speed Type Operation Config for Density Suppress Size Size (msec) Spot Used AEC Settino Size Facility #1 3phase manual na na yes 40 18x24 10x10 65 250 15 3 75 small yes Facility #2 400 3 phase manual na na yes 40 24><3:> 10x20 65 60 50 3 00 small yes Facility #3 400 3 phase AE C C N yes 40 24 x2 4 10x23 70 125 40 5 00 large yes Facility#4 400 high frequenc y AEC C N yes 40 24><3:> 10x18 65 ng ng 9 10 large n o Facility #5 400 3 phase AEC C N yes 38 18x24 10x25 65 250 ng 6 80 small no Facility #6 400 3 phase manual na na no 40 24><3:> 10x2 2 68 400 ng 2 00 small no Facility #7 400 3 phase AEC C N yes 40 24><3:> 10x15 65 250 18 4 50 large no Facility #8 400 high frequency AEC C N yes 40 2 4)(3) 13x20 65 500 8 4 4 20 small no Facility #9 400 1 phase manual na na yes 40 24><3:> 1SX19 60 200 100 20 00 large no Fac i lity #10 400 3phase AEC C 1 yes 40 24><3:> 24)(3) 66 400 5 2 00 large no Table C-5 Lateral Cervical Spine Facility ID Relative Generator Mode of Detector AEC Scatter SID FIim Field kVp mA time mAs Focal Shield Speed Type Operation Conflg for Density Suppress Size Size (msec) Spot Used AEC Settino Size Facility #1 3 phase manual Na na yes 40 18x24 10x20 70 250 25 6 25 small yes Facility#2 400 3phase manual Na na no 40 24)(3) 10x21 65 100 40 4 00 small yes Facility #3 400 3 phase AEC C N yes 40 24x24 8x18 70 125 64 8 00 large yes Facility #4 400 high frequency AEC C -1 yes 40 24><3:> 10x17 65 ng ng 8 01 large no Facility #5 400 3phase manual na na no 38 18x24 10x25 67 250 8 2 00 small no Facility #6 400 3 phase manua l na na no 40 24><3:> 10x20 74 400 ng 1 60 small no Facility #7 400 3 phase AEC C N yes 7 2 2 4)(3) 12 5x16 70 250 40 10 00 large no Fac i lity #8 400 high frequency AEC C N yes 7 2 24><3:> 10x18 65 500 90 2 45 10 small no Facil i ty #9 400 1 phase manual na na yes 40 24><3:> 12X24 70 200 125 25 00 large no Facility #10 400 3 phase AE C C N yes 40 2 4)(3) 15x25 75 400 6 2 40 l arge no

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Table C-6 AP Thoracic Spine Facility ID Relative Generator Mode of Detector AEC Scatter SID FIim Field kVp mA time mAs Focal Shield Speed Type Operation Conflg for Density Suppress Size Size (msec) Spot Used AEC Settlna Size Facility #1 &X) 3 phase manual na na yes 40 18x24 13x23 72 250 15 3 75 small yes Facility #2 400 3 phase manual na na yes 40 24x30 11><24 65 100 50 5 00 small yes Facility #3 400 3 phase AEC C N y es 40 24><24 10><23 70 125 104 13 00 large yes Facility#4 400 high frequency AEC C N yes 40 24x30 15><25 65 ng ng 14 00 large no Facility #5 400 3 phase AEC C N yes 38 30x35 10><28 70 250 ng 8 35 small no Facility #16 400 3phase manual Na na yes 40 24x30 10X22 68 400 ng 2 00 small no Facility#? 400 3 phase AEC C N yes 40 24x30 10x20 75 250 39 9 75 large no Facility #8 400 high frequency manual Na na yes 40 24x30 13><23 65 5CX) 10 7 5 35 small no Facility #9 400 1 phase manual Na na yes 40 24x30 13x23 65 5CX) 10 7 5 35 large no Facility #1 O 400 3 phase AE C C -1 y es 40 2 4x30 14><24 70 400 9 3 00 large no 0 Table C-7 Lateral Thoracic Spine FacllltylD Relative Generator Mode of Detector AEC Scatter SID FIim Field kVp mA time Mas Focal Shield Speed Type Operation Conflg for Density Suppress Size Size (msec) Spot Used AEC Settino Size Fac i lity #1 &X) 3 phase manual na na yes 40 18><24 11><22 75 250 25 6 25 small yes Facility #2 400 3 phase manual na na yes 40 24x30 10X22 70 100 64 6 40 small yes Facility #3 400 3 phase AEC C N yes 40 24><24 8><20 70 125 128 16 00 large yes Facility #4 400 high frequency AEC C N yes 40 2 4x30 13x22 00 ng ng 32 10 large no Facility#S 400 3 phase AEC C N yes 38 3())(35 13x30 70 250 ng 9 72 small no Facility #16 400 3 phase manual na na yes 40 24x30 10x19 68 400 ng 4 00 small no Facility #7 400 3 phase AEC C N yes 40 2 4x30 10x16 70 250 41 5 10 38 large no Facility #8 400 h i gh frequency manual na na yes 40 2 4x30 13x23 54 32 1250 40 00 small no Fa c ility #9 400 1 phase manual na na yes 40 24)(3) 13><27 00 100 1CXX) 100 00 large no Facility #10 400 3 phase AEC C N yes 40 2 4x30 15><25 83 400 13 5 20 large no

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Table C-8 AP Lumbar Spine FacllltylD Relative Generator Mode of Detector AEC Scatter SID FIim Fleld kVp mA time Mas Focal Shield Speed Type Operation Conftg for Density Suppress Size Size (msec) Spot Used AEC Settlna Size Facility #1 600 3phase manual na na yes 40 18><24 13><23 72 250 15 3 75 small yes Facility # 2 4CX) 3 phase manual na na yes 40 24)(3) 11x24 70 100 64 6 40 small yes Facility #3 4CX) 3 phase AEC C N yes 40 24><24 10x23 70 125 128 16 00 l arge yes Facility #4 4CX) high frequency AEC C 1 yes 40 24)(3) 18 x25 70 ng ng 9 83 large no Facility #5 4CX) 3phase AEC C N yes 38 3))(35 10x28 70 250 ng 9 02 small no Facility #6 4CX) 3 phase manual na na yes 40 24)(3) 10x22 68 4CX) ng 3 20 small no Facility #7 4CX) 3 phase AEC C N yes 40 2 4)(3) 10x20 75 250 47 11 75 large no Facility#8 4CX) high frequenc y manual na na yes 40 24)(3) 13x23 65 500 18 8 9 40 small no Facility#9 4CX) 1 phase AEC na N yes 40 24)(3) 10x2 2 5 70 200 ng 3:> 00 large no Facility #1 o 4CX) 3 phase AEC C -1 yes 40 24)(3) 14x24 75 4CX) 10 4 00 large no Table C-9 Lateral Lumbar Spine FacllltylD Relative Generator Mode of Detector AEC Scatter SID FIim Field kVp mA time MAs Focal Shleld Speed Type Operation Config for Density Suppress Size Size (msec) Spot Used AEC Settlna Size Facility #1 600 3 phase AEC C N yes 40 24><3) 14x19 75 4CX) 18 7 20 small yes Facility #2 4CX) 3 phase manual na na yes 40 24)(3) 10x22 74 100 100 10 00 small yes Facility #3 4CX) 3 phase AEC C N yes 40 24x24 10x23 70 125 240 3:> 00 large yes Facility#4 4CX) high frequency AEC C N yes 40 24)(3) 11x23 75 ng ng 18 50 large no Facility#S 4CX) 3phase AEC C N yes 38 3))(36 10x28 70 250 ng 16 22 small no Facility #6 4CX) 3 phase manual na na yes 40 24)(3) 10x19 68 4CX) ng 6 00 small no Facility #7 4CX) 3 phase AEC C N yes 40 24)(3) 10x20 70 250 88 2 2 00 large no Facility #8 4CX) high frequency AEC C 1 yes 40 24)(3) 10x23 65 500 55 8 27 00 small no Fac i lity #9 4CX) 1 phase AEC C N yes 40 24)(3) 12x24 70 200 ng 45 00 large no Fa c ility #10 4CX) 3 phase AEC C N yes 40 2 4)(3) 15 x25 75 4CX) 12 4 80 large no

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Table C-10 AP Abdomen Faclltty ID Relative Generator Mode of Detector AEC Scatter SID Film Field kVp mA time MAs Focal Shield Speed Type Operation Config for Density Suppress Size Size (msec) Spot Used AEC Settlna Size Facility #1 &X) 3 phase manual na na yes 40 24x30 22><2 2 70 250 15 3 75 small yes Facility #2 400 3 phase manual na na yes 40 24x30 19x23 68 100 40 4 00 small yes Facility #3 400 3 phase AEC C N yes 40 24x24 18x25 00 250 120 30 00 large yes Fa c ility #4 400 high frequenc y AEC C -1 yes 40 2 4x30 20x28 7 0 ng ng 12 00 l arge no Facility #5 400 3 phase AEC C N yes 38 30x35 22x28 70 250 ng 8 45 small no Facility #6 400 3 phase manual na na no 40 24x30 23x27 68 400 ng 3 20 small no Facility # 7 400 3 phase AEC C N yes 40 2 4x30 15x21 70 250 44 11 00 large no Facility #8 400 high frequency AEC C N yes 40 24x30 18x27 66 500 16 1 8 05 small no Facility #9 400 1 phase AEC RCL N yes 40 24x30 23X30 75 200 ng 10 00 large no Facility #10 400 3 phase AEC C N yes 40 24><30 24x30 ffi 400 16 6 40 large no Table C-11 AP Pelvis FacllltylD Relative Generator Mode of Detector AEC Scatter SID Film Field kVp mA time MAs Focal Shield Speed Type Operation Config for Density Suppress Size Size (msec) Spot Used AEC Settlna Size Facility #1 &X) 3 phase manual na na yes 40 18x24 14x20 70 250 15 3 75 small yes Facility #2 400 3 phase manual na na yes 40 30x24 22><18 72 100 50 5 00 small no Facility#3 400 3 phase AEC C N yes 40 24x24 18x18 00 250 108 27 00 large no Facility #4 400 high frequenc y AEC C 1 yes 40 30x24 23x20 70 ng ng 8 87 large no Facility #5 400 3 phase AEC C N yes 38 18x24 18x20 70 250 ng 7 f:15 small no Facility #6 400 3 phase manual na Na no 40 24><30 19x24 68 400 ng 3 20 small no Facility #7 400 3 phase AEC C N yes 40 24x30 15x16 70 250 14 3 50 large no Facility #8 400 high frequen c y AEC C N yes 40 30x24 23x20 66 500 14 3 7 15 small no Facility#9 400 1 phase AEC RCL N yes 40 30 X2 4 24 X22 75 200 ng 10 00 large no Facility#10 400 3 phase AEC C -1 yes 40 24x30 18x24 7 0 400 5 2. 00 large no

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Table C-12 AP Hip FacllltylD Relative Generator Mode of Detector AEC Scatter SID FIim Field kVp mA time MAs Focal Shield Speed Type Operation Conflg for Density Suppress Size Size (msec) Spot Used AEC Settino Size Facility #1 600 3 phase manual na na yes 40 18x24 12x11 66 250 15 3 75 small yes Facility # 2 400 3 phase manual na na yes 40 2 4x3J 13x20 7 0 100 50 5 00 small n o Facility #3 400 3 phase AEC C N yes 40 24x24 8x18 &) 250 36 9 00 large no Facility #4 400 high frequency AEC C -1 yes 40 3)x24 10x13 66 ng ng 1 2. 10 large no Facility #5 400 3 phase AEC C N yes 38 18x24 10X24 66 250 ng 4 50 small no Facility #6 400 3 phase manual na na yes 40 24x3J 24x19 68 400 ng 3 20 small no Facility # 7 400 3 phase AEC C N yes 40 2 4x3J 15x16 70 250 14 3 50 large no Facility #8 400 high frequen c y AEC C N yes 40 3)x24 18x10 66 500 3 6 1 80 small no Facility #9 400 1 phase AEC RCL N yes 40 18 X2 4 13 X 18 75 200 ng 10 00 large no Facility #10 400 3 phase AEC C -1 yes 40 24x3J 20x15 75 400 2 0 80 large no

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Table C-13 Waters Sinus Facility ID Relative Generator Mode of Detector AEC Scatter SID Film Field KVp mA time mAs Focal Shield Speed Type Operation Conflg for Density Suppress Size Size (msec) Spot Used AEC Settlna Size Facility #1 EO) 3 phase manual na na yes 40 18x24 12x15 75 250 7 1 .75 small yes Facility #2 4CX) 3 phase manual na na yes 40 24)(3) 11x17 65 100 64 6.40 small yes Fac ility #3 4CX) 3 phase AEC C -1 yes 40 24x24 13x15 70 125 3)4 38 00 large yes Facility #4 4CX) high frequency AEC C N yes 40 24)(3) 13x15 70 ng ng 14.20 large no Facility #5 4CX) 3 phase AEC C N yes 38 18x24 13x13 65 250 ng 20 40 small no Facility #6 4CX) 3 phase manual na na yes 40 24)(3) 13x13 80 4CX) ng 8 00 small no Facility #7 4CX) 3 phase AEC C N yes 72 24)(3) 14x19 70 250 116 29 00 large no Facility #8 4CX) high frequency A E C C N yes 40 24)(3) 18><20 65 500 55 6 27 80 small no Fac ility t#9 4CX) 1 phase A E C C N yes 72 24)(3) 12X16 75 200 ng 25 00 large no Facility #1 O 400 3 phase AEC C -2 yes 40 24)(3) 13x16 70 4CX) 36 14 40 large no Table C-14. Lateral Sinus FacllltylD Relative Generator Mode of Detector AEC Scatter SID FIim Fleld kVp mA time MAs Focal Shield Speed Type Operation Config for Density Suppress Size Size (msec) Spot Used AEC Settino Size Facility #1 EO) 3 phase manual na Na yes 40 18x24 15x14 68 250 7 1 75 small yes Facility #2 4CX) 3 phase manual na Na no 40 24><31 20x20 &) 100 50 5 00 small yes Facility #3 4CX) 3 phase AEC C -1 yes 40 24x24 8x15 70 125 16 2.00 large yes Facility #4 4CX) high frequency AEC C N yes 40 24)(3) 10x14 65 ng ng 10.~ l arge no Facility #5 4CX) 3 phase manual na Na no 38 18x24 13x13 65 250 6 4 1.00 small no Facility #6 4CX) 3 phase manual na Na yes 40 24)(3) 13x13 70 4CX) ng 5 00 small no Facility #7 4CX) 3 phase AEC C N yes 72 24)(3) 13 5x16 70 250 44 11 00 large no Facility #8 4CX) high frequency AEC C N yes 40 24)(3) 18><20 65 500 41 3 20.00 small no Facility t#9 4CX) 1 phase AEC C N yes 40 24)(3) 12X18 70 200 ng 17.50 large no Facility #10 4CX) 3 phase AEC C -1 yes 40 24)(3) 13 x16 &) 4CX) 12 4 80 large no

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Table C-15. Lateral Chest Facility ID Relative Generator Mode of Detector AEC Scatter SID FIim Field kVp mA time mAs Focal Shield Speed Type Operation Conflg for Density Suppress Size Size (msec) Spot Used AEC Settino Size Facility #1 Ero 3 phase manual na na No 72 18><24 13x11 74 250 15 3 75 small yes Facility #2 400 3 phase manual na na No 72 24x30 12x11 85 100 40 4 00 small yes Facility #3 400 3 phase manual na na No 72 24)(3) 23x15 75 125 14 1 70 small yes Facility #4 400 high frequency AEC C N yes 72 24><30 25x20 75 ng ng 17 00 small no Facility ##5 400 3 phase manual na na no 00 24><30 25><20 75 250 8 2 00 small no Facility#6 400 3 phase manual na na no 42 24x30 23x18 58 400 ng 3 20 small no Facility #7 400 3 phase AEC C N yes 72 24x30 16x15 .5 70 250 49 12 25 small no Facility #8 400 high frequency manual na na no 72 24x30 20x18 84 400 6 .2 5 2.50 small no Facility #9 400 1 phase AEC RCL N yes 72 24><30 21x14 00 200 ng 18 00 small no Facility #1 O 400 3 phase AEC RCL N yes 72 24><30 15x10 95 400 10 4 00 small no Table C-16. AP Chest FacilltylD Relative Generator Mode of Detector AEC Scatter SID Film Field kVp mA time mAs Focal Shield Speed Type Operation Config for Density Suppress Size Size (msec) Spot Used AEC Settino Size Facility #1 Ero 3 phase manual na na No 72 18x24 12x12 66 250 7 1.75 small yes Facility #2 400 3 phase manual na na No 72 24)(3) 12x12 70 100 32 3.20 small yes Facility#3 400 3phase manual na na No 72 24x30 18x20 75 125 14 1 70 small yes Facility#4 400 high frequency AEC C -2 Yes 72 24><30 20x25 75 ng ng 12 00 small no Facility ##5 400 3 phase manual na na No 61 24)(3) 20x25 62 250 5 1.25 small no Facility #6 400 3 phase manual na na No 40 24x30 19x23 58 400 ng 1.00 small no Facility#7 400 3 phase AEC C N Yes 72 24x30 19x20 70 250 37 9.25 small no Facility #8 400 high frequency manual na na No 72 24x30 23x29 68 500 4 2.00 small no Facility #9 400 1 phase AEC Rl N Yes 72 24><30 18X18 80 200 ng 10 00 small no Facility #1 O 400 3 phase AEC RCL -1 Yes 72 24x30 11 5x12 5 00 400 4 1.00 small no

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Table C-17 PA Chest FacilltylD Relative Generator Mode of Detector AEC Scatter SID Film Field KVp mA time mAs Focal Shield Speed Type Operation Conflg for Density Suppress Size Size (msec) Spot Used AEC Settlna Size Facility #1 &X) 3 phase manual na na no 7 2 18 ><2 4 1 2x 1 2 66 250 7 1 75 small yes Fac i lity # 2 400 3 phase manual na na n o 7 2 2 4x3J 11 x 12 7 2 100 40 4 00 small yes Facility #3 400 3 phase manual na na n o 72 2 ~ 18 x 18 68 100 1 2 1 00 small ye s Facility #4 400 h i gh frequency AEC C 2 yes 72 2 4><:D 20x25 75 ng ng 1 7. 00 small no Facility #5 400 3 phase manual na na no 7 2 2~ 20x25 67 250 5 1 25 small no Facility #6 400 3 phase manual na na no 40 24><:D 19><23 58 400 ng 1 00 small no Facility # 7 400 3 phase AEC C N yes 7 2 2 4x3J 19x20 70 250 31 7. 75 small no Facility #8 400 high frequen c y manual na na no 72 24)(.JJ 23x23 68 500 4 2 00 small no Fa cil ity #9 400 1 phase AEC Rl N yes 7 2 2 4x3J 18 X 18 80 200 ng 10 00 small n o Facility #1 O 400 3phase AEC R C L -1 Yes 72 2 4><:D 11 5 x1 2 5 00 400 5 2. 00 small n o Table C-18 Non-Exam Specific Operational Data FacllttylD HVL Grid Ratio Avg. Lung OD Avg. Lung OD Avg. Lung OD Repeat Rate % AP Chest PA Chest Lateral Chest Facility #1 3 07 10 : 1 1 495 1 015 1 115 4 5 Facility #2 2 .89 1 2: 1 1 03 1 4 1 11 0 5 Facility#3 3 2 8 1 2: 1 2 236 2. 5 7 1 415 8 0 Facility #4 3 .7 2 1 2: 1 2 44 2. 655 1 665 5 5 Facility #5 2 .94 10 : 1 0 625 0 475 0 .7 15 4 0 Facility #6 2 .66 10 : 1 0 65 0 595 0 47 2. 0 Facility #7 3 4 6 10 : 1 2 215 2. 16 1 995 1 0 Facility #8 3 1 6 1 2: 1 0 99 0 84 1 125 4 3 Facility#9 2 91 12 : 1 0 875 0 425 1 735 3 5 Fa ci lity #1 O 3.44 1 2: 1 1 1 1 295 1 48 3 0

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APPENDIXD AVERAGE MASS ENERGY ABSORPTION COEFFICIENTS

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Ca l culation of the average mass energy absorption coefficients for air, soft tissue, bone and lung at 70 kVp using the x-ray spectrum generated by XCOMP5R #of %of Air Soft Tissue Bone Lung ke V Photons Spectrum ~nfP %*ex/p J.lenl'p %*J.lenl'p 1 0 0 3616 0 1170 0 2 0 0 529 1 0 531 0 3 0 0 160 8 0 170 0 4 0 0 75 97 0 73 9 0 5 0 0 38 96 0 38 2 0 6 0 0 22 42 0 22 1 0 7 0 0 7 563 0 7.62 0 8 0 0 9 246 0 9 24 0 9 0 0 7.785 0 7 755 0 JO 0 0 4 640 0 4 650 0 11 0 0 3 972 0 3.982 0 1 2 0 0 3 304 0 3 314 0 1 3 0 0 2 636 0 2.646 0 14 2 2.00E-05 l 968E+OO 3 94E-05 1 978 3 96E-05 15 8 8.00E-05 1 300E+OO l 04E-04 1 310 1 05E-04 16 30 3 00E-04 1 145E + OO 3 44E-04 1 155 3.46E-04 1 7 80 8.00E-04 9 902-01 7 92E-04 0 999 7 99E-04 18 176 l 76E-03 8 353E-Ol l 47E-03 0 844 l 49E-03 19 327 3 27E-03 6.804E-Ol 2 22E-03 0 688 2.25E-03 2 0 53 7 5 37E-0 3 5 255E-01 2 82E-03 0 533 2 86E-03 21 785 7 85E-0 3 4 880E-Ol 3 8 3 E-03 0 495 3 89E-03 2 2 1062 l 06E-02 4.504E-Ol 4 78E-03 0 457 4 85E-03 23 1358 l .3 6E-02 4 129E-Ol 5 61E-0 3 0 419 5.69E-03 24 1658 l 66E-02 3 753E-01 6 22E-03 0 381 6 32E-03 2 5 1949 l 95E-02 3 378E-Ol 6 58E-03 0 343 6 69E-03 26 2223 2.22E-02 3 003E-Ol 6 67E-03 0 305 6 78E-03 2 7 2472 2 47E-02 2.627E-Ol 6 49E-03 0 267 6 60E-03 2 8 2691 2 69E-02 2 252E-Ol 6 06E-03 0 229 6 16E-03 29 28 7 9 2 88E-02 l 876E-Ol 5 40E-03 0 191 5 50E-03 30 3035 3 04E-02 1 501E-Ol 4 56E-03 0.153 4.64E-03 31 3132 3.13E-02 l.420E-01 4 45E-03 0 145 4.53E-03 3 2 3195 3.20E-02 l 340E-01 4 28E-03 0.136 4 35E-03 33 3236 3.24E-02 1 259E-Ol 4 07E-03 0.128 4 13E-03 34 325 7 3.26E-02 l.178E-01 3 84E-03 0 119 3.89E-03 35 3260 3 26E-02 l.098E-Ol 3 58E-03 0 111 3 61E-03 36 324 7 3 25E-02 1 017E-01 3 .3 0E-03 0 102 3 33E-03 3 7 3221 3 22E-02 9 361E-02 3 02E-03 0 094 3.03E-03 38 3182 3 18E-02 8 554E-02 2 72E-03 0.086 2 72E-03 39 3133 3 13E-02 7 747E-02 2 43E-03 0 077 2 42E-03 40 3075 3 08E-02 6 940E-02 2 13E-03 0 069 2 l lE-03 41 2998 3.00E-02 6.676E-02 2 00E-03 0 066 l 98E-03 4 2 2912 2 91E-02 6 412E-02 l 87E-03 0 063 l 84E-03 148 ex/p %*J..Len/p eJ P %*~ J p 978 0 1150 0 436 0 539 0 206 0 172 0 9 2 5 0 75 0 9 0 9 0 38 9 0 5 5 6 0 22 5 0 22 75 0 7 765 0 25 20 0 9 430 0 20 525 0 7 923 0 1 3. 400 0 4 750 0 1 1.550 0 4 070 0 9.700 0 3.390 0 7.850 0 2 710 0 6 000 l 20E-04 2.030 4 06E-05 4 150 3.32E-04 1 350 1 08E-04 3.674 l lOE-03 1.189 3 57E-04 3 198 2 56E-03 1 028 8 23E-04 2 722 4 79E-03 0 868 l 53E-03 2 246 7 34E-03 0 707 2 3 lE-03 1 770 9 5 lE-03 0 546 2 93E-03 1 646 1 29E-02 0 507 3 98E-0 3 1 521 1 62E-02 0 468 4.97E-03 1 397 l 90E-02 0 429 5 8 3 E-0 3 1.272 2 llE-02 0 390 6 47E-03 1 148 2 24E-02 0.352 6 85E-03 1 024 2 28E-02 0 313 6 95E-03 0 899 2 22-02 0 274 6 77E-03 0.775 2 09E-02 0 235 6 32E-03 0 650 l 87E-02 0.196 5 64E-03 0 526 l 60E-02 0 157 4 77E-03 0.496 l 55E-02 0 149 4 66E-03 0 466 l 49E-02 0.141 4 49E-03 0.436 1 41E-02 0 132 4 28E-03 0.406 1 32E-02 0.124 4 05E-03 0 376 1 22E-02 0.116 3 78E-03 0 345 l 12E-02 0.108 3 50E-03 0 315 l.02E-02 0 100 3 21E-03 0.285 9 08E-03 0 091 2 91E-03 0 255 7 99E-03 0 083 2 61E-03 0 225 6 92E-03 0 075 2 31E-03 0 215 6.43E-03 0 072 2 15E-03 0.204 5 94E-03 0.069 2 00E-03

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43 2823 2 82E-02 44 2 7 31 2 73E-02 45 2637 2 64E-02 46 2541 2.54E-02 47 2443 2 44E-02 48 2344 2 34E-02 49 2244 2.24E-02 50 2143 2 14E-02 51 2038 2 04E-02 52 1931 l.93E-02 53 18 2 4 l.82E-02 54 1718 l 72E-02 55 1613 l 61E-02 56 1508 l.51E-02 57 1403 l 40E-02 58 1298 l 30E-02 59 1200 l 20E-02 60 1100 l lOE-02 61 98 7 9.87E-03 62 883 8 83E-03 63 781 7.SlE-03 64 679 6 79E-03 65 579 5 79E-03 66 479 4 79E-03 6 7 381 3 81E-03 68 287 2.87E-03 69 188 l.88E-03 70 94 9 40E-04 70kVp Sumof%*~p Average~p 6 148E-02 1 74E-03 5 884E-02 l 61E-0 3 5 621E-02 l 48E-03 5 .3 57E-02 l 36E-03 5 093E-02 1 24E-03 4 829E-02 l 13E-03 4 565E-02 1 02E-03 4 301E-02 9.22E-04 4 171E-02 8 SOE-04 4 042E-02 7 80E-04 3 912E-02 7 14E-04 3 782E-02 6 50E-04 3 653E-02 5 89E-04 3 523E-02 5 31E-04 3 393E-02 4 76E-04 3 263E-02 4 24E-04 3 134E-02 3 76E-04 3 004E-02 3 30E-04 2 974E-02 2 93E-04 2 943E-02 2 60E-04 2 913E-02 2.27E-04 2 882E-02 1 96E-04 2 852E-02 l 65E-04 2 821E-02 l 35E-04 2 791E-02 1.06E-04 2 760E-02 7.92E-05 2 730E-02 5.13E-05 2 699E-02 2 54E-05 Air l 19E-Ol l 71E-03 149 0 061 l 71E-03 0 058 l.58E-03 0 055 l.46E-03 0 053 l 33E-03 0 050 l 22E-03 0 047 1 lOE-03 0 044 9.96E-04 0 042 8 94E-04 0 041 8 29E-04 0 040 7 65E-04 0 039 7 04E-04 0 038 6 46E-04 0 037 5.90E-04 0.036 5 36E-04 0 034 4 84E-04 0 033 4 34E-04 0 032 3.89E-04 0 031 3.45E-04 0 0 3 1 3 07E-04 0 031 2 72E-04 0 031 2 38E-04 0 030 2.0SE-04 0 030 l.7 3 E-04 0 030 l 42E-04 0 029 1 12E-04 0 029 8 32E-05 0 029 5 40E-05 0 028 2 67E-05 Soft Tissue l 21E-Ol l 72E-03 0 194 5 46E-03 0 183 5 00E-03 0 173 4 55E-03 0.162 4.12E-03 0 152 3 70E-03 0 141 3 3 lE-03 0 131 2.93E-03 0 120 2 57E-03 0 116 2 36E-03 0 111 2 15E-03 0.107 1 95E-03 0 102 l 76E-03 0 098 l 58E-03 0 094 l.41E-03 0 089 l 25E-03 0.085 l lOE-03 0 080 9.65E-04 0 076 8.36E-04 0.074 7.34E-04 0 073 6 42E-04 0 071 5 55E-04 0 069 4 72E-04 0 068 3 93E-04 0 066 3 17E-04 0 065 2 46E-04 0 063 l.SlE-04 0 061 l 15E-04 0 060 5 61E-05 Bone 3 96E-Ol 5 66E-03 0 065 l 84E-03 0.062 l 70E-03 0.059 l 55E-03 0 056 l 41E-03 0.052 l 28E-03 0 049 l 15E-03 0 046 l 03E-03 0 043 9 15E-04 0 042 8 49E-04 0.041 7 84E-04 0 040 7 21E-04 0.038 6 61E-04 0 037 6 03E-04 0.036 5 48E-04 0.035 4 95E-04 0.034 4.44E-04 0 033 3 98E-04 0.032 3 53E-04 0.032 3 14E-04 0.031 2 78E-04 0.031 2.43E-04 0.031 2 09E-04 0.031 l 77E-04 0 030 1.45E-04 0.030 l 14E-04 0.030 8 49E-05 0 029 5 SOE-05 0 029 2 72E-05 Lung l 25E-Ol l 79E-03

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APPENDIXE EFFECTIVE DOSE AND RISK CALCULATIONS

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Table E-1 AP Skull Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 40 mAs mAs Exam mAs [mV/R] (rad] Factor [rem) Thyroid A3 9 1 25 0 28125 34 60 1.009 0 0072 0.05 0 0004 Active Bone Marrow 0.0005 0 12 0 0001 Bone surface 0 001 3 0 01 0 0000 Remainder 0.0000 0 05 0 0000 Skin 0.0055 0 01 0 0001 Calculation of dose to active marro)v Absorbed Fract. Active Fract ..... Organ/ MOSFETs mV exam mVat CF DCF Dose marrow assigned Absorbed Vl ..... Position 40m.As mAs exam mAs [mV/R] [rad] to MOSFET dose [rad] Head Spine Al 0 1 25 0 36 10 1 009 0 0000 0 1470 0 0000 Skull A2 4 1 25 0 125 32.20 1 009 0 0034 0 1470 0 0005 Rt Arm A4 0 1 25 0 34 80 1 009 0 0000 0 0779 0.0000 Lt Arm A5 0 1 25 0 33.30 1 009 0.0000 0.0779 0 0000 Total dose (rad) to active ma"ow 0.0005 Calculati.on of dose to bone surface Absorbed Fract. Bone Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose assigned Absorbed Position 40m.As mAs exam mAs [mV/R] [rad] toMOSFET dose [rad] Head Spine Al 0 1 25 0 36 10 3 316 0 0000 0 1160 0 0000 Skull A2 4 1 25 0 125 32 20 3 316 0.0113 0 1160 0 0013 Rt Arm A4 0 1 25 0 34 80 3 316 0 0000 0.0980 0 0000 Lt Arm A5 0 1 25 0 33 30 3.316 0 0000 0 0980 0 0000 Total dose (rad) to bone surf ace 0.0013

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Calculation of dose to remainder Organ/ MOSFETs Position Rt Arm A4 Lt Arnt A5 Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Total effective dose ESE AP Skull Leukemia Male Respiratory Female Respiratory Male Digestive Female Digestive Other Female Breast Relative Risk mV exam mVat 40mAs mAs exam mAs 0 1 25 0 0 1 25 0 Total dose (rad) to remainder mV exam 80mAs mAs 25 1 25 1 1 25 Total dose (rad) to skin f(d) 0.0005 rem 0 0079 R l 185E-06 3 1028-06 3 1028-06 3 946E-06 3 9468-06 5 950E-06 5 950E-06 mVat exam mAs 0 390625 0 015625 g(b) 132 3 7 .3 309492 14 926005 1 1 74 1 0 0660047 Absorbed CF DCF Dose [mV/R] [rad] 34 80 1 009 0 0000 3 3. 30 1 009 0 0000 0.0000 Absorbed CF DCF Dose [mV/R] [rad] 32.90 1 009 0 0105 28 80 1 009 0 0005 0.0055 Male Respiratory Female Respiratory Male Digestive Female Digestive Other Female Breast 1 000023 1 000046 1 000004 1 000007 1 000006 1 000000 Vl N

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Table E-2. AP Skull with Thyroid Shield Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 40mAs mAs exam mAs [mV/R] [rad] Factor [rem] Thyroid A3 0 1 25 0 34.60 1.009 0 0000 0 05 0.0000 Active Bone Marrow 0 0005 0 12 0 0001 Bone surface 0 0013 0 01 0 0000 Remainder 0.0000 0 05 0 0000 Skin 0 0055 0 01 0 0001 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose marrow assigned Absorbed Position 40mAs mAs exam mAs [mV/R] [rad] toMOSFET dose [rad] Vl l.,J Head Spine Al l 1 25 0 03125 36 10 1 009 0 0008 0 1470 0 0001 Skull A2 3 1 25 0 09 3 75 32 20 1 009 0 0026 0 1470 0 0004 Rt Arm A4 0 1 25 0 34 80 1 009 0.0000 0 0779 0 0000 Lt Arm A5 0 1 25 0 33 .3 0 1 009 0 0000 0 0779 0 0000 Total dose (rad) to active mallow 0.0005 Calculation of dose to bone surface Absorbed Fract. Bone Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose assigned Absorbed Position 40mAs mAs exam mAs [mV/R] [rad] toMOSFET dose [rad] Head Spine A2 0 1.25 0 36 10 3 316 0 0000 0 1160 0.0000 Skull Al 4 1.25 0 125 32 20 3 316 0 0113 0 1160 0 0013 Rt Arm A4 0 1 25 0 34 80 3. 316 0 0000 0 0980 0 0000 Lt Arm A5 0 1 25 0 33 30 3 316 0 0000 0 0980 0 0000 Total dose (rad) to bone surface 0.0013

PAGE 169

Calculation of dose to remainder Organ/ MOSFETs Position RtArm A4 Lt Arm A5 Calculati.on of dose to skin MOSFETs Position Entrance Al Exit A2 Total effective dose ESE AP Skull Leukemia Male Respiratory Female Respiratory Male Digestive Female Digestive Other Female Breast Relative Risk mV exam mVat 40 mAs mAs exam mAs 0 1 25 0 0 1 25 0 Total dose (rad) to remainder mV exam 80mAs mAs 25 1 25 I 1.25 Total dose (rad) to skin f(d) 0.0001 rem 0 0079 R 3 082E-07 8.067E-07 8 067E-07 1 026E-06 l 026E-06 l 547E-06 1 547E-06 mVat exam mAs 0.390625 0 015625 g(b) 132 3 7.330949 14 92601 I 1 74 1 0 066005 Absorbed CF DCF Dose [mV/R] [rad] 34 80 1 009 0 0000 33 30 1 009 0 0000 0.0000 Absorbed CF DCF Dose [mV/R] [rad] 32 90 1 009 0 0105 28 80 1 009 0 0005 0.0055 Leukemia Male Respiratory Female Respiratory Male Digestive Female Digestive Other Female Breast 1 000041 1 000006 1 000012 1 000001 1 000002 1 000002 1 000000 ...... Vl

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Table E-3 PA Skull Absorbed Tissue Effective Organ/ MOSFETs mVat e:xam mVat CF DCF Dose Weighting Dose Position 42mAs mAs exam mAs [mV/RJ [rad] Factor [rem] Thyroid A3 2 1 25 0 059524 34.60 1 009 0 0015 0 05 0 0001 Active Bone Marrow 0.0005 0.12 0 0001 Bone surface 0.0014 0.01 0 0000 Remainder 0 0000 0 05 0.0000 Skin 0 0055 0.01 0 0001 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose marrow assigned Absorbed Vl Vl Position 42mAs mAs exam mAs [mV/R] [rad] to MOSFET dose [rad] Head Spine Al 5 1.25 0 14881 36.10 1 .009 0 0036 0.1470 0 0005 Skull A2 0 1 .25 0 32 20 1 .009 0 0000 0 1470 0.0000 Rt Arm A4 0 1 25 0 34 80 1.009 0 0000 0 0779 0 0000 Lt Arm A5 0 1 25 0 33.30 1 009 0.0000 0 0779 0 0000 Total dose (rad) to active marrow 0.0005 Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose assigned Absorbed Position 42mAs mAs exam mAs [mV/R] [rad] to MOSFET dose [rad] Head Spine Al 5 1 .2 5 0 14881 36. 10 3 316 0 0120 0 1160 0 0014 Skull A2 0 1 25 0 32 20 3 .3 16 0 0000 0 1160 0 0000 RtArm A4 0 1 25 0 34 80 3 .3 16 0 0000 0 0980 0 0000 Lt Arm A5 0 1 .2 5 0 33.3 0 3.3 16 0 0000 0 0980 0 0000 Total dose (rad) to bone surface 0.0014

PAGE 171

Calculation of dose to remainder Organ/ MOSFETs Position Rt Arm A4 Lt Arm A5 Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Total effective dose ESE PA Skull Leukemia Male Respiratory Female Respiratory Male Digestive Female Digestive Other Female Breast Relative Risk mV exam mVat 42mAs mAs exam mAs 0 1 .2 5 0 0 1 25 0 Total dose (rad) to remainder mV exam 80mAs mAs 25 1 25 I 1 25 Total dose (rad) to skin f(d) 0.0002 rem 0 0258 R 5 080E-07 l 330E-06 1 330E-06 1 691E-06 l 691E-06 2 551E-06 2 551E-06 mVat exam mAs 0 390625 0 015625 g(b) 132 3 7 330949 14.92601 l 1 74 l 0 066005 Absorbed CF DCF Dose [mV/R] [rad] 34 80 1 009 0 0000 33.3 0 1 009 0 0000 0.0000 Absorbed CF DCF Dose [mV/R] [rad) 32 90 1 009 0 0105 28 80 1 009 0 0005 0.0055 Leukemia Male Respiratory Female Respiratory Male Digestive Female Digestive Other Feinale Breast 1 000067 1 000010 1 000020 1.000002 1 000003 1 000003 1.000000 Vl 0\

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Table E-4 PA Skull with Thyroid Shield Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 42mAs mAs Exam mAs [mV/R) [rad] Factor [rem] Thyroid A3 1 1 25 0 02976 2 34 60 1 .0 09 0 0008 0 05 0 0000 Active Bone Marrow 0 0007 0 12 0 0001 Bone surface 0 0019 0 01 0 0000 Remainder 0 0000 0 05 0 0000 Skin 0 0055 0 01 0 0001 Ca/cuwtion of dose to active marrow Absorbed Fract. Active Fract. ....... Organ/ MOSFETs mV mVat CF DCF Dose marrow assigned Absorbed V, exam -J Position 42mAs mAs Exam mAs [mV/R] [rad) toMOSFET dose [rad] Head Spine Al 7 1 25 0 2083 33 36.10 1 009 0 0051 0 1470 0 0007 Skull A2 0 1.25 0 32 20 1 009 0 0000 0 1470 0 0000 Rt Arm A4 0 1 25 0 34 80 1 009 0 0000 0 0779 0 0000 Lt Arm A5 0 1 25 0 33 .3 0 1 009 0 0000 0 0779 0.0000 Total dose (rad) to active marrov 0.0007 Calculation of dose to bone surface Absorbed Fract. Bone Fract Organ/ MOSFETs mV exam mVat CF DCF Dose assigned Absorbed Position 42mAs mAs Exam mAs [mV/R] [rad] toMOSFET dose [rad] Head Spine Al 7 1 25 0 208333 36 10 3 316 0 0168 0 1160 0 0019 Skull A2 0 1 25 0 3 2 20 3.3 16 0 0000 0 1160 0 0000 Rt Arm A4 0 1 25 0 3 4 80 3 .3 16 0 0000 0 0980 0 0000 Lt Arm A5 0 1 25 0 3 3.3 0 3 .3 16 0 0000 0 0980 0 0000 Total dose (rad) to bone surface 0.0019

PAGE 173

Calculation of dose to remainder Organ/ MOSFETs Position Rt Arm A4 Lt Arm A5 Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Total effective dose ESE PA Skull Leukemia Male Respiratory Female Respiratory Male Digestive Female Digestive Other Female Breast Relative Risk mV exam mVat 42mAs mAs Exam mAs 0 1 25 0 0 1 25 0 Total dose (rad) to remainder mV exam 80mAs mAs 25 1.25 1 1.25 Total dose (rad) to skin f(d) 0.0002 rem 0 0258 R 4 916E-07 1 287E-06 1 287E-06 1 637E-06 1 637E-06 2 468E-06 2 468E-06 mVat Exam mAs 0 390625 0 015625 g(b) 132 3 7 330949 14 92601 I 1 74 1 0 066005 Leukemia 1 000065 Male Respiratory 1 000009 Female Respiratory 1 000019 CF DCF [mV/R] 34 80 1 009 33 30 1 009 CF DCF (mV/R] 32.90 1 009 28 80 1 009 Male Digestive 1 000002 Absorbed Dose [rad] 0 0000 0 0000 0.0000 Absorbed Dose [rad] 0.0105 0 0005 0.0055 Female Digestive 1.000003 Other 1 000002 Female Breast 1 000000 00

PAGE 174

Table E-5 Lateral Skull Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 40mAs mAs exam mAs [mV/R] [rad] Factor [rem] Thyroid A3 0 1 75 0 34. 6 0 1 009 0 0000 0 05 0 0000 Active Bone Marrow 0 0007 0 12 0 0001 Bone surface 0 0017 0 01 0 0000 Remainder 0 0000 0 05 0 0000 Skin 0 0074 0 01 0 0001 Calculation of dose to active marrow Absorbed Fract Active Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose marrow assigned Absorbed Position 40mAs mAs exam mAs [mV/R] [rad) to MOSFET dose [rad] Head Spine Al 2 1 75 0.0875 36 10 1 009 0 0021 0 1470 0 0003 Skull A2 2 1 75 0 0875 32 20 1 009 0 0024 0 1470 0 0004 Vl \0 Rt Arm A4 0 1 75 0 34 80 1 009 0 0000 0 0779 0 0000 Lt Arm A5 0 1 75 0 3 3.3 0 1 009 0 0000 0 0779 0 0000 Total dose (rad) to active marrow 0.0007 Calculation of dose to bone surface Absorbed Fract. Bone Fract Organ/ MOSFETs mV exam mVat CF DCF Dose assigned Absorbed Position 40mAs mAs exam mAs [mV/R] [rad] to MOSFET dose [rad] Head Spine Al 2 1 75 0 0875 36 10 3. 316 0 0070 0 1160 0 0008 Skull A2 2 1 75 0 0875 32 20 3. 316 0 0079 0 1160 0 0009 RtArm A4 0 1 75 0 34 80 3 316 0 0000 0 0980 0 0000 Lt Arm A5 0 1 75 0 3 3.3 0 3 .3 16 0 0000 0 0980 0 0000 Total dose (rad) to bone surface 0.0017

PAGE 175

Calculation of dose to remainder Organ/ MOSFETs mV exam mVat Position 40mAs mAs examm.As Rt Arm A4 0 1 75 0 Lt Arm A5 0 1 75 0 Total dose (rad) to remainder Calculation of dose to skin MOSFETs mV exam mVat Position 80m.As mAs exam mAs Entrance Al 24 1 75 0 525 Exit A2 1 1 75 0 021875 Total dose (rad) to skin Total effective dose 0.0002 rem ESE LAT Skull 0 0091 R f(d ) Leukemia 4 164E-07 Male Respiratory l 090E-06 Female Respiratory 1 090-06 Male Digestive Fen1ale Digestive Other Female Breast Relative Risk Leukemia 1 000055 l 386E-06 l 386E-06 2 091E-06 2 091E-06 Male Respiratory 1 000008 g(b) 132 3 7 330949 14 92601 1 1 74 1 0 066005 Female Respiratory 1.000016 CF DCF [mV/R) 34 80 1 009 33 30 1 009 CF DCF [mV/R] 32.90 1 009 28 80 1 009 Male Digestive 1 000001 Absorbed Dose [rad] 0 0000 0 0000 0.0000 Absorbed Dose [rad] 0 0141 0 0007 0.0074 Female Digestive 1 000002 Other 1 000002 Female Breast 1 000000 0

PAGE 176

Table E-6 Townes Skull Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 40mAs mAs exam mAs [mV/R] [rad] Factor [rem] Thyroid A3 2 1 75 0 0875 34 60 1 009 0 0022 0.05 0 0001 Active Bone Marrow 0 0009 0 12 0 0001 Bone surface 0 0025 0 01 0 0000 Remainder 0 0012 0 05 0 0001 Skin 0 0109 0 01 0 0001 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose marrow assigned Absorbed Position 40mAs mAs exam mAs [mV/R) [rad] toMOSFET dose [rad] Head Spine Al l 1 75 0.04375 36 10 1 009 0 0011 0.1470 0 0002 Skull A2 3 1 75 0.13125 3 2 20 1 009 0 0036 0.1470 0 0005 RtArm A4 0 1 75 0 3 4 80 1 009 0 0000 0 0779 0 0000 Lt Arm A5 2 1 75 0 0875 3 3 30 1 009 0.0023 0 0779 0 0002 Total dose (rad) to active marroiv 0.0009 Calculation of dose to bone surface Absorbed Fract. Bone Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose assigned Absorbed Position 40mAs mAs exam mAs [mV/R] [rad] to MOSFET dose [rad] Head Spine Al 1 1 75 0 04375 36 10 3. 316 0 0035 0 1160 0 0004 Skull A2 3 1 75 0 13125 32 20 3 316 0 0118 0 1160 0 0014 RtArm A4 0 1 75 0 34 80 3 316 0.0000 0 0980 0 0000 Lt Arm A5 2 1 75 0 0875 3 3. 30 3 316 0 0076 0 0980 0 0007 Total dose (r,1d) to hone surface 0.0025

PAGE 177

Calculation of dose to remainder Organ/ MOSFETs Position Rt Arm A4 Lt Ann A5 Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Total effective dose ESE Townes Skull Leukemia Male Respiratory Female Respiratory Male Digestive Female Digestive Other Female Breast Relative Risk mV exam mVat 40mAs mAs exam mAs 0 1.75 0 2 1.75 0 0875 Total dose (rad) to remainder mV exam 80m.As mAs 36 1 75 l 1 75 Total dose (rad) to skin f(d) 0.0004 rem O Ol31R 9 925E-07 2 598E-06 2 598E-06 3. 304E-06 3 .3 04E-06 4 983E-06 4 983E-06 mVat exam mAs 0 7875 0.021875 g(b) 132.3 7 330949 14 92601 1 1 74 1 0.066005 Leukemia l 0001 3 1 Male Respiratory 1 000019 Female Respiratory 1 0000 3 9 CF DCF [mV/R] 34 80 1 009 33.30 1 009 CF DCF [mV/R] 32 90 1 009 28 80 1 009 Male Digestive 1 000003 Absorbed Dose [rad] 0.0000 0 0023 0.0012 Absorbed Dose [rad] 0.0212 0.0007 0.0109 Female Digestive 1 000006 Other l 000005 Female Breast 1 000000 ..... 0\ N

PAGE 178

Table E-7. AP Cervical Spine Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 40 mAs mAs exam mAs mV/R] [rad) Factor (rem] Esophagus D4 0 3 75 0 34.80 1 009 0 0000 0 05 0.0000 Thyroid A3 7 3.75 0 65625 34 60 1 009 0.0168 0.05 0 0008 Breast D2 0 3.75 0 32.70 1 009 0 0000 0 05 0 0000 Average Lung 0 0000 0 12 0.0000 RtLung D3 0 3.75 0 32.00 1 .0 46 0 0000 LtLung DI 0 3.75 0 33 30 1 .0 46 0.0000 Stomach D5 0 3 75 0 38.50 1.009 0 0000 0.12 0 0000 Liver NM 3.75 0 3 1 98 1 .009 0.0000 0 05 0.0000 Bladder NM 3.75 0 32.91 1 .009 0 0000 0 05 0 0000 Colon NM 3 75 0 3 1 98 1 .009 0.0000 0.12 0.0000 Active Bone Marrow 0.0000 0 12 0.0000 ,___. Bone surface 0.0000 0 01 0 0000 w Skin 0.0121 0 01 0.0001 Average Ovary 0.0000 0.20 0.0000 RtOvary NM 3.75 0 33.44 1 .009 0.0000 Lt Ovary NM 3.7 5 0 31 18 1 009 0 0000 Testes NM 3.7 5 0 33.04 1 009 0 0000 0 20 0 0000 Remainder-F 0 0000 0 05 0.0000 Remainder-M 0 0000 0.05 0.0000 Calculation of dose to active ma"o)V Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 40 roAs mAs exam mAs mV/R] [rads] toMOSFET dose [rad Head Spine Al 0 3.75 0 36.10 1 .009 0.0000 0.1470 0 0000 Skull A2 0 3.75 0 32.20 1 009 0 0000 0 1470 0 0000 Rt Arm A5 0 3 75 0 33 30 1 009 0 0000 0.0779 0 0000 Lt Arm A4 0 3 75 0 34. 80 1 .009 0 0000 0 0779 0 0000 Total dose (r,,d) to active marrov 0.0000

PAGE 179

Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 40mAs mAs exam mAs [mV/R] rad] toMOSFET dose [rad] Head Spine Al 0 3.75 0 3 6 10 3 316 0 0000 0 1160 0.0000 Skull A2 0 3.75 0 32 20 3 316 0.0000 0 1160 0 0000 Rt Arm A5 0 3 75 0 33 30 3.316 0 0000 0.0980 0 0000 Lt Arm A4 0 3. 75 0 3 4 80 3. 316 0 0000 0 0980 0 0000 Total dose (rad) to bone surface 0.0000 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 40mAs mAs exam mAs [mV/R] [rad] RtArm A5 0 3 75 0 33 30 1 009 0 0000 ...... Lt Arm A4 0 3 75 0 34 80 1 009 0 0000 O'\ Esophagus D4 0 3 75 0 3 4 80 1 009 0 0000 Breast D2 0 3 75 0 32 70 1 009 0 0000 Stomach D5 0 3 75 0 38 50 1 009 0 0000 Liver NM 3. 75 0 31 98 1.009 0 0000 Bladder NM 3 75 0 32 91 1 009 0 0000 Colon NM 3 75 0 31 98 1 009 0 0000 Average Lung 0 0000 RtLung D3 0 3 75 0 32.00 1 046 0 0000 LtLung Dl 0 3. 75 0 33 30 1 046 0 0000 Average Ovary 0 0000 Rt Ovary NM 3. 75 0 33 44 1 009 0 0000 Lt Ovary NM 3 75 0 31.18 1 009 0 0000 Testes NM 3 75 0 33 04 1 009 0 0000 Total dose (rad) to remainder-F 0.0000 Total dose (rad) to remainder-M 0.0000

PAGE 180

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Mak Effective Dose mVat 80mAs 18 1 exam mAs 3.75 3.75 mVat CF exam mAs [mV/R] 0.84375 32.90 0.046875 28.80 Total dose (rad) to skin 0.0010 rem 0.0010 rem 0.0010 rem DCF 1 .009 1 .009 ESE AP C-Spine 0.0147 R f(d ) Leukemia 2.330E-06 Male Respiratory 6 098E-06 Female Respiratory 6.098E-06 Male Digesti ve Female Digesti ve Other Female Breast Relative Risk Leukemia 1 .00030 8 7.756E-06 7.756E-06 1 170E-05 l 170E-05 Male Respiratory 1 .0000 45 g(b) 1 32.3 7.330949 14.92601 1 1 .7 4 1 0 066005 Female Respiratory 1 .00009 1 Male Digestive 1 .000008 Absorbed Dose [rad] 0.0227 0.0014 0.0121 Female Digesti ve 1.000013 Other 1 .0000 12 Female Breast 1 .00000 1 0\ Vl

PAGE 181

Table E-8 Lateral Cervical Spine Absorbed Tissue Effective Organ/ MOSFETs mVat exam MVat CF DCF Dose Weighting Dose Position 40mAs mAs exam mAs [mV/R] [rad] Factor (rem] Esophagus D4 1 6 25 0 15625 34 80 1 009 0 0040 0 05 0 0002 Thyroid A3 5 6 25 0 78125 34 60 1 009 0 0200 0 05 0 0010 Breast D2 0 6.25 0 3 2 70 1.009 0 0000 0 05 0 0000 Average Lung 0 0000 0.12 0 0000 Rt Lung D3 0 6 25 0 32 00 1 046 0 0000 LtLung DI 0 6.25 0 33. 30 1 046 0 0000 Stomach D5 0 6 25 0 38 50 1 009 0 0000 0 12 0 0000 Liver NM 6 25 0 3 1 98 1 009 0 0000 0 05 0 0000 Bladder NM 6 25 0 32 91 1 009 0 0000 0 05 0 0000 Colon NM 6 25 0 3 1 98 1 009 0 0000 0 12 0.0000 Active Bone Marrow 0 0033 0 12 0 0004 ...... Bone surface 0 0119 0 01 0.0001 ' Skin 0 0220 0 01 0 0002 Average Ovary 0 0000 0 20 0 0000 Rt Ovary NM 6 25 0 33 44 1 009 0 0000 Lt Ovary NM 6 25 0 31 18 1 009 0 0000 Testes NM 6 25 0 3 3 .04 1 009 0 0000 0.20 0 0000 Remainder-F 0 0032 0.05 0 0002 Remainder-M 0.0032 0 05 0 0002 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 40mAs m.As exam m.As [mV/R] [rads] toMOSFET dose [rad] Head Spine Al 2 6 25 0 .3 125 36 10 1 009 0 0077 0 1470 0 0011 Skull A2 0 6 25 0 32 20 1 009 0 0000 0 1470 0 0000 Rt Arm A5 0 6 25 0 33 30 1 009 0 0000 0 0779 0 0000 Lt Arm A4 7 6 25 1.09 3 75 34 80 1 009 0 0278 0 0779 0 0022 Total dose (rad) to active marrol-V 0.0033

PAGE 182

Calculation of dose to hone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 40mAs mAs e~ammAs [mV/R] rad] toMOSFET dose [rad] Head Spine Al 2 6 25 0 3125 36 10 3 .3 16 0 0251 0 1160 0 0029 Skull A2 0 6 25 0 32 20 3 .3 16 0 0000 0 1160 0 0000 Rt Arm A5 0 6 25 0 33 30 3 316 0 0000 0 0980 0 0000 Lt Arm A4 7 6 .2 5 1 09 3 75 34 80 3. 316 0 091 3 0 0980 0 0089 Total dose (rad) to hone surface 0.0119 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 40mAs mAs exam mAs [mV/R] rad] Rt Arm A5 0 6 25 0 33. 30 1 009 0 0000 Lt Arm A4 7 6 25 1 09 3 75 3 4 80 1 009 0 0278 -:a Esophagus D4 I 6 25 0 15625 34 80 1 009 0 0040 Breast D2 0 6 25 0 32 70 1 009 0 0000 Stomach D5 0 6 25 0 38 50 1 009 0 0000 Liver NM 6 25 0 31 98 1 009 0 0000 Bladder NM 6 25 0 32 91 1 009 0 0000 Colon NM 6 25 0 31 98 1 009 0 0000 Average Lung 0 0000 RtLung D3 0 6 25 0 32 00 1 046 0 0000 LtLung Dl 0 6 25 0 3 3. 30 1 046 0 0000 Average Ovary 0 0000 RtOvary NM 6 25 0 3 3. 44 1 009 0 0000 Lt Ovary NM 6 25 0 31 18 1 009 0 0000 Testes NM 6 25 0 3 3 04 1 009 0 0000 Total dose (rad) to remainder-F 0.0032 Total dose (rad) to remainder-M 0.0032

PAGE 183

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 21 6 25 0 6 25 mVat CF exam mAs [mV/R] 1.640625 32 90 0 28 80 Total dose (rad) to skin 0.0019 0.0021 0.0021 rem rem rem DCF 1.009 1 009 ESE LAT C-Spine 0 1111 R f ( d) Leukemia 5 076E-06 Male Respiratory 1 328E-05 Female Respiratory l 328E-05 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 000672 1.690E-05 l 690E--05 2 548E-05 2 548E-05 Male Respiratory 1 000097 g(b) 132 3 7 .3 30949 14 92601 1 1 74 1 0 066005 Female Respiratory 1 000198 Male Digestive 1.000017 Absorbed Dose [rad] 0 0441 0 0000 0.0220 Female Digestive 1 000029 Other 1 000025 Female Breast 1 000002 ...... 0\ 00

PAGE 184

Table E-9 AP Thoracic Spine Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R] [rad] Factor [rem] Esophagus B3 3 3 75 0 140625 27 50 1 009 0 0045 0 05 0 0002 Thyroid A3 2 3 75 0 09375 31 90 1.009 0 0026 0 05 0 0001 Breast A2 22 3 75 1 03125 28 80 1 009 0 0316 0 05 0 0016 Average Lung 0 0071 0 12 0 0008 RtLung C3 5 3.75 0 234375 34 00 1 046 0 0063 LtLung C4 6 3 75 0 28125 33 10 1 046 0 0078 Stomach Cl 2 3 75 0 09375 32 30 1.009 0 0026 0 12 0 0003 Liver A2 2 3 75 0 09375 28 80 1 009 0 0029 0 05 0 0001 Bladder C2 0 3. 75 0 34 20 1 009 0 0000 0 05 0 0000 Colon D5 0 3 75 0 29 90 1 009 0 0000 0 12 0.0000 Active Bone Marrow 0 0013 0 12 0 0002 Bone surface 0 0051 0 01 0.0001 a,. \0 Skin 0 0152 0 01 0 0002 Average Ovary 0 0000 0 20 0 0000 Rt Ovary B5 0 3 75 0 30 60 1 009 0 0000 Lt Ovary Bl 0 3 75 0 27 00 1.009 0 0000 Testes D2 0 3 75 0 30 30 1 009 0 0000 0 20 0.0000 Remainder-F 0 0118 0 05 0 0006 Remainder-M 0 0118 0 05 0.0006 Calculation of dose to acti.ve ma"ow Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rads] toMOSFET dose rad] Spine middle Al 1 3 75 0 046875 32 90 1 009 0 0013 0 1588 0 0002 RtArm A5 5 3. 75 0 234375 34 60 1 009 0 0060 0 0779 0.0005 Lt Ann A4 6 3. 75 0 28125 3 3. 10 1 009 0 0075 0 0779 0 0006 Pelvis D3 0 3 75 0 33 50 1 009 0 0000 0 2191 0 0000 Total dose (rad) to active ma"mv 0.0013

PAGE 185

Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R rad] to MOSFET dose rad] Spine middle Al 1 3. 75 0 046875 3 2 90 3. 316 0 0041 0 1850 0 0008 Rt Ann A5 5 3. 75 0 234 3 75 34 60 3 .3 16 0 0197 0 0980 0 0019 Lt Arm A4 6 3 75 0 28125 33. 10 3.3 16 0 0247 0 0980 0 0024 Pelvis D 3 0 3. 75 0 33. 50 3 3 16 0 0000 0 2190 0 0000 Total dose (rad) to bone surface 0.0051 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] Rt Amt A4 5 3. 75 0 234 3 75 33. 10 1 009 0 006 3 1--' .....J Lt Arm A5 6 3 75 0 28125 3 4 60 1 009 0 0072 0 Esophagus B3 3 3 75 0 140625 27 50 1 009 0 0045 Breast B4 22 3. 75 1 03125 31 70 1 009 0 0288 Stomach Cl 2 3. 75 0 09375 3 2 30 1 009 0 0026 Liver A2 2 3 75 0 09 3 75 28 80 1.009 0 0614 Bladder C2 0 3 75 0 34 20 1 009 0 0000 Colon D5 0 3 75 0 29 90 1 009 0 0000 Average Lung 0 0071 RtLung C 3 5 3 75 0 234375 3 4 00 1 046 0 006 3 LtLung C4 6 3 75 0 28125 33 10 1 046 0 0078 Average Ovary 0 0000 Rt Ovary BS 0 3. 75 0 30 60 1 009 0 0000 Lt Ovary Bl 0 3. 75 0 27 00 1 009 0 0000 Testes D2 0 3. 75 0 3 0 .3 0 1 009 0 0000 Total dose (rad) to remainder-F 0.0118 Total dose (rad) to remainder-M 0.0118

PAGE 186

Calculation of dose to sldn MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat 80mAs 23 1 exam mAs 3.75 3 75 mVat CF exam mAs [mV/R] 1.078125 32 90 0 046875 28 80 Total dose (rad) to skin 0.0036 0.0042 0.0042 rem rem rem DCF 1 009 1 009 ESE AP T-Spine 0 0190 R f(d) Leukemia l 015E-05 Male Respiratory 2.657E-05 Female Respiratory 2 657E-05 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 001343 3 380E-05 3 380E-05 5 097E-05 5 098E-05 Male Respiratory 1 000195 g(b) 132 3 7.330949 14.92601 1 1 74 1 0 066005 Female Respiratory 1 000397 Male Digestive 1 000034 Absorbed Dose rad] 0 0290 0 0014 0.0152 Female Digestive 1 000059 Other 1 000051 Female Breast 1 000003

PAGE 187

Table E-10 Lateral Thoracic Spine Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs mV/R] rad Factor [rem] Esophagus B3 0 24 0 27 50 1 009 0 0000 0 05 0 0000 Thyroid A3 3 24 0 9 31 90 1 009 0 0249 0 05 0 0012 Breast A2 0 24 0 28 80 1 009 0 0000 0.05 0 0000 Average Lung 0 0162 0 12 0 0019 Rt Lung C3 4 24 1 2 34 00 1 046 0 0323 LtLung C4 0 24 0 33 10 1 046 0 0000 Stomach Cl 0 24 0 32 .3 0 1 009 0 0000 0 12 0 0000 Liver A2 2 24 0 6 32.90 1 009 0.0161 0 05 0 0008 Bladder C2 0 24 0 3 4 20 1 009 0 0000 0 05 0 0000 Colon D5 0 24 0 29 90 1 009 0 0000 0 12 0 0000 Active Bone Marrow 0 0079 0 12 0 0010 Bone surface 0 0320 0 01 0 0003 -l N Skin 0 0604 0 01 0 0006 Average Ovary 0 0000 0.20 0 0000 Rt Ovary B5 0 24 0 3 0 60 1 009 0 0000 Lt Ovary Bl 0 24 0 27 00 1 009 0.0000 Testes D2 0 24 0 30 30 1 009 0 0000 0 20 0 0000 Remainder-F 0 0150 0 05 0 0007 Remainder-M 0 0110 0 05 0 0005 Calculation of dose to active marrov Absorbed Fract Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs mV/R] [rads] toMOSFET dose [rad Spine middle Al 2 24 0.6 32 90 1 009 0 0161 0 1588 0 0026 Rt Arm A5 9 24 2 7 34 60 1 009 0 0690 0 0779 0 0054 Lt Ann A4 0 24 0 3 3 10 1 009 0 0000 0 0779 0 0000 Pelvis D 3 0 24 0 33 50 1 009 0 0000 0 2191 0 0000 Total dose (rad) to active marrov 0.0079

PAGE 188

Calculati.on of dose to bone surface Absorbed Fract. Bone Fract Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exammAs [mV/R] [rad] toMOSFET dose [rad] Spine middle Al 2 24 0 6 32 90 3 316 0 0530 0 1850 0 0098 Rt Arm A5 9 24 2 7 34 60 3. 316 0 2267 0 0980 0 0222 Lt Arm A4 0 24 0 33 10 3 316 0 0000 0 0980 0 0000 Pelvis D3 0 24 0 33. 50 3 316 0 0000 0.2190 0 0000 Total dose (rad) to bone surf ace 0.0320 Calculanon of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] Rt Arm A4 9 24 2 7 33 10 1 009 0 0721 Lt Arm A5 0 24 0 34 60 1 009 0 0000 ....... Esophagus B3 0 24 0 27 50 1 009 0 0000 -......l w Breast B4 0 24 0 31 70 1 009 0 0000 Stomach Cl 0 24 0 32.30 1 009 0 0000 Liver A2 2 24 0 6 28 80 1 009 0 0614 Bladder C2 0 24 0 34.20 1 009 0 0000 Colon D5 0 24 0 29 90 1 009 0 0000 Average Lung 0 0162 RtLung C3 4 24 1 2 3 4 00 1 046 0.0323 LtLung C4 0 24 0 33 10 1 046 0 0000 Average Ovary 0 0000 Rt Ovary BS 0 24 0 30 60 1 009 0 0000 Lt Ovary Bl 0 24 0 27 00 1 009 0 0000 Testes D2 0 24 0 30 30 1 009 0 0000 Total dose (rad) to remainder-F 0.0150 Total dose (rad) to remainder-M 0.0110

PAGE 189

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80m.As mAs 15 24 0 24 mVat CF exam mAs [mV/R] 4 5 32.90 0 28 80 Total dose (rad) to skin 0.0059 0.0066 0.0064 rem rem rem DCF 1.009 1 009 ESE LAT T-Spine 0 0842 R f(d) Leukemia l 584E-05 Male Respiratory 4 083E-05 Female Respiratory 4 2098-05 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 002096 5 193E-05 5 354E-05 7 9538-05 7 831E 05 Male Respiratory 1 000299 g(b) 132 3 7 3 3 0949 14 92601 1 1 74 1 0 066005 Female Respiratory 1 000628 Male Digestive 1 000052 Absorbed Dose [rad] 0 1209 0 0000 0.0604 Female Digestive 1 00009 3 Other 1 000080 Female Breast 1 000005

PAGE 190

Table E-11 AP Lumbar Spine Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R [rad] Factor [rem Esophagus B3 0 3. 75 0 27 50 1 009 0 0000 0 05 0 0000 Thyroid A3 0 3. 75 0 31 90 1 009 0 0000 0 05 0 0000 Breast A2 0 3. 75 0 28 80 1 009 0 0000 0.05 0 0000 Average Lung 0 0000 0 12 0 0000 Rt Lung C3 0 3 75 0 34 00 1 046 0 0000 LtLung C4 0 3 75 0 3 3 10 1 046 0.0000 Stomach Cl 7 3 75 0 328125 32.30 1 009 0 0090 0 12 0 0011 Liver A2 5 3 75 0 234375 32 90 1 009 0 006 3 0 05 0 0003 Bladder C2 7 3. 75 0 328125 34 20 1 009 0 0085 0 05 0 0004 Colon D5 2 3. 75 0 09375 29 90 1 009 0 0028 0 12 0 0003 Active Bone Marrow 0 0002 0 12 0 0000 ....... Bone surface 0 0008 0 01 0 0000 -...J Vl Skin 0 0152 0 01 0 0002 Average Ovary 0 0057 0 20 0 0011 Rt Ovary BS 5 3 75 0 234375 30.60 1 009 0 0068 Lt Ovary Bl 3 3 75 0 140625 27 00 1 009 0 0046 Testes D2 0 3 75 0 30 30 1 009 0.0000 0 20 0.0000 Remainder-F 0 0408 0 05 0 0020 Re1nainder-M 0.0402 0 05 0 0020 Calculation of dose to active ma"ow Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rads] toMOSFET dose [rad] Spine middle Al 1 3 75 0 046875 32 90 1 009 0 0013 0.1588 0 0002 Rt Arm AS 0 3 75 0 34 60 1 009 0 0000 0 0779 0 0000 Lt Arm A4 0 3. 75 0 33 10 1 009 0 0000 0 0779 0 0000 Pelvis D 3 1 3 75 0 046875 3 3. 50 1 009 0 0012 0 2191 0 0003 Tot,,l dose (rad) to active marro.-v 0.0002

PAGE 191

Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80m.As mAs exam m.As [mV/R] [rad] toMOSFET dose [rad] Spine middle Al l 3 75 0 046875 32 90 3.316 0.0041 0.1850 0.0008 Rt Arm A5 0 3 75 0 34 60 3 316 0 0000 0 0980 0 0000 Lt Arm A4 0 3 75 0 33 10 3 316 0 0000 0 0980 0 0000 Pelvis D3 l 3 75 0 046875 33 50 3 316 0.0041 0 2190 0 0009 Total dose (rad) to bone surface 0.0008 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80m.As mAs exam mAs [mV/R] [rad] RtArm A4 0 3 75 0 33 10 1 009 0 0000 Lt Arm A5 0 3 75 0 34 60 1 009 0 0000 -.l 0\ Esophagus B3 0 3 75 0 27 50 1 009 0.0000 Breast B4 0 3. 75 0 31 70 1.009 0 0000 Stomach Cl 7 3 75 0 328125 32 30 1 009 0 0090 Liver A2 5 3 75 0 234375 28 80 1 009 0 1535 Bladder C2 7 3 75 0 328125 34 20 1 009 0 1809 Colon D5 2 3.75 0 09375 29.90 1.009 0.0591 Average Lung 0.0000 RtLung C3 0 3 75 0 34 00 1.046 0 0000 Lt Lung C4 0 3 75 0 33 10 1.046 0 0000 Average Ovary 0 0057 Rt Ovary BS 5 3 75 0 234375 30 60 1 009 0 0068 Lt Ovary Bl 3 3 75 0 140625 27 00 1 009 0 0046 Testes D2 0 3 75 0 30 30 1 009 0 0000 Total dose (rad) to remainder-F 0.0408 Total dose (rad) to remainder-M 0.0402

PAGE 192

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 2 3 3. 75 1 3. 75 mVat CF exam mAs [mV/R] 1 078125 32 90 0 046875 28 80 Total dose (rad) to skin 0.0023 0.0055 0.0043 rem rem rem DCF 1 009 1 009 ESE AP L-Spine 0 0190 R f(d ) Leukemia 1 198-05 Male Respiratory 2 763E-05 Female Respiratory 3. 505E-05 Male Digestive Female Digestive Other Fen1ale Breast Relative Risk Leukemia 1 001584 3. 515E-05 4 458E-05 6 012E-05 5 301E-05 Male Respiratory 1 000203 g(b ) 132 .3 7 .3 30949 14 92601 1 1 74 1 0 066005 Female Respiratory 1 00052 3 Male Digestive 1 0000 3 5 Absorbed Dose [rad] 0 0290 0 0014 0.0152 Female Digestive 1 000078 Other 1 000060 Female Breast 1 00000 3

PAGE 193

Table E-12 Lateral Lumbar Spine Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R] [rad] Factor [rem] Esophagus B3 0 6 25 0 27 50 1 014 0.0000 0 05 0 0000 Thyroid A3 0 6 25 0 31 90 1 014 0 0000 0 05 0 0000 Breast A1 0 6 25 0 28 80 1 014 0 0000 0 05 0 0000 Average Lung 0 0000 0 12 0 0000 RtLung C3 0 6 25 0 34.00 1 046 0 0000 LtLung C4 0 6 25 0 33 10 1 046 0 0000 Stomach Cl 1 6 25 0 078125 32 30 1 014 0 0021 0 12 0 0003 Liver A1 5 6 25 0 390625 3 2 90 1 014 0 0105 0 05 0 0005 Bladder C2 2 6 25 0 15625 3 4 20 1 014 0 0041 0 05 0 0002 Colon D5 2 6.25 0 15625 29 90 1 014 0 0046 0.12 0 0006 Active Bone Marrow 0 0000 0 12 0 0000 ...... Bone surface 0 0000 0 01 0 0000 -l 00 Skin 0 0253 0 01 0 000 3 Average Ovary 0.0070 0 20 0 0014 Rt Ovary B5 5 6 25 0 390625 30 60 1.014 0 0113 Lt Ovary Bl 1 6 25 0 078125 27 00 1 014 0.0026 Testes D2 0 6 25 0 30 .3 0 1 014 0.0000 0.20 0 0000 Remainder-F 0 0275 0 05 0 0014 Rernainder-M 0.0268 0.05 0 0013 Calculation of dose to active marrow Absorbed Fract. Active Fract Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rads] toMOSFET dose [rad] Spine middle Al 0 6 25 0 3 2 90 1 014 0.0000 0 1588 0 0000 Rt Arm A5 0 6 25 0 34 60 1 014 0 0000 0 0779 0 0000 Lt Arm A4 0 6 25 0 3 3 10 1 014 0 0000 0 0779 0 0000 Pelvis D3 2 6 25 0 15625 33. 50 1 014 0 0041 0 2191 0 0009 Total dose (rad) to active marro,v 0.0000

PAGE 194

Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] toMOSFET dose [rad] Spine middle Al 0 6 25 0 32 90 3.316 0 0000 0 1850 0 0000 Rt Arm A5 0 6 25 0 34 60 3 316 0.0000 0 0980 0 0000 Lt Arm A4 0 6 25 0 33 10 3 316 0 0000 0 0980 0.0000 Pelvis D 3 0 6 25 0 33 50 3 316 0 0000 0 2190 0 0000 Total dose (rad) to bone surface 0.0000 Calculation of dose to renuzinder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] RtArm A4 0 6 25 0 3 3.10 1 014 0 0000 Lt Arm A5 0 6 25 0 34 60 1 014 0 0000 -l \0 Esophagus B3 0 6 25 0 27 50 1 014 0 0000 Breast B4 0 6.25 0 31 70 1 014 0 0000 Stomach Cl 1 6.25 0 078125 32.30 1 014 0 0021 Liver A2 5 6 25 0 390625 28 80 1 014 0 1542 Bladder C2 2 6.25 0 15625 34 20 1 014 0.0519 Colon D5 2 6 25 0.15625 29 90 1 014 0 0594 Average Lung 0 0000 RtLung C3 0 6 25 0 34.00 1 046 0.0000 LtLung C4 0 6 25 0 33 10 1 046 0 0000 Average Ovary 0.0070 Rt Ovary B5 5 6 25 0 390625 30 60 1 014 0 0113 Lt Ovary Bl 1 6 25 0 078125 27 00 1 014 0.0026 Testes D2 0 6 25 0 30 30 1 014 0 0000 Total dose (rad) to remainder-F 0.0275 Total dose (rad) to remainder-M 0.0268

PAGE 195

Calculation of dose to skin MOSFETs mVat exam mVat CF DCF Position 80mAs mAs exam mAs [mV/R] Entrance Al 24 6 25 1 875 32 90 1.014 Exit A2 0 6 25 0 28 80 1 014 Total dose (rad) to skin Subtotal Effective Dose Female Effective Dose Male Effective Dose ESE LAT L-Spine Leukemia Male Respiratory Female Respiratory Male Digestive Female Digestive Other Female Breast Relative Risk 0.0389 R f(d) 9 355E-06 l 995E-05 2 902E-05 2 538E-05 3 691E-05 4 697E-05 3 827E-05 0.0018 0.0046 0.0031 g(b) 132 3 7.330949 14 92601 1 1.74 1 0 066005 Leukemia 1 001238 Male Respiratory 1 000146 Female Respiratory 1 000433 rem rem rem Male Digestive 1 000025 Absorbed Dose rad] 0 0506 0 0000 0.0253 Female Digestive 1 000064 Other 1 000047 Female Breast 1 000003 00 0

PAGE 196

Table E-13 AP Abdomen Supine Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R [rad] Factor [rem] Esophagus B3 0 6 25 0 27 50 1 009 0 0000 0 05 0 0000 Thyroid A3 0 6 25 0 31 90 1 009 0 0000 0 05 0 0000 Breast A2 0 6 .2 5 0 28 80 1 009 0 0000 0 05 0.0000 Average Lung 0 0011 0 12 0 0001 RtLung C3 1 6 25 0 078125 34 00 1 046 0 0021 LtLung C4 0 6 25 0 33 10 1 046 0 0000 Stomach Cl 11 6 25 0 859375 3 2 30 1 009 0 0235 0 12 0 0028 Liver A2 0 6 25 0 32 90 1 009 0 0000 0 05 0 0000 Bladder C2 11 6 25 0 859 3 75 34 20 1 009 0 0222 0 05 0 0011 Colon D5 0 6 25 0 29 90 1 009 0 0000 0 12 0 0000 Active Bone Marrow 0 0006 0 12 0 0001 ....... Bone surface 0 0026 0 01 0 0000 00 ....... Skin 0 0264 0 01 0 0003 Average Ovary 0 0045 0.20 0 0009 Rt Ovary BS 4 6 25 0 3125 30 60 1 009 0 0090 Lt Ovary Bl 0 6 25 0 27.00 1 009 0 0000 Testes D2 0 6 25 0 30 30 1.009 0.0000 0 20 0 0000 Remainder-F 0 0 3 18 0 05 0 0016 Remainder-M 0 0 3 11 0 05 0 0016 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rads] toMOSFET dose [rad] Spine middle Al 1 6.25 0 078125 32 90 1 009 0 0021 0 1588 0.0003 Rt Arm A5 2 6 25 0 15625 34 60 1 009 0 0040 0 0779 0 0003 Lt Arm A4 0 6 25 0 33 10 1 009 0 0000 0 0779 0 0000 Pelvis D 3 0 6 25 0 33 50 1.009 0 0000 0 2191 0 0000 Total dose (rad) to acti-ve marroiv 0.0006

PAGE 197

Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] toMOSFET dose [rad] Spine middle Al 1 6 25 0 078125 3 2 90 3 316 0.0069 0.1850 0 0013 Rt Arm A5 2 6 25 0.15625 3 4 60 3 316 0 01 3 1 0 0980 0 0013 Lt Arm A4 0 6 25 0 33. 10 3 .3 16 0 0000 0 0980 0 0000 Pelvis D 3 0 6 25 0 3 3 50 3 316 0 0000 0 21 90 0 0000 Total dose (rad) to bone surface 0.0026 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs mV/R] [rad] Rt Arm A4 2 6 25 0 15625 33 10 1 009 0 0042 Lt Arm A5 0 6 25 0 34 60 1 009 0 0000 00 N Esophagus B 3 0 6 25 0 27 50 1 009 0 0000 Breast B4 0 6 25 0 3 1 70 1 009 0 0000 Stomach Cl 11 6 25 0 859 3 75 3 2 30 1 009 0 0235 Liver A2 0 6 .2 5 0 28 80 1 009 0 0000 Bladder C2 11 6 25 0 859 3 75 34 20 1 009 0 284 3 Colon D5 0 6 25 0 29 90 1 009 0 0000 Average Lung 0 0011 RtLung C3 1 6 25 0 078125 34 00 1 046 0 0021 LtLung C4 0 6 25 0 33 10 1.046 0 0000 Average Ovary 0 0045 Rt Ovary B5 4 6 25 0 3125 3 0 60 1 009 0 0090 Lt Ovary Bl 0 6 25 0 27 00 1 009 0 0000 Testes D2 0 6 25 0 3 0 30 1 009 0.0000 Total dose (rad) to remainder-F 0.0318 Total dose (rad) to remainder-M 0.0311

PAGE 198

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 24 6 25 1 6 25 mVat CF exam mAs [mV/R] 1 875 32 90 0 078125 28 80 Total dose (rad) to skin 0.0044 0.0069 0.0060 rem rem rem DCF 1 009 1 009 ESE AP Abdomen 0 0178 R f(d) Leukemia 1 567E-05 Male Respiratory 3. 804E-05 Female Respiratory 4 399E-05 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1.002073 4 838E-05 5 595E-05 7 867E-05 7 296E-05 Male Respiratory 1 000279 g(b) 1 3 2 .3 7 330949 14 92601 1 1 74 1 0 066005 Female Respiratory 1 000657 Male Digestive 1 000048 Absorbed Dose [rad] 0 0504 0 0024 0.0264 Female Digestive 1 000097 Other 1 000079 Female Breast 1 000005 00 w

PAGE 199

Table E-14 PA Abdomen Supine Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exammAs [mV/R] [rad] Factor [rem] Esophagus B3 0 6.25 0 27 50 1 009 0 0000 0.05 0 0000 Thyroid A3 0 6.25 0 31 90 1.009 0.0000 0.05 0.0000 Breast A2 0 6 25 0 28 80 1.009 0 0000 0 05 0 0000 Average Lung 0 0000 0 12 0 0000 Rt Lung C3 0 6.25 0 34 00 1 046 0.0000 LtLung C4 0 6.25 0 33 10 1 046 0.0000 Stomach Cl 0 6 25 0 32 30 1 009 0.0000 0.12 0.0000 Liver A2 2 6 25 0 15625 32 90 1 009 0.0042 0 05 0 0002 Bladder C2 7 6 25 0 546875 34 20 1 009 0 0141 0 05 0 0007 Colon D5 0 6 25 0 29 90 1 009 0 0000 0.12 0 0000 Active Bone Marrow 0 0000 0.12 0 0000 Bone surface 0 0000 0.01 0 0000 00 Skin 0 0264 0 01 0 0003 Average Ovary 0.0000 0 20 0 0000 Rt Ovary B5 0 6 25 0 30 60 1 009 0 0000 Lt Ovary Bl 0 6 25 0 27.00 1 009 0 0000 Testes D2 0 6 25 0 30 30 1 009 0.0000 0 20 0 0000 Remainder-F 0 0242 0 05 0 0012 Remainder-M 0 0242 0 05 0 0012 Calculation of dose to active marrow Absorbed Fract Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rads] toMOSFET dose [rad] Spine middle Al 0 6 25 0 32 90 1 009 0 0000 0.1588 0.0000 Rt Arni A5 0 6 25 0 34 60 1 009 0 0000 0 0779 0 0000 Lt Arm A4 0 6 25 0 33 10 1 009 0 0000 0 0779 0.0000 Pelvis D 3 0 6 25 0 33 50 1 009 0 0000 0 2191 0.0000 Total dose (rad) to active marrolv 0.0000

PAGE 200

Calculati,on of dose to bone surface Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exammAs [mV/R] [rad] toMOSFET dose [rad] Spine middle Al 0 6.25 0 32 90 3 316 0 0000 0 1850 0 0000 Rt Arm A5 0 6 25 0 34 60 3 .3 16 0 0000 0 0980 0 0000 Lt Arm A4 0 6 25 0 3 3. 10 3.316 0 0000 0 0980 0 0000 Pelvis D 3 0 6 25 0 3 3. 50 3.3 16 0 0000 0 2190 0 0000 Total dose (rad) to bone surf ace 0.0000 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] RtArm A4 0 6 25 0 33 10 1 009 0 0000 ...... Lt Arm A5 0 6 25 0 34 60 1 009 0 0000 00 Vl Esophagus B 3 0 6 25 0 27 50 1 009 0 0000 Breast B4 0 6 25 0 31 70 1 009 0.0000 Stomach Cl 0 6 25 0 32 30 1 009 0 0000 Liver A2 2 6 25 0 15625 28 80 1 009 0 0614 Bladder C2 7 6 25 0 546875 34.20 1 009 0 1809 Colon D5 0 6 25 0 29 90 1 009 0 0000 Average Lung 0.0000 RtLung C3 0 6 25 0 34 00 1 046 0 0000 LtLung C4 0 6.25 0 3 3 10 1 046 0 0000 Average Ovary 0 0000 RtOvary BS 0 6.25 0 30 60 1 009 0 0000 Lt Ovary Bl 0 6 25 0 27 00 1 009 0 0000 Testes D2 0 6 25 0 30.30 1 009 0 0000 Total dose (rad) to remainder-F 0.0242 Total dose (rad) to remainder-M 0.0242

PAGE 201

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 24 6 25 1 6 25 mVat CF exam mAs [mV/R] 1.875 32 90 0 078125 28 80 Total dose (rad) to skin 0.0012 0.0024 0.0024 rem rem rem DCF 1 009 1 009 ESE PA Abdomen 0 0178 R f(d) Leukemia 5.812E-06 Male Respiratory l 521E-05 Female Respiratory l 521E-05 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 000769 l 9 3 5E-05 l 935E-05 2 918E-05 2.918E-05 Male Respiratory 1 000112 g(b) 1 3 2 3 7 .33 0949 14 92601 1 1 74 I 0 066005 Female Respiratory 1 000227 Male Digestive 1 000019 Absorbed Dose [rad] 0 0504 0 0024 0.0264 Female Digestive 1 000034 Other 1 000029 Female Breast 1 000002 ...... 00 0\

PAGE 202

Table E-15. AP Abdomen Upright Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R] [rad] Factor [rem] Esophagt1s B3 0 6 25 0 27 50 1.009 0 0000 0 05 0.0000 Thyroid A3 0 6 25 0 31 90 1 009 0 0000 0 05 0 0000 Breast A2 4 6 25 0 .3 125 28 80 1 009 0 0096 0 05 0 0005 Average Lung 0 0000 0 12 0 0000 RtLung C3 0 6 25 0 34 00 1 046 0 0000 Lt Lung C4 0 6 25 0 3 3 10 1 046 0 0000 Stomach Cl 8 6 25 0 625 32 30 1 009 0 0171 0.12 0 0021 Liver A2 3 6 25 0 2 3 4 3 75 32 90 1 009 0 0063 0 05 0 0003 Bladder C2 11 6 25 0 859 3 75 3 4 20 1 009 0 0222 0 05 0 0011 Colon D5 3 6 25 0 234375 29 90 1.009 0 0069 0 12 0.0008 Active Bone Marrow 0 0016 0 12 0.0002 Bone surface 0 0064 0 01 0 0001 00 --.J Skin 0 0264 0 01 0 0003 Average Ovary 0 0068 0 20 0 0014 Rt Ovary BS 6 6 25 0 46875 30 60 1 009 0 0135 Lt Ovary Bl 0 6 25 0 27 00 1 009 0 0000 Testes 02 0 6 25 0 30 30 1 009 0 0000 0 20 0 0000 Remainder-F 0 0514 0 05 0 0026 Remainder-M 0 0491 0 05 0 0025 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rads] toMOSFET dose rad] Spine middle Al 1 6 25 0.078125 32 90 1 009 0 0021 0 1588 0 0003 RtArm A5 8 6 25 0 625 3 4 60 1 009 0 0160 0 0779 0 0012 Lt Arm A4 0 6 25 0 33 10 1 009 0 0000 0 0779 0 0000 Pelvis 03 0 6 25 0 33 50 1 009 0 0000 0 2191 0 0000 Total dose (rad) to active marro1v 0.0016

PAGE 203

Calculation of dose to bone surface Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] toMOSFET dose [rad] Spine middle Al 1 6.25 0.078125 32.90 3.3 16 0.0069 0.1850 0.0013 Rt Arm A5 8 6.25 0.625 34.60 3.316 0.0525 0.0980 0.0051 Lt Arm A4 0 6.25 0 33.10 3.316 0 0000 0 .09 80 0.0000 Pelvis D3 0 6 25 0 33.50 3.3 16 0.0000 0.2190 0.0000 Total dose (rad) to bone s11.rface 0.0064 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] Rt Arm A4 8 6.25 0 .62 5 33.10 1 .0 09 0.0167 _. Lt Arm A5 0 6.25 0 3 4.60 1 009 0 0000 00 00 Esophagus B3 0 6.25 0 27.50 1 .00 9 0.0000 Breast B4 4 6.25 0.3125 31.70 1 .009 0.0087 Stomach Cl 8 6.25 0.625 32.30 1 .009 0.0171 Liver A2 3 6.25 0.234375 28.80 1 .009 0.0921 Bladder C2 11 6.25 0.859375 3 4 .2 0 1 009 0 2843 Colon D5 3 6.25 0.234375 29.90 1 .009 0 0887 Average Lung 0.0000 RtLung C3 0 6.25 0 34.00 1 .0 46 0 0000 Lt Lung C4 0 6.25 0 33.10 1 046 0.0000 Average Ovary 0.0068 Rt Ovary B5 6 6.25 0.46875 30.60 1 009 0 01 3 5 Lt Ovary Bl 0 6 .2 5 0 27.00 1 009 0 0000 Testes D2 0 6.25 0 30.30 1 009 0.0000 Total dose (rad) to remainder-F 0.0514 Total dose (rad) to remainder-M 0.0491

PAGE 204

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat 80mAs 24 I exam mAs 6 25 6 25 mVat CF exam mAs [mV/R] 1 875 32.90 0 078125 28 80 Total dose (rad) to skin 0.0053 0.0092 0.0078 rem rem rem DCF 1 009 1 009 ESE AP Abdomen 0 0178 R f(d) Leukemia 2 065E-05 Male Respiratory 4 9 3 6E-05 Female Respiratory 5 871E-05 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 002732 6 278E-05 7 468E-05 l 036E-04 9 468E-05 Male Respiratory 1 000362 g(b) 132 3 7.330949 14 92601 I 1 74 I 0.066005 Female Respiratory 1 000876 Male Digestive 1.00006 3 Absorbed Dose [rad] 0 0504 0 0024 0.0264 Female Digestive 1 000130 Other 1 000104 Female Breast 1 000006

PAGE 205

Table E-16 AP Pelvis Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R] [rad] Factor [rem] Esophagus B3 0 3 75 0 27 50 1 009 0.0000 0 05 0 0000 Thyroid A3 0 3 75 0 31 90 1 009 0 0000 0 05 0 0000 Breast A2 0 3 75 0 28 80 1 009 0 0000 0.05 0 0000 Average Lung 0 0000 0 12 0 0000 RtLung C3 0 3.75 0 34 00 1 046 0 0000 LtLung C4 0 3 75 0 33 10 1 046 0 0000 Stomach Cl 1 3.75 0 046875 32 .3 0 1 009 0 0013 0 12 0 0002 Liver A2 0 3 75 0 3 2 90 1 009 0 0000 0 05 0 0000 Bladder C2 6 3 75 0 28125 34.20 1 009 0 0073 0 05 0 0004 Colon D5 3 3 75 0 140625 29 90 1 009 0 0042 0 12 0 0005 Active Bone Marrow 0 0000 0 12 0 0000 Bone surface 0 0000 0 01 0 0000 0 Skin 0 0113 0 01 0.0001 Average Ovary 0 0065 0 20 0 0013 Rt Ovary BS 5 3.75 0.234375 30 60 1 009 0 0068 Lt Ovary Bl 4 3 75 0 1875 27 00 1 009 0 0061 Testes D2 0 3 75 0 30 30 1 009 0 0000 0 20 0.0000 Remainder-F 0 0251 0 05 0 0013 Remainder-M 0 0245 0 05 0 0012 Calculation of dose to active marrm-v Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rads] toMOSFET dose [rad] Spine middle Al 0 3.75 0 32 90 1 009 0 0000 0 1588 0 0000 Rt Arm AS 0 3 75 0 34 60 1 009 0 0000 0 0779 0 0000 Lt Arm A4 0 3 75 0 33 10 1 009 0 0000 0 0779 0 0000 Pelvis D3 1 3 75 0 046875 3 3 50 1 009 0 0012 0 2191 0 0003 Total dose (rad) to active marrow 0.0000

PAGE 206

Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] toMOSFET dose [rad] Spine middl e Al 0 3.75 0 32 90 3.3 1 6 0 0000 0 1850 0 0000 RtArm A5 0 3.75 0 3 4 .60 3.3 1 6 0.0000 0 0980 0 0000 Lt Arm A4 0 3 75 0 33. 1 0 3.3 1 6 0 0000 0 0980 0 0000 Pelvis D3 1 3.75 0.046875 33.50 3.316 0 0041 0.2190 0.0009 Total dose (rad) to bone surface 0.0000 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] Rt Arm A4 0 3.75 0 33. 10 1 009 0.0000 lo--' Lt Arm A5 0 3.75 0 34 .6 0 1 009 0 0000 I.O """"' Esophagus B3 0 3.75 0 27 50 1 009 0.0000 Breast B4 0 3.75 0 31.70 1 .0 09 0.0000 Stomach Cl 1 3 75 0.046875 32.30 1 .009 0 0013 Liver A2 0 3.75 0 28. 80 1 .009 0.0000 Bladder C2 6 3.75 0 .2 8125 3 4 20 1 009 0 1551 Colon D5 3 3.75 0 14 0625 29 90 1 009 0.0887 Average Lung 0.0000 RtLung C3 0 3.75 0 34.00 1 .0 46 0.0000 LtLung C4 0 3.75 0 33.10 1 .0 46 0.0000 Average Ovary 0 0065 Rt Ovary B5 5 3.75 0 234375 30.60 1 .009 0.0068 Lt Ovary Bl 4 3.75 0. 1875 27.00 1 .009 0.0061 Testes D2 0 3.75 0 30.30 1 .009 0 0000 Total dose (rad) to remainder-F 0.0251 Total dose (rad) to remainder-M 0.0245

PAGE 207

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat 80mAs 18 0 exam mAs 3.75 3.75 mVat CF e:xam mAs [mV/R] 0.84375 32.90 0 28.80 Total dose (rad) to skin 0.0011 0.0037 0.0024 rem rem rem DCF 1 009 1 009 ESE AP Pelvis 0 0178 R f(d) Leukemia 7 330E-06 Male Respiratory l.498E-05 Female Respiratory 2.339E-05 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 000970 l 905E-05 2.975E-05 3 680E-05 2 873E-05 Male Respiratory 1 000110 g(b) 132 3 7 330949 14.92601 1 1 74 1 0 066005 Female Respiratory 1 000349 Male Digestive 1 000019 Absorbed Dose [rad] 0 0227 0.0000 0.0113 Female Digestive 1 000052 Other 1 000037 Female Breast 1.000002

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Table E-17. AP Hip Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R] [rad] Factor [rem] Esophagus B3 0 3.75 0 27.50 1 009 0.0000 0 05 0 0000 Thyroid A3 0 3.75 0 31.90 1 009 0 0000 0 05 0.0000 Breast A2 0 3 75 0 28.80 1 009 0.0000 0 05 0.0000 Average Lung 0 0000 0 12 0 0000 RtLung C3 0 3.75 0 34.00 1 046 0 0000 LtLung C4 0 3 75 0 33 10 1 046 0.0000 Stomach Cl 0 3 75 0 32 30 1.009 0.0000 0 12 0.0000 Liver A2 0 3 75 0 32.90 1 009 0 0000 0 05 0.0000 Bladder C2 3 3 75 0 140625 34 20 1.009 0.0036 0 05 0 0002 Colon D5 0 3 75 0 29 90 1 009 0.0000 0 12 0 0000 Active Bone Marrow 0 0000 0 12 0 0000 _. Bone surface 0 0000 0 01 0 0000 I w Skin 0.0113 0 01 0 0001 Average Ovary 0.0000 0 20 0 0000 Rt Ovary B5 0 3 75 0 30 60 1.009 0.0000 Lt Ovary Bl 0 3. 75 0 27 00 1 009 0 0000 Testes D2 0 3 75 0 30 30 1 009 0 0000 0 20 0 0000 Remainder-F 0 0078 0.05 0 0004 Remainder-M 0.0078 0 05 0 0004 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rads] toMOSFET dose [rad] Spine middle Al 0 3.75 0 32.90 3 316 0 0000 0.1588 0 0000 Rt Arm A5 0 3.75 0 34 60 3 316 0 0000 0 0779 0 0000 Lt Arm A4 0 3 75 0 33.10 3 316 0 0000 0.0779 0 0000 Pelvis D3 l 3 75 0 046875 33 50 3 316 0 0041 0 2191 0 0009 Total dose (rad) to active marrolv 0.0000

PAGE 209

Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] toMOSFET dose [rad] Spine middle Al 0 3 75 0 32 90 1 009 0 0000 0.1850 0 0000 Rt Arm A5 0 3.75 0 34 60 1 009 0 0000 0.0980 0 0000 Lt Arm A4 0 3 75 0 33 10 1 009 0 0000 0 0980 0 0000 Pelvis D3 1 3 75 0 046875 33. 50 1 009 0.0012 0 2190 0 0003 Total dose (rad) to bone surf ace 0.0000 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] Rt Arm A4 0 3.75 0 33 10 1 009 0 0000 Lt Arm A5 0 3.75 0 34 60 1 009 0 0000 Esophagus B3 0 3 75 0 27 50 1 009 0.0000 Breast B4 0 3 75 0 31 70 1 009 0 0000 Stomach Cl 0 3 75 0 32 30 1 009 0 0000 Liver A2 0 3 75 0 28 80 1 009 0 0000 Bladder C2 3 3.75 0.140625 34.20 1 009 0 0775 Colon D5 0 3.75 0 29 90 1 009 0.0000 Average Lung 0 0000 RtLung C3 0 3 75 0 34 00 1 046 0 0000 LtLung C4 0 3 75 0 33 10 1.046 0 0000 Average Ovary 0 0000 Rt Ovary B5 0 3 75 0 30 60 1 009 0 0000 Lt Ovary Bl 0 3 75 0 27 00 1 009 0 0000 Testes D2 0 3 75 0 30 30 1 009 0.0000 Total dose (rad) to remainder-F 0.0078 Total dose (rad) to remainder-M 0.0078

PAGE 210

Calculation of dose to skin MOSFETs Position Entrance Al Ex.it A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat 80mAs 18 0 exam mAs 3 75 3. 75 mVat CF exam mAs [mV/R) 0.84375 32 90 0 28 80 Total dose (rad) to skin 0.0003 rem 0.0007 rem 0.0007 ren1 DCF 1 009 1 009 ESE AP Hip 0 0147 R f(d) Leukemia l 659E-06 Male Respiratory 4 342E-06 Female Respiratory 4.342E-06 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 000219 5 523E-06 5 523E-06 8 329E-06 8 .3 29E-06 Male Respiratory 1 000032 g(b) 1 3 2 .3 7.330949 14 92601 1 1 74 1 0 066005 Female Respiratory 1 000065 Male Digestive 1 000006 Absorbed Dose [rad] 0 0227 0 0000 0.0113 Female Digestive 1 000010 Other 1 000008 Female Breast 1 00000 l \0 V'I

PAGE 211

Table E-18 Waters Sinus Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R] [rad] Factor [rem] Thyroid A3 0 1 75 0 34.60 1 009 0 0000 0 05 0 0000 Active Bone Marrow 0 0004 0 12 0 0001 Bone surface 0 0011 0 01 0 0000 Remainder 0 0000 0 05 0 0000 Skin 0 0074 0 01 0 0001 Calculation of dose to active marrow Absorbed Fract. Active Fract Organ/ MOSFETs mV exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] to MOSFET dose [rad] ...... Head Spine Al 1 1 75 0 021875 36 10 1 009 0 0005 0 1470 0 0001 \0 Skull A2 4 1.75 0 0875 32 20 1 009 0 0024 0 1470 0.0004 Rt Arm A4 0 1 75 0 34 80 1 009 0 0000 0 0779 0 0000 Lt Arm A5 0 1 75 0 33. 30 1 009 0 0000 0 0779 0 0000 Total dose (rad) to active marrmv 0.0004 Calculation of dose to bone surf ace Absorbed Fract. Bone Fract Organ/ MOSFETs mV exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exammAs [mV/R] [rad] toMOSFET dose [rad] Head Spine Al 1 1 75 0.021875 36 10 3 316 0 0018 0 1160 0 0002 Skull A2 4 1 75 0 0875 32 20 3 .3 16 0 0079 0 1160 0 0009 RtArm A4 0 1.75 0 34 80 3. 316 0 0000 0 0980 0 0000 Lt Arm A5 0 1 75 0 3 3.3 0 3 316 0 0000 0 0980 0 0000 Total dose (rad) to bo11e surface 0.0011

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Calculation of dose to remainder Organ/ MOSFETs mV exam mVat Position 80mAs mAs exammAs RtArm A4 0 1 75 0 Lt Arm AS 0 1 75 0 Total dose (rad) to remainder Calculation of dose to skin MOSFETs mV exam mVat Position 80mAs mAs exam mAs Entrance Al 24 1 75 0 525 Exit A2 1 1 75 0 021875 Total dose (rad) to skin Total effective dose 0.0001 rem ESE Waters Sinus 0 0099 R f(d) g(b) Leukemia 3.327E-07 1 32.3 Male Respiratory 8 706E-07 7.330949 Female Respiratory 8.706E-07 14 .9260 1 Male Digestive l.107E-06 1 Female Digestive l 107E-06 1.74 Other 1 670E-06 1 Female Breast l .670E-06 0 066005 Relative Risk Leukemia 1.000044 Male Respiratory 1 000006 Female Respiratory 1 000013 CF DCF [mV/R] 34.80 1 009 33.30 1 009 CF DCF [mV/R] 32.90 1.009 28 80 1 009 Male Digestive 1 000001 Absorbed Dose [rad] 0 0000 0 0000 0.0000 Absorbed Dose [rad] 0 0141 0 0007 0.0074 Female Digestive 1 000002 Other 1 000002 Female Breast 1 000000 \0 '1

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Table E-19 Lateral Sinus Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R) [rad] Factor [rem] Thyroid A3 6 1 75 0 13125 34 60 1.009 0 0034 0 05 0 0002 Active Bone Marrow 0 0002 0 12 0 0000 Bone surface 0 0004 0 01 0 0000 Ren1ainder 0 0000 0 05 0 0000 Skin 0 0056 0 01 0 0001 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] to MOSFET dose [rad] Head Spine Al 1 1 75 0 021875 36 10 1 009 0 0005 0 1470 0 0001 \0 00 Skull A2 1 1 75 0 021875 32 20 1 009 0 0006 0 1470 0 0001 Rt Arm A4 0 1 75 0 34 80 1 009 0.0000 0 0779 0 0000 Lt Ann A5 0 1 75 0 33 30 1 009 0 0000 0 0779 0.0000 Total dose (rad) to active ma"ow 0.0002 Calculation of dose to bone surft,ce Absorbed Fract. Bone Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] toMOSFET dose [rad] Head Spine Al 1 1 75 0 021875 36 10 3 316 0 0018 0 1160 0.0002 Skull A2 1 1 75 0 021875 32 20 3. 316 0 0020 0 1160 0 0002 RtArm A4 0 1 75 0 34 80 3 316 0 0000 0 0980 0 0000 Lt Arm A5 0 1 75 0 33 30 3. 316 0 0000 0 0980 0 0000 Total dose (rad) to bone surface 0.0004

PAGE 214

Calculation of dose to remainder Organ/ MOSFETs Position RtArm A4 Lt Arm A5 Calculation of dose to skin MOSFETs Position Entrance Exit Total effective dose ESE LAT Sinus Leukemia Male Respiratory Female Respiratory Male Digestive Female Digestive Other Female Breast Relative Risk Al A2 mV exam mVat 80mAs mAs exam mAs 0 1 75 0 0 1 75 0 Total dose (rad) to remainder mV exam 80mAs mAs 18 1 75 1 1 75 Total dose (rad) to skin f(d ) 0.0002 rem 0 0079 R 6 03 3 E-07 1 579E-06 1 579E-06 2 008E-06 2 008E-06 3.029E-06 3. 029E-06 mVat exam mAs 0 .3 9 3 75 0 021875 g(b ) 132. 3 7. 3 30949 14 92601 1 1 74 1 0 066005 Leukemia 1 000080 Male Respiratory 1 000012 Female Respiratory 1 0000 2 4 CF DCF [mV/R] 34 80 1 009 3 3. 30 1 009 CF DCF [mV/R] 3 2 90 1 009 28 80 1 009 Male Digestive 1 000002 Absorbed Dose (rad] 0 0000 0 0000 0.0000 Absorbed Dose [rad] 0 0106 0 0007 0.0056 Female Digestive 1 00000 3 Other 1 00000 3 Female Breast 1 000000 \0 \0

PAGE 215

Table E-20 AP Sinus Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam m.As [mV/R] [rad] Factor [rem] Thyroid A3 1 1 75 0 021875 34 60 1 009 0 0006 0 05 0 0000 Active Bone Marrow 0 0004 0 12 0 0001 Bone surface 0 0011 0 01 0 0000 Remainder 0 0000 0 05 0 0000 Skin 0 0065 0 01 0 0001 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose marrow assigned Absorbed N Position 80mAs m.As exam m.As [mV/R] [rad] toMOSFET dose [rad] 0 0 Head Spine Al 1 1 75 0 021875 36 10 1 009 0 0005 0 1470 0 0001 Skull A2 4 1 75 0 0875 32 20 1 009 0.0024 0.1470 0.0004 Rt Arm A4 0 1 75 0 34 80 1.009 0 0000 0 0779 0 0000 Lt Arm A5 0 1 75 0 33 30 1 009 0 0000 0.0779 0 0000 Total dose (rad) to active marrow 0.0004 Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mV exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam m.As [mV/R] [rad] toMOSFET dose (rad] Head Spine Al 1 1 75 0 021875 36 10 3 316 0 0018 0 1160 0 0002 Sla1ll A2 4 1 75 0.0875 32 20 3 316 0 0079 0 1160 0 0009 Rt Arm A4 0 1 75 0 34 80 3 316 0 0000 0 0980 0 0000 LtArm A5 0 1 75 0 33 30 3 316 0 0000 0 0980 0 0000 Total dose (rad) to bone surface 0.0011

PAGE 216

Calculation of dose to remainder Organ/ MOSFETs Position RtArm A4 Lt Arm A5 Calculation of dose to slan MOSFETs Position Entrance Al Exit A2 Total effective dose ESE AP Sinus Leukemia Male Respiratory Female Respiratory Male Digestive Female Digestive Other Female Breast Relative Risk mV exam mVat 80mAs mAs exam mAs 0 1.75 0 0 1 75 0 Total dose (rad) to remainder mV exam 80mAs mAs 22 1 75 0 1 75 Total dose (rad) to slan f(d) 0.0002 rem 0 0091 R 3 781E-07 9 896E-07 9 896E-07 1 259E-06 1 259E-06 1 898E-06 1 898E-06 mVat exam mAs 0.48125 0 g(b) 132 .3 7 330949 14 92601 1 1 74 1 0 066005 Leukemia 1 000050 Male Respiratory 1 000007 Female Respiratory 1 000015 CF DCF [mV/R] 34.80 1 009 33 30 1 009 CF DCF [mV/R] 32 90 1.009 28 80 1 009 Male Digestive 1 000001 Absorbed Dose [rad] 0 0000 0 0000 0.0000 Absorbed Dose [rad] 0.0129 0.0000 0.0065 Female Digestive 1 000002 Other 1 000002 Female Breast 1 000000 t--.) 0

PAGE 217

Table E-21 AP Chest Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80m.As mAs exam mAs [mV/R] [rad] Factor [rem] Esophagus D4 1 1 75 0 021875 34 80 1 009 0 0006 0 05 0 0000 Thyroid A3 4 1 75 0 0875 34 60 1 009 0.0022 0 05 0 0001 Breast D5 2 1 75 0 04375 3 8 50 1 009 0 0010 0 05 0 0001 Average Lung 0 0009 0 12 0 0001 RtLung D3 1 1 75 0 021875 32 00 1.046 0 0006 LtLung DI 2 1 75 0 04375 3 3. 30 1 046 0 0012 Stomach D5 2 1 75 0.04375 38 50 1 009 0 0010 0 12 0 0001 Liver A2 2 1 75 0 04375 3 2 20 1 009 0 0012 0 05 0 0001 Bladder A4 0 1 75 0 3 4 80 1 009 0 0000 0 05 0 0000 Colon NM 1 75 0 3 1 98 1 009 0 0000 0 12 0 0000 Active Bone Marrow 0 0001 0 12 0 0000 N Bone surface 0.0005 0 01 0 0000 0 N Skin 0 0012 0 01 0 0000 Average Ovary 0 0000 0 20 0 0000 RtOvary A2 0 1 75 0 32 20 1 009 0 0000 Lt Ovary NM 1 75 0 31 18 1 009 0 0000 Testes NM 1 75 0 33.04 1 009 0 0000 0 20 0 0000 Remainder-F 0 0136 0 05 0 0007 Remainder-M 0 0136 0 05 0 0007 Calculation of dose to active ma"ow Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rads] toMOSFET dose [rad] Spine middle Al 0 1 75 0 36 10 1 009 0 0000 0 1588 0 0000 Rt Arm A5 1 1 75 0 021875 3 3 30 1 009 0 0006 0 0779 0 0000 Lt Arm A4 2 1 75 0 04375 34 80 1 009 0 0011 0 0779 0 0001 Pelvis NM 1 75 0 3 2 20 1 009 0 0000 0 2191 0 0000 Total dose (rad) to active marrolv 0.0001

PAGE 218

Calculati.on of dose to hone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] toMOSFET dose [rad] Spine middle Al 0 1 75 0 36 10 3 316 0 0000 0 1850 0 0000 Rt Arm A5 1 1 75 0 021875 33 30 3.3 16 0 0019 0 0980 0 0002 Lt Arm A4 2 1 75 0 04375 34 80 3 316 0 0037 0 0980 0 0004 Pelvis NM 1 75 0 3 2 20 3.3 16 0 0000 0 2190 0 0000 Total dose (rad) to hone surface 0.0005 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] Rt Arm A5 1 1.75 0 021875 33 30 1 009 0 0006 N Lt Arm A4 2 1.75 0 04375 3 4 80 1 009 0 0011 0 w Esophagus D4 1 1 75 0.021875 34 80 1 009 0.0006 Breast D5 2 1 75 0 04 3 75 38 50 1.009 0 0010 Stomach D5 2 1 75 0 04 3 75 38 50 1 009 0 0010 Liver A2 2 1.75 0 04375 3 2 20 1 009 0 0549 Bladder A4 3 1 75 0 065625 3 4 80 1 009 0.0762 Colon NM 1 75 0 31 98 1 009 0 0000 Average Lung 0 0009 RtLung D3 1 1 75 0 021875 3 2 00 1 046 0.0006 LtLung DI 2 1 75 0.04375 3 3. 30 1.046 0 0012 Average Ovary 0 0000 Rt Ovary A2 0 1 75 0 32 20 1 009 0 0000 Lt Ovary NM 1 75 0 31.18 1 009 0 0000 Testes NM 1.75 0 3 3 04 1 009 0.0000 Total dose (rad) to remainder-F 0.0136 Total dose (rad) to remainder-M 0.0136

PAGE 219

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 4 1 75 0 1 75 mVat CF exam mAs [mV/R] 0 0875 32 90 0 28 80 Total dose (rad) to skin 0.0005 0.0012 0.0012 rem rem rem DCF 1 009 1 009 ESE AP Chest 0 0063 R f(d) Leukemia 2.903E-06 Male Respiratory 7.599E-06 Female Respiratory 7 597E-06 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 000384 9 665E-06 9 664E-06 l 457E-05 l 458E-05 Male Respiratory 1 000056 g(b) 132 3 7 330949 14 92601 1 1.74 1 0 066005 Female Respiratory 1 000113 Male Digestive 1 000010 Absorbed Dose [rad 0 0024 0 0000 0.0012 Female Digestive 1 000017 Other 1 000015 Female Breast 1 000001

PAGE 220

Table E-22 AP Chest with Thyroid Shield Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R [rad] Factor [rem] Esophagus D4 0 1 75 0 34 80 1 009 0 0000 0 05 0.0000 Thyroid A3 3 1 75 0 065625 3 4 60 1 009 0 0017 0 05 0 0001 Breast D5 4 1 75 0 0875 38 50 1 009 0 0020 0 05 0 0001 Average Lung 0 0009 0 12 0 0001 RtLung D 3 2 1 75 0 04375 32 00 1 046 0 0013 Lt Lung D1 1 1 75 0 021875 33 30 1 046 0 0006 Stomach NM 1 75 0 38 50 1 009 0 0000 0 12 0 0000 Liver NM 1 75 0 3 2 20 1 009 0 0000 0 05 0 0000 Bladder A4 0 1 75 0 3 4 80 1 009 0 0000 0 05 0 0000 Colon NM 1 75 0 31 98 1 009 0 0000 0 12 0 0000 Active Bone Marrow 0 0000 0 12 0 0000 N Bone surface 0 0002 0 01 0 0000 0 Vl Skin 0 0012 0 01 0 0000 Average Ovary 0 0000 0 20 0 0000 Rt Ovary A2 0 1 75 0 32 20 1 009 0 0000 Lt Ovary NM 1 75 0 31 18 1 009 0 0000 Testes NM 1 75 0 3 3 04 1 009 0 0000 0 20 0 0000 Remainder-F 0 0004 0 05 0 0000 Remainder-M 0 0004 0 05 0.0000 Calculation of dose to acti.ve marrow Absorbed Fract Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs (mV/R] [rads] toMOSFET dose rad] Spine middle Al 0 1 75 0 36 10 1 009 0 0000 0 1588 0 0000 Rt Ann A5 l 1 75 0 021875 33 30 1 009 0 0006 0 0779 0 0000 Lt Arm A4 0 1 75 0 34 80 1 009 0 0000 0 0779 0 0000 Pelvis NM 1 75 0 3 2 20 1 009 0 0000 0 2191 0 0000 Total dose (rad) to active marrow 0.0000

PAGE 221

Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] toMOSFET dose rad Spine middle Al 0 1 75 0 36 10 3. 316 0 0000 0 1850 0 0000 RtArm A5 1 1 75 0 021875 33. 30 3 316 0 0019 0 0980 0 0002 Lt Arm A4 0 1 75 0 34 80 3 316 0 0000 0 0980 0 0000 Pelvis NM 1 75 0 3 2 20 3.3 16 0 0000 0 2190 0 0000 Total dose (rad) to bone surface 0.0002 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] Rt Arm A5 l 1 75 0.021875 33 30 1 009 0 0006 N Lt Arm A4 0 1 75 0 34 80 1 009 0 0000 0 Esophagus D4 0 1 75 0 34 80 1 009 0 0000 Breast D5 4 1 75 0 0875 3 8 50 1 009 0 0020 Stomach NM 1 75 0 38 50 1 009 0 0000 Liver NM 1 75 0 32 20 1 009 0 0000 Bladder A4 0 1 75 0 34 80 1 009 0 0000 Colon NM 1 75 0 31 98 1 009 0 0000 Average Lung 0.0009 Rt Lung D3 2 1 75 0 04375 32 00 1 046 0 0013 LtLung Dl 1 1 75 0 021875 33 30 1 046 0 0006 Average Ovary 0 0000 Rt Ovary A2 0 1 75 0 32 20 1 009 0 0000 Lt Ovary NM 1 75 0 31.18 1 009 0 0000 Testes NM 1 75 0 33 04 1 009 0 0000 Total dose (rad) to remainder-F 0.0004 Total dose (rad) to remainder-M 0.0004

PAGE 222

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 4 1 75 0 1 75 mVat CF exam mAs [mV/R] 0.0875 3 2 90 0 28 80 Total dose (rad) to skin 0.0003 0.0003 0.0003 rem rem rem DCF 1 009 1 009 ESE AP Chest 0 0063 R f(d) Leukemia 8 113E-07 Male Respiratory 2 134E-06 Female Respiratory 2 113E-06 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1.000107 2 715E-06 2 687E-06 4.073E-06 4 094E-06 Male Respiratory 1 000016 g(b) 132 3 7 330949 14 92601 1 1 74 1 0 066005 Female Respiratory 1 000032 Male Digestive 1 000003 Absorbed Dose [rad] 0 0024 0 0000 0.0012 Female Digestive 1 000005 Other 1 000004 Female Breast 1 000000

PAGE 223

Table E-23 PA Chest Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80m.As mAs exam m.As mV/R] [rad) Factor [rem] Esophagus D4 2 1 75 0 04375 34 80 1 009 0 0011 0 05 0 0001 Thyroid A3 1 1 75 0 021875 34 60 1 009 0 0006 0 05 0 0000 Breast D5 0 1 75 0 38 50 1 009 0 0000 0 05 0 0000 Average Lung 0 0012 0 12 0 0001 Rt Lung D3 2 1.75 0 04375 3 2 00 1 046 0 0013 Lt Lung D1 2 1 75 0.04375 33 30 1 046 0.0012 Stomach A2 1 1 75 0 021875 38 50 1 009 0 0005 0 12 0 0001 Liver NM 1 75 0 32 20 1 009 0 0000 0 05 0 0000 Bladder A4 0 1.75 0 3 4 80 1 009 0 0000 0 05 0 0000 Colon NM 1.75 0 31 98 1 009 0 0000 0 12 0.0000 Active Bone Marrow 0 0004 0 12 0 0000 N Bone surface 0 0015 0 01 0 0000 0 00 Skin 0.0012 0.01 0 0000 Average Ovary 0 0000 0 20 0 0000 Rt Ovary A2 0 1 75 0 32 20 1 009 0 0000 Lt Ovary NM 1.75 0 31.18 1 009 0 0000 Testes NM 1 75 0 33 04 1 009 0 0000 0 20 0 0000 Remainder-F 0.0003 0 05 0 0000 Remainder-M 0 0004 0 05 0 0000 Calculation of dose to ,,ctive marrow Absorbed Fract. Active Fract Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80 m.As mAs exam mAs [mV/R] [rads) toMOSFET dose [rad] Spine middle Al 4 1.75 0 0875 36 10 1 009 0 0021 0 1588 0 0003 Rt Arm A5 1 1.75 0 021875 33 30 1 009 0 0006 0 0779 0.0000 Lt Arm A4 0 1 75 0 34 80 1 009 0 0000 0 0779 0 0000 Pelvis NM 1 75 0 3 2 20 1 009 0 0000 0 2191 0 0000 Total dose (rad) to active marro,v 0.0004

PAGE 224

Calculation of dose to bone surface Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80m.As mAs exam mAs [mV/R] rad] toMOSFET dose [rad] Spine middle Al 4 1 .75 0.0875 36. 10 3.3 16 0 0070 0 1850 0 0013 Rt Arm A5 1 1 .75 0.021875 33 30 3.316 0.0019 0 0980 0.0002 Lt Arm A4 0 1 75 0 3 4 80 3.3 16 0.0000 0.0980 0 0000 Pelvis NM 0 1 75 0 32.20 3.3 1 6 0.0000 0.2190 0 0000 Total dose (rad) to bone surface 0.0015 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80m.As mAs exam m.As [mV/R] [rad] Rt Arn1 A5 1 1 .75 0 021875 33.30 1 009 0.0006 tv LtArm A4 0 1 75 0 3 4 .80 1 009 0.0000 0 '-0 Esophagus D4 2 1 75 0 04375 3 4 80 1 009 0.0011 Breast D5 0 1 75 0 3 8 50 1 .009 0.0000 Stomach A2 1 1 75 0.021875 3 8 50 1 009 0 0005 Liver NM 1 .75 0 32.20 1 009 0 0000 Bladder A4 0 1 75 0 3 4 .80 1 .009 0 0000 Colon NM 1 .75 0 3 1 .9 8 1 009 0 0000 A ve rage Lung 0 0012 RtLung D3 2 1 75 0 04375 32.00 1 .0 46 0 0013 LtLung DI 2 1 75 0 04375 33 .3 0 1 .0 46 0 0012 Average Ovary 0.0000 RtOvary A2 0 1 .75 0 32.20 1 009 0.0000 Lt Ovary NM 1 75 0 31.18 1 009 0 0000 Testes NM 1 .75 0 33 04 1 009 0.0000 Total dose (rad) to remainder-F 0.0003 Total dose (rad) to remainder-M 0.0004

PAGE 225

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 4 1 75 0 1 75 mVat CF exam mAs [mV/R] 0 0875 32 90 0 28 80 Total dose (rad) to skin 0.0004 rem 0.0004 rem 0.0004 rem Absorbed DCF Dose [rad] 1 009 0 0024 1 009 0 0000 0.0012 ESE PA Chest 0 006 3 R N f(d) Leukemia 9 303E-07 Male Respiratory 2 446E-06 Female Respiratory 2 424E-06 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 000123 3 11 lE-06 3. 084E-06 4 671E-06 4 691E-06 Male Respiratory 1 000018 g(b) 132 3 7. 33 0949 14 92601 l 1.74 1 0 066005 Female Respiratory 1 0000 3 6 Male Digestive 1 000003 Female Digestive 1 000005 Other 1 000005 Female Breast 1 000000 0

PAGE 226

Table E-24 Lateral Chest Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R] [rad] Factor [rem] Esophagus D4 2 3 75 0 09375 34 80 1 009 0 0024 0 05 0 0001 Thyroid A3 4 3.75 0 1875 34 60 1 009 0 0048 0 05 0 0002 Breast D5 1 3. 75 0 046875 3 8 50 1 009 0 0011 0 05 0 0001 Average Lung 0 0020 0 12 0 0002 Rt Lung D 3 2 3.75 0 09375 32 00 1 046 0.0027 Lt Lung Dl 1 3.75 0 046875 3 3. 30 1 046 0.0013 Stomach A2 0 3. 75 0 38 50 1 009 0 0000 0 12 0 0000 Liver NM 3 75 0 32 20 1 009 0 0000 0.05 0 0000 Bladder A4 0 3 .75 0 34 80 1 009 0 0000 0 05 0 0000 Colon NM 3. 75 0 31 98 1 009 0 0000 0 12 0 0000 Active Bone Marrow 0 0008 0 12 0 0001 N Bone surface 0 0034 0 01 0 0000 ...... ...... Skin 0 0038 0 01 0 0000 Average Ovary 0 0000 0 20 0 0000 Rt Ovary A2 0 3 75 0 32 20 1 009 0 0000 Lt Ovary NM 3 75 0 31 18 1 009 0 0000 Testes NM 3 75 0 3 3 04 1 009 0 0000 0 20 0 0000 Remainder-F 0 0012 0 05 0 0001 Remainder-M 0 0008 0 05 0 0000 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs m.As exam mAs (mV/R] (rads] toMOSFET dose [rad Spine middle Al 2 3 75 0.09375 36 10 1 009 0 0023 0.1588 0.0004 Rt Arm A5 5 3 75 0 234375 33 30 1 009 0 0062 0 0779 0 0005 LtArm A4 0 3 75 0 34 80 1 009 0 0000 0 0779 0 0000 Pelvis NM 3. 75 0 32 20 1 009 0 0000 0 2191 0 0000 Total dose (rad) to active marrow 0.0008

PAGE 227

Calculation of dose to hone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam m.As [mV/R] [rad] toMOSFET dose [rad] Spine middle Al 2 3 75 0 09375 3 6 10 3 316 0 0075 0 1850 0 0014 Rt Ann A5 5 3 75 0 234375 33 30 3 316 0 0204 0 0980 0.0020 Lt Arm A4 0 3 75 0 34 80 3 316 0 0000 0 0980 0 0000 Pelvis NM 3. 75 0 32.20 3 316 0 0000 0 2190 0 0000 Total dose (rad) to bone surface 0.0034 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] Rt Arm A5 5 3 75 0 234375 33.30 1 009 0.0062 N Lt Arm A4 0 3 75 0 34 80 1.009 0.0000 ...... N Esophagus 04 2 3 75 0.09375 34 80 1 009 0.0024 Breast 05 I 3 75 0 046875 38 50 1.009 0 0011 Stomach A2 0 3 75 0 38.50 1 009 0 0000 Liver NM 3 75 0 32.20 1 009 0 0000 Bladder A4 0 3 75 0 34.80 1.009 0 0000 Colon NM 3 75 0 31 98 1.009 0 0000 Average Lung 0.0020 Rt Lung 03 2 3.75 0 09375 32 00 1 046 0.0027 LtLung 01 1 3.75 0 046875 33 30 1 046 0.0013 Average Ovary 0 0000 Rt Ovary A2 0 3 75 0 32 20 1 009 0 0000 Lt Ovary NM 3 75 0 3 1 18 1 009 0 0000 Testes NM 3 75 0 33.04 1 009 0.0000 Total dose (rad) to remainder-F 0.0012 Total dose (rad) to remainder-M 0.0008

PAGE 228

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 6 3 75 0 3 75 mVat CF exam mAs [mV/R] 0.28125 32 90 0 28 80 Total dose (rad) to skin 0.0008 rem 0.0009 rem 0.0009 rem Absorbed DCF Dose rad 1.009 0 0076 1 009 0 0000 0.0038 ESE LAT Chest 0 0189 R N f(d) Leukemia 2 124E-06 Male Respiratory 5 502E-06 Female Respiratory 5 615E-06 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 000281 6 999E-06 7 142E-06 l 066E-05 1 055E-05 Male Respiratory 1 000040 g(b) 132 3 7 330949 14 92601 1 1 74 1 0 066005 Female Respiratory 1 000084 Male Digestive 1 000007 Female Digestive 1 000012 Other 1 000011 Female Breast 1 000001 ...... w

PAGE 229

Table E-25 LAO Chest Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R] [rad] Factor [rem] Esophagus D4 2 3 .75 0 09375 34 80 1 009 0 0024 0 05 0 0001 Thyroid A3 1 3 75 0 046875 34 60 1 009 0 0012 0 05 0 0001 Breast D5 0 3 75 0 3 8 50 1 009 0 0000 0 05 0 0000 Average Ltmg 0 0027 0 12 0 0003 RtLung D3 3 3 75 0 140625 32.00 1 046 0 0040 LtLung DI 1 3 .75 0 046875 33 30 1 046 0 0013 Stomach A2 1 3 75 0.046875 38 50 1 009 0 0011 0 12 0 0001 Liver A4 1 3 75 0 046875 32 20 1 009 0 0013 0 05 0 0001 Bladder A4 0 3 75 0 34 80 1 009 0 0000 0 05 0 0000 Colon NM 3 75 0 31 98 1 009 0 0000 0 12 0 0000 Active Bone Marrow 0 0006 0 12 0 0001 N Bone surface 0 0023 0 01 0 0000 """"" Skin 0 0031 0.01 0 0000 Average Ovary 0.0000 0 20 0 0000 RtOvary A2 0 3.75 0 32 20 1 009 0 0000 Lt Ovary NM 3 75 0 31 18 1 009 0 0000 Testes NM 3 75 0 33 04 1 009 0 0000 0 20 0 0000 Remainder-F 0.0039 0 05 0 0002 Remainder-M 0.0038 0 05 0 0002 Calculation of dose to active marrow Absorbed Fract Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rads toMOSFET dose [rad] Spine middle Al 1 3 75 0 046875 36 10 1.009 0 0011 0 1588 0 0002 Rt Arm A5 4 3 75 0 1875 33 30 1 009 0 0050 0 0779 0 0004 Lt Arm NM 3 75 0 34 80 1 009 0 0000 0 0779 0 0000 Pelvis NM 3. 75 0 32 20 1 009 0 0000 0 2191 0 0000 Total dose (rad) to active marro1v 0.0006

PAGE 230

Calculati.on of dose to bone surface Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R to MOSFET dose [rad] Spine middle Al 1 3.75 0.046875 36.10 3 316 0 1850 0 0007 Rt Arm A5 4 3.75 0 1875 33 .3 0 3.3 16 0 0164 0.0980 0 0016 Lt Arm NM 3.75 0 34.80 3.3 16 0 0000 0 0980 0.0000 Pelvis NM 3.75 0 32 20 3.316 0 0000 0 2190 0 0000 Total dose (rad) to bone surface 0.0023 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs mV/R] [rad] RtArm A5 4 3.75 0 1875 33 30 1 009 0 0050 N Lt Arm NM 3.75 0 34.80 1 .009 0.0000 lo-" V'I Esophagus D4 2 3.75 0.09375 34.80 1 009 0.0024 Breast D5 0 3.75 0 38.50 1.009 0.0000 Stomach A2 1 3.75 0.046875 38 50 1 .009 0 0011 Liver A4 l 3.75 0 046875 32.20 1 009 0 0274 Bladder A4 0 3.75 0 3 4 .80 1 009 0 0000 Colon NM 3.75 0 3 1 98 1 009 0 0000 Average Lung 0 0027 Rt Lung D3 3 3.75 0 140625 32.00 1 046 0.0040 LtLung DI 1 3.75 0.046875 33 .3 0 1 046 0.0013 Average Ovary 0.0000 Rt Ovary A2 0 3.75 0 32.20 1 009 0 0000 Lt Ovary NM 3.75 0 31 18 1 009 0.0000 Testes NM 3.75 0 33 04 1 .009 0 0000 Total dose (rad) to remainder-F 0.0039 Total dose (rad) to remainder-M 0.0038

PAGE 231

Calculation of dose to sldn MOSFETs Position Entrance Al Exit A1 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 5 3 75 0 3. 75 mVat CF exam mAs [mV/R] 0.234375 32 90 0 28 80 Total dose (rad) to sldn 0.0008 rem 0.0010 rem 0.0010 rem Absorbed DCF Dose [rad] 1 009 0 0063 1 009 0 0000 0.0031 ESE LAO Chest 0 0113 R N f(d) Leukemia 2 441E-06 Male Respiratory 6 374E-06 Female Respiratory 6 404E-06 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 000323 8 108E-06 8 147-06 l.226E-05 l 223E-05 Male Respiratory 1 000047 g(b) 132 3 7 330949 14 92601 I 1 74 1 0 066005 Female Respiratory 1 000096 Male Digestive 1 000008 Female Digestive 1 000014 Other 1 000012 Female Breast 1 000001 0\

PAGE 232

Table E-26 RPO Chest Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80m.As mAs exam mAs [mV/R] [rad] Factor [rem] Esophagus D4 0 3 75 0 34 80 1 009 0 0000 0.05 0 0000 Thyroid A3 6 3. 75 0 28125 34 60 1 009 0 0072 0 05 0 0004 Breast D5 5 3. 75 0 2 3 4 3 75 3 8 50 1 009 0 0054 0 05 0 000 3 Average Lung 0 0013 0 12 0 0002 Rt Lung D 3 0 3 75 0 3 2 00 1 046 0 0000 Lt Lung Dl 2 3. 75 0 09375 33. 30 1 046 0 0026 Stomach A2 2 3 75 0 09375 38 50 1 009 0 0022 0 12 0 0003 Liver A4 1 3. 75 0 046875 32 20 1 009 0 001 3 0 05 0 0001 Bladder A4 0 3. 75 0 3 4 80 1 009 0 0000 0 05 0 0000 Colon NM 3 75 0 3 1 98 1 009 0 0000 0.12 0 0000 Active Bone Marrow 0 0002 0 12 0 0000 N Bone surface 0 0007 0 01 0 0000 ...... -l Skin 0 00 3 1 0 01 0 0000 Average Ovary 0 0000 0 20 0 0000 Rt Ovary A2 0 3 75 0 3 2 20 1 009 0 0000 Lt Ovary NM 3 75 0 31 18 1 009 0 0000 Testes NM 3. 75 0 33. 04 1 009 0 0000 0 20 0 0000 Remainder-F 0.00 3 6 0 05 0 0002 Remainder-M 0 00 3 6 0 05 0 0002 Calculation of dose to active marrow Absorbed Fract. Active Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80mAs mAs exam mAs [rnV/R] [rads] toMOSFET dose [rad) Spine middle Al 1 3 75 0.046875 36 10 1 009 0 0011 0 1588 0 0002 Rt Ann A5 0 3 75 0 33. 30 1 009 0 0000 0 0779 0 0000 Lt Ann NM 3. 75 0 3 4 80 1 009 0 0000 0 0779 0 0000 P e lvis NM 3. 75 0 3 2 20 1 00 9 0.0000 0 2191 0 0000 Total dose (rad) to active marrov 0.0002

PAGE 233

Calculation of dose to bone surf ace Absorbed Fract. Bone Fract. Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R rad] toMOSFET dose rad] Spine middle Al 1 3.75 0.046875 36. 10 3.3 16 0.0038 0.1850 0 0007 Rt Arm A5 0 3 75 0 33.30 3.3 16 0 0000 0 0980 0.0000 Lt Arm NM 3.75 0 3 4 80 3.3 1 6 0 .0 000 0 0980 0 0000 Pelvis NM 3.75 0 32.20 3.3 16 0 .00 00 0 .2 1 90 0 0000 Total dose (rad) to bone surface 0.0007 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat ei:am mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] RtArm A5 0 3.75 0 33.30 1 009 0 0000 N Lt Arm NM 3.75 0 34 80 1 009 0 0000 00 Esophagus D4 0 3.75 0 3 4 80 1 009 0 0000 Breast D5 5 3.75 0 234375 3 8 50 1 009 0 0054 Stomach A2 2 3.75 0.09375 3 8 50 1 .009 0 0022 Liver A4 1 3.75 0 046875 32.20 1 009 0 0274 Bladder A4 0 3.75 0 3 4 80 1 009 0.0000 Colon NM 3. 75 0 3 1 98 1 .009 0.0000 Average Lung 0.0013 RtLung D 3 0 3.75 0 32.00 1 046 0 0000 LtLung DI 2 3.75 0 09375 33.30 1 046 0 0026 Average Ovary 0 0000 RtOvary A2 0 3.75 0 32.20 1 009 0 0000 Lt Ovary NM 3.75 0 31 18 1 009 0.0000 Testes NM 3 75 0 33.04 1 009 0 0000 Total dose (rad) to remainder-F 0.0036 Total dose (rad) to remainder-M 0.0036

PAGE 234

Calculation of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 5 3. 75 0 3. 75 mVat CF exam mAs [mV/R] 0 234 3 75 32 90 0 28 80 Total dose (rad) to skin 0.0012 rem 0.0013 rem 0.0013 rem Absorbed DCF Dose [rad] 1 009 0 006 3 1 009 0 0000 0.0031 ESE RPO Chest 0 0113 R f(d) Leukemia 3. 274E-06 Male Respiratory 8 569E-06 Female Respiratory 8 569E-06 Male Digestive Female Digestive Other Female Breast Relative Risk Leukemia 1 .0 004 33 l.090E-05 l 090E-05 1 644E-05 l.644E-05 Male Respiratory 1 0000 63 g(b ) 1 3 2 .3 7 .33 0949 14 92601 1 1 74 1 0 0 6 6005 Female Respiratory 1 000128 Male Digestive 1 00001 I Female Digestive 1 000019 Other 1 00001 6 Female Breast 1 000001 I--" \0

PAGE 235

Table E-27 RAO Chest Absorbed Tissue Effective Organ/ MOSFETs mVat exam mVat CF DCF Dose Weighting Dose Position 80mAs mAs exam mAs [mV/R] [rad] Factor [rem) Esophagus D4 0 3. 75 0 3 4 80 1 009 0 0000 0 05 0 0000 Thyroid A3 0 3 75 0 34 60 1 009 0 0000 0 05 0 0000 Breast Dl 5 3 75 0 234375 3 3 .3 0 1 009 0 0062 0 05 0 0003 Average Lung 0 0013 0 12 0 0002 RtLung D3 2 3 75 0 09375 32.00 1 046 0 0027 LtLung D4 0 3 75 0 34 80 1 046 0 0000 Stomach A3 2 3 75 0 09375 34 60 1 009 0 0024 0 12 0 0003 Liver A2 2 3 75 0 09375 32 20 1 009 0 0026 0 05 0.0001 Bladder A2 0 3 75 0 32 20 1 009 0 0000 0 05 0.0000 Colon NM 3 75 0 31.98 1 009 0 0000 0 12 0 0000 Active Bone Marrow 0 0004 0 12 0.0000 N Bone surface 0 0015 0 01 0 0000 N 0 Skin 0 0031 0 01 0 0000 Average Ovary 0 0000 0 20 0 0000 Rt Ovary DI 0 3 75 0 33 30 1 009 0 0000 Lt Ovary NM 3 75 0 31 18 1 009 0 0000 Testes NM 3. 75 0 33 04 1 009 0 0000 0 20 0 0000 Remainder-F 0 0067 0.05 0.0003 Remainder-M 0 0068 0 05 0.0003 Calculation of dose to active marrow Absorbed Fract Active Fract Organ/ MOSFETs mVat exam mVat CF DCF Dose marrow assigned Absorbed Position 80m.As m.As exam m.As [mV/R] rads] to MOSFET dose [rad] Spine middle Al 1 3 75 0 046875 36 10 1 009 0 0011 0 1588 0 0002 Rt Arm A4 2 3 75 0 09 3 75 34 80 1 009 0 0024 0 0779 0 0002 Lt Arm A3 0 3 75 0 34 60 1 009 0 0000 0 0779 0 0000 Pelvis NM 3 75 0 3 2 20 1 009 0 0000 0 2191 0 0000 Total dose (rad) to active marrolv 0.0004

PAGE 236

Calculation of dose to bone surface Absorbed Fract Bone Fract Organ/ MOSFETs mVat exam mVat CF DCF Dose assigned Absorbed Position 80mAs mAs exam mAs [mV/R] [rad] to MOSFET dose [rad] Spine middle Al 1 3 75 0 046875 36 10 3 316 0 0038 0 1850 0 0007 RtArm A4 2 3. 75 0 09375 34 80 3 316 0 0078 0 0980 0 0008 Lt Arm A3 0 3 75 0 34 60 3. 316 0 0000 0 0980 0 0000 Pelvis NM 3. 75 0 32 20 3 316 0 0000 0.2190 0 0000 Total dose (rad) to bone surface 0.0015 Calculation of dose to remainder Absorbed Organ/ MOSFETs mVat exam mVat CF DCF Dose Position 80mAs mAs exam mAs [mV/R] [rad] Rt Arm A4 2 3 75 0 09375 34.80 1 009 0 0024 N Lt Arm A3 0 3.75 0 34 60 1 009 0 0000 N Esophagus D4 0 3. 75 0 34 80 1 009 0 0000 Breast D1 5 3. 75 0 234 3 75 33 30 1 009 0 0062 Stomach A3 2 3 75 0 09375 34.60 1 009 0 0024 Liver A2 2 3 75 0 09375 32 20 1 009 0 0549 Bladder A2 0 3 75 0 3 2 20 1 009 0 0000 Colon NM 3 75 0 31 98 1.009 0 0000 Average Lung 0 0013 Rt Lung D3 2 3 75 0 09375 32 00 1 046 0 0027 LtLung D4 0 3 75 0 34 80 1 046 0 0000 Average Ovary 0 0000 Rt Ovary Dl 0 3 75 0 33 30 1 009 0 0000 Lt Ovary NM 3 75 0 31 18 1.009 0.0000 Testes NM 3. 75 0 33 04 1 009 0 0000 Total dose (rad) to remainder-F 0.0067 Total dose (rad) to remainder-M 0.0068

PAGE 237

Calculati.on of dose to skin MOSFETs Position Entrance Al Exit A2 Subtotal Effective Dose Female Effective Dose Male Effective Dose mVat exam 80mAs mAs 5 3. 75 0 3 75 mVat CF exam mAs [mV/R 0 234375 32 90 0 28 80 Total dose (rad) to sldn 0.0010 0.0013 0.0013 rem rem rem DCF 1 009 1 009 ESE rao chest 0 0069 R f(d) Leukemia 3 196E-06 Male Respiratory 8 .3 71E-06 Female Respiratory 8 361E-06 Male Digestive Female Digestive Other Fen1ale Breast Relative Risk Leukemia 1 00042 3 l 065E-05 1 064E-05 l 605E-05 1 606E-05 Male Respiratory 1 000061 g(b) 132 3 7 330949 14 92601 1 1 74 1 0 066005 Female Respiratory 1.000125 Male Digestive 1 00001 l Absorbed Dose [rad] 0 0063 0 0000 0.0031 Female Digesti v e 1.000019 Other 1.000016 Female Breast 1 000001

PAGE 238

LIST OF REFERENCES Almen, A and S Mattsson (1996) '' On the calculation of effective dose to children and adolescents ' J Radiol Prot 16(2) : 81-89 Atherton, J V and W Ruda (1995) '' CT doses in cylindrical phantoms ." Phys Med Biol 40 : 891-911 Atherton, J. V and W Huda (1996) 'Energy imparted and effective doses in computed tomography Med Phys 23(5) : 735-741 Ballinger P W (1 99 5) Merrill's Atlas of Radiographic Positions and Radiologic Procedures St Loui s, Mosby BC (1998) Vital Statistics of the United States Washington, D C U S Depa1tment of Commerce Bureau of the Census ; 1990-1998 Beck T J (1978) Quantification of current practice in the roentgenography of infants and children for absorbed dose calculations Master's thesis, The Johns Hopkins University Baltimore Beck T J and M Rosenstein (1979) Quantification of current practice in pediatric roentgenography for organ dose calculations Rockville MD Food and Drug Administration Behrman R E and V C Vaughan ( 1987) Nelson Textbook of Pediatrics. Philadelphia PA, W B Saunders BEIR (1990) Health Effects of Exposure to Low Levels of Ionizing Radiation Washington, DC National Research Council Bontrager K L (1 99 7) Textbook of Radiographic Positioning and Related Anatomy St Louis Mosby Bouchet L G ., W E. Bolch, D A Weber H L Atkins and J W Poston (1996) '' A revised dosimetric model of the adult head and brain J Nucl Med 37 : 1226-1236 Bouslog J (1935) 'Roentgenologic studies of infants' gastrointestinal tract ." Journal of Pediatrics 6 : 234 223

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224 Bower M W (1997) A Physical Anthropomorphic Phantom of a One-Year-Old Child with Real-Time Dosimetry Doctoral dissertation University of Florida Gainesville Bower M W and D E Hintenlang (1998) '' The characterization of a cornmerical MOSFET dosimeter system for use in diagnostic x-ray ." Health Physics 75(2) : 197-204 Boyd, E (1927) ' Growth of thymus ; its relation to status thymicolymphaticus and thymic symptoms ." American Journal of Diseases in Children 33 : 867 Bunger B M ., J R Cook and M K Barrick (1981) 'Life table methodology for evaluating radiation risk : An application based on occupational exposures .'' Health Physics 40 : 439-455 Caffey J (1956a) '' The first sixty years of pediatric roentgenology in the United States-1896 to 1956 ." The American Journal ofRoentgenology Radium Therapy and Nuclear Medicine 76 : 437-454 Caffey, J (1956b ) Pediatric X-Ray Diagnosis Chicago Year Book Publishers Cember, H (1996) Introduction to Health Physics New York, McGraw-Hill Chen W L ., J W Poston, and G G Warner (1978) An Evaluation of the Distribution of Absorbed Dose in Child Phantoms Exposed to Diagnostic Medical X-Rays Oak Ridge TN Oak Ridge National Laboratory Codmam E A (1896) 'Letter : Practical medical use of the x-ray ." Boston Medical and Surgical Journal 135 : 50-51 Cohrssen J. J and V T Covello (1989) Risk Analysis : A Guide to Principles and Methods for Analyzing Health and Environmental Risks Washington, D C ., U S Council on Environmental Quality Constantinou C ., J Cameron, L DeWerd and M Liss (1986) 'Development of radiographic chest phantom ." Medical Physics 13(6) : 917-921 Conway B J ., P F Butler J E Dllfl: T R Fewell R E Gross R J Jennings G H Koustenis J L McCrohan F G Rueter and C K Showalter (1984) ''Beam quality independent attenuation phantom for estimating patient exposure from x-ray automatic exposure controlled chest examinations ." Medical Physics 11(6) : 827-832 Conway B J ., J E Duff, T R Fewell R J Jennings L N Rothenberg and R C Fleischman (1990) '' A patient-equivalent attenuation phantom for estimating patient exposure from automatic exposure controlled x-ray examinations of the abdomen and lumbo-sacral spine .'' Medical Physics 17 : 448-453

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225 Cox, P. (1896) 'News of the week : Practical skiagraphy ." Medical Record 49: 524 Cristy M (1980) Mathematical Phantoms Representing Children of Various Ages for Use in Estimates of Internal Dose Oak Ridge Tennessee, Oak Ridge National Laboratory Cristy, M ( 1981) '' Active bone marrow distribution as a function of age in humans .'' Phys Med Biol 26(3) : 389-400 Cristy M and K F Eckerman (1987) Specific Absorbed Fractions of Energy at Various Ages from Internal Photon Sources Oak Ridge Tennessee Oak Ridge National Laboratory Davis E P (1896 ). '' Study of infant body and the pregnant womb by the roentgen ray ." American Journal of Medical Science ID : 263 Drexler G ., W Panzer L Widenmann G Williams and M Zankl (1984) The Calculation of Dose from External Photon Exposures Using Reference Human Phantoms and Monte Carlo Methods Part ill : Organ Doses in X-Ray Diagnosis Munich Ger1nany Gesellschaft fur Strahlenund Umweltforschung Eckerman, K F ., M Cristy and J C Ryman (1996) The ORNL Mathematical Phantom Series Unpublished Ellis R E ., M J R Healy B Shleien and T Tucker (1975) A System for Estimation of Mean Active Bone Marrow Dose Rockville, Maryland, Food and Drug Administration Fabrikant, J I (1990) 'Factors that modify risks of radiation-induced cancer ." Health Physics 59(1) : 77-87 Gage W V (1896 ). 'News of the week : Need of caution in the use of Roentgen rays ." Medical Record 50 : 307 George AW (1908) 'Use of Roentgen ray in study of diseases in children .'' Boston Medical and Surgical Journal 158 : 381 Gkanatsios N A and W Ruda (1997) '' Computation of energy imparted in diagnostic radiology ." Med Phys 24(4) : 571-579 Gladstone D J and L M Chin (1991) '' Automated data collection and analysis system for MOSFET radiation detectos ." Med Phys 18(3) : 542-547 Gladstone D J and L M Chin (1995) 'Real-time in vivo measurement of radiation dose during radioimmunotherapy in mice using a miniature MOSFET dosimeter probe .'' Radiat Res 141 : 330-335

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226 Griscom, N T (1995) ''The foundation and early meetings of The Society for Pediatric Radiology ." Pediatric Radiology 25 : 657-660 Griscom, N T (1996) In A History of the Radiological Sciences Pediatric Radiology R Gagliardi and B McClennan Reston, Virginia American Roentgen Ray Society : 345-367 Griscom N T and D Jaramillo (1995) '' Trends in papers presented at meetings of the Society for Pediatric Radiology ' Pediatric Radiology 25 : 161-164 Hart, D ., D Jones and B Wall (1994) No11nalized Organ Doses for Medical X-Ray Examinations Calculated Using Monte Carlo Techniques Chilton, United Kingdom National Radiological Protection Board Hart, D ., D G Jones and B F Wall (1996) Coefficients for Estimating Effective Dose from Paediatric X-Ray Examinations Chilton, United Kingdom, National Radiological Protection Board Haschke, F ., S J Fomon and E Ziegler (1981) 'Body composition of a nine-year-old reference boy ." Pediatric Research 15 : 847-849. Henderson, S G (1942) '' Gastrointestinal tract in healthy newborn infant .' American Journal ofRoentgenology Radium Therapy and Nuclear Medicine 48 : 302 Henderson, S G and L. S Sher1nan (1946) 'Roentgen anatomy of skull of newborn infant .' Radiology 46 : 107 Herman, K P ., L Geworski T Hatzhy R Lietz and D Harder (1986) 'Muscle and fat equivalent polyethylene based phantom materials for x-ray dosimetry at tube voltages below 100 kV Phys Med Biol 31(9) : 1041-1046 Herman K P ., L Geworski M Muth and D Harder (1985) 'Water equivalent phantom material for x-ray dosimetry from 10 to 100 kV ." Phys Med Biol 30(11) : 1195-1200 Hickey, P M (1904) 'The development of the skeleton ." Transactions of the American Roentgen Ray Society : 120-127 Hickey P M (1906) 'The development of the elbow ." Transactions of the America! Roentgen Ray Society : 55-61 Hodges P C (1933) 'Estimation of cardiac size in children ." Journal of the American Medical Association 101 : 914 Hubbell J H (1982) 'Photon mass attenuation and energy-absorption coefficients from 1 keV to 20 MeV ." Int J Appl Radiat !sot 33 : 1269-1290

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227 Ruda, W and J V Atherton (I 995) 'Energy imparted in computed tomography .'' Med Phys 22(8) : 1263-1269 Ruda, W J V Atherton, D Ware and W Cumming (1997) '' An approach for the estimation of effective radiation dose at CT in pediatric patients '' Radiology 203 : 417422 Ruda W and K Bissessur (1990) 'Effective dose equivalents, H E in diagnostic radiology ." Med Phys 17(6) : 998-1003 Ruda, W and N A Gkanatsios (1997) 'Effective dose and energy imparted in diagnostic radiology Med Phys 24(8) : 1311-1316 Ruda, W B Lentle, et al (1989) The effective dose equivalent in radiology .'' J Can Assoc Radiol 40 : 3-4 Hughes, R C D Huffman, J V Snelling T. E Zipperian, A J Ricco and C A Kelsey (1988) 'Miniature radiation dosimeter for in vivo radiation measurements Int J Radiation Oncology Biol Phys 14 : 963-967 Hwang J M L ., R L Shoup and J W Poston (1976a) Modifications and Additions to the Pediatric and Adult Mathematical Phantoms Oak Ridge Tennessee Oak Ridge National Laboratory Hwang J M L ., R L Shoup G G Warner and J W Poston (1976b) Mathematical Description of a Oneand Five-Year-Old Child for Use in Dosimetry Calculations Oak Ridge, Tennessee Oak Ridge National Laboratory Hwang, J.M L ., R L Shoup and J W Poston (1976c) Mathematical Description of a Newborn Human for Use in Dosimetry Calculations Oak Ridge, Tennessee, Oak Ridge National Laboratory ICRP (1975) Report on the Task Group on Reference Man Elmsford New York, Pergamon Press International Commission on Radiological Protection ICRP (1977) Recommendations of the International Commission on Radiological Protection Elmsford, New York, Pergamon Press, International Commission on Radiological Protection ICRP (1985) Quantitative Bases for Developing a Unified Index of Harm Elmsford New York, Pergamon Press International Commission on Radiological Protection

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228 ICRP (1989) Age-Dependent Doses to Members of the Public from Intake of Radionuclides : Part I Elmsford, New York, International Commission on Radiological Protection ICRP (1991) 1990 Recommendations of the International Commission on Radiological Protection Elmsford New York, Pergamon Press International Commission on Radiological Protection ICRP (1995) Basic Anatomical and Physiological Data for Use in Radiological Protection : The Skeleton Elmsford New York ; Pergamon Press International Commission on Radiological Protection ICRU (1989) Tissue Substitutes in Radiation Dosimetry and Measurement Bethesda, Maryland International Commission on Radiation Units and Measurements ICRU (1993) Phantoms and Computational Models in Theral) Diagnosis, and Protection Bethesda, Maryland, International Commission on Radiation Units and Measurements Johnson, K A (1998) Measurement of Organ Doses of Pediatric Patients Undergoing Computed Tomography Examinations Master's thesis University of Florida, Gainesville Jones, D G and B F Wall (1985) Organ Doses from Medical X-Ray Examinations Calculated Using Monte Carlo Techniques Chilton, United Kingdom National Radiological Protection Board. Josephi, M G (1935) 'Measurements of size of hearts in nom1al children ." American Journal of Diseases in Children 50 : 929 Kirks, D R and N T Griscom (1998) Practical Pediatric Imaging : Diagnostic Radiology of Infants and Children Philadelphia P Lippincott-Raven Kodimer K A (1995) Monte Carlo calculations of specific absorbed fractions and S values for anthropomorphic pediatric phantoms. Master's thesis,, Texas A&M University, College Station. Kramer R ., M Zankl G Williams and G Drexler (1982) The Calculation of Dose from External Photon Exposures Using Reference Human Phantoms and Monte Carlo Methods Part I : The Male (ADAM) and Female (EV A) Adult Mathematical Phantoms Munich, Germany Gesellschaft fur Strahlenund Umweltforschung Lincoln M E and R Stillman (1928) '' Studies of hearts of nonnal children ; Roentgen ray studies ." American Journal of Diseases in Children 35 : 791

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229 Maresh M and AH Washburn (1940) 'Paranasal sinuses from birth to late adolescence ." American Journal ofDiseases in Children 60 : 841 Muirhead C R and S. C Darby (1987) 'Modelling the relative and absolute risks of radiation-induced cancers ." Journal of the Royal Statistical Society A150(Part 2) : 83-118 Murphy, G P W Lawrence and R E Lenhard (1995) American Cancer Society Textbook of Clinical Oncoilogy Washington, D C American Cancer Society NCRP (1980) Influence of Dose and its Distribution in Time on Dose-Response Relationships for Low-LET Radiations Bethesda, Maryland, National Council on Radiation Protection and Measurements NCRP (1987) Ionizing Radiation Exposure of the Population of the United States Bethesda Marylan~ National Council on Radiation Protection and Measurements NCRP (1989) Exposure of the U S Population from Diagnostic Medical Radiation Bestheda, Maryland National Council on Radiation Protection and Measurements Nelson, W R and R H Hirayama (1985) The EGS4 Code System Stanford Stanford Linear Accerlerator Center NRC (1983) Risk Assessment in the Federal Government : Managing the Process Washington, D C ., National Research Council, National Academy Press Poston, J W (1993) '' Application of the effective dose equivalent to nuclear medicine patients J Nucl Med 34( 4) : 714-716 Ramani R ., O'Brien (1997) '' Clinical dosimetry using MOSFETs ." Int J Radiation Oncology Biol Phys 37 : 959-964 Rosenstein, M (1976a) Handbook of Selected Organ Doses for Projections Common in Diagnostic Radiology Rockville Maryland Food and Drug Administration. Rosenstein, M (1976b) Organ Doses in Diagnostic Radiology Rockville Maryland Food and Drug Administration Rosenstein, M ( 1988) Handbook of Selected Tissue Doses for Projections Common in Diagnostic Radiology Rockville Maryland, Food and Drug Administration Rosenstein, M T J Beck and G G Warner (1979) Handbook of Selected Organ Doses for Projections Common in Pediatric Radiology Rockville Maryland Food and Drug Administration

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230 Rosenstein, M ., 0 H Suleiman, R L Burkhart S H Stem and G Williams (1992) Handbook of Selected Tissue Doses for the Upper Gastrointestinal Fluoroscopic Examination Rockville Maryland Food and Drug Administration Seibert J A ., G T Barnes and R G Gould (1994) Specification, Acceptance Testing and Quality Control ofDiagnostic X-Ray Imaging Equipment Woodbury Connecticut American Institute of Physics Sharko G A and D M Wilmot (1987) Pediatric Imaging for the Technologist New York, Springer-Verlag Shimizu Y ., H Kato W J Schull D L Preston, S Fujia and D A Pierce (1987) Life Span Study Report 11 : Part 1 Comparison of Risk Coefficients for Site-Specific Cancer Mortality Based on the DS86 and T65D Shield Kerma and Organ Dose Hiroshima Japan, Radiation Effects Research Foundation Shleien, B (1973) A Review ofDeterminations of Radiation Dose to the Active Bone Marrow from Diagnostic X-Ray Examinations Rockville, Maryland Food and Drug Administration Shrimpton, P C ., D G Jones M C Hillier, B F Wall J C Le heron and K Faulkner (1991) Survey of CT Practice in the UK Part 2 : Dosimetric Aspects Didcot United Kingdom, National Radiological Protection Board Smith R M (1951 ) 'Medicine as science : Pediatrics .'' The New England Journal of Medicine 244 : 176-181 Snyder W S ., M R Ford and G G Warner (1 9 78) Estimates of Specific Absorbed Fractions for Photon Sources Uniformly Distributed in Various Organs of a Heterogeneous Phantom New York, New York, Society of Nuclear Medicine Snyder W S ., M R Ford G G Warner and H L Fisher (1969 ). Estimates of Absorbed Fractions for Monoenergetic Photon Sources Uniformly Distributed in Various Organs of a Heterogeneous Phantom New York, New York Society of Nuclear Medicine Sosman, M C (1 9 51 ). 'Fifty years of medical progress : Medicine as a science : Roentgenology ." New England Journal of Medicine 244 : 552 Soubra M ., J Cygler and G Mackay (1994) 'Evaluation of a dual bias metal oxide silicon semiconductor field effect transistor detector as a radiation dosimeter .'' Medical Physics 21(4) : 567-572 Spiegel P K (1995) '' The first clinical x-ray made in America ." American Journal of Radiology 164 : 241-243

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231 Stabin M G (1996) 'MIRDOSE : Personal computer software for internal dose assessment in nuclear medicine ." J Nucl Med 37 : 538-546 Stern S H ., M Rosenstein, L Renaud and M Zankl (1995) Handbook of Selected Tissue Doses for Fluoroscopic and Cineangiographic Examination of the Coronary Arteries Rockville Maryland Food and Drug Administration Swischuk, L E (19 9 7 ). Imaging of the Newborn, Infant, and Young Child Baltimore Williams & Wilkins Thomas D ., S Darby F Fagnani P Hubert M Vaeth and K. Weiss (1992) 'Definition and estimation of lifetime det1iment from radiation exposures : Principles and methods ." Health Physics 63 : 250-272 UNSCEAR (1977) Radiation Carcinogenesis in Man New York, New York United Nations Scientific Committee for the Effects of Atomic Radiation UNSCEAR (1986) Genetic and Somatic Effects of Ionizing Radiation New York New York, United Nations Scientific Committee for the Effects of Atomic Radiation Vaeth M and D A Pierce (1990) '' Calculating excess lifetime risk in relative risk models .' Environmental Health Perspectives 87 : 83-94 Vettese, F ., C Donichak, P Bourgeault and G Sarrabayrouse (1996) '' Assessment of a new p-MOSFET usable as a dose rate insensitive gamma dose sensor .'' IEEE Transactions on Nuclear Science 43(3) : 991-996 White D R (1977 ). '' The formulation of tissue substititue materials using basic interaction data ." Phys Med Biol. 22 : 889-999 White D R. C Constantinou and R J. Martin (1986) 'Foamed epoxy resin-based substitutes ." Br J Radio! 59 : 787790 White D R ., R J Martin and R Darlison (1977) 'Epoxy resin-based tissue substitutes ." Br J Radio! 50 : 814-821 Zankl M ., N Petoussi R Veit G Drexler and H Fendel (1989) In BIR Report No 2 0 Organ Doses for a Child in Diagnostic Radiology; Comparison of a Realistic and a MIRD Type Phantom B M Moores B F Wall, H Eriskdat and H Schibilla London, United Kingdom British Institute of Radiology: 196 198

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BIOGRAPIDCAL SKETCH Kathleen Marie (Buckley) Hintenlang was born in Saranac Lake New York, in 1964 to Thomas and Barbara Buckley She attended Saranac Lake Central High School from 1978 to 1982, graduating in 1982 with a Regent's diploma concentrated on mathematics and science She entered Rochester Institute of Technology Rochester New York in September of 1982 Following three clinical internships she graduated from the nuclear medicine program in the College of Science with a Bachelor of Science degree in May 1987 She entered the medical physics program in the College of Engineering s Nuclear Engineering Sciences Department at the University of Florida in January of 1988 With a research assistantship provided by the Department of Radiology and under the supervision of Dr Clyde Williams and Dr Libby Brateman she graduated with a Master of Science degree in May 1990 She accepted the position of Assistant Radiation Control Officer for the University in October 1989 In 1992 she married Dr David E Hintenlang Associate Professor in the Nuclear and Radiological Engineering Department They have one daughter Lauren Lea born in March of 1994 and one son Hunter Austin born in August of 1997 In November of 1994 she was admitted to candidacy in the Environmental Engineering Sciences Department with grants provided by the Children s Miracle Network Foundation and under the supervision of Dr Emmett Bolch and Dr Jon Williams to perfonn the research leading to a Doctor of Philosophy degree She was granted dual certification by the American Board of Radiology in the specialties of diagnostic radiological physics and medical nuclear physics in June of 1997 232

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I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy ~" W Emmett Bolch r Chairman Professor of Environmental Engineering Sciences I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy Jonathan :t : Williams I Prdfessor of Radiology I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosop y Lawrence T Fitzgeral Associate Professor o clear and Radiological Engineering I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate in scope and quality, as a dissertation for the degree of Doctor of Philosophy. Randolph L arter Professor of Statistics l certify that I have read this study ar1d that in rny opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosoph Thomas L Crisman Professor of Enviro ental Engineering Sciences \

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This dissertation was submitted to the Graduate Faculty of the College of Engineering and to the Graduate School and was accepted as partial fulfillment of the requirements for the degree of Doctor of Philosophy December ~ 1998 L ~-----Winfred M Phillips Dean College of Engineering Mihran J Ohanian Dean Graduate School

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