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Quantifying Computed Radiography (CR) and Digital Radiography (DR) Image Quality and Patient Dose for Pediatric Radiology

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Title:
Quantifying Computed Radiography (CR) and Digital Radiography (DR) Image Quality and Patient Dose for Pediatric Radiology
Creator:
JOHNSON, KENNITA A. ( Author, Primary )
Copyright Date:
2008

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Bone marrow ( jstor )
Dosage ( jstor )
Lungs ( jstor )
Neonates ( jstor )
Ovaries ( jstor )
Pelvis ( jstor )
Skin ( jstor )
Spine ( jstor )
Sudden infant death syndrome ( jstor )
Western canon ( jstor )

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University of Florida
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University of Florida
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Copyright Kennita A. Johnson. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
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8/1/2013
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53208575 ( OCLC )

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QUANTIFYING COM PU TED RADIOGRAPHY (CR) AND DIGITAL RADIOGRAPHY (DR) IMAGE QUALITY AND PATIENT DOSE FOR PEDIATRIC RADIOLOGY By KENNITA A. JOHNSON 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 2003

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Copyright 2003 by Kennita A. Johnson

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To my parents, Kenneth and Barbara Johnson and my brother, Kenneth Javae Johnson.

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iv ACKNOWLEDGMENTS I would like to express sincere gratitude to the members of her committee, Dr. David E. Hintenlang, Dr. Manuel M. Arreola, Dr. Wesley E. Bolch, Dr. Jonathan L. Williams, Dr. Johannes H. van Oostrom, Dr. William Properzio and Dr. Libby Brateman for their wisdom and patience. I would like to extend an extra appreciation to Dr. Hintenlang for his patience over the last seven years. I would like to give special recognition to my committee co-chair Dr. Arreola for his technical expertise and for lending an ear. I would like to thank Dr. Lynn Rill for all of her insight and advice. I would like to thank the technologist in the Department of Radiology at Shands Hospital at the University of Florida, especially Fred and Sheri for their expertise. I would like to thank ChildrenÂ’s Miracle Network, NIH, Department of Radiology, Department of Biomedical Engineering, Department of Nuclear and Radiological Engineering for their continued funding of the project. I wish to thank my family and friends for their inspiration and encouragement, especially Bennie for keeping the insanity under control. Finally, I would like to extend a special appreciation to my parents, Kenneth and Barbara Johnson and her brother, Kenneth Javae Johnson for their unconditional support and allowing me to follow my dreams.

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v TABLE OF CONTENTS page ACKNOWLEDGMENTS.................................................................................................iv LIST OF TABLES...........................................................................................................viii LIST OF FIGURES...........................................................................................................xi ABSTRACT.....................................................................................................................xi x CHAPTER 1 INTRODUCTION........................................................................................................1 Digital Imaging Basics.................................................................................................2 Image Processing...................................................................................................3 Picture Archiving and Communications Systems (PACS)...................................4 Computed Radiography................................................................................................5 Digital Radiography....................................................................................................10 Computed Tomography..............................................................................................13 Image Quality.............................................................................................................15 Contrast................................................................................................................15 Spatial Resolution................................................................................................18 Noise....................................................................................................................20 Image Quality Measurements.....................................................................................21 Modulation Transfer Function....................................................................................22 Noise Power Spectrum........................................................................................27 Detective Quantum Efficiency............................................................................28 Patient Dose................................................................................................................30 Image Quality, Dose and Radiographic Technique....................................................31 Summary.....................................................................................................................34 2 HYPOTHESIS............................................................................................................36 3 LITERATURE REVIEW...........................................................................................38 4 MEAUREMENT OF IMAGE QUALITY.................................................................45 Introduction.................................................................................................................45 Materials and Methods...............................................................................................45

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vi Software...............................................................................................................45 Equipment............................................................................................................46 Modulation Transfer Function.............................................................................47 Line pair phantom method...........................................................................47 Line spread function method........................................................................49 Noise Power Spectrum........................................................................................50 Integral DQE.......................................................................................................51 Incident Signal-to-Noise, q..................................................................................52 Pixel Value to Exposure Conversion, k...............................................................53 Results and Discussion...............................................................................................54 Modulation Transfer Function.............................................................................54 Noise Power Spectrum........................................................................................58 Integral DQE.......................................................................................................61 Summary.....................................................................................................................63 5 DEVELOPMENT OF RADI OGRAPHIC TECHNIQUES.......................................64 Introduction.................................................................................................................64 Materials and Methods...............................................................................................64 Pediatric Anthropomorphic Phantoms................................................................64 MOSFET Dosimeters..........................................................................................67 Dose Measurements.............................................................................................68 Image Quality Measurements..............................................................................69 Radiographic Technique Determination..............................................................70 Results and Discussion...............................................................................................72 Relationship between IDQE and Air Kerma at the Image Receptor...................72 Relationship between IDQE and Entrance Skin Exposure..................................74 Pediatric Radiographic Techniques............................................................................77 Effective Doses...........................................................................................................80 Summary.....................................................................................................................81 6 CONCLUSION...........................................................................................................83 APPENDIX A EXAMPLE OF MTF CALCULATION USING LINE PAIR PHANTOM..............87 B MATLAB CODES.....................................................................................................89 Modulation Transfer Function....................................................................................89 Noise Power Spectrum...............................................................................................90 C NOISE POWER SPECTRUM GRAPHS...................................................................93 D INTEGRAL DETECTIVE QUANT UM EFFICIENCY GRAPHS.........................105 E COEFFICIENTS FOR IDQE EQUATIONS...........................................................171

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vii F EFFECTIVE DOSE CALCULATIONS..................................................................173 G PROBLEMS WITH CT PHANTOMS.....................................................................239 LIST OF REFERENCES.................................................................................................242 BIOGRAPHICAL SKETCH...........................................................................................246

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viii LIST OF TABLES Table page 1-1 Relationship between exposur e class, mAs and exposure.........................................9 1-2 Bits and gray level relationship................................................................................18 1-3 Resolution requirements (H oheisel and Batz, 2000)................................................19 4-1 Measurement configurations for Agfa CR system and Canon DR system..............51 4-2 Incident signal-to-noise ratio, q for Room 1 (Agfa CR system) and Room 5 (Canon DR system) (photons/mm2*mGy)..............................................................52 5-1 Information on newborn and one-year-old UF phantoms........................................66 5-2 Tube outputs (mGy/mAs) for Room 1 (Agfa CR system) and Room 5 (Canon DR system)..................................................................................................71 5-3 The IDQE for the same entrance skin exposure (0.01 mGy) for newborn patients.....................................................................................................................75 5-4 The entrance skin exposure (mGy) for newborn patients for the same IDQE value of 4..................................................................................................................75 5-5 Newborn radiographic technique chart....................................................................79 5-6 One-Year-Old radiographic technique chart............................................................80 5-7 Effective doses (mSv) for newborn pa tients using techniques in Table 5-3............81 A-1 Standard deviation and mean of light and dark regions of the Hüttner Phantom....87 A-2 Calculation of the MTF............................................................................................88 E1 Coefficients for the Agfa CR system at a 40 inch SID wit hout use of the grid.....171 E-2 Coefficients for the Agfa CR system at a 40 inch SID with use of the grid..........171 E-3 Coefficients for the Canon DR system at a 40 inch SID with the use of the grid..171

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ix E-4 Coefficients for the Agfa CR system at a 72 inch SID without the use of the grid.........................................................................................................................17 1 E-5 Coefficients for the Agfa CR system at a 72 inch SID with the use of the grid....172 E-6 Coefficients for the Canon DR system at a 72 inch SID with the use of the grid..172 F-1 Newborn effective doses for Agfa CR system at 50 kVp......................................175 F-2 Newborn effective doses for Agfa CR system at 55 kVp......................................177 F-3 Newborn effective doses for Agfa CR system at 60 kVp......................................179 F-4 Newborn effective doses for Agfa CR system at 65 kVp......................................181 F-6 Newborn effective doses for Agfa CR system at 75 kVp......................................185 F-7 Newborn effective doses for Agfa CR system at 80 kVp......................................187 F-8 Newborn effective doses for Agfa CR system at 85 kVp......................................189 F-9 Newborn effective doses for Canon DR system at 50 kVp....................................191 F-10 Newborn effective doses for Canon DR system at 55 kVp....................................193 F-11 Newborn effective doses for Canon DR system at 60 kVp....................................195 F-12 Newborn effective doses for Canon DR system at 65 kVp....................................197 F-13 Newborn effective doses for Canon DR system at 70 kVp...................................199 F-14 Newborn effective doses for Canon DR system at 75 kVp....................................201 F-15 Newborn effective doses for Canon DR system at 80 kVp....................................203 F-16 Newborn effective doses for Canon DR system at 85 kVp....................................205 F-17 One-Year-Old effective doses for Agfa CR system at 50 kVp..............................207 F-18 One-Year-Old effective doses for Agfa CR system at 55 kVp..............................209 F-19 One-Year-Old effective doses for Agfa CR system at 60 kVp..............................211 F-20 One-Year-Old effective doses for Agfa CR system at 65 kVp..............................213 F-21 One-Year-Old effective doses for Agfa CR system at 70 kVp..............................215 F-22 One-Year-Old effective doses for Agfa CR system at 75 kVp..............................217 F-23 One-Year-Old effective doses for Agfa CR system at 80 kVp..............................219

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x F-24 One-Year-Old effective doses for Agfa CR system at 85 kVp..............................221 F-25 One-Year-Old effective doses for Canon DR system at 50 kVp...........................223 F-26 One-Year-Old effective doses for Canon DR system at 55 kVp..........................225 F-27 One-Year-Old effective doses for Canon DR system at 60 kVp...........................227 F-28 One-Year-Old effective doses for Canon DR system at 65 kVp...........................229 F-29 One-Year-Old effective doses for Canon DR system at 70 kVp...........................231 F-30 One-Year-Old effective doses for Canon DR system at 75 kVp...........................233 F-31 One-Year-Old effective doses for Canon DR system at 80 kVp...........................235 F-32 One-Year-Old effective doses for Canon DR system at 85 kVp...........................237

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xi LIST OF FIGURES Figure page 1-1 Histogram showing the number of each pixel values in an image.............................3 1-2 Mapping image brightness ........................................................................................4 1-3 Phosphorescence process in CR plates.......................................................................6 1-4 The Agfa CR system cassette ....................................................................................7 1-5 The Agfa CR scanning procedure .............................................................................8 1-6 The Canon DR system .............................................................................................10 1-7 DR scintillation process...........................................................................................11 1-8 DR pixel configuration.............................................................................................13 1-9 Single and multi-slice helical CT Scanners..............................................................14 1-10 Imaged and reconstructed planes in multi-slice CT.................................................15 1-11 Image c ontrast..........................................................................................................16 1-12 Linear response of input exposure to pixel value.....................................................17 1-13 Resolution of objects loca ted in close proximity.....................................................19 1-14 Example of a line pair phantom...............................................................................19 1-15 Transfer characteristics............................................................................................23 1-16 Point and line spread functions................................................................................24 1-17 MTF response from LSF input.................................................................................26 1-19 Two-Dimensional NPS of a flat field image............................................................27 1-20 Quantum efficiency of materials typically used in digital images...........................30 4-1 Hüttner phantom ......................................................................................................48

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xii 4-2 Image of E1 Leeds Phantom...................................................................................50 4-3 Pixel value vs. log of air kerma for Canon DR system............................................53 4-4 Pixel value vs. log of air kerma*speed/200 for Agfa CR system............................53 4-5 Image of the slit cam era through a microscope........................................................55 4-6 3D image of slit camera...........................................................................................56 4-7 Modulation transfer function of Agfa CR system using line pair function..............56 4-8 3D image of line on Leeds E1 phantom...................................................................57 4-9 Modulation transfer function for Agfa CR system and Canon DR system using line spread function..................................................................................................57 4-10 The noise power spectrum for Agfa CR system at 40 inch SID, without the grid........................................................................................................................... 59 4-11 The total system noise for Agfa CR syst em at 40 inch SID, without the grid........59 4-12 The NPS of all the systems and co nfigurations at 70 kVp and 0.6 mAs.................60 4-13 The total system noise for all syst ems and configurations at 70 kVp......................60 4-14 IDQE for various techniques for Agfa CR system at 40 inch SID without the grid........................................................................................................................... 62 4-15 IDQE for both systems at all configurations at 70 kVp...........................................62 5-1 Mathematical phantom models................................................................................65 5-2 UF Anthropomorphic Phantom................................................................................66 5-3 MOSFET dosimetry system.....................................................................................67 5-4 Anthropomorphic phantom placed on the table or at the chestboard.......................68 5-5 IDQE vs. air kerma at the image receptor for Agfa CR system at 40 inch SID with the grid.............................................................................................................73 5-6 IDQE vs. air kerma at the image rece ptor for all configurations at 70 kVp............73 5-7 IDQE vs. log of air kerma at the image receptor for Agfa CR system at 40 inch SID with the grid......................................................................................................76 5-8 IDQE vs. mAs used in newborn imaging at 70 kVp................................................76

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xiii 5-9 Reduced AEC values vs. ESE for newborn For the Agfa CR system at a 40 inch SID using the grid.............................................................................................78 5-10 Image of newborn patient using Agfa CR system at 70 kVp at 40 inch SID with grid...................................................................................................................79 A-1 Anatomy of Hüttner line pair phantom....................................................................87 C-1 The NPS vs. frequency for the Agfa CR system at a 40 inch SID without using the grid......................................................................................................................9 3 C-2 The NPS vs. frequency for the Agfa CR system at a 40 inch SID using the grid...94 C-3 The NPS vs. frequency for the Canon system at a 40 inch SID using the grid........95 C-4 The NPS vs. frequency for the Agfa CR system at a 72 inch SID without using the grid......................................................................................................................9 6 C-5 The NPS vs. frequency for the Agfa CR system at a 72 inch SID using the grid........................................................................................................................... 97 C-6 The NPS vs. frequency for the Canon DR system at a 72 inch SID using the grid........................................................................................................................... 98 C-7 For the Agfa CR system at a 40 inch SID without using the grid, the area under the NPS curve (iNPS) vs. radiogr aphic technique (kVp and mAs).........................99 C-8 For the Agfa CR system at a 40 inch SID using the grid, the area under the NPS curve (iNPS) vs. radiograp hic technique (kVp and mAs).............................100 C-9 For the Canon DR system at a 40 inch SID using the grid , the area under the NPS curve (iNPS) vs. radiograp hic technique (kVp and mAs).............................101 C-10 For the Agfa CR system at a 72 inch SID without using the grid, the area under the NPS curve (iNPS) vs. radiographic technique (kVp and mAs).............102 C-11 For the Agfa CR system at a 72 inch SID using the grid, the area under the NPS curve (iNPS) vs. radiograp hic technique (kVp and mAs).............................103 C-12 For the Canon DR system at a 72 inch SID using the grid, the area under the NPS curve (iNPS) vs. radiograp hic technique (kVp and mAs).............................104 D-1 For the Agfa CR system at a 40 inch SID without using the grid, IDQE vs. radiographic technique (kVp and mAs).................................................................105 D-2 For the Agfa CR system at a 40 inch SID using the grid, IDQE vs. radiographic technique (kVp and mAs).................................................................106

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xiv D-3 For the Canon DR system at a 40 inch SID using the grid, IDQE vs. radiographic technique (kVp and mAs).................................................................107 D-4 For the Agfa CR system at a 72 inch SID without using the grid, IDQE vs. radiographic technique (kVp and mAs).................................................................108 D-5 For the Agfa CR system at a 72 inch SID using the grid, IDQE vs. radiographic technique (kVp and mAs)......................................................................................109 D-6 For the Canon DR system at a 72 inch SID using the grid, IDQE vs. radiographic technique (kVp and mAs).................................................................110 D-7 For the Agfa CR system at a 40 inch SID without using the grid, IDQE vs.air kerma [mGy] at th e image receptor........................................................................111 D-8 For the Agfa CR system at a 40 inch SID using the grid, IDQE vs. air kerma [mGy] at the Image Receptor.................................................................................112 D-9 For the Canon DR system at a 40 inch SID using the gridm, IDQE vs. air kerma [mGy] at th e image receptor.......................................................................113 D-10 For the Agfa CR system at a 72 inch SID without using the grid ,IDQE vs. air kerma [mGy] at image receptor.............................................................................114 D-11 For the Agfa CR system at a 72 inch SID using the grid, IDQE vs. air kerma [mGy] at the image receptor...................................................................................115 D-12 For the Canon DR system at a 72 inch SID using the grid, IDQE vs. air kerma [mGy] at the image receptor...................................................................................116 D-13 For the Agfa CR system at 40 inch SI D without using the grid, IDQE vs. log air kerma at the im age receptor [mGy]..................................................................117 D-14 For the Agfa CR system at a 40 inch SID using the grid, IDQE vs. log air kerma [mGy] at th e image receptor........................................................................118 D-15 For the Canon DR system at a 40 inch SID using the grid, IDQE vs. log air kerma [mGy] at th e image receptor........................................................................119 D-16 For the Agfa CR system at 72 inch SI D without using the grid, IDQE vs. log air kerma [mGy] at the image receptor..................................................................120 D-17 For the Agfa CR system at a 72 inch SID using the grid, IDQE vs. log air kerma [mGy] at th e image receptor........................................................................121 D-18 For the Canon DR system at a 72 inch SID using the grid, IDQE vs. log air kerma [mGy] at th e image receptor........................................................................122

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xv D-19 For the Agfa CR system at a 40 inch SID without using the grid, IDQE vs. entrance skin exposure for newborn patients.........................................................123 D-20 Reduced AEC values For Newborn Patients For the Agfa CR system at a 40 inch SID without using the grid.............................................................................124 D-21 IDQE vs. entrance skin exposure for newborn patients for the Agfa CR system at a 40 inch SID using the grid...................................................................125 D-22 Reduced AEC values for newborn patients for the Agfa CR system at a 40 inch SID using the grid...........................................................................................126 D-23 IDQE vs. entrance skin exposure for newborn patients for the Canon CR system at a 40 inch SID using the grid...................................................................127 D-24 Reduced AEC values for newborn patients for the Canon CR system at a 40 inch SID using the grid...........................................................................................128 D-25 IDQE vs. entrance skin exposure for newborn patients for the Agfa CR system at a 72 inch SID without using the grid......................................................129 D-26 Reduced AEC values for newborn patients for the Agfa CR system at a 72 inch SID without using the grid.............................................................................130 D-27 IDQE vs. entrance skin exposure for newborn patients For the Agfa CR system at a 72 inch SID using the grid...................................................................131 D-28 Reduced AEC values for newborn patients for the Agfa CR system at a 72 inch SID using the grid...........................................................................................132 D-29 IDQE vs. entrance skin exposure for newborn patients for the Canon DR system at a 72 inch SID using the grid...................................................................133 D-30 Reduced AEC values for newborn patients for the Canon DR system at a 72 inch SID using the grid...........................................................................................134 D-31 IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 40 inch SID without using the grid......................................................135 D-32 Reduced AEC vs. entrance skin exposure values for one year old patients for the Agfa CR system at a 40 inch SID without using the grid...........................136 D-33 IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 40 inch SID using the grid...................................................................137 D-34 Reduced AEC values vs. entrance skin exposure for one year old patients for the Agfa CR system at a 40 inch SID using the grid........................................138

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xvi D-35 IDQE vs. entrance skin exposure for one year old patients for the Canon CR system at a 40 inch SID using the grid............................................................139 D-36 Reduced AEC values vs. entrance skin exposure for one year old patients for the Canon CR system at a 40 inch SID using the grid.....................................140 D-37 IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID without using the grid......................................................141 D-38 Reduced AEC values vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID without using the grid...........................142 D-39 IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID using the grid...................................................................143 D-40 Reduced AEC values vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID using the grid........................................144 D-41 IDQE vs. entrance skin exposure for one year old patients for the Canon DR system at a 72 inch SID using the grid............................................................145 D-42 Reduced AEC values vs. entrance skin exposure for one year old patients for the Canon DR system at a 72 inch SID using the grid.....................................146 D-43 IDQE vs. effective dose for newborn patients for the Agfa CR system at a 40 inch SID without using the grid........................................................................147 D-44 Reduced AEC values vs. effective dose for newborn patients for the Agfa CR system at a 40 inch SID without using the grid...............................................148 D-45 IDQE vs. effective dose for newborn patients for the Agfa CR system at a 40 inch SID using the grid......................................................................................149 D-46 Reduced AEC values vs. effective dose for newborn patients for the Agfa CR system at a 40 inch SID using the grid............................................................150 D-47 IDQE vs. effective dose for newborn patients for the Canon CR system at a 40 inch SID using the grid......................................................................................151 D-48 Reduced AEC values vs. effective dose for newborn patients for the Canon CR system at a 40 inch SID using the grid............................................................152 D-49 IDQE vs. effective dose for newborn patients for the Agfa CR system at a 72 inch SID without using the grid.............................................................................153 D-50 Reduced AEC values vs. effective dose for newborn patients for the Agfa CR system at a 72 inch SID without using the grid...............................................154

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xvii D-51 IDQE vs. effective dose for newborn patients for the Agfa CR system at a 72 inch SID using the grid......................................................................................155 D-52 Reduced AEC values vs. effective dose for newborn patients for the Agfa CR system at a 72 inch SID using the grid............................................................156 D-53 IDQE vs. effective dose for newborn patients for the Canon DR system at a 72 inch SID using the grid......................................................................................157 D-54 Reduced AEC values vs. effective dose for newborn patients for the Canon DR system at a 72 inch SID using the grid............................................................158 D-55 IDQE vs. effective dose for one year old patients for the Agfa CR system at a 40 inch SID without using the grid......................................................................159 D-56 Reduced AEC values vs. effective dose for one year old patients for the Agfa CR system at a 40 inch SID without using the grid......................................160 D-57 IDQE vs. effective dose for one year old patients for the Agfa CR system at a 40 inch SID using the grid...............................................................................161 D-58 Reduced AEC values vs. effective dose for one year old patients for the Agfa CR system at a 40 inch SID using the grid...................................................162 D-59 IDQE vs. entrance skin exposure for one year old patients for the Canon CR system at a 40 inch SID using the grid...................................................................163 D-60 Reduced AEC values vs. effective dose for one year old patients for the Canon CR system at a 40 inch SID using the grid.................................................164 D-61 IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID without using the grid......................................................165 D-62 Reduced AEC values vs. effective dose for one year old patients for the Agfa CR system at a 72 inch SID without using the grid......................................166 D-63 IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID using the grid...................................................................167 D-64 Reduced AEC values vs. effective dose for one year old patients for the Agfa CR system at a 72 inch SID using the grid...................................................168 D-65 IDQE vs. entrance skin exposure for one year old patients for the Canon DR system at a 72 inch SID using the grid............................................................169 D-66 Reduced AEC values vs. effective dose for one year old patients for the Canon DR system at a 72 inch SID using the grid.................................................170 G-1 Proper orientation of a CT phantom.......................................................................239

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xviii G-2 The CTP446 high resolution module.....................................................................240 G-3 Orientation of a CT phantom fo r planar reconstructed images..............................240 G-4 Planar reconstructed images...................................................................................241

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xix 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 QUANTIFYING COMPUTED RADIOGRAPHY (CR) AND DIGITAL RADIOGRAPHY (DR) IMAGE QUALITY AND PATIENT DOSE FOR PEDIATRIC RADIOLOGY By Kennita A. Johnson August 2003 Chair: David E. Hintenlang Cochair: Manuel Arreola Major Department: Biomedical Engineering With the advent of digital imaging modalities, there is a potential for dose reduction especially for pediatric patients due to the wide dynamic range and the image processing capabilities of digital systems. A Canon digital radiography (DR) system and an Agfa computed radiography (CR) system are currently in use at Shands Hospital at the University of Florida. Using objective measures of image quality (modulation transfer function (MTF), noise power spectrum (NPS), a nd integral detective quantum efficiency (IDQE)), these systems can be evaluated and compared for pediatric chest imaging. Using MIRD tissue-equivalent pediatric pha ntoms constructed at the University of Florida, organ absorbed and effective doses of chest examinations can be measured. With these measurements, a relationship between image quality and dose is used to predict appropriate techniques used for pediatric chest imaging.

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xx The radiographic techniques developed in this research for the Agfa CR system were identical to the radiographic techniques th at a technologist would select for a patient the same size and weight of the pediatric phantoms. The method for predicting appropriate radiographic techniques is useful for setting up new systems such as the Canon DR system at Shands at the University of Florida which is not used on patients under 4 years of age. This research determined that the Canon DR system had superior image quality, as measured by the IDQE, at lower doses than the Agfa CR system at standard resolution.

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1 CHAPTER 1 INTRODUCTION Children are more radiosensitive due to their rapidly dividing cells. Because of their age, any radiation damage to cells would have a longer period of time to proliferate over their lifetime (NCRP 1987). As a human grows from an infant to an adult, the tissue composition, individual organ sizes and whole body size are continuously changing, which are additional factors in the increased radiosensitivity of children (Johnson, 1998). Frequently, effective doses for pediatric patients undergoing radiological examinations are scaled from standard adult male phantom data. Simply scaling effective doses will not accurately take into account the differences in tissue composition and patient size. With the advances in technology and increased sensitivity in detectors, the potential for better image quality at lower doses needs to be investigated. Digital imaging has some similarities with conventional film-screen radiography. They use the same x-ray tube and generator system for exposing the patient, which means the technologist selects the same parameters such as peak tube potential, tube current and exposure time (Fauber, 2000). But digital imaging overcomes some of the limitations of screen-film radiography, which will be discussed in the next section. To take advantage of these digital systems, the appropriate radiographic techniques are necessary. The appropriate radiographic techniques will take into account both image quality and patient dose. Image quality measurements can be either subjective or objective. Subjective image quality measurements can vary from observer to observer and could also involve

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2 added exposure to patients. Objective measures are more reliable for an initial assessment of image quality and comparing different systems. These measurements can be used to determine the characteristics of the imaging systems, which would help in optimizing dose before observer studies involving human subjects are conducted. Modulation Transfer Function (MTF), Noise Power Spectrum (NPS), and Detective Quantum Efficiency (DQE) along with doses measured using pediatric-sized phantoms, can optimize radiographic techniques for computed radiography (CR) and digital radiography (DR). Digital Imaging Basics There are certain properties that all digital imaging systems have in common regardless of the image receptor. Digital images are defined as an image constructed from numerical data in a two-dimensional array and are discrete in two respects. The image is discrete with respect to its spatial organization. A digital image is made up of a matrix of numbers, with the pixel being the smallest component. Many investigators believe that a matrix size of 2048 x 2048 pixels is required for chest radiography. Once the x-rays strike the detector, the analog signal from the detector is transformed into a digital signal by an analog-to-digital converter (ADC). The digital signal is sent to a computer or digital image processor which can analyze, transform or display the image. The digital image is then stored in an archive (Hasegawa, 1991). The most practical advantage of digital imaging is the wide dynamic range of digital systems. Over a wide range of exposures, a diagnostically useful image can be produced. This reduces the occurrence of and retakes for overand underexposed images. One reason for the wide dynamic range is the sensitivity of the detectors which can detect at lower exposures than conventional film. Since the detectors are sensitive to lower

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3 exposures, there is a possibility of dose reduction. The second reason for wide dynamic range is processing of the image after it is formed. Figure 1-1. Histogram showing the number of each pixel values in an image. Image Processing When a patient image is taken, there are several pieces of information needed to complete the image. First the patient information is entered, to associate the image with the correct person. Next, a reference for the body pa rt being imaged is entered. It helps to identify what is on the image and it allows the image processing system to predict what the histogram might look like and selection of the appropriate processing algorithm. The histogram is a graphic display of the distributi on of pixel values as shown in Figure 1-1. The pixel values are represented by the horizontal axis and the total number of pixels at each value is reflected on the vertical axis. Processing algorithms or mathematical formulas are used to manipulate the histogram for a specific type of examination such as chest, abdomen, or extremities (Fauber, 2000). This helps to properly display the image on the computer monitor and helps to enhance the anatomical details important in Black White Intensity or Count 0 Pixel Value 4096

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4 diagnosing the patient. One such algorithm is the translation from digital image value to image brightness, which is performed through a look-up table (LUT). The LUT relates a digital image value to a specific brightness level. The operator controls the contents of the LUT by adjusting the window of the image display (Hasegawa, 1991). Figure 1-2a shows how subjects imaged are mapped to image brightness. By narrowing the window (Figure 1-2b), or the part of the image displayed, the image contrast can be increased. There are additional processing algorithms that allow image subtraction, edge enhancement, contrast enhancement or noise suppression (Fauber, 2000). Figure 1-2. Mapping image brightness A) The LUT maps the subjects to image brightness. B) A narrow window increases contrast. Picture Archiving and Communications Systems (PACS) Picture archiving and communication system (PACS) is a system for circulating and storing digital images. Images are stored in a DICOM standard. DICOM stands for Digital Imaging and Communication in Medicine and is an initiative sponsored by the Water Muscle Air Fat Bone Water Muscle Air Fat Bone White Blac k White Blac k Image Brightness Image Brightness Subject Subject

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5 Radiological Society of North America a nd the Health and Management Systems Society. The aim of the initiative is to integrate information and management systems so that clinical information can be communicated among all specialties and providers. It allows for patient and examination information to be stored along with the image. Major manufacturers have agreed to this standard so that different systems can communicate with each other. Networking allows for the rapid transfer of information between computers. The network consists of a digital imaging system, the workstations or viewing monitors, and the archive or storage system. Once the images are produced with the digital imaging system, the images are sent over the network to the workstations or the archive. Images are displayed on workstations where the doctors can view and manipulate the images. Images can be viewed at two sites simultaneous ly if doctors need to consult with each other. Once stored, they can be sent to different parts of the hospital or archived for future use (Gunn, 2002) which is one advantage of the PACS. It takes a few seconds to a few minutes to bring images from the archive. Although the initial startup cost of a digital imaging system and PACS is expensive, the long term cost of film and processing chemicals is saved. Computed Radiography Computed radiography (CR) was introduced by FUJIFILM Medical systems USA, Inc. in 1981. CR uses cassettes with a reusable image receptor, made of photostimulatable phosphor screen. The screen is composed of a crystalline solid. In a solid, there are discrete energy levels or bands that electrons in the atoms can occupy. The valance band contains valence electrons, which lie in the outermost shell of the atom. In the forbidden band, there are no permitted energy levels in pure materials. Electrons

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6 can only pass through this band moving from the valence to the conduction band. In the conduction band, the electrons have sufficient energy to move freely through the crystalline lattice and in particular, to conduct electricity. Figure 1-3. Phosphorescence process in CR plates Imperfections, impurities and dopants provide additional energy levels in the forbidden band. The phenomenon of phosphorescence depends on the presence of traps in the forbidden band. The electron traps are normally empty. X-ray interactions stimulate transitions from the valence band to the conduction band, then these electrons fall into the traps rather than back into the valence band. These excited electrons fall into electron traps were they can remain stable for days or even weeks. When stimulated by light of a certain wavelength, the electron is lifted out of the electron trap back into the conduction band. Some electrons fall back into traps but others fall to lower energy levels and emit light (recombination light). This phenomenon is illustrated in Figure 1-3 (Krestel, 1990, Dendy 1999). ConductionBand ValenceBand Electron Traps X-Ray Quantum Laser Photon Recombination li g ht Electron Hole

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7 The imaging plate is constructed of many layers. The active layer where the phosphorescence takes place is composed of europium-activated barium fluoride bromide (BaSrFBrI:Eu). The europium is the dopant that provides the electron traps in the forbidden layer. The phosphor emission of BaSrFBrI:Eu is in the vicinity of 400 nm. Figure 1-4 shows a typical Agfa CR cassette a nd a cross section of the imaging plate. The structure of the imaging plate (Gunn, 2002) is as follows: 1. Protective layer – thin, transparent film to protect the plate. 2. Phosphor layer – composed of BaSrFBrI:Eu. 3. Conductive layer – composed of conductive crystals in a binder. Its function is to reduce problems caused by electrostatic charges but in addition it absorbs light and therefore increases image sharpness. 4. Support (base) – this acts as a support for the other layers and is made of polyester. 5. Laminate composed of carbon particles in a binder and its function is to prevent light leaking from the backing area Figure 1-4. The Agfa CR system cassette A) holder and B) the image plate structure Once the cassette is exposed, it is taken to a “read-out” station or laser scanner. Inside the machine, the cassette is opened and the phosphor screen is taken out. The Phosphor Layer Conductive Layer Support Layer Laminate Protective Coat

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8 scanning laser beam, usually a helium-neon laser of wavelength 633 nm, scans the screen line by line. This scanning produces the recombination light as shown in Figure 1-3 and this light is captured by photomuliplier tubes (PMT) and converted to a digital signal as shown in Figure 1-5. The amount of light collected by the PMT can be adjusted for high or low x-ray exposures by changing the gain of the PMT. The fiber optic pickup guides are immediately adjacent to both sides of the laser scan line to capture the emitted light as efficiently as possible. The fiber optic pickup guides focus the light on a PMT after it is filtered to remove any of the scattered stimulated light. Once the signal is amplified and digitized, the patient image can be displayed on a monitor. After the laser scanning, the screen is subject to an intense white light to clear all the remaining traps and the screen is placed back into the cassette. The cassette is ready to use again (Krestel, 1999, Hendee, 1993). Figure 1-5. The Agfa CR scanning procedure A) process inside the scanner and B) Agfa Compact CR reader The pixel size for CR images is determined by the reader sampling frequency. Each cassette is initialized to standard or high resolution. The Agfa ADC Compact Photodetector Lase r Phosphor Image Plate Laser bea m Fiber O p tic Galvo

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9 reader has a standard resolution reading sa mpling frequency of 6 pixels/mm and a high resolution sampling frequency of 9 pixels/mm. The newer Compact Plus reader has a high resolution sampling frequency of 10 pixels/mm. This research used a 35 cm x 43 cm (14 inch x 17 inch) cassette at standard resolution, which resulted in a pixel matrix of 2048 x 2494. The actual pixel size is 0.17 mm x 0.17 mm. Similar to conventional screen-film, the Agfa CR system has the ability to change the exposure class or speed to compensate for overand underexposed images. This also allows for additional widening of the dynamic range of the digital system. Exposure class is an arbitrary scale with the value 100 being the benchmark to which all other exposure classes are compared. Table 1-1 s hows the relationship between exposure class, mAs and amount of exposure compared to 100 exposure class. Table 1-1. Relationship between exposure class, mAs and exposure Exposure Class 50 100200 400 800 mAs required to produce the same density 20010050 25 12.5 Amount of exposure compared to 100 exposure class2x 1 1/2 1/4 1/8 Conventional screen-film used optical density as a measure of film darkening. Computed radiography systems have a similar system called exposure level. The Agfa CR system measures exposure level using the Equation 1-1 where speed refers to exposure class. The manufacturer suggests that the optimal exposure level for the Agfa system is approximately 2.0. The exposure class can be adjusted to maintain an optimal exposure level to compensate for more or less radiation. Exposure Level = log (exposure) + log (speed/200) + 2.22 (1-1) One of the disadvantages of CR is that the laser is susceptible to dust and vibration, particularly as the laser beam transfer via the galvo. Additionally, disruptions in the vertical movement of the plate by mechanical means through the reader can cause

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10 artifacts. Since there is some mechanical wear on the plates as they move through the reader, the phosphor coating on the plate could become damaged or scratched, causing artifacts in the image (Gunn, 2002). Digital Radiography There are two types of digital radiography (D R): direct and indirect. The type to be evaluated in this research is the indirect-conversion systems developed by Canon USA, Inc. as shown in Figure 1-6. This system is based on thin-film transistor (TFT) arrays consisting of amorphous silicon (a-Si) photodiodes and a gadolinium scintillator top layer. When the x-rays strike the scintillator, visible light is emitted and converted to an electrical charge by the photodiodes. The charge collected at each diode is converted to a digital value by the underlying readout electronics (Chotas, 1999). This process is illustrated in Figure 1-7. Figure 1-6. The Canon DR System A) the Canon CR system chestboard and B) the Canon CR system display

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11 Figure 1-7. DR scintillation process Amorphous silicon (a-Si) has been used in fax machines, scanners and solar energy panels for more than a decade (Yamazaki, 1999). Its ample semiconductor properties make it photoconductive in the visible spectral range and can be used as a field effect transistor. Amorphous silicon is a direct band gap material and the thickness necessary to detect visible light is less than 1 m (Jing et al, 1996). Amorphous silicon responds to light in the wavelength of 400 to 650 nm with its peak response at 550-600 nm. The quantum efficiency, the ratio of input to out put quanta, is 80-90% (Street and Wu, 1996). One advantage of a-Si is its low deposition temperature (200 to 250 C), which allows for a wide variety of materials that can be used for a substrate. It also has good stability against radiation and is compatible with silicon process technology that makes it easy to manufacture (Hoheisel et al, 1998). To convert the light photons into charges, the detectors are made up of a-Si diodes 0.5 to 0.8 m thick. Thin-film transistors (TFT) are created on a flat large area substrate such as glass, metal or plastic. Uniform layers of various materials are deposited on the substrate and discrete structures are created through photolithographic and etching techniques (Antonuk, 1995). Each pixel has its own capacitor that can store electric charges (Figure 1-8). This capacitor is connected to one side of a TFT switch. (Yamada, 1999) Each pixel is

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12 connected to a row line for driving voltages and to a column line for readout. The electric charges are read out in parallel for each row (Spahn, 2000). The pixel size in digital radiography should be in the range of 150 m to provide the clinician with image resolution comparable to film-screen (Moy, 1999). The large area new metal-insulatorsemiconductor (MIS) sensor and TFT (LANMIT) was developed and manufactured by Canon, which allows the photodetector and the TFT to be manufactured as one unit (Yamazaki, 1999). Unlike the CR system, the pixel size of the DR system is fixed because of the way the LANMIT is structured (Figure 1-8). With a pixel matrix of 2688 x 2688, the large imaging area of 17 inch x 17 inch results in a pixel size of 0.16 mm x 0.16 mm. Along with the a-Si flat panel sensor, the Canon DR system consists of a touch sensitive liquid crystal display (LCD) operation panel and a control computer. The LCD operation panel provides image preview as well as all the setup for imaging technique, patient demographics and image distribution. The control computer is responsible for system management including image processing, temporary hard-disk storage, and network image distribution. The advantage of the DR system is the images are produced instantly after exposure, approximately 3 seconds. There is no need for a separate reader or any other separate equipment. The time it takes to place the cassette in the reader, and have the plate go through the reading process is also saved. There are no mechanical movements in the flat panel sensor so there is less chance of breakage. The disadvantage of the Canon DR system is that it is stationary. With the CR system, the cassettes can be taken to the bedside and back to the reader for portable examinations. If there are any

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13 complications with the x-ray tube, the room is completely unusable. With the CR system, there are multiple cassettes and several readers available in the event that one of the components in the system was broken. Figure 1-8. DR pixel configuration Computed Tomography Computed tomography (CT) was conceptualized by Oldendorf in 1961, and developed as an image modality by Hounsfield in 1973 (Kirks, 1991). CT is a tomographic imaging technique that generates cross-sectional images in the axial plane. Images are maps of the relative linear attenuation values of tissue. For a fixed x-ray position, a fan beam is passed through the patient and measurements of transmitted x-ray beam intensities are made by an array of detectors. The measured x-ray transmission values are called projections. CT images are derived from mathematical analysis of multiple projections. PIXELSwitch Driving Voltage Readout

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14 Single slice helical scanner Multislice helical scanner Figure 1-9. Single and multi-slice helical CT Scanners. The GE HiSpeed CT scanner introduced helical scanning. Instead of the tube rotating around a stationary patient one section at a time, the table with the patient simultaneously moves as the x-ray tube rotates around the patient, creating a spiral or helical pattern. The next generation of scanners called “multi-slice CT” uses the same helical scanning but there are several rows of detectors per slice. The Figure 1-9 shows the difference between the single slice and multi-slice CT. The multi-slice CT has improved image quality because it is able to take thinner slices over a larger area in a shorter amount of time. Multi-slice CT has the ability to reconstruct slices ‘retroactively’ meaning that it can reconstruct images at thinner slice thicknesses without having to rescan the patient. It also has the ability to produce planar images. Planar images are reconstructed images in the planes perpendicular to the scanning direction as shown in E q ual Scan Time

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15 Figure 1-10. It was suggested that since CT can provide planar images in addition to the cross-sectional images, CT would soon replace CR and DR as the only imaging modality. Figure 1-10. Imaged and reconstructed planes in multi-slice CT. Image Quality There are three important aspects of a medical image to convey clinically useful information: contrast, spatial resolution and noise. These are the relevant determinants of image quality. Contrast Radiographs are usually contrast limited. Contrast refers to the differences in the level of brightness of parts of the image. Image contrast (Figure 1-11) is determined both by the subject contrast produced by the body and the detector contrast of the imaging system (Wolbarst, 2000). Subject contrast is defined as the absolute value of the difference between the intensity of the x-ray beam passing through an object and the surrounding tissue. Subject contrast depends on thickness of the object, density and atomic number of material, tube potential (kVp) and filtration. In that list, the only Reconstructed plane Scanned plane Scanning direction

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16 parameter that can be controlled by the technologist in image production is tube potential. Subject contrast decreases with increasing tube potential. Higher kVp x-rays have greater penetrating ability and the differences in absorption are smaller, i.e. there is more compton than photoelectric interactions (Kelsey, 1985). Figure 1-11. Image contrast. Detector contrast refers to the ability of the detector to convert differences in photon fluence across the x-ray field into differences in signal amplitude. Detector contrast depends on the chemical composition of the detector materials, its thickness, atomic number, electron density and the physical process by which the detector converts the radiation signal to electronic signal. Digital detectors have a linear response across a greater range of radiation exposure, five orde rs of magnitude or more. A linear response gives a constant change in detector signal out put with constant change in exposure input (Hasegawa, 1991). The exposure response of a digital imaging system is a plot of the resultant pixel value versus incident x-ray exposure (Figure 1-12). It is similar in concept D1D2 D=D2-D1Image Contrast = D/D1 Distance Pixel Value

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17 to the sensitometric response of a screen-film system and contains information on the sensitivity and dynamic range of the digital imaging system (Hendee, 1993). 0 2000 4000 6000 8000 10000 020406080100 Input ExposureDetector Signal Output Figure 1-12. Linear response of input exposure to pixel value. Contrast resolution describes how large a contrast difference is required for two areas to be reliably perceived as separate and is determined by the number of gray scale steps or levels and the overall system noise. The word “bit” describes how computers store and manipulate numbers. All computers d eal with binary (on-off, yes-no) numbers instead of the more familiar decimal numbers. Any decimal number can be expressed in terms of its equivalent binary number. Each on-off condition or power of two is called a bit (Kelsey, 1985). Typical medical images require 10 to 12 bits per pixel (Hasegawa, 1991). The number of bits (n) determines the number of gray levels (2n) shown in Table 1-2. For medical images, there are 10 to 12 bits per pixel. In the absence of noise, the minimal detectable contrast level is one gray scale step (Kelsey, 1985). For examples, a 2 bit pixel has 4 gray levels. The minimal detectable contrast between each step is 25 % or ¼. As the number of bits increases, it is hard to perceive differences in one gray level

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18 with the naked eye. Humans have a range of fewer than 32 shades of gray (Fauber, 2000). Table 1-2. Bits and gray level relationship Bits Gray Levels 2 4 3 8 4 16 5 32 6 64 7 128 8 256 9 512 10 1024 11 2048 12 4096 The ratio of the object contrast to the background noise is known as the signal-tonoise ratio (SNR) (Kelsey, 1985). Since the noise specifies the uncertainty in the signal, it is usually helpful to relate the noise to the signal size (Hasegawa, 1991). Since digital images are represented with gray levels, the uncertainty or noise ( g) can be expressed as Equation 1-2, where g is the gray level of the pixel, G is the total number of gray levels and N is the number of photons per pixel required to give the brightest (highest) gray level. The SNR decreases with an increasing number of gray levels unless the number of photons also increases (Kelsey, 1985). G N gg (1-2) Spatial Resolution Spatial resolution describes how close together two objects can be and still be recognized as separate objects (Figure 1-13). Spatial resolution is measured in pixel size or in line pairs per mm (lp/mm). Pixel size is determined by dividing the size of the image in millimeters by the size of the matrix used to produce the image. A line pair

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19 consists of one bright and one dark line. At least 2 pixels are required to display one line pair. The maximum line pair resolution can be calculated by (1/2)x(1/pixel size). The resolution of an imaging system can be measured by a line pair phantom (Figure 1-14) whose lines are varying distances apart. Lines are formed by alternating attenuating materials, with non attenuating materials or air. The limiting resolution is measure by the highest number line pairs per millimeter can be seen as separate lines (Kelsey, 1985). The requirements for spatial resolution depend on what the radiologist wants to see. Resolution requirements for different body parts are listed in table 1-3. Table 1-3. Resolution requirements (Hoheisel and Batz, 2000). Body Part Resolution Soft Tissue 1-2 lp/mm Fine bone structure >3 lp/mm Mammography >5 lp/mm Figure 1-13. Resolution of objects located in close proximity (Wolbarst, A.B, 1993). Figure 1-14. Example of a line pair phantom. Ob j ects in Body Barel y Resolved Unresolved Objects in Image

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20 Noise Noise is defined as the uncertainty in a signal due to random fluctuations in that signal. The principle source of noise are quant um noise cause by x-ray input fluctuations, electronic noise and the quantization of noise from the analog-to-digital converter. The number of photons emitted from the source per unit time varies according to a poisson distribution. Other souces of random fluctuation are introduced by the process of attenuation in the materials present in the path of the radiation beam (patient, x-ray beam filtration, patient table, cassette) which also is a poisson process (Hasegawa, 1991). Medical radiographs are often noise-limited, meaning at the contrast levels obtained in radiographs, the ability to discern objects of interest is limited by the presence of noise (Hasegawa, 1991). In radiology, because of the use of ionizing radiation, to minimize radiation exposure, image noise should be dominated by quantum noise or dose (Kelsey 1985, Hasegawa 1991). If the image is not quantum noise limited, extra exposure is given to the patient with no return in additional diagnostic information. If the image is limited by electronic or noise other than photon quanta, the system was not designed correctly (Hasegawa, 1991). There are two sources of noise present in CR imaging, quantum noise and system noise. Quantum mottle is the primary source of noise in CR. It is visible as density fluctuations on the image. The fewer photons reaching the imaging plate to form the image the greater the quantum mottle visible on the digital image. System noise results from the image acquisition, phosphor conversion fluctuations, laser beam scanning, the ADC and the mechanics of moving the plates in the reader. This type of noise is more structured and obvious in an image. For instance, if there is a mechanical problem moving the plate in the reader, this can show up as jitter on the image. Image noise can

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21 be exaggerated by the postprocessing (contrast and edge enhancement) of the image (Fauber, 2000). Electronic noise can also come from the pixel reset, leakage currents, line resistances, readout amplifiers and a non-ideal analog-to-digital converter. (Hoheisel and Batz, 2000). There are three main sources of noise in digital radiography: the kTC noise of the pixel TFT, readout amplifier input noise and voltage fluctuations on the bias and gate connections. The kTC noise of the pixels TFT is the fluctuation of the charge stored on capacitance C by a rise in temperature T multiplied by BoltzmannÂ’s constant k and is a very small contribution to the total noise. The readout amplifier noise is proportional to the data line capacitance, which is proportional to the total number of pixels on the data line. The larger-format, higher resolution systems tend to have greater noise. The noise from the power supply voltage fluctuations of the bias and gate connections is also coupled to the data line since the image receptors sense the signal on all line simultaneously. This noise is visually more objectionable than random pixel noise (Street et al, 1998). Image Quality Measurements Image quality measurements can be either subjective or objective. Subjective measurements can vary from observer to observer. Objective measures are more reliable for an initial assessment of image quality and comparing different systems. These measurements can help to determine the characteristics of the imaging systems, which would help in optimizing dose before observer studies involving human subjects are conducted. Digital imaging systems should be linear and shift invariant. If G is an object and B is the image of that object, the equation B=A(G) shows mathematically how an image of

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22 object G is created. The linear condition states that for every real number and 0, A( G)= A(G). This means that an object is times as bright as a given object G, its image A( ) should be times as bright as A(G). The shift invariant condition states that if an object G is shifted in the object plane, it must also shift the same way in the image plane. Mathematically, two objects G1 and G2, which are superimposed in the object plane, the image A(G1+G2) is produced as the superimposition of the images A(G1) and A(G2), it is expressed as A(G1+G2)=A(G1) + A(G2). (Krestel, 1990). This linear, shift invariant condition is necessary in order to establish a relationship between the spatial domain and the frequency domain. This connection can be established with the Fourier transform. In 1815, Jean-Baptiste-Joseph Fourier demonstrated that just about any function or curve can be represented as a combination of sine and cosine functions of the appropriate frequencies and amplitudes. An image can be expressed as a Fourier combination of sine waves of different spatial frequencies, amplitudes and phases. The Fourier algorithm transforms the image from the spatial domain to the frequency domain. Fourier decomposition can be done using the fast Fourier transform algorithm of a computer program such as Matlab (Wolbarst, 2000). Fourier transforms become important when determining the MTF and NPS. Modulation Transfer Function Transfer Theory is used to describe the relationship between the input and output of the system. The system in this case is the CR or DR system, the input would be x-ray quanta and the output would be the image. In this situation, the imaging system can be simply treated as a “blackbox” as seen in Figure 1-15, since it does not matter how the output is generated from the input. The object of transfer theory is to determine the

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23 transfer characteristics which allow the calculation of the output given the input of the system. (Evans, 1981). Figure 1-15. Transfer characteristics In an ideal system, the radiation quanta from a point in the object plane should produce an equivalent point in the image plane. But, because most imaging systems are not ideal, a point in the object plane is often spread over an area in the image plane or blurred. The point in the object plane can be represented mathematically by a delta function as shown in Figure 1-16. The point spread function (PSF) helps to connect the coordinates of the object in the object plane with the coordinates of the resultant image in the image plane (Kelsey, 1985). The PSF is the image obtained from an infinitesimal point object (Hasegawa, 1991). If the object plane contains a number of delta function sources, each source will be imaged independently of the others and the resultant intensity distribution in the image plane will be the sum of these delta functions. If the delta function retains its shape irrespective of the position of the object in the object plane, the system is shift invariant. Mathematically, the output is the convolution of the input with the point spread function (Evans, 1981). The practical usefulness of the PSF is limited due to the difficulty of its experimental measurements. A line spread function (LSF) which is the intensity distribution of the image of an infinitely long and infinitely Imaging system Transfer Characteristics Input Output

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24 narrow line of unit intensity. Practically, a LSF can be obtained by imaging a slit or wire (Kelsey, 1985). Since any function can be described by si ne or cosine functions, the PSF or LSF can be described in that manner. The Fourier transform can be used to deconvolve these signals. By transforming the input function into the frequency domain, the output can be derived by a simple line multiplication instead of the convolution required in the spatial domain which can be quite difficult to calculate as seen in Equation 1-3. dxdy uy ux i y x f v u F )] ( 2 exp[ ) , ( ) , (1 1 (1-3) Figure 1-16. Point and line spread functions Modulation is defined as the ratio of the amplitude of the signal to the average value of the signal. The modulation transfer function (MTF) is computed by taking the Fourier transform of the LSF. Equation 1-4 describes the MTF mathematically where L(x,y) is the LSF. Figure 1-17 describes the relationship between the LSF and MTF. In p ut Point or delta function Line Output

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25 By comparing the modulations of the input and output, information about the amount of detail or resolution as a function of frequency can be determined for a given system. The output image depends not only on the object being imaged but on the imaging system used. Because the imaging system is made up of a sequence of components or imaging chain, the output from one component becomes the input to the next component. It is possible, although difficult, to measure the MTF of individual imaging system components (Kelsey, 1985). Some degree of blur or unsharpness is added during the image capture process in the real world. For instance, the readout of a CR storage phosphor plate involves a laser beam of finite size scanning in one direction while the plate is translated perpendicularly to the s can direction. Light diffusion in the phosphor screens is a major contributor to MTF degradation. This results in a broadening of the LSF and a fall off in MTF response with increasing spatial frequency. The greater the degree of blur, the broader the output LSF and the more rapidly the resultant MTF falls off with increasing spatial frequency. (Hendee, 1993). dxdy uy ux i y x L v u MTF )] ( 2 exp[ ) , ( ) , ( (1-4) The spatial resolution response of an image capture process is best described by its MTF. The MTF relates the input subject contrast to imaged subject contrast as a function of spatial frequency. Smaller imaged objects have higher spatial frequencies while larger objects have low spatial frequencies as shown in Figure 1-15. Larger objects with gradual borders are comprised of mostly lower spatial frequencies, and smaller objects with sharp borders have significant high spatial frequency content (Hendee, 1993). The imaging system may be able to faithfully reproduce the large (low frequency) parts of the object but may not be able to reproduce the fine detail (high spatial frequency) parts of the

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26 object (Kelsey, 1985). The LSF must be sampled at discrete intervals in order to enter the data into the computer. Since the function is sampled at intervals x over the range m, the transform can be calculated at intervals of u=1/m, up to a frequency of umax=1/2 x. The maximum umax is called the Nyquist frequency. Figure 1-17. MTF response from LSF input. Limiting spatial resolution is often used to describe image receptor or system performance. Limiting spatial resolution is determined with a lead bar test pattern as shown previously in Figure 1-14, imaged at a low x-ray potential. When the image is viewed, the highest number of line pairs per unit distance (lp/mm) that can be visualized is the limiting spatial resolution. This is a s ubjective test. The limiting resolution can also be determined objectively as the spatial frequency where the MTF response has dropped to approximately 0.04 (Hendee, 1993). Line Spread Function Modulation Transfer Function (A) (B) (C)Spatial Frequency Spatial Frequency Spatial Frequency Response Response Response Position Position Position Pixel Value Pixel Value Pixel Value

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27 Noise Power Spectrum The Noise Power Spectrum (NPS) is a measure of the noise at each spatial frequency and is defined as the Fourier transform of the autocorrelation function of a flat field image (Evans, 1981). The autocorrelation function is a mathematical description of how a function correlates with itself. The autocorrelation function is calculated by averaging a large number of functions generated by shifting the density function incrementally, multiplying it by the unshifted density function and integrating the product (Hasegawa, 1991). Equation 1-5 states the NPS mathematically where D(x,y) is the density difference and X and Y are the pixel size (Evans, 1981). For square pixels, X=Y. 2 ,)] ( 2 exp[ ) , ( 2 1 2 1 lim ) , ( X X Y Y Y Xdxdy uy ux i y x D Y X v u NPS (1-5) Figure 1-18. Two-Dimensional NPS of a flat field image In practice, to calculate the NPS, first obtain a flat field image, which is an image with no object between the x-ray source and the image receptor. Ideally, the resulting image should be uniform. Density measurements taken across the image will have variations due to nonuniformities in the image receptor and the inherent statistical

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28 fluctuations in the x-ray beam. The flat field image is then divided into equal parts and the fast Fourier transform is taken of each part. The Fourier amplitudes of each part are averaged together and normalized by the pixel size of the image receptor. The resultant two-dimensional NPS is shown in Figure 1-18. A slice of this two-dimensional NPS adjacent to the axis gives a one-dimensional curve. The area under the NPS curve gives an estimation of the quantum mottle and system noise. The “ideal” noise value for a system would be equal to the x-ray quantum noise, that is, no additional noise introduced by the imaging system (Hoheisel and Batz, 2000). Detective Quantum Efficiency The Detective Quantum Efficiency (DQE) of an x-ray image receptor is a measure of its efficiency in detecting x-rays referenced against an ideal detector. This concept is illustrated in Equation 1-6. An ideal detector, by definition, has an absorption efficiency of 100% and does not add any noise in the detection and signal conversion process (Hendee, 1993). An ideal detector extracts all the information in the beam, i.e., if SNRout=SNRideal then the maximum value of the DQE is equal to one (Sandborg and Carlsson, 1992). The DQE is an objective measure and can be used to compare systems. 2 2 2 2 ideal out in outSNR SNR SNR SNR DQE (1-6) Over the last decade, the evaluation of imaging systems has become more elaborate as the science of imaging systems has advanced. The characterization of imaging systems performance in the research sector often includes the calculation of DQE as a function of frequency, DQE(f). The DQE(f) is calculated from experimentally determined modulation transfer function, MTF(f) and noise power spectrum, NPS(f)

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29 using the relationship established in Equation 1-7 (Boone and Seibert, 1997). The MTF is an estimation of the signal and the NPS and q is the estimation of the noise. The factor q (units mm-2 mGy-1) is the square of the signal-to-noise ratio of the incident x-ray beam energy (E) spectrum as seen in Equation 1-8. This can be calculated using computer simulation programs. The factor k is the conversion from pixel value to exposure. The factor k can be removed from the equation if pixel values are converted to exposure prior to determination of MTF and NPS. Nyquistfdf f DQE f IDQE dE E E q EdE E q q f NPS q f MTF k f DQE0 2 2 2) ( 2 ) ( ) ( ) ( ) ( ) ( When comparing image quality at different techniques or from different systems, the frequency component of the DQE may not be as important as the image quality of the whole image. The Integral DQE (IDQE), as shown in Equation 1-9, gives a single unit descriptor of image quality. The IDQE will increase for systems with greater quantum efficiency as well as for higher system N yquist frequency (Fetterly, 2000). Figure 1-19 shows the quantum efficiency for materials typically used in digital imaging. Barium is used in CR plates and gadolinium is used in DR scintillators. There is a peak in the quantum efficiency spectrum at the k-edge. For barium, the k-edge corresponds with the mean energy of the photons in the diagnostic energy range. This matching of energies makes barium ideal for diagnostic medical imaging. (1-7) (1-8) (1-9)

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30 0102030405060708090100 Energy (kVp) Barium Gadolinium Figure 1-19. Quantum efficiency of materials typically used in digital images Patient Dose Absorbed dose is a measure of energy deposited per unit mass and provides a means to gauge the potential for biological effect. Absorbed dose is measured in gray, which is equivalent to the energy deposition of one joule per kilogram of tissue. Organ dose refers to the radiation-absorbed dose delivered to the organs of a patient during a radiologic examination. The risks to humans from radiation exposure from a diagnostic procedure can be described by the effective dose (ICRP 1990) or the effective dose equivalent (ICRP 1977). Since radiation e xposure in diagnostic radiology is nonuniform, effective dose can be thought of as the uniform whole body dose that has the same radiation risk as the nonuniform dose (Huda and Slone, 1995). Effective dose (E) takes into account the absorbed dose (D), the quality of the radiation particles (wR) and the Quantum Efficiency k edge

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31 relative risk of developing cancer and radiosensitivity of the tissues (wT). The tissue weighting factors are a ratio of the stochastic effects in a particular tissue or organ to the total risk when the whole body is uniformly irradiated (ICRP 1990). Tissue weighting factors are based on relative risk and cancer treatment options at a particular time in history and are subject to change. Now, there is a push to move from an older quality factor Q to a new radiation weighting factor, wr. Equations 1-10 and 1-11 show how effective dose (E) and effective dose equivalent (HE) is calculated from absorbed dose (D), radiation quality factor (Q or wr) and the tissue weighting factors (wt). * * ) ( ) (26 , ICRP t Ew Q mGy D mSv H (1-10) 60 ,* * ) ( ) (ICRP t rw w mGy D mSv E (1-11) Image Quality, Dose and Radiographic Technique The technologist is responsible for taking the medical image. The technologist has several parameters that they can control to take a medical image. Each of these parameters has an effect on image quality and change depending on the patient. The parameters that the technologist can control include: peak tube potential (kVp), tube current and time (mAs), source-to-image receptor distance, focal spot size and use of grid. Choosing the proper radiographic techniques, the best image quality at the lowest dose necessary to produce a diagnostically useful image can be achieved. Equipment options, which can have an effect on patient dose, fall in two categories: 1. Those that have little influence on image quality. An example would be the use of low attenuation materials between the patient and the image receptor such as patient support pads. 2. Those that involve a trade-off between image quality and patient dose i.e., changes in radiation quality, photon fluence and removal of scattered radiation. (Martin et. al., 1999 )

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32 Radiation quality refers to a combination of beam energy and filtration. The beam energy is determined by the peak kilovoltage (kVp), which is selected for each examination depending on the part of the body imaged, the size of the patient, the type of information required, and the display method (Martin et. al., 1999). To create an acceptable image, the amount of radiation needed to penetrate a patient increases with patient thickness. A selection of a higher kVp will raise the average beam energy and increase the beam penetrability. The entrance skin exposure will change with the square of the change in kVp. The lower energy photons only contribute to patient dose since they are not able to penetrate the patient to help form the image. Since, the x-ray beam from diagnostic x-ray tubes is a spectrum of energies, the filtration serves to eliminate the lower energy photons. Inherent filtration comes from tube housing and additional filtration can be sheets of aluminum or c opper (Parry et al 1999). Subject contrast decreases with increasing tube potential because of the increase in Compton scatter and decrease of photoelectric absorption. It also increases the radiographic density of the image because higher kV photons can penetrate tissues and cause images to be too dark. There may be less of a density difference between different anatomical regions if the image is too dark (Kelsey, 1985, Fauber, 2000). Also, the increase in scatter will increase the amount of noise, which does not offer any additional information in the image. Tube current, measured in milliamps, gives an estimate of the number of photons used for an image. The exposure time, measured in seconds, determines how long the xray beam will be on. The two parameters can be multiplied together to form one unit milliamperage-seconds or mAs. Tube current and exposure time have an inverse relationship when maintaining a constant mAs. The number of photons used to create an

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33 image has an effect on the image quality. As the mAs increases, the quantity of radiation increases and radiographic density increases. Since the noise is proportional to the square root of the number of photons used, increasing the number of photons reduces the noise in the image. In theory, the exposure time should be as short as possible to eliminate unsharpness caused by patient movement. Increasing the kV allows the tube current or the exposure time to be reduced (Dendy, 1999). The focal spot size selection determines the amount of detail or resolution that will be seen on the image. The larger focal spot has a greater heat loading or can withstand higher mAs values, while a smaller focal spot produces greater radiographic detail (Kelsey, 1985). The source to image distance (SID), not only affects the geometric distortion of the image but also the amount of radiation reaching the imaging plate. As SID increases, radiographic density decreases as a result of the inverse square law. Increasing the SID requires that mAs be increased to maintain the same density (Fauber, 2000). Grids are used to reduce the scatter radiation that reaches the image receptor. This helps to improve the contrast of the images. Grids must be used if scatter is significantly reducing contrast when irradiating large volumes (Dendy, 1999). Grids absorb a portion of the primary x-rays; therefore, the amount of radiation must be increased to achieve the same exposure reaching the image receptor (Parry et al 1999). Use of grids requires an increase in mAs, thus increasing patient dose. To lower the amount of exposure to the patient, the air gap technique is used to reduce scatter in pediatric chest imaging. The gap between the patient and the image receptor allows for more of the photons moving in the forward direction and less of the scattered photons to hit the image receptor, giving an

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34 improved image. With the air gap technique, there is not only a reduction in scatter but a reduction in signal (Dendy, 1999). There are many thousands of possible combinations of kVp, mA, SID, exposure time, exposure class and grid ratios. When combined with patients of various sizes, and various pathologic conditions, the selection of proper exposure factors becomes a difficult task. Radiographic technique charts make setting radiographic technique factors much more manageable for technologist. Automatic exposure control (AEC) is a system used to consistently control radiographic density by terminating the length of exposure based on the amount of radiation reaching the image receptor. Ionization chambers built into the table are used to measure the amount of radiation reaching the image receptors and maintain constant exposure level. With the AEC systems, the technologist selects the kVp and mA. Once the ionization chambers have detected a certain amount of exposure, the x-ray beam is teminated. Proper centering of the patient over the AEC chambers will ensure the appropriate cut off time (Fauber, 2000). AEC systems are not typically used on small children since they often do not cover all the chambers. Summary Image quality is to a large extent a descriptor of the subjective interpretation of visual data. Image quality of a radiographic image may be defined as the ability of the imaging system to record each point in an object as a point on the image receptor (Kamm, 1997). Detective quantum efficiency (DQE) is generally accepted as the best single objective indicator of image quality since it combines spatial resolution (i.e., MTF) and image noise (i.e., NPS) to provide a measure of the signal-to-noise ratio of the various frequency components of the image (Chotas, et al 1999). Combining image quality measurements for different radiographic techniques with patient dose

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35 considerations, the characteristics of digital imaging systems can be evaluated, optimized and compared.

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36 CHAPTER 2 HYPOTHESIS The goal of this dissertation is to optimize the radiographic techniques used to produce CR and DR pediatric chest images. By relating the image quality properties of CR and DR to radiographic technique, air kerma at the image receptor, entrance skin exposure and effective dose, the radiographic techniques can be optimized to produce the best image quality at the lowest dose. Radiographic techniques include tube potential (kVP), tube current and time (mAs), source-to-image receptor distance (SID) and grid use. The effects of changing these parameters on image quality measurements, (the modulation transfer function (MTF), the noise power spectrum (NPS) and integral detective quantum efficiency (IDQE)) will determine the characteristics of the CR and DR systems. Using pediatric anthropom orphic phantoms and MOSFET dosimeters, the effective doses to pediatric patients are dete rmined for the varying radiographic technique parameters. By relating the IDQE to entrance skin exposure, a direct correlation between image quality and radiographic technique is developed. This research will test the following hypotheses: Hypothesis 1. An increase in peak tube potential (kVp) will not change the MTF of the CR or DR systems. Hypothesis 2. The increase of tube current and time (mAs) will produce lower NPS. Hypothesis 3. The use of the grid during image production will produce higher NPS than images taken without the grid.

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37 Hypothesis 4. The use of a longer SID will produce higher NPS. Hypothesis 5. IDQE will increase for lower tube potentials. Hypothesis 6. DR will provide better image quality than CR with reduced doses for pediatric patients. Hypothesis 7. CR will provide better image quality than multi-slice CT used for planar imaging for pediatric patients. It was not possible to determine the outcome of Hypothesis 7. The CT phantom available was not adequate to measure image quality of planar images from the multislice CT scanner. Appendix G explains the limitations of the CT phantom available. Construction of a new, more appropriate CT phantom was beyond the scope of this research. The rationale behind Hypothesis 1 is that the MTF is the characterization of the imaging systemÂ’s ability to transfer information from the input to the output. As a measure of resolution, it is more a function of the pixel size of the image receptor than the radiation input of the tube. Hypotheses 2, 3 and 4 are based on the principle that more photons will produce less noise. Increasing mAs will produce more photons reaching the imaging plate, while using a grid or increasing the SID will produce less photons reaching the imaging plate. The basis for Hypothesis 5 is that IDQE increases with quantum efficiency and quantum effici ency decreases with higher tube potentials. The Gd2O2S:Tb screen used in the DR system has a higher quantum efficiency than the BaSrFBrI:Eu used in the CR system. Also, the DR system has a smaller pixel size than the CR plates at standard resolution. Ther efore, Hypothesis 6 predicts that DR will provide a better image quality that CR.

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38 CHAPTER 3 LITERATURE REVIEW With the advent of digital imaging, methods to determine the image quality of these systems had to be developed. There have been several studies that compare the image quality of digital systems with screen-film, the conventional method of producing medical images. The potential for dose reduction, due to the wide latitude of digital systems, was also investigated. Droege and Morin (1982) developed a pr actical method of determining the MTF from line pair phantoms. The MTF was determined by taking the standard deviation of regions over the line pair groups. This method was originally developed for CT scanners but can easily be adapted for projection radiography. Giger and Doi (1984) determined the MTF from conventional radiographs that were scanned and converted into digital form. They found that different algorithms enhanced the resolution, and was able to show that image processing can produce MTFs greater than one. Hillen et al. (1987) evaluated the Fuji system for objective measures of image quality and compared to screen-film systems. The MTF was determined from a periodic bar phantom and the NPS was determined at 0.3 mR. The Fuji systems and the screenfilm systems had similar signal-to-noise ratios at lower frequencies. At higher frequencies, the screen-film systems had superior image quality. In 1991, Sanada et al. compared the image quality of the Toshiba CR system with that of a screen-film system. The MTF was determined 10 µm slit device. The high

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39 resolution plates have a significantly higher MTF than the plates at standard resolution. The NPS of the CR system was much higher than that of the screen-film system. Chotas et al. (1993) established a relationship between signal-to-noise ratio and tube potential for a Philips CR system using a GE AMX portable x-ray tube. Signal-tonoise measurements were taken from regions on anthropomorphic and geometric chest phantoms. In the lung regions, there was a degredation in signal-to-noise with increasing kVp. In the mediastinium and subdiaphragm regions, the signal-to-noise was lower than that of the lung and was consistent across the range of kVp. Dose measurements on the phantoms at the different tube potentials helped to match patient risk with the signal-tonoise ratio. Workman and Cowen, in 1993, measured the image quality properties of the third generation of Fuji CR plates. The results show a significant improvement in signal-tonoise performance over previous versions of the system. Comparing these measurements with rare-earth screen-film systems under identical conditions, the CR compared favorably with the conventional system. Dobbins et al. (1995) measured the MTF( f ), NPS( f ) and DQE( f ) for four generations of Philips CR plates and established methods of determining NPS for digital systems. The NPS measurements prove that NPS decreases with higher exposures. The MTF was determined using a slit device. There was a slight difference in MTF in the scan and subscan directions. The newest models and high resolution plates proved to have superior DQE. In 1995, Boone and Seibert developed an algorithm to accurately estimate the quantum fluence for a variety of x-ray beams or input signal to noise. The tungsten anode

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40 spectral model interpolating polynomials (TASMIP) algorithm is based on measurements of tube output (mR/mAs). A computer pr ogram was developed and made available on the internet. The inputs to the computer program are kVp, tube ripple and inherent filtration. Kengyelics et al. (1998) evaluated the MTF( f ), NPS( f ), and DQE( f ) of fifth generation Phillips CR plates at different exposure/dose levels. The MTF was measured using a narrow slit of 20 µm slit. The NPS was measured over a range of exposures from 0.3 to 80 µGy. The improved system gain proved to have a superior DQE than previous versions. Siewerdsen et al. (1998) examined the performance of a flat panel imager compose of a-Si:H TFT. In this paper, theoretical calculations are compared to empirical x-ray sensitivity, NPS and DQE. The NPS was determined for three different Gd2O2S:Tb converters: Lanex Fast-B, Regular and Fine . The Lanex Fine had a very flat DQE distribution and much lower than the Fast-B. This suggests that the fine converter performs the same at high and low frequencies. They were able to get good agreement with the theoretical calculations. Strotzer et al. (1998) conducted a study to compare digital radiographs with conventional film/screen. Images were taken of 120 patients with both film/screen and using a silicon DR system. Six radiologist s using a subjective five-point preference scale, which rated underexposure, overexposure, contrast resolution, spatial resolution, and soft-tissue representation, evaluated these images. Overall image quality was ranked on a 10-point scale. It was found that digital images were nearly equivalent to screenfilm radiographs when the radiation exposure was reduced by 50%.

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41 Lauders et al. (1998a) evaluated a selenium based digital chest radiography system. The principal aim of the evaluation was to assess how the image quality and dose compared to a conventional system. The physical measurements included radiation dose, dynamic range, resolution, signal-to-noise ratio (DQE) and threshold contrast detail detectability (TCDD). Radiologist in a 3-point scale evaluated PA chest examinations of 100 patients. Entrance surface dose (ESD) was measured using thermoluminsescent dosimeters. An additional series of measurements were taken to establish a relationship between ESD and kVp using an ionization chamber and an anthropomorphic chest phantom. The DQE and TCDD response was measured for a range of exposure and kVp values. A relationship was established between DQE and kVp. For the same kVp, the selenium-based system had a higher DQE than screen-film. Launders et al. (1998b) conducted another study comparing a selenium-based system to phosphor-based systems. In this study, they evaluated field size and geometric distortion, sensitometric response, MTF, DQE and TCDD. It was shown that the there was a potential for radiation dose reduction due to the values of the dynamic range and DQE at low spatial frequencies. Bradford et al. (1999) evaluated the performance characteristics of different types of Kodak CR plates and compared them to previously published results from the Fuji system. The MTF was determined using narrow slit. The presampled MTFs of both systems are very similar. The NPS was determined at 0.03, 0.3, 3.0 and 30.0 mR. The NPS was 20% higher for the Kodak system at low exposure and 40%-70% higher at the higher exposure levels. This corresponded to a 20%-50% lower DQE for Kodak.

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42 In order to determine image quality from one image, Stierstorfer and Spahn (1999) developed a self-normalizing method to determine the DQE. One image contains test pattern and a large uniform image to measure MTF and NPS, respectively. They propose this method is fast and can be used a daily routine. Fetterly and Hangrandreou (2000) evaluated the image quality of the Lumisys ACR-2000 and compared to the Fuji AC-3 CR system. The MTF was determined using an edge device. The presampled MTF of the Fuji CR system is generally higher than that of the Lumysis CR system. The NPS was taken at 0.1, 1.0 and 10 mR for 70 and 120 kVp beams. The 1D NPS of Lumysis CR system was greater than that of the Fuji CR system. They also introduce the concept of the integral DQE. The DQE of the Lumisys CR system was 30% lower than that of Fuji CR system. In 2001, Fetterly and Hangrandreou went on to establish a relationship between x-ray spectra and DQE. They measured DQE at 70, 95 and 120 kVp. They used various filters such as aluminum, copper and “patient equivalent phantom” or PEP. They showed that there is a possibility to degrade the MTF by measuring the MTF at 120 kVp using various thicknesses of PEP. The degradation in the MTF was due to the energy deposition in the phosphor. Lower energy photons deposit their energy near the surface of the phosphor providing the greatest sharpness. By filtering the beam, the lower energy photons are taken away, leaving only the photons that penetrate deeper into the phosphor, resulting in a lower MTF. Noise increased with greater thickness of filtration. The IDQE decreased for all tube potentials with increasing filter thickness, which one could extrapolate that image quality is reduced with increasing patient thickness.

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43 Floyd et al. (2001) determined the imaging characteristics of an amorphous silicon (a-Si) flat panel detector for chest radiography. The MTF was determined with a 12 µm and the NPS was determined using 0.5 mm of additional copper filtration at 70 kVp and 0.3 mR. The grid was removed from the flat panel detector before NPS measurements were made. The DR system was compared to a CR system and the DR system was determined to have a superior MTF and DQE to CR. In 1991, Cohen et al. evaluated the effect s of reduced dose on image quality of Fuji CR system for neonatal chest images. The CR images were printed with a laser printer and compared to screen-film images. For images taken at the same exposure as screenfilm, there is no loss in image quality. For a 50% reduction in radiation dose, there is a detectable loss in image quality for the CR system. Hufton et al. (1998) measured doses to 900 pediatric patients ages 0-15 years of chest, abdomen, pelvis and skull examinations. Half of the patients were taken using the Fuji CR system and the other half had images taken on conventional screen-film. Dose measurements were taken with a dose-area product meter. Entrance skin exposure measurements were determined by using the recorded exposure factors and the measured tube output. Image quality was evaluated by six radiologist based on the Commission of the European Communities (CEC) criteria which uses the visibility of anatomical structures in clinical images as a standard . Hufton et al. found that by using CR instead of 600 speed screen/film system, doses could be reduced by 40% for abdomen, pelvis and skull examinations. Further dose reduction could be achieved by using the CR as a 1000 speed system. Since most departments use 400 speed film/screen systems, it is estimated

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44 that these departments could see a dose reduction of at least 60% for abdomen, pelvis and skull examinations. Comparisons between studies are difficult due to the differences in imaging parameters, these studies have shown that it is possible to measure the image quality of digital systems. Two of these studies prove that it is possible to find a relationship between image quality and dose.

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45 CHAPTER 4 MEAUREMENT OF IMAGE QUALITY Introduction Image quality is often a subjective measure of how much information is available in an image. The radiologist sets the standard of image quality since the doctors are the interpreters of the information presented in the image. By definition, subjective measurements vary from person to person. This makes it difficult to objectively compare the “image quality” obtained by different systems. Objective measures of image quality do not change with individual perception and allow for the determination of system characteristics. Since the DQE is generally considered to be the best overall descriptor of image quality, the integral DQE (IDQE) provides a single unit descriptor of a system’s image quality. Image quality is often measured for a standard configuration which may not be an accurate depiction of radiographi c techniques used for patient imaging. Measuring a systems image quality at clinically relevant radiographic techniques permits a characterization of the image quality across a broad range of clinical practice. Materials and Methods Software MediSurf, a product of Algotech systems Ltd.1 provides a way to view and manipulate images via the internet. Medisurf was cleared prior to market by the FDA under 501(k). Images are viewed in full diagnostic quality using the DICOM-3 protocol and can be saved on a local computer. Medi surf also has tools that allow window and 1 Algotec systems Ltd., 4 Hamelacha Street, PO Box 2408, Industrial Zone North, Raanana, Isreal

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46 level manipulation, ROI measurements and annotations. ImageJ is a public domain Java image processing program produced by the National Institutes of Health (NIH). It runs, either as an online applet, or as a downloadable application, on any computer with a Java 1.1 or later virtual machine. Through the use of Java, users can create their own image processing algorithms to manipulate images along with a library of algorithms already available. ImageJ can be downloaded from http://rsb.info.nih.gov/ij/index.html. MATLAB®, a product of Mathworks Inc.2, is a high-performance language for technical computing. Matlab allows for complex image processing and manipulation such as fast Fourier transforms. Equipment The CR and DR systems are installed in separate rooms in Shands Hospital at the University of Florida. Both rooms use a Dunlee3 x-ray tube with a Picker4 VPE 3 phase generator. The inherent filtration for the x-ray tube used with the CR is 2.2 mm Al equivalent with a half value layer of 3.70 mm Al at 80 kVp. The inherent filtration for the x-ray tube used with the DR is 2.7 mm Al equivalent with a half value layer of 3.88 mm Al at 80 kVp. Exposure measurements were made with the Radcal5 MDH ion chamber. The exposures measured in mR were converted to air kerma [mGy] by multiplying by 8.77x10-3. 2 The Mathworks, Inc., 3 Appl e Hill Drive, Natick, MA 01760 3 Dunlee, 555 North Commerce Street, Aurora, Illinois 60504 4 Philips Medical Systems, 22100 Bothell Evere tt Highway, P.O. Box 3003, Bothell, WA 98041-3003 5 Radcal Corportation, 426 West Duarte Road, Monrovia, Ca 91016

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47 The CR unit is the Agfa6 ADC system with a Compact reader and MD10 imaging plates. For this experiment, the 14 inch x 17 inch cassettes at standard resolution were used. The cassettes can be placed in the Bucky or placed on the tabletop. Agfa CR system has an imaging depth of 12 bits which corresponds to 4096 gray levels. The image matrix size for standard resolution is 2048 x 2494 which results in a 0.17mm x 0.17 mm pixel size for the 14 inch x 17 inch cassette at standard resolution. The Agfa CR system also allows for change in exposure class or speed which expands the latitude of the system when the examination information is entered and written to the plate. The DR unit is the Canon7 CXDI-11 system has 17 inch x 17 inch flat panel chestboard. The image matrix size is 2688 x 2688 which results in 0.16 mm x 0.16 mm pixel size for the 17 inch x 17 inch field. The detector is amorphous silicon TFT with a Gd2O2S:Tb screen. The grid is incorporated in the flat panel and cannot be easily removed. The Canon CDXI-11 is considered a 200 speed system. It has an imaging depth of 12 bits which corresponds to 4096 gray levels. Modulation Transfer Function Line pair phantom method Droege and Morin (1982) developed a method to determine the MTF by taking the standard deviation of pixel values within an image of a cyclic bar phantom. The Hüttner phantom, a cyclic bar phantom as shown in Figure 4-1, has a frequency range of 0.5-5 lp/mm. The Hüttner phantom was placed in contact with the cassette for the Agfa CR system and placed in contact with the chestboard for the Canon DR system. Images were 6 Agfa Corporation, 100 Challenger Road, Ridgefield Park, NJ 07660 7 Canon U.S.A., Inc., One Canon Plaza, Lake Success , NY , 11042

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48 taken at 50-70 kVp, at 5 kVp intervals for each system. All of the images were processed with a “flat field” algorithm. The images were retrieved from the PACS system and Medisurf software was used to determine the mean and standard deviation of regions of interest (ROI) over the line pair regions of the images. In Equation 4-1, the value M’ is the standard deviation of a frequency region in the cyclic bar pattern can be corrected for the noise. The noise, N as defined by Equati on 4-2 is the standard deviation of the uniform light (Nlight) and dark (Ndark) regions of the phantom. The Mo can be calculated by using the mean values of the light (Mlight) and dark (Mdark) uniform regions of the phantom as shown in Equation 4-3. Equation 4-4 evaluates the MTF for each line pair group in the phantom. An example of this calculation can be found in Appendix A. The MTF was normalized to the lowest frequency and plotted vs. frequency. Figure 4-1. Hüttner phantom A) Frequency configuration in lp/mm and B) image of phantom 2 2N M M (4-1) 22 2 2 Dark LightN N N (4-2) 2Dark Light oM M M (4-3) 0.63 0.56 0.5 0.9 0.8 0.71 1.25 1.12 1.0 1.8 1.6 1.4 2.5 2.24 2.0 3.55 3.15 2.8 5.0 4.5 4.0 No Pb +0.5 Pb

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49 ) ( 4 2 ) (0M f M f MTF (4-4) Line spread function method The presampled MTF for both the Agfa CR system and the Canon DR systems was initially performed with a slit camera but later was determined from a thin line contained in the Leeds8 E1 phantom, shown in Figure 4-2. The slit camera was placed in a holder and the holder was placed in contact with the cassette. The E1 phantom was placed in contact with the cassette for the Agfa CR system or placed in contact with the chestboard for the Canon DR system. The slit and the line of the E1 phantom was angled 2 degrees off the vertical axis. For Agfa CR system, the vertical axis corresponds to the longer axis of the 14 inch x 17 inch cassette. The images were taken for both systems at 40 inch SID, 70 kVp and enough mAs to reach an air kerma of 0.0878 mGy measured using an MDH ion chamber. A “flat field” algorithm was used to process the images on both systems. The images were retrieved from the PACS archive and saved to the local hard drive. The images were manipulated with Matlab and the code for performing the transform to obtain the MTF is described in Appendix B. To get the line spread function (LSF), ten profiles were taken perpendicular to the slit or line and normalize to the maximum pixel value. Before the ten LSF could be averaged together, a correction had to be made in order to align the maximum pixel values off set by the 2 degree configuration of the line in the image. Th e Fourier transform of the LSF produced the MTF. The MTF was the multiplied by 1/sinc( p) were is the frequency and p is the pixel size. The MTF was normalized to the MTF at zero frequency and plotted versus frequency. 8 Leeds Test Objects, Wetherby Road, Boroughbridge, North Yorkshire YO51 9UY, UK

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50 Figure 4-2. Image of E1 Leeds Phantom Noise Power Spectrum The normalized noise power spectrum (NPS) was measured for different clinically applicable configurations shown in Table 4-1. Prior to the NPS measurements, exposure measurements were taken for each combination in Table 4-1 with an MDH ion chamber on the table top, converted to air kerma and recorded. The image receptors were exposed without any additional filtration in the kVp and mAs range in Table 4-1. For the Agfa CR system, the exposure class was adjusted before the plates were placed in the reader in order to maintain an exposure level of approximately 2.0. All images for both systems were processed with a “flat field” algorithm. Images were retrieved from the PACS system and saved to the local hard drive. Images were manipulated with Matlab and the code for the NPS calculations can be found in Appendix B. Using Matlab, the center 1024x1024 region of interest (ROI) of each image was divided into sixty-four 128x128 nonoverlapping ROIs. The formula for determining the two-dimensional NPS is shown in Equation 4-5 where <|FT(u,v)|2> is the ensemble average of the squares of the Fourier amplitudes from all 64 ROIs, Nx and Ny are the number of elements in the discrete transforms and x and y are the pixel sizes in x and y direction (Dobbins et al 1995).

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51 y x y xN N v u FT v u NPS 2) , ( ) , ( (4-5) The 1D NPS needed to calculate the DQE can be determined from a thick slice of the 2D spectrum. A 4x128 slice is taken adjacent to the x-axis of the 2D NPS. The 1D NPS values were plotted versus frequency up to the Nyquist frequency. Table 4-1. Measurement configurations for Agfa CR system and Canon DR system Radiography system Grid Use SID kVp Range mAs Range 40 50-70, 5 kV intervals 0.6-40 No Grid 72 70-85, 5 kV intervals 0.6-20 40 50-70, 5 kV intervals 0.6-40 Agfa CR system Grid 72 70-85, 5 kV intervals 0.6-20 40 50-70, 5 kV intervals 0.6-40 Canon DR system Grid 72 70-85, 5 kV intervals 0.6-32 Integral DQE Because of the amount of data, a single descriptor of image quality was desirable; the integral detective quantum efficiency (IDQE) reported by Fetterly et al. (2000) provides a single quantity for photon absorption efficiency, noise and resolution. The IDQE is integrated over frequency. The DQE defined by Equation 4-6, where k is the conversion from pixel value to exposure and q is the incident signal-to-noise value to be described in more detail in the following sections. Traditionally, the IDQE is determined from Equation 4-7. For each system and c onfiguration in Table 4-1, the IDQE was determined. Nyquistfdf f DQE f IDQE f NPS q f MTF k f DQE0 2) ( 2 ) ( ) ( ) ( (4-6) (4-7)

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52 Incident Signal-to-Noise, q The incident signal-to-noise ratio, q was determined with Equations 4-8 and 4-9. In a simplified case, the noise for a beam of monoenergetic photons N would be N. Therefore, the signal to noise ratio would be N/ N or N2/N. This is very similar to the structure of Equation 4-8. Using Equations 4-8 and 4-9, q (photons/mm) and the air kerma, X (mGy) were calculated where E is energy (kV), q(E) is the number of photons for the given energy, (µen/ )air is the mass-energy absorption coefficient for air, in units of cm2/g. The values for q(E) were determined using the TASMIP computer simulation code (Boone and Siebert, 1997) to estimate the each beam spectra. The input parameters for TASMIP are peak tube potential energy, inherent filtration and tube ripple. The tube ripple is 2% and the inherent filtration is 2.2 and 2.7 mmAl equivalent for CR and DR, respectively values for q, normalized by X are listed in Table 4-2. mGy mm Photons x dE E E q X dE E E q EdE E q qAir en 2 7 2 210 6.19 ) ( ) ( ) ( Table 4-2. Incident signal-to-noise ratio, q for Room 1 (Agfa CR system) and Room 5 (Canon DR system) (photons/mm2*mGy) kVp Room 1 Room 5 50 1.26E+07 1.31E+07 55 1.38E+07 1.44E+07 60 1.48E+07 1.55E+07 65 1.57E+07 1.64E+07 70 1.65E+07 1.72E+07 75 1.73E+07 1.80E+07 80 1.80E+07 1.87E+07 85 1.86E+07 1.93E+07 (4-8) (4-9)

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53 1500 2000 2500 3000 3500 4000 -4-3-2-10Log (Air Kerma [mGy])Pixel Value Figure 4-3. Pixel value vs. log of air kerma for Canon DR system 1500 2000 2500 3000 3500 4000 4500 -4.0-3.0-2.0-1.00.0 Log (Air Kerma*Speed/200)Pixel Value Figure 4-4. Pixel value vs. log of air kerma*speed/200 for Agfa CR system Pixel Value to Exposure Conversion, k The value k converts the pixel values to exposure values. If the pixel values are converted to exposure prior to the calculation of the MTF and DQE, the constant k in Equation 4-6 is not necessary. To determine k, several flat field images for both systems that were taken at 70 kVp and increasing mAs at a 40 inch SID. Exposure was measured

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54 with an MDH ion chamber on the tabletop and converted to air kerma. Since the MDH is approximately 1.5 inches above the tabletop, the inverse square law was used to extrapolate the exposure at 40 inched SID. Mean pixel values were determined from a large area from the center of the flat field images. For Canon DR system, these pixel values were plotted versus log (air kerma) and the slope of the line is proportional to k as shown in Figure 4-3. Because the exposure class, or speed, was changed for the Agfa CR system in the NPS measurement, it must be accounted for in the determination of k. Using the relationship given by Agfa CR syst em for exposure level defined in Equation 1-1, speed and air kerma can be combined. The slope of the line given by a plot of pixel value verses the log (speed/200*air kerma) is proportional to the value of k, as shown in Figure 4-4. Results and Discussion Modulation Transfer Function Initially, the LSF experiment was tried with a slit camera. There was a problem with irregularities of the material surrounding the slit. An image of the slit through a microscope is shown in Figure 4-5. Figure 4-5a shows the material around the slit. There is visible scratches and corrosion of the slit material. Figure 4-5b shows a magnified image of light through the slit. It shows that there are inconsistencies of the edge of the slit. A 3-dimesional rendering of an x-ray image of the slit camera is illustrated in Figure 4-6. The damage to the material surrounding the slit can be seen in the 3D model. When taking profiles perpendicular to the slit, it appeared as if there were

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55 variations in the width of the slit. These variations in width caused inconsistent MTFs. Figure 4-5. Image of the slit camera through a microscope. A) Material around the slit. B) Light through the slit. To ensure that the MTF was not varying with kVp, an alternate method was employed. The line pair phantom method gives approximation of the MTF at discrete frequencies. Figure 4-7 shows the MTF using the line pair phantom for the Agfa CR system. The plot shows that there is no change in MTF with tube potential. Because a more continuous MTF was necessary for the calculation of IDQE, the slit camera was replaced with the Leeds E1 phantom. The 3D image in Figure 4-8 shows that there is no longer the variation in widths across the line. The MTFs, using the E1 phantom for both Agfa CR system and Canon DR system, are shown in Figure 4-9. The MTF of Canon DR system is higher than that of Agfa CR system. That is to be expected since the pixel size of the 14 inch x 17 inch Agfa CR system plates at standard resolution is 0.17 mm x 0.17 mm and the pixel size of the Canon DR system is 0.16mm x 0.16 mm.

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56 Figure 4-6. 3D image of slit camera 0.0 0.2 0.4 0.6 0.8 1.0 0.01.02.03.04.05.0 Frequency (cycles/mm)MTF 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp Figure 4-7. Modulation transfer function of Agfa CR system using line pair function

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57 Figure 4-8. 3D image of line on Leeds E1 phantom 0.0 0.2 0.4 0.6 0.8 1.0 0.01.02.03.04.0 Frequency (cycles/mm)MTF Agfa Canon Figure 4-9. Modulation transfer function for Agfa CR system and Canon DR system using line spread function.

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58 Noise Power Spectrum The NPS versus frequency of the Agfa CR system at 40 inch SID without the grid is shown in Figure 4-10. The areas under each curve is graphed versus radiographic technique are shown in Figure 4-11. The gra phs for the other configurations are located in Appendix C. Noise is greatly reduced by increasing mAs. For instance at 70 kVp, for the Agfa CR system at 40 inch SID without the grid, there is a 23 % reduction in noise by increasing the mAs from 0.6 to 10. When comparing systems to each other, Figure 4-12 plots the NPS versus frequency for all systems and configurations at 70 kVp and 0.6 mAs. For the Agfa CR system 72 inch configuration with the grid, there is a noticeable spike in the NPS caused by the stationary grid in the chestboard in Shands Hospital Room 1. The stationary grid leaves a fixed pattern of grid lines on the flat field images. The table Bucky in Room 1 and the Canon DR system Chestboard have oscillating grids which do not leave a fixed pattern. With increasing frequency, the NPS for the Agfa CR system decreases while the Canon DR system remains flat. Figure 4-13 shows the area under the NPS curves for both systems at all configurations at 70 kVp. This shows that for the Agfa CR system, the integrated NPS without the grid is less than the NPS with the grid. By using the grid, there is less exposure to the CR plate. In both the Agfa CR system and the Canon DR system, the 40 inch SID had a lower NPS and total noise than the 72 inch SID. Again, there is less exposure to the plate at the longer SID due to the inverse square law. When comparing the systems to each other, the Canon DR system has less noise than the Agfa CR system with the grid for the same technique.

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59 0.00E+00 2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 0.00.51.01.52.02.53.0 Frequency (Cycles/mm)NPS (mm2) 50 kVp 0.6 mAs 50 kVp 1.0 mAs 50 kVp 5.0 mAs 50 kVp 10.0 mAs 50 kVp 20.0 mAs 50 kVp 32.0 mAs 50 kVp 40.0 mAs 55 kVp 0.6 mAs 55 kVp 1.0 mAs 55 kVp 5.0 mAs 55 kVp 10.0 mAs 55 kVp 20.0 mAs 55 kVp 32.0 mAs 60 kVp 0.6 mAs 60 kVp 1.0 mAs 60 kVp 5.0 mAs 60 kVp 10.0 mAs 60 kVp 20.0 mAs 65 kVp 0.6 mAs 65 kVp 1.0 mAs 65 kVp 5.0 mAs 65 kVp 10.0 mAs 65 kVp 20.0 mAs 70 kVp 0.6 mAs 70 kVp 1.0 mAs 70 kVp 5.0 mAs 70 kVp 10.0 mAs Figure 4-10. The noise power spectrum for Agfa CR system at 40 inch SID, without the grid 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 32 mAs 40 mAs 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp 0.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04 3.00E-04Total System Noise Figure 4-11. The total system noise for Agfa CR system at 40 inch SID, without the grid

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60 0.00E+00 1.00E-05 2.00E-05 3.00E-05 4.00E-05 5.00E-05 6.00E-05 7.00E-05 8.00E-05 9.00E-05 1.00E-04 00.511.522.533.5 Frequency (cycles/mm)NPS (mm2) Agfa 40 inches No Grid Agfa 40 Inches Grid Canon 40 Inches Grid Agfa 72 Inches No Grid Agfa 72 Inches Grid Canon 72 Inches Grid Figure 4-12. The NPS of all the systems and configurations at 70 kVp and 0.6 mAs. 0.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04 3.00E-04 3.50E-04 0.61510 mAsTotal Noise Agfa 40 No Grid Agfa 40 Grid Canon 40 Grid Agfa 72 No Grid Agfa 72 Grid Canon 72 Grid Figure 4-13. The total system noise for all systems and configurations at 70 kVp.

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61 Integral DQE The IDQE is the single unit descriptor of image quality. Figure 4-14 graphs the IDQE versus kVp and mAs for the Agfa CR system using a 40 inch SID without a grid. The graphs for the other configurations are located in Appendix D. For a given kVp, the image quality generally improves with increasing mAs. One would expect image quality to improve with increasing mAs because more photons mean less noise. But, these graphs also show that there is a point were the IDQE levels off, i.e., there is no additional image quality improvement by increasing the mAs or exposure. For a given mAs, the IDQE increases with a reduction in kVp. Because IDQE increases with quantum efficiency and efficiency decreases with hi gher energies, the IDQE behavior shown is expected. Figure 4-15 compares the systems and configurations to each other at 70 kVp. Other kVp comparison graphs are found in Appendix D. For Agfa CR system, the configuration without the grid gives a higher DQE than with the grid for both 40 and 72 inch SID. By using table top techniques, more photons are able to reach the plate, improving the image quality. For both the Agfa CR system and the Canon DR systems, the shorter SID gives a higher IDQE for all mAs values. At the shorter SID, more photons reach the plate. To compare the Agfa CR system to the Canon DR system, the Agfa CR system was measured with a grid and the Canon DR system had a higher IDQE than Agfa CR system. The Canon DR system has a smaller pixel size resulting in a higher Nyquist frequency than the Agfa CR system 14 inch x 17 inch cassettes at standard resolution. Also the scintillator screen used in the Canon DR system has a greater quantum efficiency than the BaSrFB rI:Eu plates used in the Agfa CR system.

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62 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 32 mAs 40 mAs 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp 0.00 1.00 2.00 3.00 4.00 5.00 6.00IDQE (1/mm)2 Figure 4-14. IDQE for various techniques for Agfa CR system at 40 inch SID without the grid. 0.00 1.00 2.00 3.00 4.00 5.00 6.00IDQE (1/mm)2 0.6 mAs1 mAs5 mAs10 mAs A40NG A40G C40G A72NG A72G C72G Figure 4-15. IDQE for both systems at all configurations at 70 kVp. These IDQE measurements were plotted versus technique and not exposure. Comparing image quality versus technique is fine within a system. But it becomes a

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63 problem when comparing different systems that do not use the same tube. Although the tubes and generator are identical in make and model, there are differences in inherent filtration between the tubes. Even with the same techniques being used, namely kVp and mAs, this does not guarantee that the exposures are the same. Further investigation in the chapter will truly compare the two systems. Summary The IDQE can be used as a single unit desc riptor of image quality. This unit allows for comparison of image quality at differing techniques as well as different systems. Using clinically relevant radiographic techniques, image quality can be measured how it is used in clinical practice. The MTF of the Canon DR system was higher than that of the Agfa CR system due to the smaller pixel value of the Canon. The noise of the Canon DR system was lower than that of the Agfa CR system. The IDQE of the Canon DR system was higher than the Agfa CR system for the same technique. In the next section, the comparison of the two systems is made with air kerma to the image receptor, entrance skin exposure and effective dose instead of radiographic technique.

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64 CHAPTER 5 DEVELOPMENT OF RADIOGRAPHIC TECHNIQUES Introduction New imaging modalities such as digital radiography (DR) and computed radiography (CR) offer the possibility of better image quality than conventional screen/film at reduced doses. Without an appropriate method of predicting useful radiographic techniques, most facilities still use techniques originally developed for screen/film system. With the concern for dose, especially for pediatric patients, it is important to investigate the potential of these new imaging modalities. Since the sizes of children vary, it is important to determine a relationship between effective dose, tube potential and current and IDQE for CR and DR for pediatric patients. Using pediatric anthropomorphic phantoms and evaluating objective measures of image quality, the radiographic techniques for pediatric pa tients can be optimized for CR and DR. Materials and Methods Pediatric Anthropomorphic Phantoms Anthropomorphic phantoms have been designed to simulate the attenuation and scatter characteristics in the body. Two phantoms were constructed at the University of Florida to simulate newborn and one-year-old patients. The height and weight of these phantoms can be found in Table 5-1. The anthropomorphic phantoms consist of a skeleton, lungs and soft tissue. The goal of this phantom was to create a physical model of the Cristy and Eckerman pediatric model shown in Figure 5-1.

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65 Figure 5-1. Mathematical phantom models. (Cristy 1980) The phantom materials are required to match both the density and attenuation of real tissues in the body. The densities of the soft tissue, lung and bone material for the newborn and one-year-old phantoms are listed in Table 5-1. The phantoms are made of three different regions, trunk, legs and head as seen in Figure 5-2 (A). The trunk region is cylindrical and composed of a soft-tissue equivalent material which encloses the lungs and skeleton, displayed in the radiograph shown in Figure 5-2 (D). The skeleton in the trunk consists of arm bones, pelvis, spine, ribs, scapula and clavicles seen in Figure 5-2 (B). The arms were placed by the phantoms side and encased in the trunk illustrated in Figure 5-2 (C). The leg region is the frusta of two soft tissue cones surrounding leg bones. The head region is modeled after the Bouchet-Bolch head model described in “Revised dosimetric models of the pediatric head and brain” (Bouchet et al. 1997), which consists of a head, containing the mandible, teeth, cranium and upper facial region as well as a neck so that the thyroid dose can be measured. Guides (small holes) were drilled in the phantom allow for placement of the dosimeters. The dosimeters were placed in the bone and at the centroid of the soft organs for measurement.

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66 Table 5-1. Information on newborn and one-year-old UF phantoms Newborn One-Year-Old Height 50 cm 75 cm Weight 4 kg 10 kg Lung density 1.04 g/cm3 1.04 g/cm3 Bone density 1.22 g/cm3 1.18 g/cm3 Soft tissue Density 0.30 g/cm3 0.36 g/cm3 (A) (B) (C) (D) Figure 5-2. UF Anthropomorphic Phantom. Certain approximations are made in using these phantoms. These phantoms represent both male and female patients where measurements are made for both types of gonads. The breast dose was measured midway between the breasts since the breasts of newborn and one-year-old children are so small. A single measurement was made for the testes since they are very close together. The dosimeter locations in skeleton were chosen with three criteria in mind. First, the bone had to large enough to accept the MOSFET without loss of a significant percentage of the bone material. Secondly, the bones selected represent a high concentration in active bone marrow. Lastly, the locations had to cover a large percentage of the skeleton. (Bower, 1997).

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67 MOSFET Dosimeters A commercial Patient Dose Verification system manufactured by Thomson & Nielsen Electronics Ltd9., shown in Figure 5-3, was used in this research. The basic system consists of a reader, a bias supplies, power supply, and MOSFET dosimeters. Each dosimeter consists of two MOSFET devi ces mounted together operated at different bias voltage. Each MOSFET device has an active area of 0.04 mm2 and the pair are mounted under a 1 mm thick layer of black epoxy to a 20 cm long thin semi-opaque polyamide laminate cable encasing two gold wires. The extremely thin and flexible laminate cable is attached to a sturdy 1.4 m cable which is connected to the dual bias supply. The patient verification dosimeter system can accommodate up to 20 dosimeters. To facilitate monitoring of the lower absorb ed doses associated with diagnostic x-ray systems; the model TN-RD-19 high-sensitivity bias supply is used. Figure 5-3. MOSFET dosimetry system 9 Thomson & Nielsen Electronics Ltd ., 25E Northside Road, Nepean, Ontario, Canada, K2H 8S1

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68 Dose Measurements MOSFET dosimeters were placed in the guide holes of the pediatric anthropomorphic phantoms. The phantoms were placed on the table or at the chestboard as seen in Figure 5-4 and exposed for all the configurations listed in Table 4-1. The light field was centered on the torso of the phantom and the light field was opened to cover the entire torso. The MDH ion chamber was placed in the field along side the phantom to measure the exposure. MOSFET read out in mV and can be converted to organ-absorbed dose with Equation 5-1. The conversion factor (CF) converts the mV reading to air kerma [mGy]. The conversion factor is determined by exposing the MOSFETs to a known exposure and dividing the mV reading by that exposure. The bone marrow dose was determined using the MOSFET readings for the bone locations with soft tissue massenergy absorption coefficients. Using Equation 1-6, the organ absorbed doses can be converted to effective dose. The doses were normalized by the air kerma. mV CF DSi en Tissue en Tissue 1 876 . 0 (5-1) Figure 5-4. Anthropomorphic phantom placed on the table or at the chestboard

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69 Image Quality Measurements The method for determining IDQE was detailed in the previous chapter. The image quality was determined for the Agfa ADC system and Canon CXDI-11 system in the configurations listed in Table 4-1. In order to fairly compare the systems, the IDQE was plotted versus air kerma at the image receptor for each configuration listed in Table 4-1. In order to measure the air kerma at the image receptors, measurements were taken inside the Bucky using a thin exposure meter called the Barracuda manufactured by RTI Electronics Inc.10 for Agfa CR system configurations with the grid. The Barracuda matched very well with the MDH and the exposure measurements were converted to air kerma. Measurements for Agfa CR system without the grid and Canon DR system configurations were measured using the MDH ion chamber placed on the tabletop. The center of the MDH stands approximately 3.0 cm from the tabletop. Using the inverse square law, the exposure measurements were extrapolated to the tabletop and converted to air kerma. Since the Canon DR system used the same type of grid as the Agfa CR system, a Bucky factor was determined from the Agfa CR system data. The Bucky factor is the ratio of the transmitted radiation to the incident radiation. Using exposure measurements from the MDH at the tabletop as the incident radiation and the Barracuda in the Bucky as the transmitted radiation, a Bucky factor was determined. This Bucky factor was applied to the Canon DR system exposure measurements at the tabletop to determine the exposure to the image receptor behind the gird. Exposure measurements were converted to air kerma by multiplying the mR measurements by 0.087 mGy. 10 RTI Electronics, Göteborgsv 97 / 50, SE-431 37 MÖLNDAL, Sweden

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70 The IDQE was then plotted versus log of air kerma and coefficients for equations in the form of Equation 5-2 are calculated from fitting a line through the data. Coefficients a and b are contained in Appendix E. IDQE = a log (air kerma [mGy]) + b (5-2) Entrance skin exposure (ESE) for each of the phantoms was determined by taking the exposure measurements on the tabletop with the MDH ion chamber. Those measurements were extrapolated to the entrance of the phantom using the inverse square law. The entrance skin exposures were converted to air kerma. For each configuration and phantom, the IDQE was plotted versus entrance skin exposure and coefficients for equations in the form of Equation 5-2 are calculated from fitting a line through the data. Coefficients a and b are contained in Appendix E. Similarly, the IDQE was plotted vs. effective dose for both phantoms. Coefficients for equations in the form of Equation 5-2 are calculated from fitting a line through the data. Coefficients a and b contained in Appendix E. Radiographic Technique Determination The relationship between IDQE and ESE was used to develop a radiographic technique chart for pediatric chest imaging. The automatic exposure control (AEC) was used to make an initial estimate of the radiographic techniques necessary for pediatric chest imaging. The phantoms were placed on either the table or in front of the chestboard as seen in Figure 5-4 for both the Canon DR system and the Agfa CR system. The AEC system is contained in the Bucky with the grid for the Agfa CR system and as a part of the chestboard for the Canon DR system. Only the center AEC sensor was selected because the phantoms do not cover all three AEC sensors. An MDH ion chamber was placed in the field to record the exposure for each phantom image. The exposures were

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71 converted to ESE for both the newborn and one-year-old phantoms. Using the tube outputs (mGy/mAs) in Table 5-2, the mAs was converted to air kerma in mGy. Table 5-2. Tube outputs (mGy/mAs) for Room 1 (Agfa CR system) and Room 5 (Canon DR system) kVp Room 1 Room 5 40 inches 72 inches 40 inches 72 inches 50 1.68E-02 1.14E-02 55 2.08E-02 1.59E-02 60 2.55E-02 2.01E-02 65 3.19E-02 2.51E-02 70 3.82E-02 9.82E-032.95E-028.39E-03 75 1.18E-02 9.82E-03 80 1.39E-02 1.16E-02 85 1.57E-02 1.34E-02 To ascertain the image quality of the AEC images, the air kerma corresponding to the AEC examinations were converted to IDQE for each kVp using Equation 5-2. Those air kerma values were reduced by 25%, 50% and 75% and placed back into Equation 5-2 with the appropriate coefficients to determine the IDQE for the reduced AEC settings. These reduced air kerma values were converted to mAs using the tube outputs in Table 52 values for each kVp. A radiographic technique chart was developed from the mAs values corresponding to the 75% reduced AEC settings for each kVp. For the Agfa CR system, there are two configurations without the grids. To maintain the image quality of the image used with the grid, the 75% reduced IDQE values were place in Equation 5-1 using the non-grid coefficients. Those equations were solved for air kerma and the air kerma values were converted to mAs using the tube outputs. These kVp and mAs values were placed in the radiographic technique chart.

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72 Results and Discussion Relationship between IDQE and Air Kerma at the Image Receptor The relationship between IDQE and air kerma at the image receptor was established by the graphs such as Figure 5-5. The graphs for the remaining configurations are contained in Appendix D. Figure 5-5 shows that the IDQE is higher for lower tube potentials. It also shows that above air kerma values of 0.1 mGy, there is little improvement in the IDQE. The previous chapter stated that a fairer comparison between systems could be achieved if IDQE was plotted versus air kerma at the image receptor. Figure 5-6 shows IDQE for both the Canon DR system and Agfa CR system at all the configurations at 70 kVp. By using the air kerma at the image receptor, it shows that there is no difference in IDQE with SID for the Canon DR system. The same is true for the Agfa CR system; there is no difference in IDQE with SID and grid use. The Canon DR system has a higher IDQE than the Agfa CR system. This would be expected because of the smaller pixel size of Canon DR system. Also, the c onversion from incident photons to diagnostic image is more efficient for the Canon DR system. For the Canon DR system, the photons are converted into light using the scintillator and the TFTs convert the light to electronic signal which becomes the image. The Agfa CR system has more processing steps. Once the image receptor is exposed, the cassette is placed in the reader. The light is released with a laser and the light is collected by the PM tubes. The analog-to-digital converter converts the signal to an image.

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73 2.50 3.00 3.50 4.00 4.50 5.00 0.000.020.040.060.080.100.120.140.160.180.20 Air Kerma (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp Figure 5-5. IDQE vs. air kerma at the image receptor for Agfa CR system at 40 inch SID with the grid 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-01 Air Kerma [mGy]IDQE (1/mm)2 Agfa 40 No Grid Afa 72 No Grid Agfa 40 Grid Agfa 72 Grid Canon 40 Grid Canon 72 Grid Figure 5-6. IDQE vs. air kerma at the image receptor for all configurations at 70 kVp

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74 Figure 5-7 shows the IDQE versus the log of air kerma. These straight lines are approximated with a linear fit which is ideal for relating image quality with air kerma. This relationship allows the prediction of image quality from air kerma measurements. Also, by using the tube output (air kerma/ mAs), a relationship between IDQE and mAs used for the image can also be established as shown in Equation 5-3. Figure 5-8 shows the relationship between IDQE and mAs at 70 kVp for both systems and all configurations. The abbreviations used in the chart are: 1. A40NG – The Agfa CR system without the use of the grid at a 40 inch SID. 2. A40G – The Agfa CR system with the use of the grid at a 40 inch SID. 3. A72NG – The Agfa CR system without the use of the grid at a 72 inch SID. 4. A72G – The Agfa CR system with the use of the grid at a 72 inch SID. 5. C40G – The Canon DR system with the use of the grid at a 40 inch SID. 6. C72G – The Canon DR system with the use of the grid at a 72 inch SID. At lower mAs settings, the Agfa DR system at a 40 inch SID without the grid provides a better image quality than the Canon DR system, as measured by the IDQE. IDQE = a * log [tube output * mAs] + b (5-3) Relationship between IDQE and Entrance Skin Exposure Similar to the relationship between IDQE and air kerma at the image receptor, a relationship between IDQE and ESE was also developed. Graphs of IDQE versus ESE for newborn and one-year-old patients for both systems and all configurations can be found in Appendix D. The slope of the resultant equations in the form of Equation 5-2 were the same as with air kerma at the image receptor but the intercept was different. The intercepts are found in Appendix E. Because ESE changes with patient size, there are intercepts for both newborn and one-year-old patients. The equations can be used to

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75 compare the two systems, as well as different configurations of the same system. Table 53 shows the resultant IDQE after setting the ESE to 0.01 mGy for newborn patients. This shows that for the same ESE to the patient the Canon DR system provides better image quality as measured by the IDQE. Similarly, Table 5-4 shows the resultant ESE after setting the IDQE to 4 for newborn patients. Entrance skin exposure is lower for the Canon DR system. Table 5-3. The IDQE for the same entrance skin exposure (0.01 mGy) for newborn patients. A40NG A40G C40G A72NGA72G C72G 50 kVp 3.58 2.98 4.26 55 kVp 3.31 2.73 3.94 60 kVp 3.06 2.55 3.67 65 kVp 3.01 2.42 3.53 70 kVp 2.87 2.37 3.41 2.82 2.50 3.76 75 kVp 2.71 2.41 3.58 80 kVp 2.62 2.33 3.49 85 kVp 2.56 2.27 3.39 Table 5-4. The entrance skin exposure (mGy) for newborn patients for the same IDQE value of 4. A40NG A40G C40G A72NG A72G C72G 50 kVp 2.68E-02 1.13E-01 7.39E-03 55 kVp 5.86E-02 2.63E-01 1.08E-02 60 kVp 1.35E-01 5.12E-01 1.53E-02 65 kVp 3.10E-01 9.92E-01 1.98E-02 70 kVp 5.40E-01 2.18E+002.44E-02 3.62E-01 4.29E+00 1.44E-02 75 kVp 6.02E-01 1.09E+01 1.88E-02 80 kVp 1.14E+001.94E+01 2.27E-02 85 kVp 2.50E+005.57E+01 2.71E-02

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76 2.50 3.00 3.50 4.00 4.50 5.00 0.000.010.101.00 Log (Air Kerma) [mGy]IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp Figure 5-7. IDQE vs. log (air kerma) at the image receptor for Agfa CR system at 40 inch SID with the grid 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 0.05.010.015.020.0 mAsIDQE (1/mm)2 A40NG A40G C40G A72NG A72G C72G Figure 5-8. IDQE vs. mAs used in newborn imaging at 70 kVp.

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77 Pediatric Radiographic Techniques Figure 5-9 shows the IDQE for the AEC and those reduced by 25%, 50% and 75% used in the development in radiographic technique charts for the Agfa CR system at a 40 inch SID using the grid. Similar graphs are found in Appendix D for the remaining configurations. There is only a 10% 15% difference in IDQE by reducing the AEC exposures by 75%. The radiographic techni ques developed for newborn and one-yearold patients are listed in Tables 5-5 and 5-6, respectively. The tables contain mAs values that correspond to the AEC values reduced by 75%. The radiographic techniques developed here for the Agfa CR system match very well with the mAs settings that a technologist would select for pediatric patient s the same size and weight as the pediatric phantoms, especially for 70 kVp, 40 inch SID and no grid used. Since the Canon DR system is not used on the patients under 4 years of age at Shands at the University of Florida, this has proven helpful in devel oping appropriate radiographic techniques for these patients. Figure 5-10 shows images of the newborn phantom created with the Agfa CR system. The first image was obtained using AEC at 70 kVp and 250 mA with a 40 inch SID. The second image uses the technique found in Table 5-5 for 70 kVp at 40 inches with the grid. The first image is much darker and detail in the lung is not as visible. Although the image quality is better for lower tube potentials, the times associated with the mAs settings would be too long for practical use. In order to minimize motion effects, a lower mAs is needed. The grid may be necessary to reduce scatter in adult patients, but newborn and one-year-old patients are thin and do not produce nearly as much scatter as adult patients. The same argument can be used for a shorter SID. A

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78 longer SID also allows for scatter reduction, but in the smaller patients, there is not as much scatter so a short SID can be used. 2.50 3.00 3.50 4.00 4.50 5.00 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+00 Entrance Skin Expousre (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC Figure 5-9. Reduced AEC values vs. ESE for newborn For the Agfa CR system at a 40 inch SID using the grid AEC helps to eliminate some of the guess work in selecting radiographic techniques since it will automatically terminate the exposure when the optimal exposure level is reached. But small children are too small to cover all the AEC chambers and therefore, AEC is not necessarily appropriate for children. Manual techniques are best for pediatric patients. The radiographic tec hnique charts developed here are based on the response of the AEC system, which makes the Canon DR system require a higher mAs than the Agfa CR system for newborn and one-year-old patients. This is a result of how the Canon DR AEC system is configured because Table 5-3 shows that for the same ESE the Canon DR system should provide a better image quality than the Agfa CR system as

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79 measured by the IDQE. With the Canon DR system having a higher IDQE than the Agfa CR system at the same exposures, and the same anthropomorphic phantoms being used on both system, the Canon DR system should have given lower AEC settings. Although the Canon DR system provides superior image quality at lower ESE, the mechanism available for predicting the response of the system provided by Canon is not fully understood at Shands Hospital at the University of Florida. There is a well defined equation (Equation 1-1) for the Agfa CR system which provides a reliable method to determine the exposure level. (A) (B) Figure 5-10. Image of newborn patient using Agfa CR system at 70 kVp at 40 inch SID with grid, A) uses the AEC system and B) uses manual techniques. Table 5-5. Newborn radiographic technique chart A40NG A40G C40G A72NGA72G C72G 50 kVp 1.3 3.6 17.9 55 kVp 1.1 3.3 10.5 60 kVp 1.2 3.0 6.0 65 kVp 0.8 2.0 3.8 70 kVp 0.5 1.5 2.6 1.6 5.5 19.8 75 kVp 1.4 5.5 8.5 80 kVp 1.5 5.4 6.0 85 kVp 1.1 4.6 4.6

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80 Table 5-6. One-Year-Old radiographic technique chart mAs A40NG A40G C40G A72NGA72G C72G 50 kVp 2.9 8.3 31.3 55 kVp 2.6 7.4 20.8 60 kVp 2.5 6.5 11.5 65 kVp 1.7 4.1 7.1 70 kVp 1.1 2.8 4.7 2.7 10.6 19.0 75 kVp 2.3 10.3 13.1 80 kVp 2.6 10.1 9.1 85 kVp 1.9 8.5 6.9 Effective Doses Effective doses measured at techniques shown in Tables 5-5 and 5-6 with the newborn and one-year-old anthropomorphic phantoms are presented in Tables 5-7 and 58. The details of effective dose calculations are contained in Appendix F. Although, there is an increase in mAs by increasing the SID from 40 inches to 72 inches for the Agfa CR system at 70 kVp, there is a reduction of dose. The opposite is true for the Canon DR system; the effective dose increases with increasing SID. For the Agfa CR system, there is a great reduction in dose by not using the grid, ~70%. Although the Canon DR system has better image quality than the Agfa CR system overall, the effective dose for patients is higher with the Canon DR sy stem than with the Agfa CR system. The mAs values were considerably higher than the Agfa CR system values, which could lead to higher effective doses. Again, since these mAs values are based on the initial estimate provided by the AEC system, the Canon DR system will have a higher mAs settings and higher effective doses. Taking dose, kVp and mAs into consideration, the best technique for the Agfa CR system is 70 kVp, 0.5 mAs, 40 inch SID without the grid. For the Canon DR system, 70 kVp, 2.6 mAs with a 40 inch SID.

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81 Table 5-7. Effective doses (mSv) for newborn patients using techniques in Table 5-3 A40NG A40G C40G A72NG A72G C72G 50 kVp 6.03E-03 2.04E-02 5.82E-02 55 kVp 6.01E-03 2.10E-02 4.21E-02 60 kVp 1.08E-02 3.30E-02 4.28E-02 65 kVp 8.96E-03 2.80E-02 3.47E-02 70 kVp 7.82E-03 2.41E-02 2.90E-02 4.49E-03 1.65E-02 4.82E-02 75 kVp 4.98E-03 2.04E-02 2.49E-02 80 kVp 7.10E-03 2.62E-02 2.32E-02 85 kVp 7.37E-03 3.13E-02 2.54E-02 Table 5-8. Effective doses (mSv) for one-year-old using techniques in Table 5-4 mAs A40NG A40G C40G A72NG A72G C72G 50 kVp 1.45E-02 4.91E-02 1.05E-01 55 kVp 3.31E-02 1.13E-01 2.03E-01 60 kVp 7.95E-02 2.41E-01 2.83E-01 65 kVp 7.71E-02 2.17E-01 2.52E-01 70 kVp 9.21E-02 2.78E-01 3.11E-01 5.97E-02 2.50E-01 3.59E-01 75 kVp 8.66E-02 4.12E-01 4.14E-01 80 kVp 1.06E-01 4.37E-01 3.13E-01 85 kVp 1.28E-01 6.07E-01 4.02E-01 The IDQE can be used as a dose indicator. Systems with a higher IDQE have the ability to produce a better image quality at lower doses. Using the equations relating IDQE with effective dose, Table 5-9 shows the IDQE for the same effective dose of 0.01 mSv. Like previous tables, it shows that the Canon DR system has a better image quality than the Agfa CR system, as measured by the IDQE. Similarly, Table 5-10 shows the effective dose for the same IDQE value of 4. The Canon DR system has the ability to produce the same image quality at a lower effective dose than the Agfa CR system. Summary The image quality measurements taken in the previous chapter were plotted versus air kerma at the image receptor, ESE and effective dose. With these plots, relationships between image quality and radiation quantities were established. The relationship between IDQE and ESE allowed the development of radiographic technique charts for

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82 pediatric patients, especially for the Canon DR system which has not been previously used for small children. The radiographic techniques at the lower tube potentials had large mAs settings which would correspond to a longer exposure times. The longer exposure times lead to motion artifacts in images. To help optimize radiographic technique, the effective dose measurements gave additional information about each radiographic technique. After balancing all the parameters for the best image quality at the lowest dose, radiographic technique ch arts were developed for both the Agfa CR system and the Canon DR system for use with pediatric patients. Table 5-9. IDQE for the same effective dose (0.01 mSv) for newborn patients A40NG A40G C40G A72NG A72G C72G 50 kVp 4.22 3.63 5.59 55 kVp 3.94 3.37 5.24 60 kVp 3.52 3.03 4.67 65 kVp 3.39 2.86 4.40 70 kVp 3.23 2.75 4.23 3.27 2.84 4.68 75 kVp 3.13 2.72 4.47 80 kVp 2.98 2.60 4.26 85 kVp 2.82 2.47 4.01 Table 5-10. Effective dose for the same IDQE value of 4 for newborn patients. A40NG A40G C40G A72NG A72G C72G 50 kVp 5.97E-03 2.43E-02 1.62E-03 55 kVp 1.16E-02 5.05E-02 2.11E-03 60 kVp 3.78E-02 1.39E-01 4.20E-03 65 kVp 8.33E-02 2.73E-01 5.55E-03 70 kVp 1.49E-01 6.17E-01 7.02E-03 9.20E-02 1.09E+00 3.65E-03 75 kVp 1.58E-01 2.84E+00 4.92E-03 80 kVp 3.32E-01 5.65E+00 6.61E-03 85 kVp 9.05E-01 2.01E+01 9.78E-03

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83 CHAPTER 6 CONCLUSION The Agfa CR system uses reusable photostimulatable phosphor plates made of BaSRFBrI:Eu material. The Canon DR system uses an amorphous silicon TFT array with a Gd2O2S:Tb scintillator screen. Both of the digital systems tie into the PACS where the images are displayed and stored. It is important to measure the image quality of these digital systems to take advantage of potential for dose reduction. Evaluating the image quality in an objective manner allows for the comparison of these systems. The objective measures of image quality measured in this study were MTF, NPS and IDQE. The MTF is a measure of the spatial system resolution, NPS is a measure of noise and IDQE is a single unit descriptor of the overall system image quality. Normally, objective image quality measurements are taken at standard distances and tube potentials. In this research, the objective image quality measurements were taken at clinically relevant parameters in order to accurately observe what the image quality would be in clinical practice. In the past, these measurements are only used to evaluate systemÂ’s performance, and compare systems to each other. These image quality measurements were taken further by establishing a relationship between image quality and different radiological parameters such as entrance skin exposure. This relationship is very useful because it shows how image quality of a digital imaging system changes with input exposure. In this research, the relationship between image quality and the radiological quantities was coupled to the tube output to develop radiographic technique charts for pediatric chest imaging. Effective doses measured with anthropomorphic

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84 pediatric phantoms provided additional information and aided in the optimization of radiographic techniques for pediatric patients. The effective doses for the Canon DR system is were higher than the Agfa CR system for the radiographic techniques predicted in this research. At Shands at the University of Florida, the Agfa CR system is used for imaging the smallest patients (less than 4 years of age). The radiographic techniques developed in this research for the Agfa CR system were identical to the radiographic techniques that a technologist would select fo r a patient the same size and weight of the pediatric phantoms. The technologist uses experience, as well as a little trial and error, to determine the proper radiographic techniques to produce the best image. The method developed in this research was able to predict the same radiographic techniques for the Agfa CR system as a technologist without th e trial and error. The method for predicting appropriate radiographic techniques is also useful for setting up new systems such as the Canon DR system at Shands at the University of Florida which is currently not used on patients under 4 years of age. The first five hypotheses were proven true. Hypothesis 1 states that “an increase in peak tube potential (kVp) will not change the MTF of the CR or DR systems.” Determining the MTF using the line pair phantom proved that the MTF does not change with tube potential. Hypothesis 2 states, “the increase of tube current and time (mAs) will produce lower NPS” and Hypothesis 4 states “the use of a longer SID will produce higher NPS.” For both the Agfa CR system and the Canon DR system, the NPS decreased with higher mAs, and shorter SID. Hypothesis 3 states that “the use of the grid during image production will produce higher NPS than images taken without the grid.” For the Agfa CR system, there was a decrease in NPS with the removal of the grid. The

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85 NPS decreased for those cases because more photons were able to reach the imaging plates. Hypothesis 5 states “IDQE will increase for lower tube potentials.” IDQE decreased with higher kVp for both systems. The final hypothesis, “DR will provide better image quality than CR with reduced doses for pediatric patients,” was also proven true. The Canon DR system did have superior image quality to the Agfa CR system for lower effective dose. This research has proven that it is possible to measure image quality objectively at clinically relevant parameters for digital systems. This was the first time a mathematical relationship between image quality and radiation quantities had been established. This information is not only useful in comparing systems but it also helps to produce optimal radiographic techniques for pediatric patients. Future Work. In the future, the MTF and NPS measurements should be repeated for the Canon DR system without the grid to compare to the Agfa CR system without the grid. It was not feasible in this research to remove the grid from the Canon DR system since it was in constant clinical use. Image quality measurements should be repeated using the same x-ray tube for both the CR and DR systems. This will help to eliminate some of the differences in x-ray tube output and discrepancies in the image quality measurements between the CR and DR systems. To expedite the prediction of radiographic techniques, one user-friendly so ftware program could be developed that would incorporate all the image quality measurements. The inputs to the software program would be flat field and line images to determine the NPS and MTF, respectively. The output would be NPS, MTF and IDQE calcu lations. If x-ray tube information is

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86 included in the software program, it could generate an exposure chart for the digital imaging system.

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87 APPENDIX A EXAMPLE OF MTF CALCULATION USING LINE PAIR PHANTOM The following is a calculation of the MTF for the Agfa CR system at 50 kVp, 10 mAs and 40 inch SID using the Hüttner line pair phantom. The standard deviation and mean values were determined using Medisurf software. Figure A-1 identifies the different regions of the Hüttner line pair phantom. The values for the mean and standard deviation for the light and dark regions are s hown in Table A-1. Equation A-1 shows the calculation of the noise, N and Equation A-2 shows of Mo. The M’ values found in Equation A-3 and Table A-2 are the standard deviation of the line pair regions of frequency, f. Equation A-4 is the calculation of the MTF at frequencies, f and the values are displayed in Table A-2. The “Norm” values in Table A-2 are the MTF(f) values divided by MTF(0.5). Figure A-1. Anatomy of Hüttner line pair phantom. Table A-1. Standard deviation and mean of li ght and dark regions of the Hüttner Phantom Standard Deviation Mean Light 29.467 923.181 Dark 14.247 1671.52 Dark Region Light Region Line Pair Regions of varying frequencies, f

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88 0 2 2 2 2 2 2 2) ( 4 2 ) ( 374.1695 2 52 . 1671 181 . 923 2 1671.52 region dark of M 923.181 region light of M 535.6405 2 247 . 14 467 . 29 2 14.247 region dark of deviation Standard 29.467 region light of deviation Standard M f M f MTF N M M M M M ean M ean M N N N N NDark Light o Dark Light Dark Light Dark Light Table A-2. Calculation of the MTF f (lp/mm) M' M MTF (f) Norm. 0.5 255.314 254.26290.7547781.000 0.56 252.986 251.92510.7478390.991 0.63 238.418 237.292 0.7044 0.933 0.71 221.069 219.85420.6526360.865 0.8 210.237 208.95920.6202950.822 0.9 193.334 191.94370.5697840.755 1.0 174.56 173.01890.5136060.680 1.12 165.715 164.09090.4871030.645 1.25 146.622 144.78390.42979 0.569 1.4 129.374 127.287 0.3778510.501 1.6 111.63 109.20450.3241730.429 1.8 94.775 91.905710.2728220.361 2.0 76.925 73.360860.2177710.289 2.25 69.039 65.044160.1930830.256 2.4 51.786 46.326550.13752 0.182 2.8 44.168 37.618770.1116710.148 3.15 38.438 30.6894 0.0911010.121 3.55 33.68 24.468380.0726340.096 4.0 18.516 0 0 0.000 4.5 15.872 0 0 0.000 5.0 19.547 0 0 0.000 (B-1) (B-2) (B-3) (B-4)

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89 APPENDIX B MATLAB CODES Modulation Transfer Function The following is the Matlab code for the calculation of the modulation transfer function. % Clearing memory and screen values clear;clc; % Reading the image Q=imread('line.tif','tif'); % Converting it to double precision Q=double(Q); % Determining the size of the image [M,N]=size(Q); % Determining the line spread function (LSF) from the image, finding the peak of the LSF and adjusting the LSF to account for the angle. B=zeros(1,64); for i=1:2:N A=Q(i,:); A=A-min(A); A=A/max(A); [Y,I]=max(A); A=A(I-32:I+31); B=B+A; end B=B-min(B); B=B/max(B); figure(3);plot(B); B=B-.1; for i=1:64 if B(i)<0 B(i)=0; end end ZZ45=B;

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90 % Terminating the long tails on the LSF [M,N]=size(ZZ45); for i=1:N if ZZ45(i)<0.1*max(ZZ45) ZZ45(i)=0; end end G=zeros(1,100); ZZ45=cat(2,G,ZZ45,G); ZZ45=ZZ45/max(ZZ45); [Y,I]=max(ZZ45); ZZ45=ZZ45(1,I-64:I+64); % writing the line spread function to a text file dlmwrite('lsfslit.txt',ZZ45,'\r'); % plotting the line spread function figure(1); subplot(1,2,1 );plot(ZZ45,'rd-') title('Line Spread Function using Slit at small degree angle') % Calculating the MTF values ZZMTF45=abs(real(fft(ZZ45))); % Normalizing the MTF values to the zero frequency MTF value ZMTF45=ZZMTF45/ZZMTF45(1); %Plotting the normalized MTF values figure(1); subplot(1,2,2);plot(ZMTF45(1:64),'rd-') title('Line Spread Function using Slit at small degree angle') %writing the MTF values to a text file dlmwrite('slit.txt',ZMTF45(1:64),'\r'); Noise Power Spectrum The following is the Matlab code for noise power spectrum. %Clearing the memory and screen values clc;clear; % Reading in dicom flat field image info = dicominfo('I0001_1'); A = dicomread(info); %figure(1);imagesc(A);

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91 %Splitting the image into 128 x 128 regions and taking the Fourier Transform of each section F=zeros(128,128); for i=500:128:1396 for j=500:128:1396 T = A(i:i+127,j:j+127); P = (log(abs(fft2(T))).^2); F = F+P; end end % Averaging the sections and normalizing the image by pixel size. For Agfa CR system, the pixel area normalization is 0.17*0.17, and 0.16*0.16 for Canon DR system. K=(F/64)*((.17*.17)/(128*128)); % Flipping the image to ensure that it is displayed correctly H(1:63,1:63)=fliplr(flipud(K(1:63,1:63))); H(64:128,1:63)=fliplr(flipud(K(64:128,1:63))); H(1:63,64:128)=fliplr(flipud(K(1:63,64:128))); H(64:128,64:128)=fliplr(flipud(K(64:128,64:128))); % Image of 2D NPS figure(2); colormap gray; imagesc(H); %Calculating the 1D NPS % Determining the size of the 2D NPS image [MA,NA] = size(H); CXA = [NA/2:NA]; [M1A,N2A] = size(CXA); %Selecting rows in the 2D NPS image to use for the 1D NPS curve CY1 = ones(M1A,N2A)*(65); CY2 = ones(M1A,N2A)*(66); CY3 = ones(M1A,N2A)*(67); CY4 = ones(M1A,N2A)*(68); % Slices of the 2D NPS image adjacent to the X axis LSF1 = improfile(H,CXA,CY1); LSF2 = improfile(H,CXA,CY2); LSF3 = improfile(H,CXA,CY3); LSF4 = improfile(H,CXA,CY4); % Averaging 1D NPS line segments

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92 LSF=(LSF1+LSF2+LSF3+LSF4)/4; % Plotting 1D NPS figure(3); plot(LSF,'red'); % Writing 1D NPS data to file. file=input('File name?','s') DLMWRITE(file,LSF,'/t')

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93 APPENDIX C NOISE POWER SPECTRUM GRAPHS Figure C-1. The NPS vs. frequency for the Ag fa CR system at a 40 inch SID without using the grid 0.00E+00 2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 0.00.51.01.52.02.53.0 Frequency (Cycles/mm)NPS (mm2) 50 kVp 0.6 mAs 50 kVp 1.0 mAs 50 kVp 5.0 mAs 50 kVp 10.0 mAs 50 kVp 20.0 mAs 50 kVp 32.0 mAs 50 kVp 40.0 mAs 55 kVp 0.6 mAs 55 kVp 1.0 mAs 55 kVp 5.0 mAs 55 kVp 10.0 mAs 55 kVp 20.0 mAs 55 kVp 32.0 mAs 60 kVp 0.6 mAs 60 kVp 1.0 mAs 60 kVp 5.0 mAs 60 kVp 10.0 mAs 60 kVp 20.0 mAs 65 kVp 0.6 mAs 65 kVp 1.0 mAs 65 kVp 5.0 mAs 65 kVp 10.0 mAs 65 kVp 20.0 mAs 70 kVp 0.6 mAs 70 kVp 1.0 mAs 70 kVp 5.0 mAs 70 kVp 10.0 mAs

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94 Figure C-2. The NPS vs. frequency for the Agfa CR system at a 40 inch SID using the grid 0.00E+00 2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 1.40E-04 00.511.522.53 Frequency ( cycles/mm)NPS (mm2) 50 kVp 0.6 mAs 50 kVp 1.0 mAs 50 kVp 5.0 mAs 50 kVp 10.0 mAs 50 kVp 20.0 mAs 50 kVp 32.0 mAs 50 kVp 40.0 mAs 55 kVp 0.6 mAs 55 kVp 1.0 mAs 55 kVp 5.0 mAs 55 kVp 10.0 mAs 55 kVp 20.0 mAs 55 kVp 32.0 mAs 60 kVp 0.6 mAs 60 kVp 1.0 mAs 60 kVp 5.0 mAs 60 kVp 10.0 mAs 60 kVp 20.0 mAs 65 kVp 0.6 mAs 65 kVp 1.0 mAs 65 kVp 5.0 mAs 65 kVp 10.0 mAs 65 kVp 20.0 mAs 70 kVp 0.6 mAs 70 kVp 1.0 mAs 70 kVp 5.0 mAs 70 kVp 10.0 mAs

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95 Figure C-3. The NPS vs. frequency for the Ca non system at a 40 inch SID using the grid 0.00E+00 2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 00.511.522.53 Frequency (cycles/mm)NPS (mm2) 50 kVp 0.6 mAs 50 kVp 1 mAs 50 kVp 5 mAs 50 kVp 10 mAs 50 kVp 20 mAs 50 kVp 32 mAs 50 kVp 40 mAs 55 kVp 0.6 mAs 55 kVp 1 mAs 55 kVp 5 mAs 55 kVp 10 mAs 55 kVp 20 mAs 55 kVp 32 mAs 60 kVp 0.6 mAs 60 kVp 1 mAs 60 kVp 5 mAs 60 kVp 10 mAs 60 kVp 20 mAs 65 kVp 0.6 mAs 65 kVp 1 mAs 65 kVp 5 mAs 65 kVp 10 mAs 65 kVp 20 mAs 70 kVp 0.6 mAs 70 kVp 1 mAs 70 kVp 5 mAs 70 kVp 10 mAs

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96 Figure C-4. The NPS vs. frequency for the Agfa CR system at a 72 inch SID without using the grid 0.00E+00 2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 00.511.522.53 frequency (cycles/mm)NPS (mm2) 70 kVp 0.6 mAs 70 kVp 1.0 mAs 70 kVp 5.0 mAs 70 kVp 10.0 mAs 70 kVp 20.0 mAs 75 kVp 0.6 mAs 75 kVp 1.0 mAs 75 kVp 5.0 mAs 75 kVp 10.0 mAs 75 kVp 20.0 mAs 80 kVp 0.6 mAs 80 kVp 1.0 mAs 80 kVp 5.0 mAs 80 kVp 10.0 mAs 80 kVp 20.0 mAs 85 kVp 0.6 mAs 85 kVp 1.0 mAs 85 kVp 5.0 mAs 85 kVp 10.0 mAs 85 kVp 20.0 mAs

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97 Figure C-5. The NPS vs. frequency for the Agfa CR system at a 72 inch SID using the grid 0.00E+00 2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 1.40E-04 00.511.522.53 frequency (cycles/mm)NPS (mm2) 70 kVp 0.6 mAs 70 kVp 1.0 mAs 70 kVp 5.0 mAs 70 kVp 10.0 mAs 70 kVp 20.0 mAs 75 kVp 0.6 mAs 75 kVp 1.0 mAs 75 kVp 5.0 mAs 75 kVp 10.0 mAs 75 kVp 20.0 mAs 80 kVp 0.6 mAs 80 kVp 1.0 mAs 80 kVp 5.0 mAs 80 kVp 10.0 mAs 80 kVp 20.0 mAs 85 kVp 0.6 mAs 85 kVp 1.0 mAs 85 kVp 5.0 mAs 85 kVp 10.0 mAs 85 kVp 20.0 mAs

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98 Figure C-6. The NPS vs. frequency for the Canon DR system at a 72 inch SID using the grid 0.00E+00 2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 0.00.51.01.52.02.53.0 frequency (cycles/mm)NPS (mm2) 70 kVp 0.6 mAs 70 kVp 1 mAs 70 kVp 5 mAs 70 kVp 10 mAs 70 kVp 20 mAs 70 kVp 32 mAs 75 kVp 0.6 mAs 75 kVp 1 mAs 75 kVp 5 mAs 75 kVp 10 mAs 75 kVp 20 mAs 75 kVp 32 mAs 80 kvp 0.6 mas 80 kVp 1 mAs 80 kVp 5 mAs 80 kVp 10 mAs 80 kVp 20 mAs 80 kVp 32 mAs 85 kVp 0.6 mAs 85 kVp 1 mAs 85 kVp 5 mAs 85 kVp 10 mAs 85 kVp 20 mAs

PAGE 119

99 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 32 mAs 40 mAs 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp 0.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04 3.00E-04iNPS Figure C-7. For the Agfa CR system at a 40 inch SID without using the grid, the area under the NPS curve (iNPS) vs. radiographic technique (kVp and mAs)

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100 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 32 mAs 40 mAs 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp 0.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04 3.00E-04 3.50E-04iNPS Figure C-8. For the Agfa CR system at a 40 inch SID using the grid, the area under the NPS curve (iNPS) vs. radiographic technique (kVp and mAs)

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101 0.6 mAs 1.0 mAs 5.0 mAs 10.0 mAs 20.0 mAs 32.0 mAs 40.0 mAs 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp 0.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04 3.00E-04 3.50E-04iNPS Figure C-9. For the Canon DR system at a 40 inch SID using the grid , the area under the NPS curve (iNPS) vs. radiographic technique (kVp and mAs)

PAGE 122

102 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 70 kVp 75 kVp 80 kVp 85 kVp 0.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04 3.00E-04iNPS Figure C-10. For the Agfa CR system at a 72 inch SID without using the grid, the area under the NPS curve (iNPS) vs. radiographic technique (kVp and mAs)

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103 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 70 kVp 75 kVp 80 kVp 85 kVp 0.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04 3.00E-04 3.50E-04iNPS Figure C-11. For the Agfa CR system at a 72 inch SID using the grid, the area under the NPS curve (iNPS) vs. radiographic technique (kVp and mAs)

PAGE 124

104 0.6 mAs 1.0 mAs 5.0 mAs 10.0 mAs 20.0 mAs 32.0 mAs 70 kVp 75 kVp 80 kVp 85 kVp 0.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04 3.00E-04iNPS Figure C-12. For the Canon DR system at a 72 inch SID using the grid, the area under the NPS curve (iNPS) vs. radiographic technique (kVp and mAs)

PAGE 125

105 APPENDIX D INTEGRAL DETECTIVE QUANTUM EFFICIENCY GRAPHS 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 32 mAs 40 mAs 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp 0.00 1.00 2.00 3.00 4.00 5.00 6.00IDQE (1/mm)2 Figure D-1. For the Agfa CR system at a 40 inch SID without using the grid, IDQE vs. radiographic technique (kVp and mAs). .

PAGE 126

106 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 32 mAs 40 mAs 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00IDQE (1/mm)2 Figure D-2. For the Agfa CR system at a 40 inch SID using the grid, IDQE vs. radiographic technique (kVp and mAs).

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107 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 32 mAs 40 mAs 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp 0.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000 8.000IDQE (1/mm)2 Figure D-3. For the Canon DR system at a 40 inch SID using the grid, IDQE vs. radiographic technique (kVp and mAs).

PAGE 128

108 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 70 kVp 75 kVp 80 kVp 85 kVp 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00IDQE (1/mm)2 Figure D-4. For the Agfa CR system at a 72 inch SID without using the grid, IDQE vs. radiographic technique (kVp and mAs)

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109 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 70 kVp 75 kVp 80 kVp 85 kVp 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50IDQE (1/mm)2 Figure D-5. For the Agfa CR system at a 72 inch SID using the grid, IDQE vs. radiographic technique (kVp and mAs).

PAGE 130

110 0.6 mAs 1 mAs 5 mAs 10 mAs 20 mAs 32 mAs 70 kVp 75 kVp 80 kVp 85 kVp 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00IDQE (1/mm)2 Figure D-6. For the Canon DR system at a 72 inch SID using the grid, IDQE vs. radiographic technique (kVp and mAs)

PAGE 131

111 Figure D-7. For the Agfa CR system at a 40 inch SID without using the grid, IDQE vs. Air Kerma [mGy] at the image receptor 3.00 3.50 4.00 4.50 5.00 5.50 0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-01 Air Kerma (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 132

112 Figure D-8. For the Agfa CR system at a 40 inch SID using the grid, IDQE vs. Air Kerma [mGy] at the Image Receptor 2.50 3.00 3.50 4.00 4.50 5.00 0.000.020.040.060.080.100.120.140.160.180.20 Air Kerma (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 133

113 Figure D-9. For the Canon DR system at a 40 inch SID using the gridm, IDQE vs. Air Kerma [mGy] at the image receptor 3.500 4.000 4.500 5.000 5.500 6.000 6.500 7.000 7.500 8.000 0.00E+002.00E-024.00E-026.00E-028.00E-021.00E-011.20E-011.40E-01 Air Kerma (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 134

114 Figure D-10. For the Agfa CR system at a 72 inch SID without using the grid ,IDQE vs. Air Kerma [mGy] at image receptor 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.000.050.100.150.200.250.300.35 Air Kerma (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 135

115 Figure D-11. For the Agfa CR system at a 72 inch SID using the grid, IDQE vs. Air Kerma [mGy] at the image receptor 2.20 2.40 2.60 2.80 3.00 3.20 3.40 0.000.020.040.060.080.100.120.140.16 Air Kerma (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 136

116 Figure D-12. For the Canon DR system at a 72 inch SID using the grid, IDQE vs. Air Kerma [mGy] at the image receptor 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 0.00E+002.00E-024.00E-026.00E-028.00E-021.00E-011.20E-011.40E-011.60E-01 Air Kerma (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 137

117 Figure D-13. For the Agfa CR system at 40 in ch SID without using the grid, IDQE vs. Log Air Kerma at the image receptor [mGy] 2.50 3.00 3.50 4.00 4.50 5.00 5.50 1.00E-031.00E-021.00E-011.00E+00 Log Air Kerma (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 138

118 Figure D-14. For the Agfa CR system at a 40 inch SID using the grid, IDQE vs. Log Air Kerma [mGy] at the image receptor 2.50 3.00 3.50 4.00 4.50 5.00 0.000.010.101.00 Log (Air Kerma) [mGy]IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 139

119 Figure D-15. For the Canon DR system at a 40 inch SID using the grid, IDQE vs. Log Air Kerma [mGy] at the image receptor 3.500 4.000 4.500 5.000 5.500 6.000 6.500 7.000 7.500 8.000 1.00E-031.00E-021.00E-011.00E+00 Log Air Kerma (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 140

120 Figure D-16. For the Agfa CR system at 72 in ch SID without using the grid, IDQE vs. Log Air Kerma [mGy] at the image receptor 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.000.010.101.00 Log Air Kerma (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 141

121 Figure D-17. For the Agfa CR system at a 72 inch SID using the grid, IDQE vs. Log Air Kerma [mGy] at the image receptor 2.20 2.40 2.60 2.80 3.00 3.20 3.40 0.000.010.101.00 Log Air Kerma (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 142

122 Figure D-18. For the Canon DR system at a 72 inch SID using the grid, IDQE vs. Log Air Kerma [mGy] at the image receptor 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 1.00E-031.00E-021.00E-011.00E+00 Log Air Kerma (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 143

123 Figure D-19. For the Agfa CR system at a 40 inch SID without using the grid, IDQE vs. Entrance Skin Exposure for Newborn Patients 3.00 3.50 4.00 4.50 5.00 5.50 0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-018.00E-019.00E-01 Entrance Skin Exposure (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 144

124 Figure D-20. Reduced AEC values for newborn patients for the Agfa CR system at a 40 inch SID without using the grid 3.00 3.50 4.00 4.50 5.00 5.50 0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-018.00E-019.00E-01 Entrance Skin Expousre (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC .75*AEC .5*AEC .25*AEC Lo g . ( 50

PAGE 145

125 Figure D-21. IDQE vs. entrance skin exposure for newborn patients for the Agfa CR system at a 40 inch SID using the grid 2.50 3.00 3.50 4.00 4.50 5.00 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+00 Entrance Skin Exposure (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 146

126 Figure D-22. Reduced AEC values for newborn patients for the Agfa CR system at a 40 inch SID using the grid 2.50 3.00 3.50 4.00 4.50 5.00 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+00 Entrance Skin Expousre (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 147

127 Figure D-23. IDQE vs. entrance skin exposure for newborn patients For the Canon CR system at a 40 inch SID using the grid 3.500 4.000 4.500 5.000 5.500 6.000 6.500 7.000 7.500 8.000 0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-01 Entrance Skin Exposure (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 148

128 Figure D-24. Reduced AEC values For Newborn Patients For the Canon CR system at a 40 inch SID using the grid 3.500 4.000 4.500 5.000 5.500 6.000 6.500 7.000 7.500 8.000 8.500 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+00 Entrance Skin Expousre (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 149

129 Figure D-25. IDQE vs. entrance skin exposure for newborn patients for the Agfa CR system at a 72 inch SID without using the grid 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-014.50E-01 Entrance Skin Exposure (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 150

130 Figure D-26. Reduced AEC values for newborn patients for the Agfa CR system at a 72 inch SID without using the grid 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-014.50E-01 Entrance Skin Expousre (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 151

131 Figure D-27. IDQE vs. entrance skin exposure for newborn patients for the Agfa CR system at a 72 inch SID using the grid 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-014.50E-01 Entrance Skin Exposure (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 152

132 Figure D-28. Reduced AEC values for newborn patients for the Agfa CR system at a 72 inch SID using the grid 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-014.50E-01 Entrance Skin Expousre (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 153

133 Figure D-29. IDQE vs. entrance skin exposure for newborn patients for the Canon DR system at a 72 inch SID using the grid 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-014.50E-015.00E-01 Entrance Skin Exposure (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 154

134 Figure D-30. Reduced AEC values for newborn patients for the Canon DR system at a 72 inch SID using the grid 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-018.00E-019.00E-01 Entrance Skin Expousre (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 155

135 Figure D-31. IDQE vs. Entrance Skin Exposure For One Year Old Patients For the Agfa CR system at a 40 inch SID without using the grid 3.00 3.50 4.00 4.50 5.00 5.50 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+00 Entrance Skin Exposure (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 156

136 Figure D-32. Reduced AEC vs. entrance skin exposure values for one year old patients for the Agfa CR system at a 40 inch SID without using the grid 3.00 3.50 4.00 4.50 5.00 5.50 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+00 Entrance Skin Expousre (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 157

137 Figure D-33. IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 40 inch SID using the grid 2.50 3.00 3.50 4.00 4.50 5.00 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+001.60E+00 Entrance Skin Exposure (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 158

138 Figure D-34. Reduced AEC values vs. entrance skin exposure for one year old patients for the Agfa CR system at a 40 inch SID using the grid 2.50 3.00 3.50 4.00 4.50 5.00 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+001.60E+001.80E+00 Entrance Skin Expousre (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 159

139 Figure D-35. IDQE vs. entrance skin exposure for one year old patients for the Canon CR system at a 40 inch SID using the grid 4.000 4.500 5.000 5.500 6.000 6.500 7.000 7.500 8.000 0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-018.00E-019.00E-01 Entrance Skin Exposure (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 160

140 Figure D-36. Reduced AEC values vs. entrance skin exposure for one year old patients for the Canon CR system at a 40 inch SID using the grid 3.500 4.500 5.500 6.500 7.500 8.500 9.500 0.00E+005.00E-011.00E+001.50E+002.00E+002.50E+00 Entrance Skin Expousre (mGy)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC Log(50

PAGE 161

141 Figure D-37. IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID without using the grid 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-014.50E-015.00E-01 Entrance Skin Exposure (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 162

142 Figure D-38. Reduced AEC values vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID without using the grid 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E -013.00E-013.50E-014.0 0E-014.50E-015.00E-01 Entrance Skin Expousre (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 163

143 Figure D-39. IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID using the grid 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-014.50E-015.00E-01 Entrance Skin Exposure (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 164

144 Figure D-40. Reduced AEC values vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID using the grid 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-014.50E-015.00E-01 Entrance Skin Expousre (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 165

145 Figure D-41. IDQE vs. entrance skin exposure for one year old patients for the Canon DR system at a 72 inch SID using the grid 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-014.50E-015.00E-01 Entrance Skin Exposure (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

PAGE 166

146 Figure D-42. Reduced AEC values vs. entrance skin exposure for one year old patients for the Canon DR system at a 72 inch SID using the grid 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 7.50 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+001.60E+001.80E+00 Entrance Skin Expousre (mGy)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 167

147 Figure D-43. IDQE vs. Effective Dose For Ne wborn Patients For the Agfa CR system at a 40 inch SID without using the grid 3.00 3.50 4.00 4.50 5.00 5.50 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-01 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 168

148 Figure D-44. Reduced AEC values vs. effective dose for newborn patients for the Agfa CR system at a 40 inch SID without using the grid 3.00 3.50 4.00 4.50 5.00 5.50 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-01 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC .75*AEC .5*AEC .25*AEC Lo g . ( 50

PAGE 169

149 Figure D-45. IDQE vs. Effective Dose For Ne wborn Patients For the Agfa CR system at a 40 inch SID using the grid 2.50 3.00 3.50 4.00 4.50 5.00 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-01 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

PAGE 170

150 Figure D-46. Reduced AEC values vs. effective dose for newborn patients for the Agfa CR system at a 40 inch SID using the grid 2.50 3.00 3.50 4.00 4.50 5.00 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-01 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

PAGE 171

151 Figure D-47. IDQE vs. Effective Dose for newborn patients for the Canon CR system at a 40 inch SID using the grid 3.500 4.000 4.500 5.000 5.500 6.000 6.500 7.000 7.500 8.000 0.00E+002.00E-024.00E-026.00E-028.00E-021.00E-011.20E-011.40E-011.60E-011.80E-012.00E-01 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

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152 Figure D-48. Reduced AEC values vs. effective dose for newborn patients for the Canon CR system at a 40 inch SID using the grid 3.500 4.000 4.500 5.000 5.500 6.000 6.500 7.000 7.500 8.000 8.500 0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-018.00E-01 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

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153 Figure D-49. IDQE vs. Effective Dose for ne wborn patients for the Agfa CR system at a 72 inch SID without using the grid 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.00E+002.00E-024.00E-026.00E-028.00E-021.00E-011.20E-011.40E-011.60E-01 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

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154 Figure D-50. Reduced AEC values vs. effective dose for newborn patients for the Agfa CR system at a 72 inch SID without using the grid 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.00E+002.00E-024.00E-026.00E-028.00E-021.00E-011.20E-011.40E-011.60E-01 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

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155 Figure D-51. IDQE vs. effective dose for new born patients for the Agfa CR system at a 72 inch SID using the grid 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 0.00E+002.00E-024.00E-026.00E-028.00E-021.00E-011.20E-011.40E-011.60E-01 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

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156 Figure D-52. Reduced AEC values vs. effective dose for newborn patients for the Agfa CR system at a 72 inch SID using the grid 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 0.00E+002.00E-024.00E-026.00E-028.00E-021.00E-011.20E-011.40E-011.60E-01 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

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157 Figure D-53. IDQE vs. Effective Dose for Ne wborn Patients for the Canon DR system at a 72 inch SID using the grid 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 0.00E+002.00E-024.00E-026.00E-028.00E-021.00E-011.20E-011.40E-011.60E-01 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

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158 Figure D-54. Reduced AEC values vs. effective dose for newborn patients for the Canon DR system at a 72 inch SID using the grid 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 7.50 0.00E+005.00E-021.00E-011.50E-012.00E-012.50E-013.00E-013.50E-014.00E-014.50E-01 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

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159 Figure D-55. IDQE vs. Effective Dose for On e Year Old Patients for the Agfa CR system at a 40 inch SID without using the grid 3.00 3.50 4.00 4.50 5.00 5.50 0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-018.00E-019.00E-011.00E+00 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

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160 Figure D-56. Reduced AEC values vs. effective dose for one year old patients for the Agfa CR system at a 40 inch SID without using the grid 3.00 3.50 4.00 4.50 5.00 5.50 0.00E+001.00E-012.00E-013.00E-014.00E-01 5.00E-016.00E-017.00E-01 8.00E-019.00E-011.00E+00 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

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161 Figure D-57. IDQE vs. effective dose for one y ear old patients for the Agfa CR system at a 40 inch SID using the grid 2.50 3.00 3.50 4.00 4.50 5.00 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+00 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

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162 Figure D-58. Reduced AEC values vs. effective dose for one year old patients for the Agfa CR system at a 40 inch SID using the grid 2.50 3.00 3.50 4.00 4.50 5.00 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+00 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

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163 Figure D-59. IDQE vs. entrance skin exposure for one year old patients for the Canon CR system at a 40 inch SID using the grid 3.500 4.000 4.500 5.000 5.500 6.000 6.500 7.000 7.500 8.000 0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-018.00E-01 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp

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164 Figure D-60. Reduced AEC values vs. effective dose for one year old patients for the Canon CR system at a 40 inch SID using the grid 3.500 4.500 5.500 6.500 7.500 8.500 9.500 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+001.60E+001.80E+00 Effective Dose (mSv)IDQE (1/mm)2 50 kVp 55 kVp 60 kVp 65 kVp 70 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC Log(50

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165 Figure D-61. IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID without using the grid 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+001.60E+00 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

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166 Figure D-62. Reduced AEC values vs. effective dose for one year old patients for the Agfa CR system at a 72 inch SID without using the grid 2.40 2.60 2.80 3.00 3.20 3.40 3.60 3.80 4.00 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+001.60E+00 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

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167 Figure D-63. IDQE vs. entrance skin exposure for one year old patients for the Agfa CR system at a 72 inch SID using the grid 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+001.60E+001.80E+00 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

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168 Figure D-64. Reduced AEC values vs. effective dose for one year old patients for the Agfa CR system at a 72 inch SID using the grid 2.00 2.20 2.40 2.60 2.80 3.00 3.20 3.40 3.60 0.00E+005.00E-011.00E+001.50E+002.00E+002.50E+003.00E+00 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

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169 Figure D-65. IDQE vs. entrance skin exposure for one year old patients for the Canon DR system at a 72 inch SID using the grid 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 0.00E+002.00E-014.00E-016.00E-018.00E-011.00E+001.20E+001.40E+00 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp

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170 Figure D-66. Reduced AEC values vs. effective dose for one year old patients for the Canon DR system at a 72 inch SID using the grid 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 0.00E+005.00E-011.00E+001.50E+002.00E+002.50E+003.00E+00 Effective Dose (mSv)IDQE (1/mm)2 70 kVp 75 kVp 80 kVp 85 kVp AEC 0.75*AEC 0.50*AEC 0.25*AEC

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171 APPENDIX E COEFFICIENTS FOR IDQE EQUATIONS Table E1. Coefficients for the Agfa CR syst em at a 40 inch SID without use of the grid Entrance Skin Exposure Effective Dose Slope Exposure to the Plate Newborn One Year Old Newborn One Year Old 50 kVp 0.429 5.6917 5.5523 5.4449 6.1972 6.1812 55 kVp 0.3891 5.2301 5.1037 5.0062 5.7343 5.3901 60 kVp 0.3603 4.838 4.7209 4.6307 5.1805 4.7383 65 kVp 0.2878 4.2613 4.3372 4.2619 4.7152 4.3087 70 kVp 0.2844 4.1041 4.1754 4.101 4.5413 4.0077 Table E-2. Coefficients for the Agfa CR system at a 40 inch SID with use of the grid Entrance Skin Exposure Effective Dose Slope Exposure to the Plate Newborn One Year Old Newborn One Year Old 50 kVp 0.4206 5.7185 4.9176 4.7972 5.563 5.5472 55 kVp 0.3897 5.2394 4.5202 4.4087 5.1638 4.8191 60 kVp 0.369 4.9039 4.2467 4.1411 4.7287 4.2759 65 kVp 0.3445 4.5988 4.0027 3.9041 4.4467 3.9808 70 kVp 0.3032 4.2746 3.7639 3.6771 4.1464 3.6022 Table E-3. Coefficients for the Canon DR system at a 40 inch SID with the use of the grid Entrance Skin Exposure Effective Dose Slope Exposure to the Plate NewbornOne Year Old Newborn One Year Old 50 kVp 0.8758 9.9513 8.2979 8.064 9.6274 9.5946 55 kVp 0.796 9.0601 7.6041 7.3916 8.9058 8.2017 60 kVp 0.7754 8.6114 7.2429 7.0358 8.2431 7.2917 65 kVp 0.6853 7.862 6.6875 6.5045 7.5595 6.6327 70 kVp 0.6571 7.5363 6.4402 6.2647 7.2585 6.079 Table E-4. Coefficients for the Agfa CR syst em at a 72 inch SID without the use of the grid Entrance Skin Exposure Effective Dose Slope Exposure to the Plate NewbornOne Year Old Newborn One Year Old 70 kVp 0.3282 4.391 4.3339 4.2928 4.7832 4.1104 75 kVp 0.3138 4.2141 4.1595 4.1203 4.5792 3.8326 80 kVp 0.2922 4.0137 3.9628 3.9263 4.3221 3.682 85 kVp 0.261 3.8063 3.7608 3.7282 4.026 3.4111

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172 Table E-5. Coefficients for the Agfa CR system at a 72 inch SID with the use of the grid Entrance Skin Exposure Effective Dose Slope Exposure to the Plate NewbornOne Year Old Newborn One Year Old 70 kVp 0.2482 3.9291 3.6386 3.6065 3.9794 3.4705 75 kVp 0.2269 3.7149 3.4585 3.4292 3.7629 3.2231 80 kVp 0.2203 3.5909 3.3468 3.3184 3.6186 3.136 85 kVp 0.2011 3.4079 3.1915 3.1655 3.3965 2.9229 Table E-6. Coefficients for the Canon DR system at a 72 inch SID with the use of the grid Entrance Skin Exposure Effective Dose Slope Exposure to the Plate NewbornOne Year Old Newborn One Year Old 70 kVp 0.6759 7.6576 6.8678 6.7819 9.6274 9.5946 75 kVp 0.6616 7.3765 6.6302 6.5462 8.9058 8.2017 80 kVp 0.6266 7.066 6.3731 6.2935 8.2431 7.2917 85 kVp 0.6155 6.8828 6.2216 6.1435 7.5595 6.6327

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173 APPENDIX F EFFECTIVE DOSE CALCULATIONS This data is the calculation of effective dose to the anthropomorphic newborn and one-year-old phantoms from chest examinations from the tube in Room 1 for the Agfa CR system and the tube in Room 5 for the Canon DR system at Shands at the University of Florida. The MOSFET dosimeters were calibrated by exposing the dosimeters until a 200 mV reading was obtained. This number is divided by the exposure(mR) to get a MOSFET Calibration Factor (CF) in mV/mR. The dose conversion factor (DCF) is a ratio of the average mass energy absorption coefficient of tissue to air. The ratios of soft tissue/air, bone/air and lung/air is 1.014, 3.078 and 1.051, respectively. The organ-absorbed dose (OAD) in mGy for each organ sited was calculated by taking the mV reading for the MOSFET and dividing it by the calibration factor, then mulitiplying it by 0.876 to convert dose in air. This number is then multiplied by the DCF. This is shown in Equation F-1. mV CF DSi en Tissue en Tissue 1 876 . 0 (F-1) The active bone marrow was calculated by multiplying the MOSFET value by the DCF corresponding to soft tissue which is illustrated in Equation F-2. The absorbed dose of each of the skeletal components was then multiplied by the fraction of active bone

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174 marrow assigned to the MOSFET (BMW). These values were then summed together to get the total absorbed dose to the active marrow shown in Equation F-3. mV CF DSi en SoftTissue en Site BoneMarrow 1 876 . 0 (F-2) Sites BMSite arrow TotalBoneMBMW mGy D D * ) ( (F-3) The bone surface was calculated by multiplying the MOSFET value by the DCF corresponding to bone which is illustrated in Equation F-4. The absorbed dose of each skeletal components was then multiplied by the fraction of active bone marrow assigned to the MOSFET (BMW). These values were then summed together to get the total absorbed dose to the active marrow shown in Equation F-5. mV CF DSi en Bone en eSite BoneSurfac 1 876 . 0 (F-4) Sites BSSite urface TotalBoneSBMW mGy D D * ) ( (F-5) The organ-absorbed dose values for the remainder organs were the average of the liver, stomach, bladder and colon organ-absorbed doses. The organ-absorbed dose values for the surface were the average of the MO SFET located on the surface such as breast, back, eye, etc. The effective dose (mSv) was calculated by multiplying the organ-absorbed dose by the tissue weighting factor (TWF) for each organ, then summing all the organ sites together as shown in Equation F-6. The radiation weighting factor, wr is one for photons.

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175 Organ r organTWF w mGy D mSv E * * ) ( ) ( (F-6) Table F-1. Newborn effective doses for Agfa CR system at 50 kVp Male 0.092mSv Female 0.109mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 1.1 29.29 1.014 0.334 0.05 0.017 Average Lung 0.000 0.12 0.000 Rt. Lung 0.0 30.46 1.014 0.000 Lt Lung 0.0 31.82 1.014 0.000 Rt. Arm 1.2 32.34 1.014 0.330 Lt Arm 0.6 31.62 1.014 0.169 Breast 1.8 29.47 1.014 0.543 0.05 0.027 Esophagus 0.0 31.42 1.014 0.000 0.05 0.000 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.20 0.000 Colon 0.3 33.99 1.014 0.078 0.12 0.009 Bladder 0.0 29.82 1.014 0.000 0.05 0.000 Stomach 0.7 29.38 1.014 0.212 0.12 0.025 Average Ovary 0.085 0.20 0.017 Rt. Ovary 0.3 30.84 1.014 0.086 Lt. Ovary 0.3 31.72 1.014 0.084 Spine Middle 0.4 29.12 1.014 0.122 Skull 0.0 27.29 1.014 0.000 Thyroid 0.1 28.38 1.014 0.031 0.05 0.002 Rt. Eye 0.2 30.46 1.014 0.058 Back 0.0 32.55 1.014 0.000 Marrow 0.058 0.12 0.007 Bone Surface 0.217 0.01 0.002 Remainder 0.142 0.01 0.001 Surface/Skin 0.150 0.01 0.002

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176 Table F-1. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 1.2 32.34 1.0140.330 0.0779 0.026 Lt Arm 0.6 31.62 1.0140.169 0.0779 0.013 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 0.4 29.12 1.0140.122 0.1588 0.019 Skull 0.0 27.29 1.0140.000 0.1470 0.000 Total Bone Marrow absorbed dose (mGy) 0.058 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 1.2 32.33773.077871.001 0.0980 0.098 Lt Arm 0.6 31.6193.077870.512 0.0980 0.050 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 0.4 29.12283.077870.370 0.1850 0.069 Skull 0.0 27.28773.077870.000 0.1160 0.000 Total Bone Surface absorbed dose (mGy) 0.216

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177 Table F-2. Newborn effective doses for Agfa CR system at 55 kVp Male 0.119mSv Female 0.120mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 0.1 29.29 1.014 0.030 0.05 0.002 Average Lung 0.084 0.12 0.010 Rt. Lung 0.1 30.46 1.014 0.029 Lt Lung 0.5 31.82 1.014 0.140 Rt. Arm 0.0 32.34 1.014 0.000 Lt Arm 0.9 31.62 1.014 0.253 Breast 2.1 29.47 1.014 0.633 0.05 0.032 Esophagus 0.3 31.42 1.014 0.085 0.05 0.004 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.20 0.000 Colon 0.1 33.99 1.014 0.026 0.12 0.003 Bladder 0.3 29.82 1.014 0.089 0.05 0.004 Stomach 1.2 29.38 1.014 0.363 0.12 0.044 Average Ovary 0.029 0.20 0.006 Rt. Ovary 0.2 30.84 1.014 0.058 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 0.3 29.12 1.014 0.092 Skull 0.4 27.29 1.014 0.130 Thyroid 0.3 28.38 1.014 0.094 0.05 0.005 Rt. Eye 0.3 30.46 1.014 0.087 Back 0.3 32.55 1.014 0.082 Marrow 0.053 0.12 0.006 Bone Surface 0.172 0.01 0.002 Remainder 0.107 0.01 0.001 Surface/Skin 0.201 0.01 0.002

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178 Table F-2 Continued Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 0.0 32.34 1.0140.000 0.0779 0.000 Lt Arm 0.9 31.62 1.0140.253 0.0779 0.020 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 0.3 29.12 1.0140.092 0.1588 0.015 Skull 0.4 27.29 1.0140.130 0.1470 0.019 Total Bone Marrow absorbed dose (mGy) 0.053 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 0.0 32.33773.077870.000 0.0980 0.000 Lt Arm 0.9 31.6193.077870.767 0.0980 0.075 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 0.3 29.12283.077870.278 0.1850 0.051 Skull 0.4 27.28773.077870.395 0.1160 0.046 Total Bone Surface absorbed dose (mGy) 0.172

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179 Table F-3. Newborn effective doses for Agfa CR system at 60 kVp Male 0.195mSv Female 0.207mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 1.0 29.29 1.014 0.303 0.05 0.015 Average Lung 0.344 0.12 0.041 Rt. Lung 1.5 30.46 1.014 0.437 Lt Lung 0.9 31.82 1.014 0.251 Rt. Arm 0.9 32.34 1.014 0.247 Lt Arm 0.5 31.62 1.014 0.140 Breast 3.7 29.47 1.014 1.115 0.05 0.056 Esophagus 0.0 31.42 1.014 0.000 0.05 0.000 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.20 0.000 Colon 0.0 33.99 1.014 0.000 0.12 0.000 Bladder 0.5 29.82 1.014 0.149 0.05 0.007 Stomach 1.7 29.38 1.014 0.514 0.12 0.062 Average Ovary 0.0 0.058 0.20 0.012 Rt. Ovary 0.4 30.84 1.014 0.115 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 0.6 29.12 1.014 0.183 Skull 0.0 27.29 1.014 0.000 Thyroid 0.0 28.38 1.014 0.000 0.05 0.000 Rt. Eye 0.0 30.46 1.014 0.000 Back 0.0 32.55 1.014 0.000 Marrow 0.059 0.12 0.007 Bone Surface 0.218 0.01 0.002 Remainder 0.205 0.01 0.002 Surface/Skin 0.279 0.01 0.003

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180 Table F-3. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 0.9 32.34 1.0140.247 0.0779 0.019 Lt Arm 0.5 31.62 1.0140.140 0.0779 0.011 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 0.6 29.12 1.0140.183 0.1588 0.029 Skull 0.0 27.29 1.0140.000 0.1470 0.000 Total Bone Marrow absorbed dose (mGy) 0.059 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 0.9 32.33773.077870.750 0.0980 0.074 Lt Arm 0.5 31.6193.077870.426 0.0980 0.042 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 0.6 29.12283.077870.555 0.1850 0.103 Skull 0.0 27.28773.077870.000 0.1160 0.000 Total Bone Surface absorbed dose (mGy) 0.218

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181 Table F-4. Newborn effective doses for Agfa CR system at 65 kVp Male 0.251mSv Female 0.263mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 1.7 29.29 1.014 0.515 0.05 0.026 Average Lung 0.356 0.12 0.043 Rt. Lung 1.2 30.46 1.014 0.350 Lt Lung 1.3 31.82 1.014 0.363 Rt. Arm 1.5 32.34 1.014 0.412 Lt Arm 1.0 31.62 1.014 0.281 Breast 3.8 29.47 1.014 1.145 0.05 0.057 Esophagus 0.0 31.42 1.014 0.000 0.05 0.000 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.20 0.000 Colon 0.1 33.99 1.014 0.026 0.12 0.003 Bladder 0.1 29.82 1.014 0.030 0.05 0.001 Stomach 2.8 29.38 1.014 0.847 0.12 0.102 Average Ovary 0.0 0.058 0.20 0.012 Rt. Ovary 0.4 30.84 1.014 0.115 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 0.1 29.12 1.014 0.031 Skull 0.6 27.29 1.014 0.195 Thyroid 0.0 28.38 1.014 0.000 0.05 0.000 Rt. Eye 0.0 30.46 1.014 0.000 Back 0.0 32.55 1.014 0.000 Marrow 0.088 0.12 0.011 Bone Surface 0.292 0.01 0.003 Remainder 0.295 0.01 0.003 Surface/Skin 0.286 0.01 0.003

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182 Table F-4. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 1.5 32.34 1.0140.412 0.0779 0.032 Lt Arm 1.0 31.62 1.0140.281 0.0779 0.022 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 0.1 29.12 1.0140.031 0.1588 0.005 Skull 0.6 27.29 1.0140.195 0.1470 0.029 Total Bone Marrow absorbed dose (mGy) 0.088 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 1.5 32.33773.077871.251 0.0980 0.123 Lt Arm 1.0 31.6193.077870.853 0.0980 0.084 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 0.1 29.12283.077870.093 0.1850 0.017 Skull 0.6 27.28773.077870.593 0.1160 0.069 Total Bone Surface absorbed dose (mGy) 0.292

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183 Table F-5. Newborn effective doses for Agfa CR system at 70 kVp Male 0.318mSv Female 0.321mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 2.1 29.29 1.014 0.637 0.05 0.032 Average Lung 0.525 0.12 0.063 Rt. Lung 1.4 30.46 1.014 0.408 Lt Lung 2.3 31.82 1.014 0.642 Rt. Arm 1.2 32.34 1.014 0.330 Lt Arm 0.9 31.62 1.014 0.253 Breast 4.7 29.47 1.014 1.417 0.05 0.071 Esophagus 0.6 31.42 1.014 0.170 0.05 0.008 Pelvis 0.2 28.70 1.014 0.062 Testes 0.0 27.21 1.014 0.000 0.20 0.000 Colon 0.2 33.99 1.014 0.052 0.12 0.006 Bladder 0.6 29.82 1.014 0.179 0.05 0.009 Stomach 2.9 29.38 1.014 0.877 0.12 0.105 Average Ovary 0.0 0.014 0.20 0.003 Rt. Ovary 0.1 30.84 1.014 0.029 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 0.9 29.12 1.014 0.275 Skull 0.0 27.29 1.014 0.000 Thyroid 0.0 28.38 1.014 0.000 0.05 0.000 Rt. Eye 0.0 30.46 1.014 0.000 Back 0.1 32.55 1.014 0.027 Marrow 0.103 0.12 0.012 Bone Surface 0.369 0.01 0.004 Remainder 0.352 0.01 0.004 Surface/Skin 0.361 0.01 0.004

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184 Table F-5. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 1.2 32.34 1.0140.330 0.0779 0.026 Lt Arm 0.9 31.62 1.0140.253 0.0779 0.020 Pelvis 0.2 28.70 1.0140.062 0.2191 0.014 Spine Middle 0.9 29.12 1.0140.275 0.1588 0.044 Skull 0.0 27.29 1.0140.000 0.1470 0.000 Total Bone Marrow absorbed dose (mGy) 0.103 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 1.2 32.33773.077871.001 0.0980 0.098 Lt Arm 0.9 31.6193.077870.767 0.0980 0.075 Pelvis 0.2 28.70323.077870.188 0.2190 0.041 Spine Middle 0.9 29.12283.077870.833 0.1850 0.154 Skull 0.0 27.28773.077870.000 0.1160 0.000 Total Bone Surface absorbed dose (mGy) 0.369

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185 Table F-6. Newborn effective doses for Agfa CR system at 75 kVp Male 0.122mSv Female 0.139mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 0.2 29.29 1.014 0.061 0.05 0.003 Rt. Lung 2.1 30.46 1.014 0.612 Lt Lung 0.7 31.82 1.014 0.195 Rt. Arm 1.6 32.34 1.014 0.439 Lt Arm 2.1 31.62 1.014 0.590 Breast 0.2 29.47 1.014 0.060 0.05 0.003 Esophagus 1.2 31.42 1.014 0.339 0.05 0.017 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.2 0.000 Colon 0.3 33.99 1.014 0.078 0.12 0.009 Bladder 0.0 29.82 1.014 0.000 0.05 0.000 Stomach 0.3 29.38 1.014 0.091 0.12 0.011 Rt. Ovary 0.3 30.84 1.014 0.086 Lt. Ovary 0.3 31.72 1.014 0.084 Spine Middle 1.5 29.12 1.014 0.458 Skull 0.5 27.29 1.014 0.163 Thyroid 0.0 28.38 1.014 0.000 0.05 0.000 Rt. Eye 0.0 30.46 1.014 0.000 Back 3.3 32.55 1.014 0.901 Average Ovary 0.085 0.2 0.017 Average Lung 0.404 0.12 0.048 Marrow 0.177 0.12 0.021 Bone Surface 0.620 0.01 0.006 Remainder 0.063 0.01 0.001 Surface/Skin 0.240 0.01 0.002

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186 Table F-5. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 1.6 32.34 1.0140.439 0.0779 0.034 Lt Arm 2.1 31.62 1.0140.590 0.0779 0.046 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 1.5 29.12 1.0140.458 0.1588 0.073 Skull 0.5 27.29 1.0140.163 0.1470 0.024 Total Bone Marrow absorbed dose (mGy) 0.177 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 1.6 32.33773.077871.334 0.0980 0.131 Lt Arm 2.1 31.6193.077871.791 0.0980 0.175 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 1.5 29.12283.077871.389 0.1850 0.257 Skull 0.5 27.28773.077870.494 0.1160 0.057 Total Bone Surface absorbed dose (mGy) 0.620

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187 Table F-7. Newborn effective doses for Agfa CR system at 80 kVp Male 0.201mSv Female 0.204mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 0.9 29.29 1.014 0.273 0.05 0.014 Rt. Lung 2.5 30.46 1.014 0.729 Lt Lung 2.1 31.82 1.014 0.586 Rt. Arm 1.0 32.34 1.014 0.275 Lt Arm 1.0 31.62 1.014 0.281 Breast 0.7 29.47 1.014 0.211 0.05 0.011 Esophagus 1.6 31.42 1.014 0.452 0.05 0.023 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.2 0.000 Colon 0.1 33.99 1.014 0.026 0.12 0.003 Bladder 0.0 29.82 1.014 0.000 0.05 0.000 Stomach 1.3 29.38 1.014 0.393 0.12 0.047 Rt. Ovary 0.1 30.84 1.014 0.029 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 1.5 29.12 1.014 0.458 Skull 0.4 27.29 1.014 0.130 Thyroid 0.0 28.38 1.014 0.000 0.05 0.000 Rt. Eye 0.0 30.46 1.014 0.000 Back 2.9 32.55 1.014 0.791 Average Ovary 0.014 0.2 0.003 Average Lung 0.658 0.12 0.079 Marrow 0.135 0.12 0.016 Bone Surface 0.468 0.01 0.005 Remainder 0.141 0.01 0.001 Surface/Skin 0.251 0.01 0.003

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188 Table F-7. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 1.0 32.34 1.0140.275 0.0779 0.021 Lt Arm 1.0 31.62 1.0140.281 0.0779 0.022 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 1.5 29.12 1.0140.458 0.1588 0.073 Skull 0.4 27.29 1.0140.130 0.1470 0.019 Total Bone Marrow absorbed dose (mGy) 0.135 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 1.0 32.33773.077870.834 0.0980 0.082 Lt Arm 1.0 31.6193.077870.853 0.0980 0.084 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 1.5 29.12283.077871.389 0.1850 0.257 Skull 0.4 27.28773.077870.395 0.1160 0.046 Total Bone Surface absorbed dose (mGy) 0.468

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189 Table F-8. Newborn effective doses for Agfa CR system at 85 kVp Male 0.189mSv Female 0.183mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 1.0 29.29 1.014 0.303 0.05 0.015 Rt. Lung 2.3 30.46 1.014 0.671 Lt Lung 1.5 31.82 1.014 0.419 Rt. Arm 1.0 32.34 1.014 0.275 Lt Arm 1.7 31.62 1.014 0.478 Breast 0.4 29.47 1.014 0.121 0.05 0.006 Esophagus 2.1 31.42 1.014 0.594 0.05 0.030 Pelvis 0.1 28.70 1.014 0.031 Testes 0.1 27.21 1.014 0.033 0.2 0.007 Colon 0.0 33.99 1.014 0.000 0.12 0.000 Bladder 0.0 29.82 1.014 0.000 0.05 0.000 Stomach 0.8 29.38 1.014 0.242 0.12 0.029 Rt. Ovary 0.0 30.84 1.014 0.000 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 2.2 29.12 1.014 0.671 Skull 0.6 27.29 1.014 0.195 Thyroid 0.2 28.38 1.014 0.063 0.05 0.003 Rt. Eye 0.1 30.46 1.014 0.029 Back 2.5 32.55 1.014 0.682 Average Ovary 0.000 0.2 0.000 Average Lung 0.545 0.12 0.065 Marrow 0.201 0.12 0.024 Bone Surface 0.690 0.01 0.007 Remainder 0.109 0.01 0.001 Surface/Skin 0.216 0.01 0.002

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190 Table F-8. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 1.0 32.34 1.0140.275 0.0779 0.021 Lt Arm 1.7 31.62 1.0140.478 0.0779 0.037 Pelvis 0.1 28.70 1.0140.031 0.2191 0.007 Spine Middle 2.2 29.12 1.0140.671 0.1588 0.107 Skull 0.6 27.29 1.0140.195 0.1470 0.029 Total Bone Marrow absorbed dose (mGy) 0.201 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 1.0 32.33773.077870.834 0.0980 0.082 Lt Arm 1.7 31.6193.077871.450 0.0980 0.142 Pelvis 0.1 28.70323.077870.094 0.2190 0.021 Spine Middle 2.2 29.12283.077872.037 0.1850 0.377 Skull 0.6 27.28773.077870.593 0.1160 0.069 Total Bone Surface absorbed dose (mGy) 0.690

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191 Table F-9. Newborn effective doses for Canon DR system at 50 kVp Male 0.052mSv Female 0.061mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 0.0 29.29 1.014 0.000 0.05 0.000 Average Lung 0.203 0.12 0.024 Rt. Lung 1.2 30.46 1.014 0.350 Lt Lung 0.2 31.82 1.014 0.056 Rt. Arm 0.1 32.34 1.014 0.027 Lt Arm 0.4 31.62 1.014 0.112 Breast 0.1 29.47 1.014 0.030 0.05 0.002 Esophagus 0.0 31.42 1.014 0.000 0.05 0.000 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.20 0.000 Colon 0.1 33.99 1.014 0.026 0.12 0.003 Bladder 0.1 29.82 1.014 0.030 0.05 0.001 Stomach 0.3 29.38 1.014 0.091 0.12 0.011 Average Ovary 0.043 0.20 0.009 Rt. Ovary 0.3 30.84 1.014 0.086 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 0.2 29.12 1.014 0.061 Skull 0.7 27.29 1.014 0.228 Thyroid 0.1 28.38 1.014 0.031 0.05 0.002 Rt. Eye 0.0 30.46 1.014 0.000 Back 0.9 32.55 1.014 0.246 Marrow 0.054 0.12 0.006 Bone Surface 0.156 0.01 0.002 Remainder 0.038 0.01 0.000 Surface/Skin 0.069 0.01 0.001

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192 Table F-9. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 0.1 32.34 1.0140.027 0.0779 0.002 Lt Arm 0.4 31.62 1.0140.112 0.0779 0.009 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 0.2 29.12 1.0140.061 0.1588 0.010 Skull 0.7 27.29 1.0140.228 0.1470 0.033 Total Bone Marrow absorbed dose (mGy) 0.054 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 0.1 32.33773.077870.083 0.0980 0.008 Lt Arm 0.4 31.6193.077870.341 0.0980 0.033 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 0.2 29.12283.077870.185 0.1850 0.034 Skull 0.7 27.28773.077870.692 0.1160 0.080 Total Bone Surface absorbed dose (mGy) 0.156

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193 Table F-10. Newborn effective doses for Canon DR system at 55 kVp Male 0.076mSv Female 0.076mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 0.1 29.29 1.014 0.030 0.05 0.002 Rt. Lung 0.6 30.46 1.014 0.175 Lt Lung 0.7 31.82 1.014 0.195 Rt. Arm 0.7 32.34 1.014 0.192 Lt Arm 0.5 31.62 1.014 0.140 Breast 0.0 29.47 1.014 0.000 0.05 0.000 Esophagus 1.0 31.42 1.014 0.283 0.05 0.014 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.2 0.000 Colon 0.2 33.99 1.014 0.052 0.12 0.006 Bladder 0.0 29.82 1.014 0.000 0.05 0.000 Stomach 0.4 29.38 1.014 0.121 0.12 0.015 Rt. Ovary 0.0 30.84 1.014 0.000 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 0.8 29.12 1.014 0.244 Skull 0.6 27.29 1.014 0.195 Thyroid 0.1 28.38 1.014 0.031 0.05 0.002 Rt. Eye 0.3 30.46 1.014 0.087 Back 1.0 32.55 1.014 0.273 Average Ovary 0.000 0.2 0.000 Average Lung 0.185 0.12 0.022 Marrow 0.093 0.12 0.011 Bone Surface 0.305 0.01 0.003 Remainder 0.041 0.01 0.000 Surface/Skin 0.090 0.01 0.001

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194 Table F-10. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 0.7 32.34 1.0140.192 0.0779 0.015 Lt Arm 0.5 31.62 1.0140.140 0.0779 0.011 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 0.8 29.12 1.0140.244 0.1588 0.039 Skull 0.6 27.29 1.0140.195 0.1470 0.029 Total Bone Marrow absorbed dose (mGy) 0.093 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 0.7 32.33773.077870.584 0.0980 0.057 Lt Arm 0.5 31.6193.077870.426 0.0980 0.042 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 0.8 29.12283.077870.741 0.1850 0.137 Skull 0.6 27.28773.077870.593 0.1160 0.069 Total Bone Surface absorbed dose (mGy) 0.305

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195 Table F-11. Newborn effective doses for Canon DR system at 60 kVp Male 0.138mSv Female 0.143mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 1.5 29.29 1.014 0.455 0.05 0.023 Rt. Lung 1.9 30.46 1.014 0.554 Lt Lung 0.9 31.82 1.014 0.251 Rt. Arm 0.4 32.34 1.014 0.110 Lt Arm 0.2 31.62 1.014 0.056 Breast 0.6 29.47 1.014 0.181 0.05 0.009 Esophagus 1.5 31.42 1.014 0.424 0.05 0.021 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.2 0.000 Colon 0.2 33.99 1.014 0.052 0.12 0.006 Bladder 0.1 29.82 1.014 0.030 0.05 0.001 Stomach 0.3 29.38 1.014 0.091 0.12 0.011 Rt. Ovary 0.0 30.84 1.014 0.000 Lt. Ovary 0.2 31.72 1.014 0.056 Spine Middle 1.7 29.12 1.014 0.519 Skull 0.0 27.29 1.014 0.000 Thyroid 0.0 28.38 1.014 0.000 0.05 0.000 Rt. Eye 0.0 30.46 1.014 0.000 Back 1.9 32.55 1.014 0.519 Average Ovary 0.028 0.2 0.006 Average Lung 0.403 0.12 0.048 Marrow 0.095 0.12 0.011 Bone Surface 0.341 0.01 0.003 Remainder 0.131 0.01 0.001 Surface/Skin 0.175 0.01 0.002

PAGE 216

196 Table F-11. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 0.4 32.34 1.0140.110 0.0779 0.009 Lt Arm 0.2 31.62 1.0140.056 0.0779 0.004 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 1.7 29.12 1.0140.519 0.1588 0.082 Skull 0.0 27.29 1.0140.000 0.1470 0.000 Total Bone Marrow absorbed dose (mGy) 0.095 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 0.4 32.33773.077870.334 0.0980 0.033 Lt Arm 0.2 31.6193.077870.171 0.0980 0.017 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 1.7 29.12283.077871.574 0.1850 0.291 Skull 0.0 27.28773.077870.000 0.1160 0.000 Total Bone Surface absorbed dose (mGy) 0.341

PAGE 217

197 Table F-12. Newborn effective doses for Canon DR system at 65 kVp Male 0.108mSv Female 0.117mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 0.3 29.29 1.014 0.091 0.05 0.005 Rt. Lung 0.2 30.46 1.014 0.058 Lt Lung 1.3 31.82 1.014 0.363 Rt. Arm 0.6 32.34 1.014 0.165 Lt Arm 0.3 31.62 1.014 0.084 Breast 0.4 29.47 1.014 0.121 0.05 0.006 Esophagus 0.7 31.42 1.014 0.198 0.05 0.010 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.2 0.000 Colon 0.3 33.99 1.014 0.078 0.12 0.009 Bladder 0.0 29.82 1.014 0.000 0.05 0.000 Stomach 0.9 29.38 1.014 0.272 0.12 0.033 Rt. Ovary 0.3 30.84 1.014 0.086 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 1.7 29.12 1.014 0.519 Skull 0.1 27.29 1.014 0.033 Thyroid 0.0 28.38 1.014 0.000 0.05 0.000 Rt. Eye 0.0 30.46 1.014 0.000 Back 3.3 32.55 1.014 0.901 Average Ovary 0.043 0.2 0.009 Average Lung 0.211 0.12 0.025 Marrow 0.107 0.12 0.013 Bone Surface 0.377 0.01 0.004 Remainder 0.097 0.01 0.001 Surface/Skin 0.255 0.01 0.003

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198 Table F-12. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 0.6 32.34 1.0140.165 0.0779 0.013 Lt Arm 0.3 31.62 1.0140.084 0.0779 0.007 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 1.7 29.12 1.0140.519 0.1588 0.082 Skull 0.1 27.29 1.0140.033 0.1470 0.005 Total Bone Marrow absorbed dose (mGy) 0.107 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 0.6 32.33773.077870.500 0.0980 0.049 Lt Arm 0.3 31.6193.077870.256 0.0980 0.025 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 1.7 29.12283.077871.574 0.1850 0.291 Skull 0.1 27.28773.077870.099 0.1160 0.011 Total Bone Surface absorbed dose (mGy) 0.377

PAGE 219

199 Table F-13. Newborn effective doses for Canon DR system at 70 kVp Male 0.162mSv Female 0.173mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 0.4 29.29 1.014 0.121 0.05 0.006 Rt. Lung 2.0 30.46 1.014 0.583 Lt Lung 1.5 31.82 1.014 0.419 Rt. Arm 1.2 32.34 1.014 0.330 Lt Arm 1.3 31.62 1.014 0.365 Breast 0.0 29.47 1.014 0.000 0.05 0.000 Esophagus 1.2 31.42 1.014 0.339 0.05 0.017 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.2 0.000 Colon 0.0 33.99 1.014 0.000 0.12 0.000 Bladder 0.0 29.82 1.014 0.000 0.05 0.000 Stomach 1.4 29.38 1.014 0.423 0.12 0.051 Rt. Ovary 0.4 30.84 1.014 0.115 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 1.3 29.12 1.014 0.397 Skull 0.7 27.29 1.014 0.228 Thyroid 0.1 28.38 1.014 0.031 0.05 0.002 Rt. Eye 0.0 30.46 1.014 0.000 Back 2.6 32.55 1.014 0.710 Average Ovary 0.058 0.2 0.012 Average Lung 0.501 0.12 0.060 Marrow 0.151 0.12 0.018 Bone Surface 0.510 0.01 0.005 Remainder 0.120 0.01 0.001 Surface/Skin 0.177 0.01 0.002

PAGE 220

200 Table F-13. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 1.2 32.34 1.0140.330 0.0779 0.026 Lt Arm 1.3 31.62 1.0140.365 0.0779 0.028 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 1.3 29.12 1.0140.397 0.1588 0.063 Skull 0.7 27.29 1.0140.228 0.1470 0.033 Total Bone Marrow absorbed dose (mGy) 0.151 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 1.2 32.33773.077871.001 0.0980 0.098 Lt Arm 1.3 31.6193.077871.109 0.0980 0.109 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 1.3 29.12283.077871.204 0.1850 0.223 Skull 0.7 27.28773.077870.692 0.1160 0.080 Total Bone Surface absorbed dose (mGy) 0.510

PAGE 221

201 Table F-14. Newborn effective doses for Canon DR system at 75 kVp Male 0.122mSv Female 0.139mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 0.2 29.29 1.014 0.061 0.05 0.003 Rt. Lung 2.1 30.46 1.014 0.612 Lt Lung 0.7 31.82 1.014 0.195 Rt. Arm 1.6 32.34 1.014 0.439 Lt Arm 2.1 31.62 1.014 0.590 Breast 0.2 29.47 1.014 0.060 0.05 0.003 Esophagus 1.2 31.42 1.014 0.339 0.05 0.017 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.2 0.000 Colon 0.3 33.99 1.014 0.078 0.12 0.009 Bladder 0.0 29.82 1.014 0.000 0.05 0.000 Stomach 0.3 29.38 1.014 0.091 0.12 0.011 Rt. Ovary 0.3 30.84 1.014 0.086 Lt. Ovary 0.3 31.72 1.014 0.084 Spine Middle 1.5 29.12 1.014 0.458 Skull 0.5 27.29 1.014 0.163 Thyroid 0.0 28.38 1.014 0.000 0.05 0.000 Rt. Eye 0.0 30.46 1.014 0.000 Back 3.3 32.55 1.014 0.901 Average Ovary 0.085 0.2 0.017 Average Lung 0.404 0.12 0.048 Marrow 0.177 0.12 0.021 Bone Surface 0.620 0.01 0.006 Remainder 0.063 0.01 0.001 Surface/Skin 0.240 0.01 0.002

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202 Table F-14. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 1.6 32.34 1.0140.439 0.0779 0.034 Lt Arm 2.1 31.62 1.0140.590 0.0779 0.046 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 1.5 29.12 1.0140.458 0.1588 0.073 Skull 0.5 27.29 1.0140.163 0.1470 0.024 Total Bone Marrow absorbed dose (mGy) 0.177 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 1.6 32.33773.077871.334 0.0980 0.131 Lt Arm 2.1 31.6193.077871.791 0.0980 0.175 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 1.5 29.12283.077871.389 0.1850 0.257 Skull 0.5 27.28773.077870.494 0.1160 0.057 Total Bone Surface absorbed dose (mGy) 0.620

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203 Table F-15. Newborn effective doses for Canon DR system at 80 kVp Male 0.201mSv Female 0.204mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 0.9 29.29 1.014 0.273 0.05 0.014 Rt. Lung 2.5 30.46 1.014 0.729 Lt Lung 2.1 31.82 1.014 0.586 Rt. Arm 1.0 32.34 1.014 0.275 Lt Arm 1.0 31.62 1.014 0.281 Breast 0.7 29.47 1.014 0.211 0.05 0.011 Esophagus 1.6 31.42 1.014 0.452 0.05 0.023 Pelvis 0.0 28.70 1.014 0.000 Testes 0.0 27.21 1.014 0.000 0.2 0.000 Colon 0.1 33.99 1.014 0.026 0.12 0.003 Bladder 0.0 29.82 1.014 0.000 0.05 0.000 Stomach 1.3 29.38 1.014 0.393 0.12 0.047 Rt. Ovary 0.1 30.84 1.014 0.029 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 1.5 29.12 1.014 0.458 Skull 0.4 27.29 1.014 0.130 Thyroid 0.0 28.38 1.014 0.000 0.05 0.000 Rt. Eye 0.0 30.46 1.014 0.000 Back 2.9 32.55 1.014 0.791 Average Ovary 0.014 0.2 0.003 Average Lung 0.658 0.12 0.079 Marrow 0.135 0.12 0.016 Bone Surface 0.468 0.01 0.005 Remainder 0.141 0.01 0.001 Surface/Skin 0.251 0.01 0.003

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204 Table F-15. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 1.0 32.34 1.0140.275 0.0779 0.021 Lt Arm 1.0 31.62 1.0140.281 0.0779 0.022 Pelvis 0.0 28.70 1.0140.000 0.2191 0.000 Spine Middle 1.5 29.12 1.0140.458 0.1588 0.073 Skull 0.4 27.29 1.0140.130 0.1470 0.019 Total Bone Marrow absorbed dose (mGy) 0.135 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 1.0 32.33773.077870.834 0.0980 0.082 Lt Arm 1.0 31.6193.077870.853 0.0980 0.084 Pelvis 0.0 28.70323.077870.000 0.2190 0.000 Spine Middle 1.5 29.12283.077871.389 0.1850 0.257 Skull 0.4 27.28773.077870.395 0.1160 0.046 Total Bone Surface absorbed dose (mGy) 0.468

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205 Table F-16. Newborn effective doses for Canon DR system at 85 kVp Male 0.189mSv Female 0.183mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Liver 1.0 29.29 1.014 0.303 0.05 0.015 Rt. Lung 2.3 30.46 1.014 0.671 Lt Lung 1.5 31.82 1.014 0.419 Rt. Arm 1.0 32.34 1.014 0.275 Lt Arm 1.7 31.62 1.014 0.478 Breast 0.4 29.47 1.014 0.121 0.05 0.006 Esophagus 2.1 31.42 1.014 0.594 0.05 0.030 Pelvis 0.1 28.70 1.014 0.031 Testes 0.1 27.21 1.014 0.033 0.2 0.007 Colon 0.0 33.99 1.014 0.000 0.12 0.000 Bladder 0.0 29.82 1.014 0.000 0.05 0.000 Stomach 0.8 29.38 1.014 0.242 0.12 0.029 Rt. Ovary 0.0 30.84 1.014 0.000 Lt. Ovary 0.0 31.72 1.014 0.000 Spine Middle 2.2 29.12 1.014 0.671 Skull 0.6 27.29 1.014 0.195 Thyroid 0.2 28.38 1.014 0.063 0.05 0.003 Rt. Eye 0.1 30.46 1.014 0.029 Back 2.5 32.55 1.014 0.682 Average Ovary 0.000 0.2 0.000 Average Lung 0.545 0.12 0.065 Marrow 0.201 0.12 0.024 Bone Surface 0.690 0.01 0.007 Remainder 0.109 0.01 0.001 Surface/Skin 0.216 0.01 0.002

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206 Table F-16. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Rt. Arm 1.0 32.34 1.0140.275 0.0779 0.021 Lt Arm 1.7 31.62 1.0140.478 0.0779 0.037 Pelvis 0.1 28.70 1.0140.031 0.2191 0.007 Spine Middle 2.2 29.12 1.0140.671 0.1588 0.107 Skull 0.6 27.29 1.0140.195 0.1470 0.029 Total Bone Marrow absorbed dose (mGy) 0.201 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Rt. Arm 1.0 32.33773.077870.834 0.0980 0.082 Lt Arm 1.7 31.6193.077871.450 0.0980 0.142 Pelvis 0.1 28.70323.077870.094 0.2190 0.021 Spine Middle 2.2 29.12283.077872.037 0.1850 0.377 Skull 0.6 27.28773.077870.593 0.1160 0.069 Total Bone Surface absorbed dose (mGy) 0.690

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207 Table F-17. One-Year-Old effective doses for Agfa CR system at 50 kVp Male 0.079mSv Female 0.080mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.7 30.46 1.014 0.204 Thyroid 0.0 31.82 1.014 0.000 0.05 0.000 Rt. Arm 0.9 32.34 1.014 0.247 Lt. Arm 0.3 31.62 1.014 0.084 Breast 1.3 29.47 1.014 0.392 0.05 0.020 Liver 0.7 31.42 1.014 0.198 0.05 0.010 Stomach 0.5 28.70 1.014 0.155 0.12 0.019 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 0.3 33.99 1.014 0.078 Lt. Lung 0.4 29.82 1.014 0.119 Esophagus 0.1 29.38 1.014 0.030 0.05 0.002 Colon 0.0 30.84 1.014 0.000 0.12 0.000 Rt. Ovary 0.0 31.72 1.014 0.000 Lt. Ovary 0.2 29.12 1.014 0.061 Pelvis 0.0 27.29 1.014 0.000 Spine Middle 0.1 28.38 1.014 0.031 Testes 0.1 30.46 1.014 0.029 0.2 0.006 Average Lung 0.099 0.12 0.012 Average Ovary 0.031 0.2 0.006 Bone Marrow 0.061 0.12 0.007 Bone Surface 0.184 0.01 0.002 Remainder 0.088 0.01 0.001 Surface 0.211 0.01 0.002

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208 Table F-17. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.7 30.46 1.0140.204 0.1470 0.030 Rt. Arm 0.9 32.34 1.0140.247 0.0779 0.019 Lt. Arm 0.3 31.62 1.0140.084 0.0779 0.007 Pelvis 0.0 27.29 1.0140.000 0.2191 0.000 Spine Middle 0.1 28.38 1.0140.031 0.1588 0.005 Total Bone Marrow absorbed dose (mGy) 0.061 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.7 30.45873.0110.606 0.1160 0.070 Rt. Arm 0.9 32.33773.0110.734 0.0980 0.072 Lt. Arm 0.3 31.6193.0110.250 0.0980 0.025 Pelvis 0.0 27.28773.0110.000 0.2190 0.000 Spine Middle 0.1 28.37613.0110.093 0.1850 0.017 Total Bone Surface absorbed dose (mGy) 0.184

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209 Table F-18. One-Year-Old effective doses for Agfa CR system at 55 kVp Male 0.131mSv Female 0.133mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.2 30.46 1.014 0.058 Thyroid 0.3 31.82 1.014 0.084 0.05 0.004 Rt. Arm 0.5 32.34 1.014 0.137 Lt. Arm 0.6 31.62 1.014 0.169 Breast 1.7 29.47 1.014 0.512 0.05 0.026 Liver 0.8 31.42 1.014 0.226 0.05 0.011 Stomach 1.2 28.70 1.014 0.371 0.12 0.045 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 0.7 33.99 1.014 0.183 Lt. Lung 0.8 29.82 1.014 0.238 Esophagus 0.7 29.38 1.014 0.212 0.05 0.011 Colon 0.0 30.84 1.014 0.000 0.12 0.000 Rt. Ovary 0.1 31.72 1.014 0.028 Lt. Ovary 0.0 29.12 1.014 0.000 Pelvis 0.0 27.29 1.014 0.000 Spine Middle 0.0 28.38 1.014 0.000 Testes 0.0 30.46 1.014 0.000 0.2 0.000 Average Lung 0.211 0.12 0.025 Average Ovary 0.014 0.2 0.003 Bone Marrow 0.032 0.12 0.004 Bone Surface 0.109 0.01 0.001 Remainder 0.149 0.01 0.001 Surface 0.256 0.01 0.003

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210 Table F-18. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.2 30.46 1.0140.058 0.1470 0.009 Rt. Arm 0.5 32.34 1.0140.137 0.0779 0.011 Lt. Arm 0.6 31.62 1.0140.169 0.0779 0.013 Pelvis 0.0 27.29 1.0140.000 0.2191 0.000 Spine Middle 0.0 28.38 1.0140.000 0.1588 0.000 Total Bone Marrow absorbed dose (mGy) 0.032 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.2 30.45873.0110.173 0.1160 0.020 Rt. Arm 0.5 32.33773.0110.408 0.0980 0.040 Lt. Arm 0.6 31.6193.0110.501 0.0980 0.049 Pelvis 0.0 27.28773.0110.000 0.2190 0.000 Spine Middle 0.0 28.37613.0110.000 0.1850 0.000 Total Bone Surface absorbed dose (mGy) 0.109

PAGE 231

211 Table F-19. One-Year-Old effective doses for Agfa CR system at 60 kVp Male 0.152mSv Female 0.155mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.5 30.46 1.014 0.146 Thyroid 0.2 31.82 1.014 0.056 0.05 0.003 Rt. Arm 0.8 32.34 1.014 0.220 Lt. Arm 0.9 31.62 1.014 0.253 Breast 3.3 29.47 1.014 0.995 0.05 0.050 Liver 1.4 31.42 1.014 0.396 0.05 0.020 Stomach 0.6 28.70 1.014 0.186 0.12 0.022 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 0.5 33.99 1.014 0.131 Lt. Lung 0.4 29.82 1.014 0.119 Esophagus 1.1 29.38 1.014 0.333 0.05 0.017 Colon 0.3 30.84 1.014 0.086 0.12 0.010 Rt. Ovary 0.1 31.72 1.014 0.028 Lt. Ovary 0.0 29.12 1.014 0.000 Pelvis 0.0 27.29 1.014 0.000 Spine Middle 0.0 28.38 1.014 0.000 Testes 0.0 30.46 1.014 0.000 0.2 0.000 Average Lung 0.125 0.12 0.015 Average Ovary 0.014 0.2 0.003 Bone Marrow 0.058 0.12 0.007 Bone Surface 0.188 0.01 0.002 Remainder 0.167 0.01 0.002 Surface 0.497 0.01 0.005

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212 Table F-19. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.5 30.46 1.0140.146 0.1470 0.021 Rt. Arm 0.8 32.34 1.0140.220 0.0779 0.017 Lt. Arm 0.9 31.62 1.0140.253 0.0779 0.020 Pelvis 0.0 27.29 1.0140.000 0.2191 0.000 Spine Middle 0.0 28.38 1.0140.000 0.1588 0.000 Total Bone Marrow absorbed dose (mGy) 0.058 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.5 30.45873.0110.433 0.1160 0.050 Rt. Arm 0.8 32.33773.0110.653 0.0980 0.064 Lt. Arm 0.9 31.6193.0110.751 0.0980 0.074 Pelvis 0.0 27.28773.0110.000 0.2190 0.000 Spine Middle 0.0 28.37613.0110.000 0.1850 0.000 Total Bone Surface absorbed dose (mGy) 0.188

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213 Table F-20. One-Year-Old effective doses for Agfa CR system at 65 kVp Male 0.217mSv Female 0.223mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.4 29.29 1.014 0.121 Head Spine 0.0 30.46 1.014 0.000 Thyroid 0.1 31.82 1.014 0.028 0.05 0.001 Rt. Arm 1.6 32.34 1.014 0.439 Lt. Arm 0.9 31.62 1.014 0.253 Breast 3.5 29.47 1.014 1.055 0.05 0.053 Liver 2.3 31.42 1.014 0.650 0.05 0.033 Stomach 1.9 28.70 1.014 0.588 0.12 0.071 Bladder 0.1 27.21 1.014 0.033 0.05 0.002 Rt. Lung 0.5 33.99 1.014 0.131 Lt. Lung 0.7 29.82 1.014 0.209 Esophagus 1.2 29.38 1.014 0.363 0.05 0.018 Colon 0.0 30.84 1.014 0.000 0.12 0.000 Rt. Ovary 0.0 31.72 1.014 0.000 Lt. Ovary 0.2 29.12 1.014 0.061 Pelvis 0.0 27.29 1.014 0.000 Spine Middle 0.0 28.38 1.014 0.000 Testes 0.0 30.46 1.014 0.000 0.2 0.000 Average Lung 0.170 0.12 0.020 Average Ovary 0.031 0.2 0.006 Bone Marrow 0.072 0.12 0.009 Bone Surface 0.243 0.01 0.002 Remainder 0.318 0.01 0.003 Surface 0.528 0.01 0.005

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214 Table F-20. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.4 29.29 1.0140.121 0.1470 0.018 Head Spine 0.0 30.46 1.0140.000 0.1470 0.000 Rt. Arm 1.6 32.34 1.0140.439 0.0779 0.034 Lt. Arm 0.9 31.62 1.0140.253 0.0779 0.020 Pelvis 0.0 27.29 1.0140.000 0.2191 0.000 Spine Middle 0.0 28.38 1.0140.000 0.1588 0.000 Total Bone Marrow absorbed dose (mGy) 0.072 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.4 29.29413.0110.360 0.1160 0.042 Head Spine 0.0 30.45873.0110.000 0.1160 0.000 Rt. Arm 1.6 32.33773.0111.305 0.0980 0.128 Lt. Arm 0.9 31.6193.0110.751 0.0980 0.074 Pelvis 0.0 27.28773.0110.000 0.2190 0.000 Spine Middle 0.0 28.37613.0110.000 0.1850 0.000 Total Bone Surface absorbed dose (mGy) 0.243

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215 Table F-21. One-Year-Old effective doses for Agfa CR system at 70 kVp Male 0.233mSv Female 0.242mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.0 30.46 1.014 0.000 Thyroid 0.0 31.82 1.014 0.000 0.05 0.000 Rt. Arm 1.5 32.34 1.014 0.412 Lt. Arm 1.7 31.62 1.014 0.478 Breast 0.5 29.47 1.014 0.151 0.05 0.008 Liver 0.3 31.42 1.014 0.085 0.05 0.004 Stomach 1.2 28.70 1.014 0.371 0.12 0.045 Bladder 0.2 27.21 1.014 0.065 0.05 0.003 Rt. Lung 3.5 33.99 1.014 0.915 Lt. Lung 3.4 29.82 1.014 1.013 Esophagus 1.7 29.38 1.014 0.514 0.05 0.026 Colon 0.1 30.84 1.014 0.029 0.12 0.003 Rt. Ovary 0.1 31.72 1.014 0.028 Lt. Ovary 0.2 29.12 1.014 0.061 Pelvis 0.3 27.29 1.014 0.098 Spine Middle 1.6 28.38 1.014 0.501 Testes 0.0 30.46 1.014 0.000 0.2 0.000 Average Lung 0.964 0.12 0.116 Average Ovary 0.045 0.2 0.009 Bone Marrow 0.170 0.12 0.020 Bone Surface 0.598 0.01 0.006 Remainder 0.138 0.01 0.001 Surface 0.075 0.01 0.001

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216 Table F-21. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.0 30.46 1.0140.000 0.1470 0.000 Rt. Arm 1.5 32.34 1.0140.412 0.0779 0.032 Lt. Arm 1.7 31.62 1.0140.478 0.0779 0.037 Pelvis 0.3 27.29 1.0140.098 0.2191 0.021 Spine Middle 1.6 28.38 1.0140.501 0.1588 0.080 Total Bone Marrow absorbed dose (mGy) 0.170 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.0 30.45873.0110.000 0.1160 0.000 Rt. Arm 1.5 32.33773.0111.223 0.0980 0.120 Lt. Arm 1.7 31.6193.0111.418 0.0980 0.139 Pelvis 0.3 27.28773.0110.290 0.2190 0.064 Spine Middle 1.6 28.37613.0111.487 0.1850 0.275 Total Bone Surface absorbed dose (mGy) 0.598

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217 Table F-22. One-Year-Old effective doses for Agfa CR system at 75 kVp Male 0.297mSv Female 0.300mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.1 30.46 1.014 0.029 Thyroid 0.6 31.82 1.014 0.167 0.05 0.008 Rt. Arm 2.0 32.34 1.014 0.549 Lt. Arm 1.6 31.62 1.014 0.449 Breast 0.5 29.47 1.014 0.151 0.05 0.008 Liver 1.4 31.42 1.014 0.396 0.05 0.020 Stomach 1.6 28.70 1.014 0.495 0.12 0.059 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 2.4 33.99 1.014 0.627 Lt. Lung 3.8 29.82 1.014 1.132 Esophagus 3.4 29.38 1.014 1.028 0.05 0.051 Colon 0.1 30.84 1.014 0.029 0.12 0.003 Rt. Ovary 0.1 31.72 1.014 0.028 Lt. Ovary 0.2 29.12 1.014 0.061 Pelvis 0.5 27.29 1.014 0.163 Spine Middle 1.8 28.38 1.014 0.563 Testes 0.1 30.46 1.014 0.029 0.2 0.006 Average Lung 0.880 0.12 0.106 Average Ovary 0.045 0.2 0.009 Bone Marrow 0.207 0.12 0.025 Bone Surface 0.716 0.01 0.007 Remainder 0.230 0.01 0.002 Surface 0.090 0.01 0.001

PAGE 238

218 Table F-22. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.1 30.46 1.0140.029 0.1470 0.004 Rt. Arm 2.0 32.34 1.0140.549 0.0779 0.043 Lt. Arm 1.6 31.62 1.0140.449 0.0779 0.035 Pelvis 0.5 27.29 1.0140.163 0.2191 0.036 Spine Middle 1.8 28.38 1.0140.563 0.1588 0.089 Total Bone Marrow absorbed dose (mGy) 0.207 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.1 30.45873.0110.087 0.1160 0.010 Rt. Arm 2.0 32.33773.0111.631 0.0980 0.160 Lt. Arm 1.6 31.6193.0111.335 0.0980 0.131 Pelvis 0.5 27.28773.0110.483 0.2190 0.106 Spine Middle 1.8 28.37613.0111.673 0.1850 0.310 Total Bone Surface absorbed dose (mGy) 0.716

PAGE 239

219 Table F-23. One-Year-Old effective doses for Agfa CR system at 80 kVp Male 0.297mSv Female 0.300mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.1 30.46 1.014 0.029 Thyroid 0.6 31.82 1.014 0.167 0.05 0.008 Rt. Arm 2.0 32.34 1.014 0.549 Lt. Arm 1.6 31.62 1.014 0.449 Breast 0.5 29.47 1.014 0.151 0.05 0.008 Liver 1.4 31.42 1.014 0.396 0.05 0.020 Stomach 1.6 28.70 1.014 0.495 0.12 0.059 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 2.4 33.99 1.014 0.627 Lt. Lung 3.8 29.82 1.014 1.132 Esophagus 3.4 29.38 1.014 1.028 0.05 0.051 Colon 0.1 30.84 1.014 0.029 0.12 0.003 Rt. Ovary 0.1 31.72 1.014 0.028 Lt. Ovary 0.2 29.12 1.014 0.061 Pelvis 0.5 27.29 1.014 0.163 Spine Middle 1.8 28.38 1.014 0.563 Testes 0.1 30.46 1.014 0.029 0.2 0.006 Average Lung 0.880 0.12 0.106 Average Ovary 0.045 0.2 0.009 Bone Marrow 0.207 0.12 0.025 Bone Surface 0.716 0.01 0.007 Remainder 0.230 0.01 0.002 Surface 0.090 0.01 0.001

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220 Table F-23. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.1 30.46 1.0140.029 0.1470 0.004 Rt. Arm 2.0 32.34 1.0140.549 0.0779 0.043 Lt. Arm 1.6 31.62 1.0140.449 0.0779 0.035 Pelvis 0.5 27.29 1.0140.163 0.2191 0.036 Spine Middle 1.8 28.38 1.0140.563 0.1588 0.089 Total Bone Marrow absorbed dose (mGy) 0.207 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.1 30.45873.0110.087 0.1160 0.010 Rt. Arm 2.0 32.33773.0111.631 0.0980 0.160 Lt. Arm 1.6 31.6193.0111.335 0.0980 0.131 Pelvis 0.5 27.28773.0110.483 0.2190 0.106 Spine Middle 1.8 28.37613.0111.673 0.1850 0.310 Total Bone Surface absorbed dose (mGy) 0.716

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221 Table F-24. One-Year-Old effective doses for Agfa CR system at 85 kVp Male 0.465mSv Female 0.529mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.2 29.29 1.014 0.061 Head Spine 0.0 30.46 1.014 0.000 Thyroid 1.7 31.82 1.014 0.475 0.05 0.024 Rt. Arm 2.6 32.34 1.014 0.714 Lt. Arm 4.2 31.62 1.014 1.180 Breast 0.5 29.47 1.014 0.151 0.05 0.008 Liver 1.8 31.42 1.014 0.509 0.05 0.025 Stomach 2.4 28.70 1.014 0.743 0.12 0.089 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 5.5 33.99 1.014 1.437 Lt. Lung 5.2 29.82 1.014 1.549 Esophagus 4.4 29.38 1.014 1.330 0.05 0.067 Colon 0.5 30.84 1.014 0.144 0.12 0.017 Rt. Ovary 1.3 31.72 1.014 0.364 Lt. Ovary 0.9 29.12 1.014 0.275 Pelvis 0.2 27.29 1.014 0.065 Spine Middle 3.3 28.38 1.014 1.033 Testes 0.0 30.46 1.014 0.000 0.2 0.000 Average Lung 1.493 0.12 0.179 Average Ovary 0.319 0.2 0.064 Bone Marrow 0.335 0.12 0.040 Bone Surface 1.182 0.01 0.012 Remainder 0.349 0.01 0.003 Surface 0.075 0.01 0.001

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222 Table F-24. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.2 29.29 1.0140.061 0.1470 0.009 Head Spine 0.0 30.46 1.0140.000 0.1470 0.000 Rt. Arm 2.6 32.34 1.0140.714 0.0779 0.056 Lt. Arm 4.2 31.62 1.0141.180 0.0779 0.092 Pelvis 0.2 27.29 1.0140.065 0.2191 0.014 Spine Middle 3.3 28.38 1.0141.033 0.1588 0.164 Total Bone Marrow absorbed dose (mGy) 0.335 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.2 29.29413.0110.180 0.1160 0.021 Head Spine 0.0 30.45873.0110.000 0.1160 0.000 Rt. Arm 2.6 32.33773.0112.121 0.0980 0.208 Lt. Arm 4.2 31.6193.0113.504 0.0980 0.343 Pelvis 0.2 27.28773.0110.193 0.2190 0.042 Spine Middle 3.3 28.37613.0113.067 0.1850 0.567 Total Bone Surface absorbed dose (mGy) 1.182

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223 Table F-25. One-Year-Old effective doses for Canon DR system at 50 kVp Male 0.099mSv Female 0.099mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.0 30.46 1.014 0.000 Thyroid 0.0 31.82 1.014 0.000 0.05 0.000 Rt. Arm 0.3 32.34 1.014 0.082 Lt. Arm 0.6 31.62 1.014 0.169 Breast 0.0 29.47 1.014 0.000 0.05 0.000 Liver 0.0 31.42 1.014 0.000 0.05 0.000 Stomach 0.2 28.70 1.014 0.062 0.12 0.007 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 2.1 33.99 1.014 0.549 Lt. Lung 1.4 29.82 1.014 0.417 Esophagus 0.8 29.38 1.014 0.242 0.05 0.012 Colon 0.1 30.84 1.014 0.029 0.12 0.003 Rt. Ovary 0.0 31.72 1.014 0.000 Lt. Ovary 0.0 29.12 1.014 0.000 Pelvis 0.0 27.29 1.014 0.000 Spine Middle 1.9 28.38 1.014 0.595 Testes 0.0 30.46 1.014 0.000 0.2 0.000 Average Lung 0.483 0.12 0.058 Average Ovary 0.000 0.2 0.000 Bone Marrow 0.114 0.12 0.014 Bone Surface 0.400 0.01 0.004 Remainder 0.023 0.01 0.000 Surface 0.000 0.01 0.000

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224 Table F-25. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.0 30.46 1.0140.000 0.1470 0.000 Rt. Arm 0.3 32.34 1.0140.082 0.0779 0.006 Lt. Arm 0.6 31.62 1.0140.169 0.0779 0.013 Pelvis 0.0 27.29 1.0140.000 0.2191 0.000 Spine Middle 1.9 28.38 1.0140.595 0.1588 0.094 Total Bone Marrow absorbed dose (mGy) 0.114 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.0 30.45873.0110.000 0.1160 0.000 Rt. Arm 0.3 32.33773.0110.245 0.0980 0.024 Lt. Arm 0.6 31.6193.0110.501 0.0980 0.049 Pelvis 0.0 27.28773.0110.000 0.2190 0.000 Spine Middle 1.9 28.37613.0111.766 0.1850 0.327 Total Bone Surface absorbed dose (mGy) 0.400

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225 Table F-26. One-Year-Old effective doses for Canon DR system at 55 kVp Male 0.180mSv Female 0.163mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.0 30.46 1.014 0.000 Thyroid 0.2 31.82 1.014 0.056 0.05 0.003 Rt. Arm 1.0 32.34 1.014 0.275 Lt. Arm 0.8 31.62 1.014 0.225 Breast 0.0 29.47 1.014 0.000 0.05 0.000 Liver 0.2 31.42 1.014 0.057 0.05 0.003 Stomach 0.5 28.70 1.014 0.155 0.12 0.019 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 2.5 33.99 1.014 0.653 Lt. Lung 2.5 29.82 1.014 0.745 Esophagus 1.0 29.38 1.014 0.302 0.05 0.015 Colon 0.1 30.84 1.014 0.029 0.12 0.003 Rt. Ovary 0.0 31.72 1.014 0.000 Lt. Ovary 0.0 29.12 1.014 0.000 Pelvis 0.0 27.29 1.014 0.000 Spine Middle 3.8 28.38 1.014 1.190 Testes 0.3 30.46 1.014 0.087 0.2 0.017 Average Lung 0.699 0.12 0.084 Average Ovary 0.000 0.2 0.000 Bone Marrow 0.228 0.12 0.027 Bone Surface 0.799 0.01 0.008 Remainder 0.060 0.01 0.001 Surface 0.044 0.01 0.000

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226 Table F-26. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.0 30.46 1.0140.000 0.1470 0.000 Rt. Arm 1.0 32.34 1.0140.275 0.0779 0.021 Lt. Arm 0.8 31.62 1.0140.225 0.0779 0.018 Pelvis 0.0 27.29 1.0140.000 0.2191 0.000 Spine Middle 3.8 28.38 1.0141.190 0.1588 0.189 Total Bone Marrow absorbed dose (mGy) 0.228 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.0 30.45873.0110.000 0.1160 0.000 Rt. Arm 1.0 32.33773.0110.816 0.0980 0.080 Lt. Arm 0.8 31.6193.0110.667 0.0980 0.065 Pelvis 0.0 27.28773.0110.000 0.2190 0.000 Spine Middle 3.8 28.37613.0113.532 0.1850 0.653 Total Bone Surface absorbed dose (mGy) 0.799

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227 Table F-27. One-Year-Old effective doses for Canon DR system at 60 kVp Male 0.239mSv Female 0.248mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.0 30.46 1.014 0.000 Thyroid 0.5 31.82 1.014 0.140 0.05 0.007 Rt. Arm 1.7 32.34 1.014 0.467 Lt. Arm 1.4 31.62 1.014 0.393 Breast 0.2 29.47 1.014 0.060 0.05 0.003 Liver 0.2 31.42 1.014 0.057 0.05 0.003 Stomach 0.2 28.70 1.014 0.062 0.12 0.007 Bladder 0.1 27.21 1.014 0.033 0.05 0.002 Rt. Lung 4.1 33.99 1.014 1.071 Lt. Lung 4.1 29.82 1.014 1.221 Esophagus 1.8 29.38 1.014 0.544 0.05 0.027 Colon 0.0 30.84 1.014 0.000 0.12 0.000 Rt. Ovary 0.2 31.72 1.014 0.056 Lt. Ovary 0.1 29.12 1.014 0.031 Pelvis 0.1 27.29 1.014 0.033 Spine Middle 5.2 28.38 1.014 1.628 Testes 0.0 30.46 1.014 0.000 0.2 0.000 Average Lung 1.146 0.12 0.138 Average Ovary 0.043 0.2 0.009 Bone Marrow 0.333 0.12 0.040 Bone Surface 1.166 0.01 0.012 Remainder 0.038 0.01 0.000 Surface 0.030 0.01 0.000

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228 Table F-27. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.0 30.46 1.0140.000 0.1470 0.000 Rt. Arm 1.7 32.34 1.0140.467 0.0779 0.036 Lt. Arm 1.4 31.62 1.0140.393 0.0779 0.031 Pelvis 0.1 27.29 1.0140.033 0.2191 0.007 Spine Middle 5.2 28.38 1.0141.628 0.1588 0.258 Total Bone Marrow absorbed dose (mGy) 0.333 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.0 30.45873.0110.000 0.1160 0.000 Rt. Arm 1.7 32.33773.0111.387 0.0980 0.136 Lt. Arm 1.4 31.6193.0111.168 0.0980 0.114 Pelvis 0.1 27.28773.0110.097 0.2190 0.021 Spine Middle 5.2 28.37613.0114.834 0.1850 0.894 Total Bone Surface absorbed dose (mGy) 1.166

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229 Table F-28. One-Year-Old effective doses for Canon DR system at 65 kVp Male 0.230mSv Female 0.236mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.0 30.46 1.014 0.000 Thyroid 0.3 31.82 1.014 0.084 0.05 0.004 Rt. Arm 1.2 32.34 1.014 0.330 Lt. Arm 0.8 31.62 1.014 0.225 Breast 0.0 29.47 1.014 0.000 0.05 0.000 Liver 0.6 31.42 1.014 0.170 0.05 0.008 Stomach 0.2 28.70 1.014 0.062 0.12 0.007 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 4.4 33.99 1.014 1.150 Lt. Lung 4.4 29.82 1.014 1.311 Esophagus 1.5 29.38 1.014 0.453 0.05 0.023 Colon 0.0 30.84 1.014 0.000 0.12 0.000 Rt. Ovary 0.2 31.72 1.014 0.056 Lt. Ovary 0.0 29.12 1.014 0.000 Pelvis 0.3 27.29 1.014 0.098 Spine Middle 3.8 28.38 1.014 1.190 Testes 0.0 30.46 1.014 0.000 0.2 0.000 Average Lung 1.230 0.12 0.148 Average Ovary 0.028 0.2 0.006 Bone Marrow 0.253 0.12 0.030 Bone Surface 0.878 0.01 0.009 Remainder 0.058 0.01 0.001 Surface 0.000 0.01 0.000

PAGE 250

230 Table F-28. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.0 30.46 1.0140.000 0.1470 0.000 Rt. Arm 1.2 32.34 1.0140.330 0.0779 0.026 Lt. Arm 0.8 31.62 1.0140.225 0.0779 0.018 Pelvis 0.3 27.29 1.0140.098 0.2191 0.021 Spine Middle 3.8 28.38 1.0141.190 0.1588 0.189 Total Bone Marrow absorbed dose (mGy) 0.253 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.0 30.45873.0110.000 0.1160 0.000 Rt. Arm 1.2 32.33773.0110.979 0.0980 0.096 Lt. Arm 0.8 31.6193.0110.667 0.0980 0.065 Pelvis 0.3 27.28773.0110.290 0.2190 0.064 Spine Middle 3.8 28.37613.0113.532 0.1850 0.653 Total Bone Surface absorbed dose (mGy) 0.878

PAGE 251

231 Table F-29. One-Year-Old effective doses for Canon DR system at 70 kVp Male 0.320mSv Female 0.326mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.2 29.29 1.014 0.061 Head Spine 0.0 30.46 1.014 0.000 Thyroid 0.6 31.82 1.014 0.167 0.05 0.008 Rt. Arm 2.4 32.34 1.014 0.659 Lt. Arm 1.8 31.62 1.014 0.506 Breast 0.9 29.47 1.014 0.271 0.05 0.014 Liver 1.2 31.42 1.014 0.339 0.05 0.017 Stomach 0.9 28.70 1.014 0.279 0.12 0.033 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 5.0 33.99 1.014 1.307 Lt. Lung 4.5 29.82 1.014 1.340 Esophagus 1.3 29.38 1.014 0.393 0.05 0.020 Colon 0.0 30.84 1.014 0.000 0.12 0.000 Rt. Ovary 0.0 31.72 1.014 0.000 Lt. Ovary 0.2 29.12 1.014 0.061 Pelvis 0.0 27.29 1.014 0.000 Spine Middle 6.6 28.38 1.014 2.066 Testes 0.0 30.46 1.014 0.000 0.2 0.000 Average Lung 1.323 0.12 0.159 Average Ovary 0.031 0.2 0.006 Bone Marrow 0.428 0.12 0.051 Bone Surface 1.495 0.01 0.015 Remainder 0.154 0.01 0.002 Surface 0.136 0.01 0.001

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232 Table F-29. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.2 29.29 1.0140.061 0.1470 0.009 Head Spine 0.0 30.46 1.0140.000 0.1470 0.000 Rt. Arm 2.4 32.34 1.0140.659 0.0779 0.051 Lt. Arm 1.8 31.62 1.0140.506 0.0779 0.039 Pelvis 0.0 27.29 1.0140.000 0.2191 0.000 Spine Middle 6.6 28.38 1.0142.066 0.1588 0.328 Total Bone Marrow absorbed dose (mGy) 0.428 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.2 29.29413.0110.180 0.1160 0.021 Head Spine 0.0 30.45873.0110.000 0.1160 0.000 Rt. Arm 2.4 32.33773.0111.958 0.0980 0.192 Lt. Arm 1.8 31.6193.0111.502 0.0980 0.147 Pelvis 0.0 27.28773.0110.000 0.2190 0.000 Spine Middle 6.6 28.37613.0116.135 0.1850 1.135 Total Bone Surface absorbed dose (mGy) 1.495

PAGE 253

233 Table F-30. One-Year-Old effective doses for Canon DR system at 75 kVp Male 0.407mSv Female 0.401mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.0 30.46 1.014 0.000 Thyroid 1.2 31.82 1.014 0.335 0.05 0.017 Rt. Arm 4.1 32.34 1.014 1.126 Lt. Arm 1.5 31.62 1.014 0.421 Breast 0.0 29.47 1.014 0.000 0.05 0.000 Liver 1.3 31.42 1.014 0.368 0.05 0.018 Stomach 1.8 28.70 1.014 0.557 0.12 0.067 Bladder 0.0 27.21 1.014 0.000 0.05 0.000 Rt. Lung 4.8 33.99 1.014 1.254 Lt. Lung 4.6 29.82 1.014 1.370 Esophagus 2.9 29.38 1.014 0.877 0.05 0.044 Colon 0.5 30.84 1.014 0.144 0.12 0.017 Rt. Ovary 0.2 31.72 1.014 0.056 Lt. Ovary 0.0 29.12 1.014 0.000 Pelvis 0.5 27.29 1.014 0.163 Spine Middle 6.2 28.38 1.014 1.941 Testes 0.2 30.46 1.014 0.058 0.2 0.012 Average Lung 1.312 0.12 0.157 Average Ovary 0.028 0.2 0.006 Bone Marrow 0.464 0.12 0.056 Bone Surface 1.622 0.01 0.016 Remainder 0.267 0.01 0.003 Surface 0.029 0.01 0.000

PAGE 254

234 Table F-30. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.0 30.46 1.0140.000 0.1470 0.000 Rt. Arm 4.1 32.34 1.0141.126 0.0779 0.088 Lt. Arm 1.5 31.62 1.0140.421 0.0779 0.033 Pelvis 0.5 27.29 1.0140.163 0.2191 0.036 Spine Middle 6.2 28.38 1.0141.941 0.1588 0.308 Total Bone Marrow absorbed dose (mGy) 0.464 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.0 30.45873.0110.000 0.1160 0.000 Rt. Arm 4.1 32.33773.0113.344 0.0980 0.328 Lt. Arm 1.5 31.6193.0111.251 0.0980 0.123 Pelvis 0.5 27.28773.0110.483 0.2190 0.106 Spine Middle 6.2 28.37613.0115.763 0.1850 1.066 Total Bone Surface absorbed dose (mGy) 1.622

PAGE 255

235 Table F-31. One-Year-Old effective doses for Canon DR system at 80 kVp Male 0.314mSv Female 0.317mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.0 30.46 1.014 0.000 Thyroid 1.3 31.82 1.014 0.363 0.05 0.018 Rt. Arm 2.0 32.34 1.014 0.549 Lt. Arm 1.7 31.62 1.014 0.478 Breast 0.0 29.47 1.014 0.000 0.05 0.000 Liver 1.5 31.42 1.014 0.424 0.05 0.021 Stomach 0.6 28.70 1.014 0.186 0.12 0.022 Bladder 0.3 27.21 1.014 0.098 0.05 0.005 Rt. Lung 4.8 33.99 1.014 1.254 Lt. Lung 3.1 29.82 1.014 0.923 Esophagus 1.0 29.38 1.014 0.302 0.05 0.015 Colon 0.5 30.84 1.014 0.144 0.12 0.017 Rt. Ovary 0.3 31.72 1.014 0.084 Lt. Ovary 0.2 29.12 1.014 0.061 Pelvis 0.5 27.29 1.014 0.163 Spine Middle 6.8 28.38 1.014 2.129 Testes 0.2 30.46 1.014 0.058 0.2 0.012 Average Lung 1.089 0.12 0.131 Average Ovary 0.073 0.2 0.015 Bone Marrow 0.454 0.12 0.054 Bone Surface 1.574 0.01 0.016 Remainder 0.213 0.01 0.002 Surface 0.029 0.01 0.000

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236 Table F-31. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.0 30.46 1.0140.000 0.1470 0.000 Rt. Arm 2.0 32.34 1.0140.549 0.0779 0.043 Lt. Arm 1.7 31.62 1.0140.478 0.0779 0.037 Pelvis 0.5 27.29 1.0140.163 0.2191 0.036 Spine Middle 6.8 28.38 1.0142.129 0.1588 0.338 Total Bone Marrow absorbed dose (mGy) 0.454 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.0 30.45873.0110.000 0.1160 0.000 Rt. Arm 2.0 32.33773.0111.631 0.0980 0.160 Lt. Arm 1.7 31.6193.0111.418 0.0980 0.139 Pelvis 0.5 27.28773.0110.483 0.2190 0.106 Spine Middle 6.8 28.37613.0116.321 0.1850 1.169 Total Bone Surface absorbed dose (mGy) 1.574

PAGE 257

237 Table F-32. One-Year-Old effective doses for Canon DR system at 85 kVp Male 0.404mSv Female 0.430mSv MOSFETCF OAD Organ Sites [mV] [mR/mV]DCF [mGy] TWF OAD*TWF Face Spine 0.0 29.29 1.014 0.000 Head Spine 0.1 30.46 1.014 0.029 Thyroid 0.9 31.82 1.014 0.251 0.05 0.013 Rt. Arm 1.8 32.34 1.014 0.494 Lt. Arm 2.2 31.62 1.014 0.618 Breast 0.0 29.47 1.014 0.000 0.05 0.000 Liver 1.7 31.42 1.014 0.481 0.05 0.024 Stomach 1.4 28.70 1.014 0.433 0.12 0.052 Bladder 0.1 27.21 1.014 0.033 0.05 0.002 Rt. Lung 5.8 33.99 1.014 1.516 Lt. Lung 5.2 29.82 1.014 1.549 Esophagus 2.8 29.38 1.014 0.847 0.05 0.042 Colon 0.8 30.84 1.014 0.230 0.12 0.028 Rt. Ovary 0.5 31.72 1.014 0.140 Lt. Ovary 0.4 29.12 1.014 0.122 Pelvis 0.0 27.29 1.014 0.000 Spine Middle 5.5 28.38 1.014 1.722 Testes 0.0 30.46 1.014 0.000 0.2 0.000 Average Lung 1.532 0.12 0.184 Average Ovary 0.131 0.2 0.026 Bone Marrow 0.364 0.12 0.044 Bone Surface 1.280 0.01 0.013 Remainder 0.294 0.01 0.003 Surface 0.000 0.01 0.000

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238 Table F-32. Continued Bone Marrow Absorbed Dose Calculation Bone marrow MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BMW OAD*BMW Face Spine 0.0 29.29 1.0140.000 0.1470 0.000 Head Spine 0.1 30.46 1.0140.029 0.1470 0.004 Rt. Arm 1.8 32.34 1.0140.494 0.0779 0.039 Lt. Arm 2.2 31.62 1.0140.618 0.0779 0.048 Pelvis 0.0 27.29 1.0140.000 0.2191 0.000 Spine Middle 5.5 28.38 1.0141.722 0.1588 0.273 Total Bone Marrow absorbed dose (mGy) 0.364 Bone Surface Absorbed Dose Calcalution Bone surface MOSFETCF OAD sites [mV] [mR/mV]DCF [mGy] BSW OAD*BSW Face Spine 0.0 29.29413.0110.000 0.1160 0.000 Head Spine 0.1 30.45873.0110.087 0.1160 0.010 Rt. Arm 1.8 32.33773.0111.468 0.0980 0.144 Lt. Arm 2.2 31.6193.0111.835 0.0980 0.180 Pelvis 0.0 27.28773.0110.000 0.2190 0.000 Spine Middle 5.5 28.37613.0115.112 0.1850 0.946 Total Bone Surface absorbed dose (mGy) 1.280

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239 APPENDIX G PROBLEMS WITH CT PHANTOMS For CT, it was proposed that the MTF and NPS be calculated using the Catphan CT phantom. To image the items in the phantom, CT slices should be perpendicular to the axis of the phantom as displayed in Figure G-1(A). One slice of the Catphan is the CTP446 high resolution module with 21 line pairs groups which is displayed in Figure G1(B). Figure G-1. Proper orientation of a CT Ph antom (A) The proper orientation of the Catphan. (B) Image of the CTP446 high resolution module. The GE Lightspeed QX/I has two helical mode, high quality and high speed. High quality refers to a pitch of 3:1 and high speed refers to a pitch of 6:1. The Catphan was not adequate for the high speed scanning. Figure G-2 compares the CTP446 high resolution module at (A) high quality and (B) high speed. The high speed image shows streaks. Axis Metal Fixture

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240 Figure G-2. The CTP446 high resolution module (A) imaged with high quality 3:1 pitch and (B) imaged with high speed 6:1 pitch. Figure G-3. Orientation of a CT phantom for planar reconstructed images (A) The Catphan in a 90 degree orientation. (B) Reconstructed image of the CTP446 high resolution module. To produce reconstructed images, the phantom was turned 90 degrees and scanned parallel to the phantom axis as shown in Figure G-3 (A). The image of the CTP446 high resolution module was reconstructed and is shown in Figure G-3(B). Because the phantom was turned 90 degrees and scanned, the entire phantom was scanned including the metal fixtures on the end. The metal shows up as artifacts on the reconstructed image. Also contained in the phantom is a tungsten carbide bead. This bead shows in the helical Axis

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241 images in Figure G-1 and G-2 but not in Figure G-3. The line pairs in the reconstructed images are not as distinctly separated as in the helical images. Line pair separation is necessary for the Droege and Morin (1982) method of determining the MTF with the line pair phantom. The resolution of the phantom was not adequate for determining the MTF of the reconstructed image. To determine the NPS, flat field images are necessary. There is a part of the Catphan with no embedded objects as shown in Figure G-4 (A). The artifacts in the reconstruct image are caused by the metal in the Catphan. The artifacts make it difficult to obtain a large flat field area necessary for the NPS calculation. Figure G-4. Planar reconstructed images (A) Catphan flat field image and (B) reconstructed flat field image. The CT phantom available was not adequate for MTF and NPS measurements of reconstructed images. This phantom was constructed to be imaged with CT slices perpendicular to the phantom axis. A new phantom is needed to measure image quality in other planes.

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242 LIST OF REFERENCES Antonuk LE, Yorkston J, Huang WD, Siewerdsen JH, Boudry JM, Elmohri Y, Marx MV, “A Real-Time, Flat-Panel, Amorphous-Silicon, Digital X-Ray Imager”, Radiographics, 15(4), 993-1000 (1995) Boone, J.M., Seibert, J.A., “An accurate method for computed-generated tungsten anode x-ray spectra from 30 to 140 kV”, Medical Physics, 24 (11), 1661-1670 (1997) Bouchet, L., Bolch, W., Weber., Atkins., Poston, J., “A revised dosimetric model of the adult head and brain,” J Nucl Med. 37,1226-36 (1996) Bower, M, W.: A Physical Anthropomorphic Phantom of a One-Year-Old Child with Real-Time Dosimetry . Doctoral Dissertation, Department of Nuclear and Radiological Engineering, University of Florida, (1997). Bradford, C., Peppler, W., Dobbins, J., “Performance Characteristics of a Kodak computed radiography system”, Medical Physics, 26 (1) 27-37 (1999) Chotas, H, Floyd C., Dobbins J., Ravin C., “Digital Chest Radiography with photostimulatable storage phosphors: Signal –to-noise ratio as a function of kilovoltage with matched exposure risk”, Radiology, 186, 395-398 (1993) Chotas, H.G., Dobbins, J.T., Ravin, C.E, “P rinciples of digital radiography with largearea electronically readable detectors: A review of the basics”, Radiology, 210(3), 595-599 (1999) Christy, M., Mathematical Phantoms Representing Children of Various Ages for Use in Estimates of Internal Dose. Oak Ridge, TN, Oak Ridge National Laboratory (1980) Cohen, M., katx, B., Kalasinski, L., White, S ., Smith, J., Long, B., “Digital imaging with a photostimulable phosphor in the chest of newborns”, Radiology 181, 829-832 (1991) Curry,D., Dowdey J., Murry, R., Christensen’s Physics of Diagnostic Radiology . Philadelphia, Pennsylvania, Malvern, Lea and Febiger (1990) Dendy, PP, Heaton, B., Physics for Diagnositc Radiology , Philadelphia, Pennsylvania, IOP Publishing Ltd (1999)

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243 Dobbins, JT, “Effects of undersampling on the proper interpretaion of modulation transfer function, noise power spectra, and noise equivalent quanta of digital imaging”, Medical Physics, 22(2), 171-181 (1995) Dobbins, JT III, Ergun DL, Rutz, L, Hinshaw, DS, Blume H, Clark DC, “DQE(f) of four generations of computed radiography acquisition devices”, Medical Physics, 22, 1581-1593 (1995) Droege RT, Morin RL ,“A Practical Met hod To Measure The MTF Of CT Scanners” Medical Physics, 9 (4): 616-616 (1982) Evans, A., The Evaluation of Medical Images , Bristol, Adam Higer Ltd (1981) Fauber, T., Radiographic Imaging and Exposure , St. Louis, Missouri, Mosby Inc. (2000) Fetterly K.A., Hangrandreou, N.J., “Image quality evaluation of a desktop computed radiography system”, Medical Physics, 27(12), 2669-2679 (2001) Fetterly K.A., Hangrandreou, N.J., “Effects of x-ray spectra on DQE of a computed radiography system”, Medical Physics, 28(2), 241-249 (2001) Floyd, C.R., Baker, J.A., Choatas, H.G., Delong, D.M., Ravin, C.E., “Selenium-based digital radiography of the chest: radiologist s' preference compared with film-screen radiographs”, AJR, 165(6), 1353 (1995) Floyd, C.E., Warp, R.J., Dobbins, J.T., Chotas, H.G., Baydush, A.H., Vargas-Vorcek, R., Ravin, C.E., “Imaging Characteristics of an amorphous silicon flat-panel detector for digital chest radiography”, Radiology, 218 (3), 683-688 (2001) Giger, M.L., Doi, K., “Investigation of basic imaging properties in digital radiography. Modulation transfer function”, Medical Physics, 11 (3) 287-295 (1984) Gunn, C., Radiographic Imaging: A Practical Approach , London, England, Harcourt Publishers Ltd (2002) Hasegawa, B., The Physics of Medical X-Ray Imaging , Madison, Wisconsin, Medical Physics Publishing (1991) Hendee, W., Trueblood, J., Digital Imaging , Madison,Wisconsin, Medical Physics Publishing (1993) Hillen W., Schiebel, U., Zaengel T., “Imaging perfomance of a digital storage phosphor system”, Medical Physics 14(5), 744-751 (1987) Hoheisel M, Arques M, Chabbal J, Chaussat C, Ducourant T, Hahm G, Horbaschek H, Schulz R, Spahn M, “Amorphous silicon X-ray detectors”, Journal of NonCrystalline Solids, 227-230, 1300-1305 (1998)

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244 Huda W., Slone R., Review Of Radiologic Physics. Media, Williams and Wilkins. (1995) Hufton, AP, Doyle, SM, Carty, HM, “Digita l radiography in pediatrics: radiation dose considerations and magitude of possible dose reduction”, Br. J. Radiol, 71, 186-199 (1998) Jing T., C. A. Goodman, J. Drewery, Cho G., S. Hong W., Lee H., Kaplan S. N., PerezMendez V. and Wildermuth D., “Detection of charged particles and X-rays by scintillator layers coupled to amorphous silicon photodiode arrays”, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 368(3), 757-754 (1996) Johnson, K., Measurement of Organ Doses of Pediatric Patients Undergoing Computed Tomography Examinations. Master's Thesis, Department of Nuclear and Radiological Engineering, Univ ersity of Florida, (1998). Kamm, KF, “The future of digital imaging”, The British Journal of Radiology, 70, S145S152 (1997) Kelsey, C., Essentials of Radiology Physics , St. Louis, Mo., Warren H. Green, Inc. (1985) Kengyelics SM, Launders JH, Cowen AR, “Physical imaging performance of a compact computed radiography acquisition device”, Medical Physics, 25(3), 354-360, (1998) Kirks, D., Practical Pediatric Imaging: Diagnostic Radiology of Infants and Children , Little, Brown and Co. (1991) Kretsel, E., Imaging systems for Medical Diagnostics , Berlin and Munich, Germany Siemans (1990) Launders JH, Cowen AR, Bury RF, Hawkridge P, “A case study into the effect of radiographic factors on image quality and dose for a selenium based digital chest radiography system”, Radiation Protection Dosimetry, 80(1-3), 279-282 (1998) Launders, J.H., Kengyelics, SM, Cowen, AR, “A comprehensive physical image quality evaluation of a selenium based digital x-ray imaging system for thorax radiography”, Medical Physics, 25(6), 986 (1998) Martin CJ, Sutton DG, Sharp PF, “Balancing patient dose and image quality”, Applied Radiation and Isotopes, 50(1), 1-19 (1999) Moy, J., “Recent developments in x-ray imaging detectors”, Nuclear Instruments and methods in physics reseacrg section A, Accelerators, spectrometers, detectors and associated equipment, 442, 26-37 (2000)

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245 Moy, JP, “Large area X-ray detectors based on amorphous silicon technology”, Thin Solid Films, 337(1-2), 213-221 (1999) National Council on Radiation Protection, Exposure of the U.S. Population from Diagnostic Medical Radiation, Nationa l Council on Radiation Protection and Measurement, Bethesda, MD (1987) Neitzel, U., Maack, I., Guntherkohfahl, S., “Image quality of a digital chest radigraphy system based on a selenium detector”, Medical Physics, 21(4), 509-516 (1994) Sanada, S., Doi, K., Xu, X., Yin, F., Giger, M., MacMahon, H., “Comparison of imaging properties of a computed radiography system and screen-film”, Medical Physics, 18 (3), 414-420 (1991) Siewerdsen JH, Antonuk LE, El-Mohri Y, Yorkston J, Huang W, Cunningham IA, “Signal, noise power spectrum, and det ective quantum efficiency of indirectdetection flat-panel imagers for diagnostic radiology”, Medical Physics, 25(5), 614628 (1998) Spahn, M., Strotzer, M., Volk, M., Bohm, S., Geiger, B., Hahm, G., Feuerbach, S., “Digital Radiography with a Large-Area Amorphous-Silicon, Flat-Panel X-Ray Detector system”, Investigative Radiology, 35(4), 260-266 (2000) Sprawls, P., The Physical Principles of Diagnostic Radiology , Baltimore, Maryland, Apen Publishers (1977) Stierstorfer, K., Spahn, M., “Self-normalizing method to measure the detective quantum efficiency of a wide range of x-ray de tectors”, Medical Physics, 26 (7), 1312-1319 (1999) Street,R. A. , X. D. Wu, R. Weisfield, S. Ready, R. Apte, W. B. Jackson, M. Ngyuen and P. Nylen, “Two-dimensional amorphous silicon image sensor arrays”, Journal of Non-Crystalline Solids, 198-200, 1151-1154 (1996) Strotzer, M., Gmeinwieser J, Volk M, “Clinical applications of a flat panel x-ray detector based on amorphous silicon technology”, AJR, 171, 23-27 (1998) Wolbarst, A.B., Physics of Radiology , Madison, WI., Medical Physics Publishing (1993) Yamada, S, “Development of a Direct-conve rsion-type Flat-panel Detector for Radiography and Fluoroscopy”, Medical Imaging Technology, 17(2) ,110-116 (1999) Yamazaki, T.; Morishita, M.; Kaifu, N.; Endo, Y., “Development of flat panel digital radiography system”, Medical Imaging Technology, 17(2), 117-122 (1999)

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246 BIOGRAPHICAL SKETCH Kennita A. Johnson was born March 22, 1974 in Washington, D.C. to Kenneth and Barbara Johnson. There she attended Eleanor Roosevelt High School, where she took part in the science and technology program. There she excelled in science and won first place in the school science fair and second place in the tri-county science fair in the chemistry division with her project on chemiluminescent materials. From there she attended University of Maryland Baltimore County (UMBC) where she received her Bachelors of Science degree in physics with a minor in sociology. While attending UMBC, she held an internship at NASA Goddard Space Flight Center in the materials branch where she tested electrostatic materials and learned to program in LabVIEW. Her knowledge of LabVIEW lead to an undergraduate research project in a nonlinear optics lab where she tested materials that would be used in optical storage devices. For her graduate studies, she decided to switch gears in order to study medical physics at the University of Florida. While getting her Masters of Science degree in medical physics from the Department of Nu clear and Radiological Engineering, she developed a passion for politics and public service. This passion led her to presidencies of the student chapter of the Health Physic s Society,and the Benton Engineering Council, as well as 3 terms as a Student Governement Senator. All of her accomplishments culminated in being named to the University of Florida Hall of Fame. After finishing her Masters degree, she decided to continue her education and recieved a Doctor of

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247 Philosophy degree from the Department of Bi omedical Engineering with an emphasis on medical image formation and processing in the summer of 2003.