Physics and Radiobiology of Nuclear Medicine

Physics and Radiobiology of Nuclear Medicine

Gopal B. Saha, Ph.D. Physics and Radiobiology of Nuclear Medicine Fourth Edition 1 3

Gopal B. Saha, Ph.D. Emeritus Staff Cleveland Clinic Cleveland, OH 44195 USA ISBN 978-1-4614-4011-6 ISBN 978-1-4614-4012-3 (ebook) DOI 10.1007/978-1-4614-4012-3 Springer New York Dordrecht Heidelberg London Library of Congress Control Number: 2012948009 Springer Science+Business Media New York 1993, 2001, 2006, 2013 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. While the advice and information in this book are believed to be true and accurate at the date of going to press, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

To All my benefactors

Preface The fourth edition of this book has been prompted by a need to provide up-to-date information in keeping up with perpetual growth and improvement in instrumentation and techniques employed in nuclear medicine since its last edition in 2006. Like the past editions, the book is intended for the radiology and nuclear medicine residents to prepare for the American Board of Nuclear Medicine, American Board of Radiology and American Board of Science in Nuclear Medicine examinations, all of which require strong physics background. Also, it will serve as a textbook on nuclear medicine physics and instrumentation for nuclear medicine technologists taking the Nuclear Medicine Technology Certification Board examination. The organization of the book has been kept the same as in the previous editions consisting of 16 chapters starting with basics in initial chapters and then progressing into more developed techniques in later chapters. Chapters 1 4, 6, 8 and 11 have no major changes. An expanded description of a cyclotron and two examples of calculation of yield of activity produced are added to Chapter 5 along with the updating of Table 5.1. Chapter 7 includes additional information on the ion chamber survey meter, proportional counter, and G-M counter. The section on solid state digital cameras has been revised in Chapter 9. In Chapter 10, several changes have been made, namely, an expanded collimator section, a detailed description of contrast, and a more detailed quality control section. Changes in Chapter 12 include: detailed iterative reconstruction method, description of CT scanners in SPECT/CT, detailed description of attenuation correction in SPECT/ CT, and expanded sections on partial volume effects and quality control of CT scanners. Included in Chapter 13 are: upgraded information on detectors and PET scanners; a new section on PET/MR including the attenuation correction method and its quality control tests; the time of flight technique; several scatter correction techniques; and a section on accreditation of nuclear medicine and PET facilities. Doses in Table 14.4 have been updated, and new tables with revised pediatric dosages have been included in Chapter 14. For consistency, the section, Sources of Radiation exposure in USA has been removed from Chapter 16 and added to Chapter 15 with revised data, while the sections Dirty Bombs, Verification Card for Radioactive Patients and Radiation Phobia have been moved from vii

viii Preface Chapter 15 and added to Chapter 16. European Regulations Governing Radiations in Chapter 16 has been revised. A number of figures and tables have been added for better explanation of the text contents throughout the book. It has been a great pleasure to work with, for which I am ever grateful to, Andrew Moyer, Senior Editor of Clinical Medicine at Springer, for his sincere support during the publication of several of my books by Springer including this one. I would like to thank Ian Hayes, Editorial Assistant, and Joseph Quatela, Senior Production Editor of Springer for their support in the production of this book. Gopal B. Saha, Ph.D.

Contents Preface... vii Chapter 1 Structure of Matter... 1 Matter and Energy... 1 Radiation... 2 The Atom... 3 Electronic Structure of the Atom... 3 Structure of the Nucleus... 6 Nuclear Binding Energy... 7 Nuclear Nomenclature... 8 Chart of the Nuclides... 8 Questions... 10 Suggested Readings... 10 Chapter 2 Radioactive Decay... 11 Spontaneous Fission... 11 Isomeric Transition... 12 Gamma (γ)-ray Emission... 12 Internal Conversion... 12 Alpha (α)-decay... 14 Beta (β )-Decay... 15 Positron (β + )-Decay... 17 Electron Capture... 18 Questions... 20 Suggested Readings... 20 Chapter 3 Kinetics of Radioactive Decay... 21 Radioactive Decay Equations... 21 General Equation... 21 Half-Life... 22 Mean Life... 24 Effective Half-Life... 25 ix

x Contents Units of Radioactivity... 25 Specific Activity... 26 Calculation... 27 Successive Decay Equations... 30 General Equation... 30 Transient Equilibrium... 30 Secular Equilibrium... 31 Questions... 32 Suggested Readings... 34 Chapter 4 Statistics of Radiation Counting... 35 Error, Accuracy, and Precision... 35 Mean and Standard Deviation... 36 Gaussian Distribution... 36 Standard Deviation of Count Rates... 38 Propagation of Errors... 38 Chi-Square Test... 41 Minimum Detectable Activity... 43 Evaluation of Diagnostic Tests... 43 Questions... 45 Suggested Readings... 45 Chapter 5 Production of Radionuclides... 47 Cyclotron-Produced Radionuclides... 47 Reactor-Produced Radionuclides... 50 Fission or (n, f) Reaction... 51 Neutron Capture or (n,γ) Reaction... 52 Target and Its Processing... 52 Equation for Production of Radionuclides... 52 Radionuclide Generators... 57 99 Mo 99m TcGenerator... 59 Cyclotron production of 99m Tc... 60 Questions... 60 References and Suggested Readings... 61 Chapter 6 Interaction of Radiation with Matter... 63 Interaction of Charged Particles with Matter... 63 Specific Ionization... 64 Linear Energy Transfer... 65 Range... 65 Bremsstrahlung... 67 Annihilation... 67 Interaction of γ-radiations with Matter... 68 Mechanism of Interaction of γ-radiations... 68 Attenuation of γ-radiations... 72 Interaction of Neutrons with Matter... 75

Contents xi Questions... 76 Suggested Readings... 77 Chapter 7 Gas-Filled Detectors... 79 Principles of Gas-Filled Detectors... 79 Ionization Chambers... 81 Ion Chamber Survey Meter... 82 Dose Calibrator... 83 Pocket Dosimeter... 86 Proportional Counters... 87 Geiger Müller Counters... 87 Questions... 90 Suggested Readings... 90 Chapter 8 Scintillation and Semiconductor Detectors... 91 Scintillation Detectors... 91 Solid Scintillation Detectors... 92 Solid-State Detectors... 94 Solid Scintillation Counters... 95 NaI(Tl) Detector... 95 Photomultiplier Tube... 95 Preamplifier... 97 Linear Amplifier... 97 Pulse-Height Analyzer... 97 Display or Storage... 98 Gamma-Ray Spectrometry... 98 Photopeak... 98 Compton Valley, Edge, and Plateau... 99 Characteristic X-Ray Peak... 100 Backscatter Peak... 100 Iodine Escape Peak... 100 Annihilation Peak... 101 Coincidence Peak... 101 Liquid Scintillation Counters... 102 Characteristics of Counting Systems... 104 Energy Resolution... 104 Detection Efficiency... 106 Dead Time... 108 Gamma Well Counters... 110 Calibration of Well Counters... 110 Counting in Well Counters... 111 Effects of Sample Volume... 112 Thyroid Probe... 113 Thyroid Uptake Measurement... 114 Questions... 114 Suggested Readings... 116

xii Contents Chapter 9 Gamma Cameras... 117 Gamma Cameras... 117 Principles of Operation... 117 Detector... 119 Collimator... 120 Photomultiplier Tube... 121 X-, Y-Positioning Circuit... 121 Pulse-Height Analyzer... 123 Display and Storage... 123 Digital Cameras... 124 Solid State Digital Cameras... 124 Questions... 125 Suggested Readings... 126 Chapter 10 Performance Parameters of Gamma Cameras... 127 Spatial Resolution... 127 Intrinsic Resolution... 127 Collimator Resolution... 128 Scatter Resolution... 132 Evaluation of Spatial Resolution... 132 Bar Phantom... 132 Line-Spread Function... 134 Modulation Transfer Function... 135 Sensitivity... 137 Collimator Efficiency... 137 Uniformity... 139 Pulse-Height Variation... 139 Nonlinearity... 139 Edge Packing... 140 Gamma Camera Tuning... 141 Effects of High Counting Rates... 141 Contrast... 142 Quality Control Tests for Gamma Cameras... 145 Daily Checks... 146 Weekly Checks... 148 Monthly Checks... 148 Annual, Semiannual, or As-Needed Checks... 149 Questions... 149 References and Suggested Readings... 151 Chapter 11 Digital Computers in Nuclear Medicine... 153 Basics of a Computer... 153 Central Processing Unit... 154 Computer Memory... 155 External Storage Devices... 155

Contents xiii Input/Output Devices... 155 Operation of a Computer... 156 Digitization of Analog Data... 156 Digital-to-Analog Conversion... 157 Digital Images... 157 Application of Computers in Nuclear Medicine... 158 Digital Data Acquisition... 158 Static Study... 159 Dynamic Study... 160 Gated Study... 160 Reconstruction of Images... 162 Fusion and Subtraction of Images... 162 Display... 162 Software and DICOM... 163 PACS... 164 Questions... 166 Suggested Readings... 166 Chapter 12 Single Photon Emission Computed Tomography... 167 Tomographic Imaging... 167 Single Photon Emission Computed Tomography... 167 Data Acquisition... 169 Image Reconstruction... 170 SPECT/CT... 184 Factors Affecting SPECT... 187 Performance of SPECT Cameras... 196 Spatial Resolution... 196 Sensitivity... 197 Other Parameters... 198 Quality Control Tests for SPECT Cameras... 198 Daily Tests... 198 Weekly Tests... 198 Quality Control Tests for CT Scanners... 199 Questions... 200 References and Suggested Readings... 201 Chapter 13 Positron Emission Tomography... 203 PET Radiopharmaceuticals... 203 Detectors in PET Scanners... 204 PM Tubes and Pulse-Height Analyzers... 205 PET Scanners... 205 Block Detectors... 205 Coincidence Timing Window... 207 PET/CT Scanners... 209 PET/MR Scanners... 210

xiv Contents Principles of MR Imaging... 212 MR scanner... 216 Commercial PET/MR Scanners... 217 Mobile PET or PET/CT... 218 Micro-PET... 219 Dual- and Triple-Head Gamma Cameras... 220 Data Acquisition... 221 Time of Flight Method... 223 Two-Dimensional Versus Three-Dimensional Data Acquisition... 224 Image Reconstruction... 225 Factors Affecting PET... 226 Normalization... 227 Photon Attenuation Correction... 227 Random Coincidences... 230 Scatter Coincidences... 230 Dead Time... 232 Radial Elongation... 232 Performance of PET Scanners... 232 Spatial Resolution... 232 Sensitivity... 235 Noise Equivalent Count Rate... 235 Quality Control Tests for PET Scanners... 236 Daily Tests... 236 Weekly Tests... 236 Quality Control Tests for MR Scanners... 237 Accreditation of Nuclear Medicine and PET Facilities... 238 Questions... 240 References and Suggested Readings... 241 Chapter 14 Internal Radiation Dosimetry... 243 Radiation Units... 243 Dose Calculation... 246 Radiation Dose Rate... 246 Cumulative Radiation Dose... 247 Radiation Dose in SI Units... 251 Effective Dose Equivalent and Effective Dose... 252 Pediatric Dosages... 256 Questions... 260 References and Suggested Readings... 261 Chapter 15 Radiation Biology... 263 The Cell... 263 Effects of Radiation... 266 DNA Molecule... 266 Chromosome... 269

Contents xv Direct and Indirect Actions of Radiation... 270 Radiosensitivity of Cells... 272 Cell Survival Curves... 274 Factors Affecting Radiosensitivity... 276 Dose Rate... 277 Linear Energy Transfer... 277 Chemicals... 278 Stage of Cell Cycle... 281 Apoptosis... 281 Classification of Radiation Damage... 281 Sources of Radiation Exposure in the United States... 283 Stochastic and Deterministic Effects... 284 Acute Effects of Total Body Irradiation... 284 Hemopoietic Syndrome... 285 Gastrointestinal Syndrome... 285 Cerebrovascular Syndrome... 286 Long-Term Effects of Radiation... 286 Somatic Effects... 286 Genetic Effects... 293 Risk Versus Benefit in Diagnostic Radiology and Nuclear Medicine... 295 Risk to Pregnant Women... 296 Questions... 297 References and Suggested Readings... 299 Chapter 16 Radiation Regulations and Protection... 301 License... 301 Radiation Protection... 303 Definition of Terms... 303 Caution Signs and Labels... 304 Occupational Dose Limits... 305 ALARA Program... 305 Principles of Radiation Protection... 306 Personnel Monitoring... 309 Dos and Don ts in Radiation Protection Practice... 310 Bioassay... 311 Receiving and Monitoring of Radioactive Packages... 311 Radioactive Waste Disposal... 312 Radioactive Spill... 313 Recordkeeping... 314 Medical Uses of Radioactive Materials... 314 Applications, Amendments, and Notifications... 314 Authority and Responsibilities of the Licensee... 315 Supervision... 315 Mobile Nuclear Medicine Service... 315 Written Directives... 316

xvi Contents Measurement of Dosages... 316 Calibration, Transmission, and Reference Sources... 317 Requirement for Possession of Sealed Sources... 317 Labeling of Vials and Syringes... 317 Surveys of Ambient Radiation Exposure Rate... 317 Calibration of Survey Instruments... 318 Training and Experience Requirements for Medical Uses of By-Product Materials... 318 Report and Notification of a Medical Event... 319 Report and Notification of a Dose to an Embryo/Fetus or a Nursing Child... 320 Release of Patients Administered with Radiopharmaceuticals... 320 Recordkeeping... 323 Dirty Bombs... 323 Types of Accidental Radiation Exposure... 323 Protective Measures in Case of Explosion of a Dirty Bomb... 325 Verification Card for Radioactive Patients... 326 Radiation Phobia... 327 Transportation of Radioactive Materials... 328 European Regulations Governing Radiation... 330 Questions... 332 References and Suggested Readings... 333 Appendix A Units and Constants... 335 Appendix B Terms Used in Text... 337 Appendix C Answers to Questions... 343 Index... 345