Physics in Nuclear Medicine

Transcription

1 SIMON R. CHERRY, PH.D. Professor Department of Biomedical Engineering University of California-Davis Davis, California JAMES A. SORENSON, PH.D. Emeritus Professor of Medical Physics University of Wisconsin-Madison Madison, Wisconsin MICHAEL E. PHELPS, PH. D. Norton Simon Professor Chair, Department of Molecular and Medical Pharmacology Director, Center for Molecular Medicine Director, Crump Institute for Molecular Imaging David Geffen School of Medicine, UCLA Los Angeles, California Physics in Nuclear Medicine third edition SAUNDERS :4r : Imprint of Elsevier

2 What Is Nuclear Medicine? 1 G. Positron (R+) and (R+, ~,) Decay 25 A. Fundamental Concepts 1 H. Competitive R+ B. The and EC Decay Power of Nuclear Medicine 27 1 I, Decay by a Emission C. Historical Overview 2 and by Nuclear Fission 2'7 D. Current Practice of Nuclear J. Decay Medicine Modes and the Line of 3 E. Stability 28 The Role of Physics in Nuclear K. Sources of Medicine 6 Information on Radionuclides 30 Basic Atomic and Nuclear Physics 7 (1) Decay of Radioactivity 31 A. Quantities and Units 7 1. Types of Quantities and Units 7 A. Activity Mass and Energy Units 7 1. The Decay Constant 31 B. Radiation 8 2. Definition and Units of Activity 31 C. Atoms 9 B. Exponential Decay Composition and Structure 9 1. The Decay Factor Electron Binding Energies and 2. Half-Life 33 Energy Levels Average Lifetime Atomic Emissions 11 C. Methods for Determining Decay D. The Nucleus 13 Factors Composition Tables of Decay Factors Terminology and Notation Pocket Calculators Nuclear Families Graphic Methods Forces and Energy Levels within the D. Image-Frame Decay Corrections 36 Nucleus 14 E. Specific Activity Nuclear Emissions 16 F. Decay of a Mixed Radionuclide 6. Nuclear Binding Energy Characteristics of Stable Sample 40 Nuclei 16 G. Parent-Daughter Decay The Bateman Equations 41 Modes of Radioactive 2. Secular Equilibrium 41 Decay Transient Equilibrium No Equilibrium 43 A. General Concepts 19 B. Chemistry and Radioactivity 19 C. Decay by R_ Emission 20 D. Decay by (0-,,y) Emission 22 Radionuclide and E. Isomeric Transition (IT) and Internal Radiopharmaceutical Conversion Production 45 (IC) 23 F. Electron Capture (EC) and (EC, y) A. Reactor-Produced Radionuclides 45 Decay Reactor Principles 45

3 viii... PHYSICS IN NUCLEAR MEDICINE 2. Fission Fragments Neutron Activation 48 B. Accelerator-Produced Radionuclides Charged-Particle Accelerators Cyclotron Principles Cyclotron-Produced Radionuclides 51 C. Radionuclide Generators 52 D. Equations for Radionuclide Production Activation Cross Sections Activation Rates Buildup and Decay of Activity 57 E. Radionuclides for Nuclear Medicine General Considerations Specific Considerations 59 F. Radiopharmaceutical Preparation General Considerations Labeling Strategies Technetium 99m-Labeled Radiopharmaceuticals Radiopharmaceuticals Labeled with Positron Emitters Radiopharmaceuticals for Therapy Applications Radiopharmaceuticals in Clinical Nuclear Medicine 63 Interaction of Radiation with Matter 65 A. Interactions of Charged Particles with Matter Charged-Particle Interaction Mechanisms Collisional Versus Radiation Losses Charged-Particle Tracks Deposition of Energy Along a Charged-Particle Track The Cerenkov Effect 71 B. Charged-Particle Ranges Alpha Particles Beta Particles and Electrons 74 C. Passage of High-Energy Photons through Matter Photon Interaction Mechanisms The Photoelectric Effect Compton Scattering Pair Production Coherent (Rayleigh) Scattering Deposition of Photon Energy in Matter 80 D. Attenuation of Photon Beams Attenuation Coefficients Thick Absorbers, Narrow-Beam Geometry Thick Absorbers, Broad-Beam Geometry Polyenergetic Sources 88 Radiation Detectors 89 A. Gas-Filled Detectors Basic Principles Ionization Chambers Proportional Counters Geiger-Muller Counters 94 B. Semiconductor Detectors 98 C. Scintillation Detectors Basic Principles Photomultiplier Tubes Inorganic Scintillators Organic Liquid Scintillators 106 Electronic Instrumentation for Radiation Detection Systems 109 A. Preamplifiers 109 B. Amplifiers Amplification and Pulse-Shaping Functions Resistor-Capacitor Shaping Baseline Shift and Pulse Pile-up 114 C. Pulse-Height Analyzers Basic Functions Single-Channel Analyzers Timing Methods Multichannel Analyzers 117 D. Time-to-Amplitude Converters 121 E. Digital Counters and Rate Meters Scalers, Timers, and Counters Analog Rate Meters 123 F. Coincidence Units 124 G. High-Voltage Power Supplies 125 H. Nuclear Instrument Modules 126 I. Cathode Ray Tube Electron Gun Deflection Plates Phosphor-Coated Display Screens Focus and Brightness Controls Color Cathode Ray Tubes 128

4 J. Oscilloscopes Semiconductor Detector K. Computer Monitors 129 Spectrometers Liquid Scintillation Spectrometry Proportional Counter Nuclear Counting Statistics 131 Spectrometers 163 A. Types of Measurement Error 131 B. Nuclear Counting Statistics The Poisson Distribution The Standard Deviation The Gaussian Distribution 134 Problems in Radiation Detection and Measurement 165 A. Detection Efficiency 165 C. Propagation of Errors Components of Detection 1. Sums and Differences 135 Efficiency Constant Multipliers Geometric Efficiency Products and Ratios Intrinsic Efficiency More Complicated 4. Energy Selective Counting 169 Combinations Some Complicating Factors 170 D. Applications of Statistical 6. Calibration Sources 175 Analysis 136 B. Problems in the Detection and 1. Effects of Averaging 136 Measurement of R Particles Counting Rates 137 C. Dead Time 3. Significance of Differences 1. between Counting Causes of Dead Time Measurements 137 Mathematical Models Effects of Background 3. Window Fraction 137 Effects Minimum 4. Dead Time Detectable Activity 138 Correction Methods 181 D. 6. Comparing Counting Quality Assurance for Radiation Systems 138 Measurement Systems Estimating Required Counting Times Optimal Division of Counting Times 140 Counting Systems 185 E. Statistical Tests 140 A. Nal(TI) Well Counter The X2 Test Detector Characteristics The t-test Detection Efficiency Treatment of "Outliers" Sample Volume Effects 188 Contents** e ix 4. Linear Regression Assay of Absolute Activity Shielding and Background Energy Calibration 191 Pulse-Height Spectrometry Multiple Radionuclide Source Counting 191 A. Basic Principles Dead Time 192 B. Spectrometry with Nal(TI) Automatic Multiple-Sample 1. The Ideal Pulse-Height Systems 192 Spectrum Applications The Actual Spectrum 151 B. Counting with Conventional Nal(TI) 3. Effects of Detector Size 154 Detectors Effects of Counting Rate Large Sample Volumes General Effects of r-ray 2. Liquid and Gas Flow Energy 155 Counting Energy Linearity 157 C. Liquid Scintillation Counters Energy Resolution General Characteristics 196 C. Spectrometry with Other 2. Pulse-Height Spectrometry 198 Detectors Counting Vials 198

5 x.. * PHYSICS IN NUCLEAR MEDICINE 4. Energy and Efficiency Calibrations Quench Corrections Sample Preparation Techniques Liquid and Gas Flow Counting Automatic Multiple-Sample LS Counters Applications 202 D. Gas-Filled Detectors Dose Calibrators Gas Flow Counters 204 E. Semiconductor Detector Systems System Components Applications 207 F. In Vivo Counting Systems Nal(TI) Probe Systems Miniature 7-Ray Probes for Surgical Use Whole-Body Counters 210 The Gamma Camera : Basic Principles 211 C. D. E. 2. Image Nonuniformity Nonuniformity Correction Techniques Gamma Camera Tuning 238 Design and Performance Characteristics of Parallel-Hole Collimators Basic Limitations in Collimator Performance Spatal Thickness Geometry of Collimator Holes System Resolution 244 Performance Characteristics of Converging, Diverging, and Pinhole Collimators 245 Measurements of Gamma Camera Performance Intrinsic Resolution System Resolution Spatial Linearity Uniformity Counting Rate Performance Energy Resolution System Sensitivity 250 A. General Concepts of Radionuclide Image Quality in Imaging 211 Nuclear Medicine 253 B. Basic Principles of the Gamma Camera 212 A. Basic Methods for Characterizing Components and Evaluating..-_ " _ and Q Electronics 213 B. Spatial Resolution Collimators Factors Affecting Spatial " " Gamma " - Camera Methods for Evaluating Spatial C. Types of Gamma Cameras and Resolution 254 Their Clinical Uses 223 C. Contrast 259 -Noise 263 The Gamma Camera : Performance " - " Image Noise Random Noise "" Contrast-to-Noise Ratio Characteristics 227 E. Observer Performance Studies 268 A. Basic Performance 1. Contrast-Detail (C-D) Studies Receiver Operating Characteristic Characteristics 227 (ROC) Studies Intrinsic Spatial Resolution Detection Efficiency Energy Resolution 230 Tomographic 4. Performance at High Counting Reconstruction Rates 231 in Nuclear Medicine B. 273 Detector Limitations : Nonuniformity and Nonlinearity 234 A. General Concepts, Notation, and 1. Image Nonlinearity 234 Terminology 274

6 B. Backprojection and Fourier-Based Positron Emission Techniques 276 Tomography Simple Backprojection Direct Fourier Transform A. Annihilation Coincidence Reconstruction 278 Detection Filtered Backprojection Basic Principles of Annihilation 4. Multislice Imaging 283 Coincidence Detection 325 C. Image Quality in Fourier Transform 2. Time-of-Flight PET 327 and Filtered Backprojection 3. Spatial Resolution : Detectors Spatial Resolution : Positron Techniques 283 Physics Effects of Sampling on Image 5. Spatial Resolution : Quality 283 Depth-of-Interaction Effect Sampling Coverage and 6. Spatial Resolution : Sampling 336 Consistency Requirements Spatial Resolution : 3. Noise Propagation, Signal-to-Noise Reconstruction Filters 336 Ratio, and Contrast-to-Noise 8. Sensitivity 337 Ratio Event Types in Annihilation D. Iterative Reconstruction Coincidence Detection 340 Algorithms 291 B. PET Detector and Scanner 1. General Concepts of Iterative Designs 342 Reconstruction Block Detectors Expectation-Maximization 2. Modified Block Detectors 344 Reconstruction Dedicated PET Systems 346 E. Reconstruction of Fan-Beam and 4. Gamma Camera Systems Cone-Beam Data 294 for PET 348 C. Data Acquisition for PET Two-Dimensional Data Single Photon Emission Computed Tomography 299 Acquisition Three-Dimensional Data Acquisition Data Acquisition for Dynamic A. SPECT Systems 299 Studies and Whole-Body 1. Gamma Camera Scans 353 SPECT Systems 299 D. Data Corrections and 2. Advanced SPECT Systems Combined Modality Systems 302 B. Practical Implementation Quantitative Aspects of PET Normalization 353 2~ Correction for Random Coincidences 354 of SPECT Correction for Scattered 1. Attenuation Effects Radiation 355 and Conjugate Counting Attenuation Correction Attenuation Correction Dead Time Corrections Transmission Scans and Attenuation 6. Absolute Quantification of Maps 313 PET Images Scatter Corrections 315 E. Clinical and Research 5. Partial-Volume Effects 317 Applications of PET 358 Contents o o 9 xi C. Performance Characteristics of SPECT Systems Spatial Resolution Volume Sensitivity 320 Digital Image Processing in 3. Other Measurements of Nuclear Medicine 361 Performance Quality Assurance in SPECT 321 A. Digital Images 362 D. Clinical Applications of 1. Basic Characteristics and SPECT 322 Terminology 362

7 xii. * * PHYSICS IN NUCLEAR MEDICINE 2. Spatial Resolution and Matrix Size Image Display Acquisition Modes 366 B. Digital Image-Processing Techniques Image Visualization Regions and Volumes of Interest Time-Activity Curves Image Smoothing Edge Detection and Segmentation Co-registration of Images 373 C. Processing Environment 375 Tracer Kinetic Modeling 377 A. Basic Concepts 377 B. Tracers and Compartments Definition of a Tracer Definition of a Compartment Distribution Volume and Partition Coefficient Flux Rate Constants Steady State 383 C. Tracer Delivery and Transport Blood Flow, Extraction, and Clearance Transport 387 D. Formulation of a Compartmental Model 388 E. Examples of Dynamic Imaging and Tracer Kinetic Models Cardiac Function and Ejection Fraction Blood Flow Models Blood Flow : Trapped Radiotracers Blood Flow : Clearance Techniques Enzyme Kinetics : Glucose Metabolism Receptor Ligand Assays 401 F. Summary 402 Internal Radiation Dosimetry 405 A. Radiation Dose and Equivalent Dose : Quantities and Units 405 B. Calculation of Radiation Dose (MIRD Method) Basic Procedure and Some Practical Problems Cumulated Activity, A Equilibrium Absorbed Dose Constant, A Absorbed Fraction, ~ Specific Absorbed Fraction, (D, and the Dose Reciprocity Theorem Mean Dose per Cumulated Activity, S Whole-Body Dose, Effective Dose, and Effective Dose Equivalent Limitations of the MIRD Method 417 Radiation Safety and Health Physics 427 A. Quantities and Units Dose-Modifying Factors Exposure and Air Kerma 428 B. Regulations Pertaining to the Use of Radionuclides Nuclear Regulatory Commission Licensing and Regulations Restricted and Unrestricted Areas Dose Limits Concentrations for Airborne Radioactivity in Restricted Areas Environmental Concentrations and Concentrations for Sewage Disposal Record-Keeping Requirements Recommendations of Advisory Bodies 432 C. Safe Handling of Radioactive Materials The ALARA Concept Reduction of Radiation Doses from External Sources Reduction of Radiation Doses from Internal Sources Laboratory Design Procedures for Handling Spills 438 D. Disposal of Radioactive Waste 439 E. Radiation Monitoring Survey Meters and Laboratory Monitors 439

8 2. Personnel Dosimeters Wipe Testing 440 Appendix A: Unit Conversions 443 Appendix 8: Properties of the Elements 444 Contents + s * Ail Appendix E: Effective Dose Equivalent (msv/mbq) and Radiation Absorbed Dose Estimates (mgy/mbq) to Adult Subjects from Selected Internally Administered Radiopharmaceuticals 480 Appendix C: Characteristics of Some Medically Appendix F: The Fourier Transform 483 Important A. The FT: What It Radionuclides Represents B. Calculating FTs 484 Appendix D: Mass Attenuation C. Some Properties of FTs 485 Coefficients for Water, D. Some Examples of FTs 488 Sodium Iodide, BGO, CZT, Appendix G: Convolutions 493 and Lead 479 Index 499