The Essential Physics of Medical Imaging

Contents
Preface to the Fourth Edition v
Foreword vii
Authors viii
Contributors xi
Acknowledgments xii
Section I: Basic Concepts ..........................................1
1 Introduction to Medical Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1 .1 The Modalities 3
1 .2 Digital Imaging Basics 17
1 .3 Image Properties 18
2 Radiation and the Atom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2 .1 Classical Electromagnetism 21
2 .2 Electromagnetic Radiation 22
2 .3 Behavior of Energy at the Atomic Scale: One of the Most
Important Discoveries in the History of Science 25
2 .4 Ionizing and Non-Ionizing Radiation 28
2 .5 Particulate Radiation 29
2 .6 Mass-Energy Equivalence 30
2 .7 Structure of the Atom 31
2 .8 Radiation from Electron Transitions 33
2 .9 The Atomic Nucleus 35
2 .10 Nuclear Stability and Radioactivity 37
2 .11 Nuclear Binding Energy and Mass Defect 39
3 Interaction of Radiation with Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
3 .1 Particle Interactions 42
3 .2 X-ray and Gamma (?)-ray Interactions 48
3 .3 Attenuation of X-rays and ?-rays 54
3 .4 Absorption of Energy from X-rays and ?-rays 61
3 .5 Imparted Energy, Equivalent Dose, and Effective Dose 65
3 .6 Summary 70
4 Image Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
4 .1 Spatial Resolution 72
4 .2 Contrast Resolution 86
4 .3 Noise and Noise Texture 89
4 .4 Ratio Measures of Image Quality 98
4 .5 Image Quality Measures Based on Visual Performance 102
5 Medical Imaging Informatics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
5 .1 Ontologies, Standards, Profiles 109
5 .2 Computers and Networking 115
5 .3 Picture Archiving and Communications System 125
5 .4 Lifecycle of a Radiology Exam 151
5 .5 Radiology from Outside the Department 158
5 .6 Security and Privacy 160
5 .7 “Big Data” and Data Plumbing 167
5 .8 Algorithms for Image and Non-Image Analytics 169
5 .9 The Business of Informatics 175
5 .10 Beyond Imaging Informatics 178
Section II: Diagnostic Radiology ..................................183
6 X-ray Production, Tubes, and Generators . . . . . . . . . . . . . . . . . . . . . . . . . . 185
6 .1 Production of X-rays 185 6 .2 X-ray Tubes 190
6 .3 X-ray Generators 208
6 .4 Power Ratings, Anode Loading, and Cooling 216
6 .5 Factors Affecting X-ray Emission 219
6 .6 Summary 222
7 Radiography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
7 .1 Geometry of Projection Radiography 224
7 .2 Scattered Radiation in Projection Radiographic Imaging 227
7 .3 Technique Factors in Radiography 235
7 .4 Scintillators and Intensifying Screens 238
7 .5 Absorption Efficiency and Conversion Efficiency 240
7 .6 Computed Radiography 241
7 .7 Charge-Coupled Device and Complementary Metal-Oxide Semiconductor
Detectors 245
7 .8 Flat Panel Thin-Film-Transistor Array Detectors 248
7 .9 Other Considerations When Choosing a Digital Detector System 251
7 .10 Radiographic Detectors, Patient Dose, and Exposure Index 251
7 .11 Artifacts in Digital Radiography 254
7 .12 Special Considerations for Pediatric Digital Radiography 256
7 .13 Dual-Energy Subtraction Radiography 257
8 Breast Imaging: Mammography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
8 .1 X-ray Tube Components, Structures, and Operation 262
8 .2 Mammography X-ray Generator 273
8 .3 Compression, Scattered Radiation, and Magnification 276
8 .4 Digital Acquisition Systems 281
8 .5 Processing, Viewing, and Analyzing Images 292
8 .6 Radiation Dosimetry 298
8 .7 Regulatory Requirements 302
8 .8 Summary 308
9 Fluoroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
9 .1 Fluoroscopic Imaging Chain Overview 311
9 .2 Imaging Chain Components 312
9 .3 Fluoroscopic X-ray Source Assembly 318
9 .4 Controls 320
9 .5 Modes of Operation 322
9 .6 Image Processing 327
9 .7 Image Quality in Fluoroscopy 333
9 .8 Patient Radiation Management 339
9 .9 Operator and Staff Radiation Safety 343
9 .10 Looking Ahead 345
10 Computed Tomography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
10 .1 Basic Concepts 348
10 .2 CT System Designs 352
10 .3 Acquisition Modes 368
10 .4 Reconstruction 382
10 .5 Image Quality in CT 394
10 .6 CT Image Artifacts 401
11 X-ray Dosimetry in Projection Imaging and Computed Tomography . . . . 407
11 .1 X-ray Transmission 407
11 .2 Monte Carlo Simulation 410
11 .3 The Physics of X-ray Dose Deposition 412
11 .4 Dose Metrics 415
11 .5 Radiation Dose in Projection Radiography 421
11 .6 Radiation Dose in Fluoroscopy 425
11 .7 Radiation Dose in Computed Tomography 428
11 .8 Dose Reporting Software and Dose Registries 438
11 .9 Diagnostic Reference Levels and Achievable Doses 439
11 .10 Summary 43912 Magnetic Resonance Basics: Magnetic Fields, Nuclear Magnetic
Characteristics, Tissue Contrast, Image Acquisition . . . . . . . . . . . . . . . . . . 442
12 .1 Magnetism, Magnetic Fields, and Magnetic Properties of Materials 443
12 .2 MR System 448
12 .3 Magnetic Resonance Signal 453
12 .4 Magnetization Properties of Tissues 457
12 .5 Basic Acquisition Parameters 461
12 .6 Basic Pulse Sequences 462
12 .7 MR Signal Localization 477
12 .8 “k-Space” Data Acquisition and Image Reconstruction 484
12 .9 MR Image Characteristics 488
12 .10 Summary 492
13 Magnetic Resonance Imaging: Advanced Image Acquisition Methods,
Artifacts, Spectroscopy, Quality Control, Siting, Bioeffects, and Safety . . . 494
13 .1 Image Acquisition Time 494
13 .2 Fast Imaging Techniques 496
13 .3 Signal from Flow 507
13 .4 Perfusion and Diffusion Contrast Imaging 513
13 .5 Other Advanced Techniques 520
13 .6 MR Artifacts 526
13 .7 Magnet Siting and Quality Control 538
13 .8 MR Bioeffects and Safety 541
14 Ultrasound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 548
14 .1 Characteristics of Sound 548
14 .2 Interactions of Ultrasound with Tissues 553
14 .3 Ultrasound Transducers 558
14 .4 Ultrasound Beam Properties 565
14 .5 Image Data Acquisition and Processing 573
14 .6 Image Acquisition 581
14 .7 Image Quality, Storage, and Measurements 592
14 .8 Doppler Ultrasound 595
14 .9 Ultrasound Artifacts 607
14 .10 Ultrasound System Performance and Quality Assurance 618
14 .11 Acoustic Power and Bioeffects 622
Section III: Nuclear Medicine .....................................627
15 Radioactivity and Nuclear Transformation . . . . . . . . . . . . . . . . . . . . . . . . . 629
15 .1 Radionuclide Decay Terms and Relationships 630
15 .2 Nuclear Transformation 634
16 Radionuclide Production, Radiopharmaceuticals, and
Internal Dosimetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645
16 .1 Radionuclide Production 645
16 .2 Radiopharmaceuticals 659
16 .3 Internal Dosimetry 669
16 .4 Regulatory Issues 682
17 Radiation Detection and Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . 687
17 .1 Types of Detectors and Basic Principles 687
17 .2 Gas-Filled Detectors 691
17 .3 Scintillation Detectors 697
17 .4 Semiconductor Detectors 704
17 .5 Pulse Height Spectroscopy 707
17 .6 Non-Imaging Detector Applications 715
17 .7 Counting Statistics 723
18 Nuclear Imaging—The Gamma Camera . . . . . . . . . . . . . . . . . . . . . . . . . . . 731
18 .1 Planar Nuclear Imaging: The Anger Scintillation Camera 732
18 .2 Computers in Nuclear Imaging 756
18 .3 Summary 76219 Nuclear Tomographic Imaging—Single Photon and Positron Emission
Tomography (SPECT and PET) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763
19 .1 Focal Plane Tomography in Nuclear Medicine 763
19 .2 Single Photon Emission Computed Tomography 764
19 .3 Positron Emission Tomography 783
19 .4 Dual Modality Imaging—PET/CT, and PET/MRI 802
19 .5 Advances in PET Imaging 808
19 .6 Clinical Aspects, Comparison of PET and SPECT, and Dose 814
Section IV: Radiation Biology and Protection .......................819
20 Radiation Biology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 821
20 .1 Overview 821
20 .2 Determinants and Classification of the Biologic Response of Radiation 821
20 .3 Interaction of Radiation with Cells and Tissue 822
20 .4 Molecular and Cellular Response to Radiation 826
20 .5 Tissue and Organ System Response to Radiation 847
20 .6 Whole-Body Response to Radiation: The Acute Radiation Syndrome 857
20 .7 Radiation-Induced Carcinogenesis 865
20 .8 Hereditary Effects of Radiation Exposure 903
20 .9 Radiation Effects In Utero 905
20 .10 Radiation Risk Communications 914
21 Radiation Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 924
21 .1 Sources of Exposure to Ionizing Radiation 924
21 .2 Personnel Dosimetry 931
21 .3 Radiation Detection Equipment in Radiation Safety 939
21 .4 Fundamental Principles and Methods of Exposure Control 940
21 .5 Structural Shielding of Imaging Facilities 944
21 .6 Radiation Protection in Diagnostic and Interventional X-ray Imaging 957
21 .7 Radiation Protection in Nuclear Medicine 975
21 .8 Regulatory Agencies and Radiation Exposure Limits 989
21 .9 Prevention of Errors 994
21 .10 Management of Radiation Safety Programs 997
21 .11 Imaging of Pregnant and Potentially Pregnant Patients 999
21 .12 Medical Emergencies Involving Ionizing Radiation 1000
Section V: Appendices .........................................1011
A Fundamental Principles of Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1013
B SI and Derived Units, Physical Constants, Prefixes,
Definitions and Conversion Factors, Geometry,
and Roman and Greek Symbols Used in Medical Physics . . . . . . . . . . . . . 1029
C Radiologic Data for Elements 1–100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1039
D Mass Attenuation Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1044
E Effective Doses, Organ Doses, and Fetal Doses from
Medical Imaging Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1053
F Radiopharmaceutical Characteristics and Dosimetry . . . . . . . . . . . . . . . . 1061
G Convolution and Fourier Transforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1122
H Radiation Dose: Perspectives and Comparisons . . . . . . . . . . . . . . . . . . . . 1133
I Radionuclide Therapy Home Care Guidelines . . . . . . . . . . . . . . . . . . . . . 1143
Index 1147