Table des matières
Foreword xiii
Preface xiv
Acknowledgments xvii
Section 1: Introduction
Chapter 1 Radiographic sciences and technology: an overview 3
RADIOGRAPHIC IMAGING SYSTEMS: MAJOR MODALITIES AND COMPONENTS 4
RADIOGRAPHIC PHYSICS AND TECHNOLOGY 5
Essential physics of diagnostic imaging 5
Digital radiographic imaging modalities 5
Radiographic exposure technique 6
Image quality considerations 6
Computed tomography – physics and instrumentation 7
Quality control 8
Imaging informatics at a glance 9
RADIATION PROTECTION AND DOSE OPTIMIZATION 10
Radiobiology 10
Radiation protection in diagnostic radiography 10
Technical factors affecting dose in radiographic imaging 11
Radiation protection regulations 12
Optimization of radiation protection 13
Bibliography 13
Chapter 2 Digital radiographic imaging systems: major components 14
FILM‐SCREEN RADIOGRAPHY: SHORT REVIEW OF PRINCIPLES 14
DIGITAL RADIOGRAPHY MODALITIES: MAJOR SYSTEM COMPONENTS 18
Computed radiography 19
Flat‐panel digital radiography 19
Digital fluoroscopy 19
Digital mammography 21
Computed tomography 21
IMAGE COMMUNICATION SYSTEMS 22
Picture archiving and communication system 23
References 23
Section 2: Basic Radiographic Sciences and Technology
Chapter 3 Basic physics of diagnostic radiography 27
STRUCTURE OF THE ATOM 28
Nucleus 28
Electrons, quantum levels, binding energy, electron volts 28
ENERGY DISSIPATION IN MATTER 29
Excitation 29
Ionization 30
TYPES OF RADIATION 30
Electromagnetic radiation 31
Particulate radiation 32
X‐RAY GENERATION 32
X‐RAY PRODUCTION 32
Properties of x‐rays 33
Origin of x‐rays 33
Characteristic radiation 33
Bremsstrahlung radiation 34
X‐RAY EMISSION 34
X‐RAY BEAM QUANTITY AND QUALITY 35
Factors affecting x‐ray beam quantity and quality 36
INTERACTION OF RADIATION WITH MATTER 39
Mechanisms of interaction in diagnostic x-ray imaging 40
RADIATION ATTENUATION 43
Linear attenuation coefficient 43
Mass attenuation coefficient 43
Half value layer 44
RADIATION QUANTITIES AND UNITS 45
Bibliography 45
Chapter 4 X‐ray tubes and generators 46
PHYSICAL COMPONENTS OF THE X‐RAY MACHINE 47
COMPONENTS OF THE X‐RAY CIRCUIT 48
The power supply to the x‐ray circuit 49
The low‐voltage section control console) 49
The high‐voltage section 50
TYPES OF X‐RAY GENERATORS 51
Three‐phase generators 52
High‐frequency generators 52
Power ratings 53
THE X‐RAY TUBE: STRUCTURE AND FUNCTION 53
Major components 54
SPECIAL X‐RAY TUBES: BASIC DESIGN FEATURES 57
Double‐bearing axle 58
HEAT CAPACITY AND HEAT DISSIPATION CONSIDERATIONS 58
X‐RAY BEAM FILTRATION AND COLLIMATION 58
Inherent and added filtration 59
Effects of filtration on x‐ray tube output intensity 59
Half‐value layer 60
Collimation 60
References 60
Chapter 5 Digital image processing at a glance 61
DIGITAL IMAGE PROCESSING 61
Definition 62
Image formation and representation 62
Processing operations 63
CHARACTERISTICS OF DIGITAL IMAGES 63
GRAY SCALE PROCESSING 64
Windowing 67
CONCLUSION 69
References 69
Chapter 6 Digital radiographic imaging modalities: principles and technology 70
COMPUTED RADIOGRAPHY 71
Essential steps 71
Basic physical principles 71
Response of the IP to radiation exposure 73
The standardized exposure indicator 73
FLAT‐PANEL DIGITAL RADIOGRAPHY 76
What is FPDR? 76
Types of FPDR systems 76
Basic physical principles of indirect and direct flat‐panel detectors 76
The fill factor of the pixel in the flat‐panel detector 78
Exposure indicator 79
Image quality descriptors for DR systems 79
Continuous quality improvement for DR systems 79
DIGITAL FLUOROSCOPY 80
Digital fluoroscopy modes 80
II‐Based digital fluoroscopy characteristics 80
Flat‐panel digital fluoroscopy characteristics 83
DIGITAL MAMMOGRAPHY 85
Screen‐film mammography – basic principles 85
Full‐field digital mammography –major elements 86
DIGITAL TOMOSYNTHESIS AT A GLANCE 87
Imaging system characteristics 87
Synthesized 2D digital mammography 89
References 90
Chapter 7 Image quality and dose 91
THE PROCESS OF CREATING AN IMAGE 92
IMAGE QUALITY METRICS 93
Contrast 93
Contrast resolution 94
Spatial resolution 96
Noise 98
Contrast‐to‐noise ratio 101
Signal‐to‐noise ratio 101
ARTIFACTS 102
IMAGE QUALITY AND DOSE 103
Digital detector response to the dose 103
Detective quantum efficiency 104
References 105
Section 3: Computed Tomography: Basic Physics and Technology
Chapter 8 The essential technical aspects of computed tomography 109
BASIC PHYSICS 110
Radiation attenuation 111
TECHNOLOGY 116
Data acquisition: principles and components 117
Image reconstruction 118
Image display, storage, and communication 120
MULTISLICE CT: PRINCIPLES AND TECHNOLOGY 121
Slip‐ring technology 122
X‐ray tube technology 122
Interpolation algorithms 123
MSCT detector technology 124
Selectable scan parameters 125
Isotropic CT imaging 127
MSCT image processing 127
IMAGE POSTPROCESSING 128
Windowing 128
3‐D image display techniques 129
IMAGE QUALITY 130
Spatial resolution 130
Contrast resolution 131
Noise 131
RADIATION PROTECTION 131
CT dosimetry 132
Factors affecting patient dose 132
Optimizing radiation protection 133
CONCLUSION 134
References 134
Section 4: Continuous Quality Improvement
Chapter 9 Fundamentals of quality control 139
INTRODUCTION 139
DEFINITIONS 140
ESSENTIAL STEPS OF QC 141
QC RESPONSIBILITIES 142
STEPS IN CONDUCTING A QC TEST 142
THE TOLERANCE LIMIT OR ACCEPTANCE CRITERIA 143
PARAMETERS FOR QC MONITORING 145
Major parameters of imaging systems 145
QC TESTING FREQUENCY 145
TOOLS FOR QC TESTING 146
THE FORMAT OF A QC TEST 146
PERFORMANCE CRITERIA/TOLERANCE LIMITS FOR COMMON QC TESTS 147
Radiography 147
Fluoroscopy 150
REPEAT IMAGE ANALYSIS 151
Corrective action/Reasons for rejection 151
COMPUTED TOMOGRAPHY QC TESTS FOR TECHNOLOGISTS 152
The ACR CT accreditation phantom 152
The ACR action limits for tests done by technologists 153
Artifact evaluation 155
References 156
Section 5: PACS and Imaging Informatics
Chapter 10 PACS and imaging informatics at a glance 159
INTRODUCTION 159
PACS CHARACTERISTIC FEATURES 160
Definition 160
Core technical components 160
IMAGING INFORMATICS 163
Enterprise imaging 164
Cloud computing 164
Big data 164
Artificial intelligence 164
Machine learning 165
Deep learning 165
APPLICATIONS OF AI IN MEDICAL IMAGING 165
AI in CT image reconstruction 166
Ethics of AI in radiology 166
References 166
Section 6: Radiation Protection
Chapter 11 Basic concepts of radiobiology 171
WHAT IS RADIOBIOLOGY? 172
BASIC CONCEPTS OF RADIOBIOLOGY 173
Generalizations about radiation effects on living organisms 173
Relevant physical processes 174
Radiosensitivity 175
Dose–response models 176
Radiation interactions in tissue: target theory, direct and indirect action 177
DNA and chromosome damage 178
EFFECTS OF RADIATION EXPOSURE TO THE TOTAL BODY 179
Hematopoietic of bone marrow syndrome 180
Gastrointestinal syndrome 180
Central nervous system (CNS) syndrome 180
DETERMINISTIC EFFECTS 180
STOCHASTIC EFFECTS 181
Tissue effects 181
Life‐span shortening 181
Radiation‐induced cancers 181
Hereditary effects 182
RADIATION EXPOSURE DURING PREGNANCY 183
References 183
Chapter 12 Technical dose factors in radiography, fluoroscopy, and CT 185
DOSE FACTORS IN DIGITAL RADIOGRAPHY 186
The x‐ray generator 186
Exposure technique factors 187
X‐ray beam filtration 187
Collimation and field size 188
The SID and SSD 188
Patient thickness and density 188
Scattered radiation grid 189
The sensitivity of the image receptor 190
DOSE FACTORS IN FLUOROSCOPY 190
Fluoroscopic exposure factors 190
Fluoroscopic equipment factors 191
CT RADIATION DOSE FACTORS AND DOSE OPTIMIZATION CONSIDERATIONS 194
Dose distribution in the patient 194
CT dose metrics 195
Factors affecting the dose in CT 196
Dose optimization overview 197
References 198
Chapter 13 Essential principles of radiation protection 200
INTRODUCTION 201
WHY RADIATION PROTECTION? 201
Categories of data from human exposure 201
Radiation dose–risk models 201
Summary of biological effects 202
Radiation protection organizations/reports 202
OBJECTIVES OF RADIATION PROTECTION 203
RADIATION PROTECTION PHILOSOPHY 203
Justification 203
Optimization 204
Dose limits 204
Personal actions 205
Time 205
Shielding 206
Distance 206
RADIATION QUANTITIES AND UNITS 206
Sources of radiation exposure 207
Quantities and units 207
PERSONNEL DOSIMETRY 209
OPTIMIZATION OF RADIATION PROTECTION 211
Regulatory and guidance recommendations 211
Diagnostic reference levels (DRLs) 212
Gonadal shielding: past considerations 213
X‐ray room shielding 214
CURRENT STATE OF GONADAL SHIELDING 215
References 215
Index 217
