A Comprehensive Guide to Radiographic Sciences and Technology

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