Radiation Dose from Adult and Pediatric Multidetector Computed Tomography (eBook)

Foreword 5
Introduction 6
Contents 8
Clinical Expansion of CT and Radiation Dose 10
1.1 Introduction 10
1.2 Clinical Expansion 11
1.3 The Dose Problem 12
1.4 Approaches to the Problem 14
References 16
Part I Radiation Risks in Multidetector CT 18
Risks from Ionising Radiation 19
2.1 Introduction 19
2.2 Model Development 22
2.3 Radiation- Induced Cancer 30
2.4 Discussion and Conclusions 35
References 35
The Cancer Risk from Low- Level Radiation 40
3.1 Introduction 40
3.2 Problems with the Basis of the Linear No- Threshold Theory 41
3.3 Direct Experimental Challenges to the Basis for LNT 42
3.4 Effects of Low-Level Radiation on Biological Defense Mechanisms 42
3.5 Cancer Risk Versus Dose in Animal Experiments 47
3.6 Cancer Risk Versus Dose: Data from Human Exposures 47
3.7 Dependence of Latent Period on Dose 54
3.8 Conclusion 54
References 54
CT Parameters that Influence the Radiation Dose 57
4.1 CT Dose Descriptors 57
4.2 Equipment- Related Factors 62
4.3 Application- Related Factors 73
References 84
Collective Radiation Dose from MDCT: Critical Review of Surveys Studies 86
5.1 Introduction 86
5.2 Reference Dose Levels ( RDL) 87
5.3 Statistical Values and their Meanings 90
5.4 Interpretation of Data and Pitfalls 92
5.5 Comparison of Different Surveys 94
5.6 Surveys Comparing MDCT and SDCT 96
5.7 Paediatric Issues 97
5.8 Optimization Processes 100
5.9 Conclusion 100
References 101
Methods and Strategies for Radiation Dose Optimization – and Reduction – in MDCT with Special Focus on the Image Quality 103
6.1 Introduction: Should We Optimize/ Minimize the Patient’s Radiation Exposure? 103
6.2 Guidelines for Appropriate Use of Imaging 104
6.3 Optimization of the MDCT Technique 106
6.4 Comments 119
6.5 In Summary 119
References 119
Automatic Exposure Control in Multidetector- Row Computed Tomography 121
7.1 Definition 121
7.2 Rationale 122
7.3 Nomenclature and Types of AEC Techniques 122
7.4 AEC Mechanisms 123
7.5 Clinical Evidence for AEC Techniques 128
7.6 Trouble-shooting for AEC Techniques 128
7.7 Pitfalls 129
7.8 Summary 130
References 130
Patient Centering in MDCT: Dose Effects 132
8.1 Patient Positioning and Centering 132
8.2 Effects of Off- Centering 133
8.3 Reasons for Off- Centering 134
8.4 Strategies for Ensuring Appropriate Patient Centering 134
References 135
Part II Clinical Approaches of Dose Optimization and Reduction 136
Dose Optimization and Reduction in CT of the Head and Neck, Including Brain 137
9.1 Dose Optimization and Reduction in CT of the Head ( Brain) 137
9.2 Dose Optimization and Reduction in CT of Head and Neck Region 144
References 152
Dose Reduction and Optimization in Computed Tomography of the Chest 154
10.1 Introduction 154
10.2 Routine Chest CT 155
10.3 CT Pulmonary Angiography 156
10.4 Air Trapping and Expiratory CT 156
10.5 CT Quantification of Pulmonary Emphysema 156
10.6 Optimized MDCT Acquisitions Using Automatic Exposure Control 158
10.7 Recommendations and Proposals 159
10.8 Conclusion 159
References 159
Dose Optimization and Reduction in MDCT of the Abdomen 161
11.1 Introduction 161
11.2 Usual Radiation Dose and Reference Levels 161
11.3 Dose Reduction in Acute Abdominal Disorders 162
11.4 Dose Reduction in Chronic Abdominal Disorders 167
11.5 Effect of Body Mass Index 167
11.6 Proposals of Presets and Doses 168
11.7 Perspectives 168
11.8 Conclusion 169
References 169
Optimization of Radiation Dose in Cardiac and Vascular Multirow- Detector CT 171
12.1 Optimization of Radiation Dose in Cardiac Detector Row CT 171
12.2 Radiation Dose Optimization in CTA for Aorta and Peripheral Vessels 180
References 183
Dose Optimization and Reduction in CT of the Musculoskeletal System Including the Spine 185
13.1 Introduction 185
13.2 Typical Dose in Musculoskeletal CT Examinations 186
13.3 Motion Studies 189
13.4 Modalities for Dose Reduction inMusculoskeletal CT 189
13.5 Conclusion 193
References 193
Dose Reduction in CT Fluoroscopy 195
14.1 Introduction 195
14.2 Technical Development 197
14.3 Scanning Techniques: Real- Time Method and Quick- Check Method 197
14.4 Interventional Techniques: Clinical Procedures 198
14.5 Dose to the Patient 206
14.6 Dose to the Staff 211
14.7 Regulatory Dose Limits 218
14.8 Conclusions 218
References 220
Suggested Reading 222
Dose Optimization and Reduction in CT of Children 223
15.1 Why Dose Optimization and Reduction in CT is Even More Important in Children than in Adults 223
15.2 Impact of New CT Scanners on Paediatric Patients 224
15.3 Justification 226
15.4 Patient Preparation 228
15.5 Protocol Definition 229
References 235
Radiation Risk Management in Low Dose MDCT Screening Programs 237
16.1 Lung Cancer Screening Including Pulmonary Nodule Management 237
16.1.1 Introduction 237
16.1.2 Imaging Techniques Used for Early Lung Cancer Detection 238
16.1.3 Imaging Techniques for Lung Nodule Management 242
16.1.4 Delivered Radiation Dose 246
16.1.5 Risk Induced from Lung Cancer Screening Programs 248
16.1.6 Reduction of Dose in CT Screening Programs 249
16.1.7 Conclusions 249
References 250
16.2 Dose Reduction in Screening Programs: Colon Cancer Screening 254
16.2.1 Colorectal Cancer Screening 254
16.2.2 CT Colonography Procedure 255
16.2.3 CT Colonography Performance 256
16.2.4 Possibilities for Dose Reduction in CT Colonography 258
16.2.5 Discussion 266
16.2.6 Conclusions 269
References 269
Subject Index 272
List of Contributors 274