Rad Tech's Guide to Radiation Protection

Euclid Seeram, PhD, FCAMRT, is a Full Member of the Health Physics Society and has academic appointments as Honorary Senior Lecturer in Medical Radiation Sciences at the University of Sydney, Australia; Adjunct Associate Professor of Medical Imaging and Radiation Sciences at Monash University, Australia; Adjunct Professor in the Faculty of Science at Charles Sturt University, Australia; and Adjunct Professor of Medical Radiation Sciences at the University of Canberra, Australia.

Preface to the Second Edition xi

Acknowledgments xiii

1 Nature and Scope of Radiation Protection 1

What is Radiation Protection? 2

Scope of Radiation Protection 2

Diagnostic Radiology Modalities 3

Why Protect Patients and Personnel in Diagnostic Radiology? 3

Framework for Radiation Protection 4

Basic Schemes for Patient Exposure in Digital Radiography, Fluoroscopy, and Computed Tomography 6

Factors Affecting Dose in Diagnostic Radiology 8

Dose Management Techniques 10

Pregnancy: Radiation Protection Considerations 11

2 Diagnostic X-Rays: Essential Physical Factors 13

X-Ray Production 14

Mechanisms for Creating X-Rays 14

X-Ray Spectrum 16

X-Ray Attenuation 20

X-Ray Interactions 23

Increasing kV and Scatter Production 26

3 Radiation Quantities and Units 27

Sources of Radiation Exposure 29

Types of Exposure 30

Quantities and Units for Quantifying Ionizing Radiation 31

Quantities and Units for Quantifying Biologic Risks 33

Radiation Measurement 36

Wearing a Personnel Dosimeter 38

4 Basic Radiobiology 39

What is Radiobiology? 41

Essential Physics and Chemistry 41

Fundamental Concepts of Radiobiology 44

Deterministic Effects (Early Effects of Radiation) 49

Stochastic Effects (Late Effects of Radiation) 51

Radiation Exposure During Pregnancy 54

5 Current Standards for Radiation Protection 55

Radiation Protection Organizations 56

Objectives of Radiation Protection 57

Radiation Protection Criteria and Standards 58

Recommended Dose Limits 60

Diagnostic Reference Levels: A Useful Tool for Optimization of Protection 62

6 Dose Factors in Digital Radiography 65

Digital Radiography: Essential Considerations 66

The Standardized Exposure Indicator: Basics 68

Factors Affecting Dose in Digital Radiography 70

7 Dose Factors in Fluoroscopy 77

Major Components of Fluoroscopic Imaging Systems 78

Factors Affecting Dose in Fluoroscopy 82

Scattered Radiation in Fluoroscopy 87

8 Factors Affecting Dose in Computed Tomography 89

Computed Tomography: A Definition 90

Nobel Prize for CT Pioneers 91

CT Principles: the Basics 91

Multislice CT Technology: The Pitch 93

Dose Distribution in CT 93

CT Dose Metrics 94

Factors Affecting the Dose in CT 96

Dose Optimization in CT 99

9 Dose Management Regulations and Optimization 101

Federal Regulations for Dose Management 103

Equipment Specifications for Radiography 104

Equipment Specifications for Fluoroscopy 106

Procedures for Minimizing Dose to Patients and Personnel 109

Shielding: Design of Protective Barriers 112

Quality Assurance: Dose Management and Optimization 114

10 Pregnancy: Essential Radiation Protection Considerations 117

Rationale for Radiation Protection in Pregnancy 118

Factors Affecting Dose to the Conceptus 119

Estimating the Dose to the Conceptus 120

Continuing/Terminating a Pregnancy After Exposure 120

Dose Reduction Techniques for Pregnant Patients 121

The Pregnant Worker 121

References 125

Index 129