Fundamentals of Ionizing Radiation Dosimetry

Preface xix

Quantities and symbols xxiii

Acronyms xxxix

1 Background and Essentials 1

1.1 Introduction 1

1.2 Types and Sources of Ionizing Radiation 1

1.3 Consequences of the Random Nature of Radiation 4

1.4 Interaction Cross Sections 6

1.5 Kinematic Relativistic Expressions 9

1.6 Atomic Relaxations 11

1.7 Evaluation of Uncertainties 22

Exercises 28

2 Charged-Particle Interactions with Matter 29

2.1 Introduction 29

2.2 Types of Charged-Particle Interactions 31

2.3 Elastic Scattering 36

2.4 Inelastic Scattering and Energy Loss 55

2.5 Radiative Energy Loss: Bremsstrahlung 95

2.6 Total Stopping Power 103

2.7 Range of Charged Particles 104

2.8 Number and Energy Distributions of Secondary Particles 106

2.9 Nuclear Stopping Power and Interactions by Heavy Charged Particles 112

2.10 The W-Value (Mean Energy to Create an Ion Pair) 114

2.11 Addendum –Derivation of Expressions for the Elastic and Inelastic Scattering of Heavy Charged Particles 119

Exercises 139

3 Uncharged-Particle Interactions with Matter 143

3.1 Introduction 143

3.2 Photon Interactions with Matter 143

3.3 Photoelectric Effect 145

3.4 Thomson Scattering 154

3.5 Rayleigh Scattering (Coherent Scattering) 157

3.6 Compton Scattering (Incoherent Scattering) 161

3.7 Pair Production and Triplet Production 178

3.8 Positron Annihilation 188

3.9 Photonuclear Interactions 191

3.10 Photon Interaction Coefficients 193

3.11 Neutron Interactions 204

Exercises 211

4 Field and Dosimetric Quantities, Radiation Equilibrium – Definitions and Inter-Relations 215

4.1 Introduction 215

4.2 Stochastic and Non-stochastic Quantities 215

4.3 Radiation Field Quantities and Units 216

4.4 Distributions of Field Quantities 219

4.5 Quantities Describing Radiation Interactions 220

4.6 Dosimetric Quantities 229

4.7 Relationships Between Field and Dosimetric Quantities 233

4.8 Radiation Equilibrium (RE) 239

4.9 Charged-Particle Equilibrium (CPE) 242

4.10 Partial Charged-Particle Equilibrium (PCPE) 248

4.11 Summary of the Inter-Relations between Fluence, Kerma, Cema, and Dose 252

4.12 Addendum – Example Calculations of (Net) Energy Transferred and Imparted 252

Exercises 256

5 Elementary Aspects of the Attenuation of Uncharged Particles 259

5.1 Introduction 259

5.2 Exponential Attenuation 259

5.3 Narrow-Beam Attenuation 261

5.4 Broad-Beam Attenuation 263

5.5 Spectral Effects 270

5.6 The Build-up Factor 271

5.7 Divergent Beams –The Inverse Square Law 273

5.8 The Scaling Theorem 276

Exercises 277

6 Macroscopic Aspects of the Transport of Radiation Through Matter 279

6.1 Introduction 279

6.2 The Radiation Transport Equation Formalism 280

6.3 Introduction to Monte Carlo Derived Distributions 286

6.4 Electron Beam Distributions 287

6.5 Protons and Heavier Charged Particle Beam Distributions 296

6.6 Photon Beam Distributions 301

6.7 Neutron Beam Distributions 309

6.7.1 Fluence Distributions 309

6.7.2 Dose Distributions 311

Exercises 313

7 Characterization of Radiation Quality 315

7.1 Introduction 315

7.2 General Aspects of Radiation Spectra. Mean Energy 316

7.3 Beam Quality Specification for Kilovoltage x-ray Beams 318

7.4 Megavoltage Photon Beam Quality Specification 326

7.5 High-Energy Electron Beam Quality Specification 331

7.6 Beam Quality Specification of Protons and Heavier Charged Particles 335

7.7 Energy Spectra Determination 339

Exercises 346

8 The Monte Carlo Simulation of the Transport of Radiation Through Matter 349

8.1 Introduction 349

8.2 Basics of the Monte Carlo Method (MCM) 350

8.3 Simulation of Radiation Transport 359

8.4 Monte Carlo Codes and Systems in the Public Domain 379

8.5 Monte Carlo Applications in Radiation Dosimetry 386

8.6 Other Monte Carlo Developments 393

Exercises 394

9 Cavity Theory 397

9.1 Introduction 397

9.2 Cavities That Are Small Compared to Secondary Electron Ranges 399

9.3 Stopping-Power Ratios 413

9.4 Cavities That Are Large Compared to Electron Ranges 423

9.5 General or Burlin Cavity Theory 425

9.6 The Fano Theorem 429

9.7 Practical Detectors: Deviations from ‘Ideal’ Cavity Theory Conditions 431

9.8 Summary and Validation of Cavity Theory 435

Exercises 440

10 Overview of Radiation Detectors and Measurements 443

10.1 Introduction 443

10.2 Detector Response and Calibration Coefficient 444

10.3 Absolute, Reference, and Relative Dosimetry 445

10.4 General Characteristics and Desirable Properties of Detectors 447

10.5 Brief Description of Various Types of Detectors 460

10.6 Addendum –The Role of the Density Effect and I-Values in the Medium-to-Water Stopping-Power Ratio 467

Exercises 471

11 Primary Radiation Standards 473

11.1 Introduction 473

11.2 Free-Air Ionization Chambers 474

11.3 Primary Cavity Ionization Chambers 481

11.4 Absorbed-Dose Calorimeters 484

11.5 Fricke Chemical Dosimeter 488

11.6 International Framework for Traceability in Radiation Dosimetry 490

11.7 Addendum – Experimental Derivation of Fundamental Dosimetric Quantities 491

Exercises 493

12 Ionization Chambers 497

12.1 Introduction 497

12.2 Types of Ionization Chamber 498

12.3 Measurement of Ionization Current 504

12.4 Ion Recombination 513

12.5 Addendum –Air Humidity in Dosimetry 524

Exercises 531

13 Chemical Dosimeters 533

13.1 Introduction 533

13.2 Radiation Chemistry in Water 533

13.3 Chemical Heat Defect 538

13.4 Ferrous Sulfate Dosimeters 539

13.5 Alanine Dosimetry 547

13.6 Film Dosimetry 556

13.7 Gel Dosimetry 568

Exercises 574

14 Solid-State Detector Dosimetry 577

14.1 Introduction 577

14.2 Thermoluminescence Dosimetry 577

14.3 Optically-Stimulated Luminescence Dosimeters 591

14.4 Scintillation Dosimetry 596

14.5 Semiconductor Detectors for Dosimetry 609

Exercises 628

15 Reference Dosimetry for External Beam Radiation Therapy 631

15.1 Introduction 631

15.2 A Generalized Formalism 632

15.3 Practical Implementation of Formalisms 636

15.4 Quantities Entering into the Various Formalisms 651

15.5 Accuracy of Radiation Therapy Reference Dosimetry 669

15.6 Addendum – Perturbation Correction Factors 671

Exercises 689

16 Dosimetry of Small and Composite Radiotherapy Photon Beams 693

16.1 Introduction 693

16.2 Overview 694

16.3 The Physics of Small Megavoltage Photon Beams 696

16.4 Dosimetry of Small Beams 701

16.5 Detectors for Small-Beam Dosimetry 714

16.6 Dosimetry of Composite Fields 717

16.7 Addendum—Measurement in Plastic Phantoms 723

Exercises 726

17 Reference Dosimetry for Diagnostic and Interventional Radiology 729

17.1 Introduction 729

17.2 Specific Quantities and Units 730

17.3 Formalism for Reference Dosimetry 736

17.4 Quantities Entering into the Formalism 740

Exercises 751

18 Absorbed Dose Determination for Radionuclides 753

18.1 Introduction 753

18.2 Radioactivity Quantities and Units 755

18.3 Dosimetry of Unsealed Radioactive Sources 763

18.4 Dosimetry of Sealed Radioactive Sources 788

18.5 Addendum –The Reciprocity Theorem for Unsealed Radionuclide Dosimetry 804

Exercises 809

19 Neutron Dosimetry 813

19.1 Introduction 813

19.2 Neutron Interactions in Tissue and Tissue-Equivalent Materials 814

19.3 Neutron Sources 818

19.4 Principles of Mixed-Field Dosimetry 821

19.5 Neutron Detectors 825

19.6 Reference Dosimetry of Neutron Radiotherapy Beams 833

Exercises 838

A Data Tables 841

A.1 Fundamental and Derived Physical Constants 841

A.2 Data of Elements 843

A.3 Data for Compounds and Mixtures 846

A.4 Atomic Binding Energies for Elements 846

A.5 Atomic Fluorescent X-ray Mean Energies and Yields for Elements 857

A.6 Interaction Data for Electrons and Positrons (Electronic Form) 863

A.7 Interaction Data for Protons and Heavier Charged Particles (Electronic Form) 868

A.8 Interaction Data for Photons (Electronic Form) 874

A.9 Neutron Kerma Coefficients (Electronic Form) 879

References 881

Index 945