Table of Contents Cover Title Page Copyright Preface Quantities and Symbols1 Roman letter symbols Greek letter symbols Mathematical symbols Acronyms Chapter 1: Background and Essentials 1.1 Introduction 1.2 Types and Sources of Ionizing Radiation 1.3 Consequences of the Random Nature of Radiation 1.4 Interaction Cross Sections 1.5 Kinematic Relativistic Expressions 1.6 Atomic Relaxations 1.7 Evaluation of Uncertainties Exercises Chapter 2: Charged-Particle Interactions with Matter 2.1 Introduction 2.2 Types of Charged-Particle Interactions 2.3 Elastic Scattering 2.4 Inelastic Scattering and Energy Loss 2.5 Radiative Energy Loss: Bremsstrahlung 2.6 Total Stopping Power 2.7 Range of Charged Particles 2.8 Number and Energy Distributions of Secondary Particles 2.9 Nuclear Stopping Power and Interactions by Heavy Charged Particles 2.10 The W-Value (Mean Energy to Create an Ion Pair) 2.11 Addendum – Derivation of Expressions for the Elastic and Inelastic Scattering of Heavy Charged Particles Exercises Chapter 3: Uncharged-Particle Interactions with Matter 3.1 Introduction 3.2 Photon Interactions with Matter 3.3 Photoelectric Effect 3.4 Thomson Scattering 3.5 Rayleigh Scattering (Coherent Scattering) 3.6 Compton Scattering (Incoherent Scattering) 3.7 Pair Production and Triplet Production 3.8 Positron Annihilation 3.9 Photonuclear Interactions 3.10 Photon Interaction Coefficients 3.11 Neutron Interactions Exercises Chapter 4: Field and Dosimetric Quantities, Radiation Equilibrium – Definitions and Inter-Relations 4.1 Introduction 4.2 Stochastic and Non-stochastic Quantities 4.3 Radiation Field Quantities and Units 4.4 Distributions of Field Quantities 4.5 Quantities Describing Radiation Interactions 4.6 Dosimetric Quantities 4.7 Relationships Between Field and Dosimetric Quantities 4.8 Radiation Equilibrium (RE) 4.9 Charged-Particle Equilibrium (CPE) 4.10 Partial Charged-Particle Equilibrium (PCPE) 4.11 Summary of the Inter-Relations between Fluence, Kerma, Cema, and Dose 4.12 Addendum – Example Calculations of (Net) Energy Transferred and Imparted Exercises Chapter 5: Elementary Aspects of the Attenuation of Uncharged Particles 5.1 Introduction 5.2 Exponential Attenuation 5.3 Narrow-Beam Attenuation 5.4 Broad-Beam Attenuation 5.5 Spectral Effects 5.6 The Build-up Factor 5.7 Divergent Beams – The Inverse Square Law 5.8 The Scaling Theorem Exercises Chapter 6: Macroscopic Aspects of the Transport of Radiation Through Matter 6.1 Introduction 6.2 The Radiation Transport Equation Formalism 6.3 Introduction to Monte Carlo Derived Distributions 6.4 Electron Beam Distributions 6.5 Protons and Heavier Charged-Particle Beam Distributions 6.6 Photon Beam Distributions 6.7 Neutron Beam Distributions Exercises Chapter 7: Characterization of Radiation Quality 7.1 Introduction 7.2 General Aspects of Radiation Spectra. Mean Energy 7.3 Beam Quality Specification for Kilovoltage x-ray Beams 7.4 Megavoltage Photon Beam Quality Specification 7.5 High-Energy Electron Beam Quality Specification 7.6 Beam Quality Specification of Protons and Heavier Charged Particles 7.7 Energy Spectra Determination Exercises Chapter 8: The Monte Carlo Simulation of the Transport of Radiation Through Matter 8.1 Introduction 8.2 Basics of the Monte Carlo Method (MCM) 8.3 Simulation of Radiation Transport 8.4 Monte Carlo Codes and Systems in the Public Domain 8.5 Monte Carlo Applications in Radiation Dosimetry 8.6 Other Monte Carlo Developments Exercises Chapter 9: Cavity Theory 9.1 Introduction 9.2 Cavities That Are Small Compared to Secondary Electron Ranges 9.3 Stopping-Power Ratios 9.4 Cavities That Are Large Compared to Electron Ranges 9.5 General or Burlin Cavity Theory 9.6 The Fano Theorem 9.7 Practical Detectors: Deviations from ‘Ideal’ Cavity Theory Conditions 9.8 Summary and Validation of Cavity Theory Exercises Chapter 10: Overview of Radiation Detectors and Measurements 10.1 Introduction 10.2 Detector Response and Calibration Coefficient 10.3 Absolute, Reference, and Relative Dosimetry 10.4 General Characteristics and Desirable Properties of Detectors 10.5 Brief Description of Various Types of Detectors 10.6 Addendum – The Role of the Density Effect and I-Values in the Medium-to- Water Stopping-Power Ratio Exercises Chapter 11: Primary Radiation Standards 11.1 Introduction 11.2 Free-Air Ionization Chambers 11.3 Primary Cavity Ionization Chambers 11.4 Absorbed-Dose Calorimeters 11.5 Fricke Chemical Dosimeter 11.6 International Framework for Traceability in Radiation Dosimetry 11.7 Addendum – Experimental Derivation of Fundamental Dosimetric Quantities Exercises Chapter 12: Ionization Chambers 12.1 Introduction 12.2 Types of Ionization Chamber 12.3 Measurement of Ionization Current 12.4 Ion Recombination 12.5 Addendum – Air Humidity in Dosimetry Exercises Chapter 13: Chemical Dosimeters 13.1 Introduction 13.2 Radiation Chemistry in Water 13.3 Chemical Heat Defect 13.4 Ferrous Sulfate Dosimeters 13.5 Alanine Dosimetry 13.6 Film Dosimetry 13.7 Gel Dosimetry Exercises Chapter 14: Solid-State Detector Dosimetry 14.1 Introduction 14.2 Thermoluminescence Dosimetry 14.3 Optically-Stimulated Luminescence Dosimeters 14.4 Scintillation Dosimetry 14.5 Semiconductor Detectors for Dosimetry Exercises Chapter 15: Reference Dosimetry for External Beam Radiation Therapy 15.1 Introduction 15.2 A Generalized Formalism 15.3 Practical Implementation of Formalisms 15.4 Quantities Entering into the Various Formalisms 15.5 Accuracy of Radiation Therapy Reference Dosimetry 15.6 Addendum–Perturbation Correction Factors Exercises Chapter 16: Dosimetry of Small and Composite Radiotherapy Photon Beams 16.1 Introduction 16.2 Overview 16.3 The Physics of Small Megavoltage Photon Beams 16.4 Dosimetry of Small Beams 16.5 Detectors for Small-Beam Dosimetry 16.6 Dosimetry of Composite Fields 16.7 Addendum—Measurement in Plastic Phantoms Exercises Chapter 17: Reference Dosimetry for Diagnostic and Interventional Radiology 17.1 Introduction 17.2 Specific Quantities and Units 17.3 Formalism for Reference Dosimetry 17.4 Quantities Entering into the Formalism Exercises Chapter 18: Absorbed Dose Determination for Radionuclides 18.1 Introduction 18.2 Radioactivity Quantities and Units 18.3 Dosimetry of Unsealed Radioactive Sources 18.4 Dosimetry of Sealed Radioactive Sources 18.5 Addendum–The Reciprocity Theorem for Unsealed Radionuclide Dosimetry Exercises Chapter 19: Neutron Dosimetry 19.1 Introduction 19.2 Neutron Interactions in Tissue and Tissue-Equivalent Materials 19.3 Neutron Sources 19.4 Principles of Mixed-Field Dosimetry 19.5 Neutron Detectors 19.6 Reference Dosimetry of Neutron Radiotherapy Beams Exercises Appendix A: Data Tables A.1 Fundamental and Derived Physical Constants A.2 Data of Elements A.3 Data for Compounds and Mixtures A.4 Atomic Binding Energies for Elements A.5 Atomic Fluorescent X-ray Mean Energies and Yields for Elements A.6 Interaction Data for Electrons and Positrons (Electronic Form) A.9 Neutron Kerma Coefficients (Electronic Form) References Index End User License Agreement List of Illustrations Chapter 1: Background and Essentials Figure 1.1 Illustration of the quantities used in the definition of interaction cross sections. Figure 1.2 Triangular mnemonic rule relating the total energy, , rest energy, , and momentum (in units of ) of a particle. Figure 1.3 Shell binding energies for the K-, L-, M-, and N-shells as a function of atomic number (see Appendix A). Figure 1.4 Schematic illustration of the non-radiative transitions Auger (a), Coster–Kronig (b), and Super Coster–Kronig (c). In an Auger transition, an electron is ejected from a higher shell; the transition shown is K–L –L . In a 1 2 Coster–Kronig transition, a vacancy in any subshell is filled by an electron in a higher subshell in the same shell, with the ejection of an electron from a higher shell (L –L –M shown). In a Super Coster–Kronig transition, the electron 1 3 1 is ejected from the same shell (M –M –M shown). 1 2 4 Figure 1.5 Radiative (filled circles and lines) and non-radiative (open circles) relaxation spectra from the K shell for aluminium (Z = 13, a and c) and tungsten (Z = 74, b and d). (a) and (c) show the probabilities of a given emission per initial vacancy, where the legends indicate the percentage of the element binding energy taken by all x rays and Auger electrons. (c) and (d) illustrate the percentage of for each individual emission, showing that in low-Z elements most of the binding energy fraction corresponds to non-radiative emissions, whereas for high-Z elements, the highest fraction corresponds to radiative transitions. Figure 1.6 (a) Fluorescence yield, Ω , and average fraction of fluorescent events i (strictly, fractional participation in the photoelectric effect), P, by K-, L-, and M- i shells; note that . (b) Mean fluorescence x-ray energies, (solid lines), in the K-, L1-, and M1-shells; for comparison, the binding energies, are also shown (dashed lines). Chapter 2: Charged-Particle Interactions with Matter Figure 2.1 Electron and photon total cross sections (a) and mean free paths (b) in carbon and lead, solid and dashed lines, respectively. Figure 2.2 Simplified diagram of the main types of interactions of charged particles with an atom, depending on the impact parameter, b, relative to the atomic radius, r . Illustrated are inelastic interactions of the type hard (a) and soft (b), where a and , respectively, and inelastic radiative (c) and elastic interactions (d), where . Figure 2.3 Ratio of the small-angle approximation of the Rutherford DCS, Eq. (2.8), to the general expression for any angle given by Eq. (2.7). At the ratio is around 35%. Figure 2.4 Electron–atom total elastic cross section for the indicated elements, air (circles) and water (filled circles), as a function of the electron kinetic energy. Figure 2.5 Definition of the polar angle, θ, and the projected angles θ and θ , for a x y particle initially traveling in the direction of the z-axis. Figure 2.6 Minimum and maximum scattering angles, and , for the integration of the mean square scattering angle for electrons and protons, for elements with atomic number Z = 1 (dotted), 3, 6, 13, 26, 50, 79, and 100 (dashed), as a function of the kinetic energy. Figure 2.7 Variation of the ratio of the maximum and minimum scattering angles, , for atomic numbers between Z = 1 and 100 when . Figure 2.8 Graphical representation of the functions (Gaussian), , and in the multiple scattering theory of Molière. See Table 2.1 for the numerical values. Figure 2.9 Angular distributions of 15.7 MeV electrons transmitted through gold foils of the indicated thickness (they correspond, respectively, to 49 and 99 elastic collisions approximately). The continuous curves are for Goudsmit–Saunderson distributions calculated with partial-wave analysis DCSs; the dashed curves are distributions computed from Molière's theory. Symbols are the experimental results from Hanson et al. (1951). Figure 2.10 Energy (a) and atomic number (b) dependence of the mass scattering power for electrons. In (a) data for elements with atomic number Z = 3 (dotted), 6, 13, 26, 50, 79, and 100 (dashed) are shown. Note that in (b) the ordinate axis shows multiplied by the squared kinetic energy, E . 2 Figure 2.11 The GOS for ionization of the hydrogen atom (Z = 1) in the ground state. All energies are in units of the first ionization energy eV (www.nist.gov/pml/data/ion_energy.cfm), including those of the z-axis. The GOS for ionization of (non-relativistic) hydrogenic ions is independent of Z if energies are expressed in units of the first ionization energy. Figure 2.12 Soft and hard terms of the electronic stopping power of protons in aluminium using a cut-off value keV. At very high energies both terms approach a common value in their contribution to the stopping power (equipartition). Figure 2.13 Ratio of the relativistic to the non-relativistic expressions for the electronic stopping power of protons in carbon and uranium. The relativistic rise is