The Physics of Radiation Therapy

by Khan, Faiz M.

• ISBN13: 9780683045024
• ISBN10: 0683045024
• Format: Hardcover
• Copyright: 1994-01-01
• Publisher: Williams & Wilkins

Summary

University of Minnesota, Minneapolis. New edition of a text on clinical radiation oncology physics, for residents and clinical physicists. Previous edition 1984. Illustrated. DNLM: Health Physics.

Table of Contents

Preface to the Second Edition	vii
Preface to the First Edition	ix
Structure of Matter
The Atom	1	(1)
The Nucleus	1	(1)
Atomic Mass and Energy Units	2	(2)
Distribution of Orbital Electrons	4	(1)
Atomic Energy Levels	5	(1)
Nuclear Forces	6	(1)
Nuclear Energy Levels	7	(1)
Particle Radiation	8	(1)
Electromagnetic Radiation	9	(3)
Wave Model	9	(1)
Quantum Model	10	(2)
Nuclear Transformations
Radioactivity	12	(1)
Decay Constant	12	(1)
Activity	13	(1)
The Half Life and the Mean Life	14	(3)
Radioactive Series	17	(1)
Radioactive Equilibrium	18	(4)
Modes of Radioactive Decay	22	(4)
α Particle Decay	22	(1)
β Particle Decay	22	(1)
Negatron Emission	23	(1)
Positron Emission	24	(1)
Electron Capture	25	(1)
Internal Conversion	26	(1)
Isomeric Transition	26	(1)
Nuclear Reactions	26	(5)
The α,p Reaction	26	(1)
The α,n Reaction	27	(1)
Proton Bombardment	28	(1)
Deuteron Bombardment	28	(1)
Neutron Bombardment	28	(1)
Photodisintegration	29	(1)
Fission	30	(1)
Fusion	30	(1)
Activation of Nuclides	31	(1)
Nuclear Reactors	31	(1)
Production of X-Rays
The X-Ray Tube	32	(3)
The Anode	32	(2)
The Cathode	34	(1)
Basic X-Ray Circuit	35	(1)
Voltage Rectification	36	(2)
Physics of X-Ray Production	38	(3)
Bremsstrahlung	39	(1)
Characteristic X-Rays	40	(1)
X-Ray Energy Spectra	41	(2)
Operating Characteristics	43	(2)
Clinical Radiation Generators
Kilovoltage Units	45	(4)
Grenz-Ray Therapy	45	(1)
Contact Therapy	45	(2)
Superficial Therapy	47	(1)
Orthovoltage Therapy or Deep Therapy	47	(1)
Supervoltage Therapy	48	(1)
Resonant Transformer Units	49	(1)
Megavoltage Therapy	49	(1)
Van de Graaff Generator	49	(2)
Linear Accelerator	51	(7)
The Magnetron	52	(2)
The Kylstron	54	(1)
The Linac X-Ray Beam	54	(1)
The Electron Beam	55	(1)
Treatment Head	55	(1)
Target and Flattening Filter	55	(1)
Beam Collimation and Monitoring	56	(1)
Gantry	57	(1)
Betatron	58	(1)
Microtron	59	(1)
Cyclotron	60	(1)
Machines Using Radionuclides	61	(5)
Cobalt-60 Unit	62	(1)
Source	62	(1)
Source Housing	63	(1)
Beam Collimation and Penumbra	64	(2)
Heavy Particle Beams	66	(5)
Neutrons	66	(1)
D-T Generator	66	(1)
Cyclotron	67	(1)
Protons and Heavy Ions	67	(1)
Negative Pions	68	(3)
Interactions of Ionizing Radiation
Ionization	71	(1)
Photon Beam Description	72	(1)
Photon Beam Attenuation	72	(4)
Coefficients	76	(2)
Attenuation Coefficient	76	(1)
Energy Transfer Coefficient	77	(1)
Energy Absorption Coefficient	77	(1)
Interactions of Photons with Matter	78	(1)
Coherent Scattering	78	(1)
Photoelectric Effect	79	(2)
Compton Effect	81	(5)
Special Cases of Compton Effect	82	(1)
Direct Hit	82	(1)
Grazing Hit	82	(1)
90° Photon Scatter	82	(2)
Dependence of Compton Effect on Energy and Atomic Number	84	(2)
Pair Production	86	(1)
Annihilation Radiation	87	(1)
Variation of Pair Production with Energy and Atomic Number	87	(1)
Relative Importance of Various Types of Interactions	87	(3)
Interactions of Charged Particles	90	(1)
Heavy Charged Particles	90	(1)
Electrons	90	(1)
Interactions of Neutrons	91	(1)
Comparative Beam Characteristics	91	(3)
Measurement of Ionizing Radiation
Introduction	94	(1)
The Roentgen	94	(2)
Free-Air Ionization Chamber	96	(1)
Thimble Chambers	97	(5)
Chamber Wall	99	(1)
Effective Atomic Number	99	(1)
Chamber Calibration	100	(1)
Desirable Chamber Characteristics	101	(1)
Practical Thimble Chambers	102	(6)
Condenser Chambers	102	(2)
Chamber Sensitivity	104	(1)
Stem Effect	104	(2)
Farmer Chamber	106	(2)
Electrometers	108	(3)
String Electrometer	108	(1)
Other Electrometers	109	(1)
Operational Amplifiers	109	(2)
Special Chambers	111	(2)
Extrapolation Chamber	111	(1)
Parallel-Plate Chambers	111	(2)
Ion Collection	113	(1)
Saturation	113	(1)
Collection Efficiency	114	(1)
Chamber Polarity Effects	114	(2)
Environmental Conditions	116	(1)
Measurement of Exposure	117	(2)
Quality of X-Ray Beams
Half Value Layer	119	(1)
Filters	120	(2)
Measurement of Beam Quality Parameters	122	(6)
Half Value Layer	122	(1)
Peak Voltage	122	(1)
Direct Measurement	123	(1)
Voltage Divider	123	(1)
Sphere-Gap Method	123	(1)
Indirect Measurement	123	(1)
Fluorescence Method	123	(1)
Attenuation Method	124	(1)
Penetrameter	124	(2)
Effective Energy	126	(1)
Mean Energy	127	(1)
Measurement of Megavoltage Beam Energy	128	(1)
Measurement of Energy Spectrum	129	(2)
Measurement of Absorbed Dose
Radiation Absorbed Dose	131	(1)
Relationship Between Kerma, Exposure, and Absorbed Dose	132	(3)
Kerma	132	(1)
Exposure and Kerma	133	(1)
Absorbed Dose and Kerma	133	(2)
Calculation of Absorbed Dose from Exposure	135	(5)
Absorbed Dose to Air	135	(1)
Absorbed Dose to any Medium	135	(2)
Dose Calibration with Ion Chamber in Air	137	(1)
Dose Measurement from Exposure with Ion Chamber in a Medium	138	(2)
The Bragg-Gray Cavity Theory	140	(6)
Stopping Power	141	(1)
Chamber Volume	142	(3)
Effective Point of Measurement	145	(1)
Plane Parallel Chambers	145	(1)
Cylindrical Chambers	145	(1)
Calibration Protocol for Megavoltage Beams	146	(1)
Cavity-Gas Calibration Factor (Ngas)	146	(1)
Chamber as a Bragg-Gray Cavity	147	(13)
Photon Beams	148	(3)
Electron Beams	151	(1)
Dose Calibration Parameters	152	(1)
Chamber Calibration Factor, Nx	153	(1)
Cavity-Gas Calibration Factor, Ngas	153	(1)
W/e	154	(1)
Ion Recombination Correction: Aion, Pion	154	(1)
Wall-Correction Factors: Awall, βwall, Pwall	154	(2)
Replacement Correction Factor, Prepl	156	(1)
Calibration Phantom	157	(1)
Simplified Equations	158	(2)
Transfer of Absorbed Dose from One Medium to Another	160	(1)
Photon Beams	160	(1)
Electron Beams	161	(1)
Exposure from Radioactive Sources	161	(2)
Measurement of Absorbed Dose	163	(13)
Calorimetry	163	(1)
Chemical Dosimetry	164	(1)
Ferrous Sulfate (Fricke) Dosimeter	165	(1)
G Value	165	(2)
Solid State Methods	167	(1)
Thermoluminescence Dosimetry	167	(1)
Simplified Theory of TLD	168	(1)
Lithium Fluoride	169	(1)
Practical Considerations	170	(2)
Film Dosimetry	172	(4)
Dose Distribution and Scatter Analysis
Phantoms	176	(3)
Depth Dose Distribution	179	(1)
Percentage Depth Dose	179	(9)
Dependence on Beam Quality and Depth	180	(1)
Initial Dose Buildup	180	(2)
Effect of Field Size and Shape	182	(3)
Dependence on Source-Surface Distance	185	(3)
Tissue-Air Ratio	188	(8)
Effect of Distance	188	(1)
Variance with Energy, Depth, and Field Size	189	(1)
Backscatter Factor	190	(1)
Relationship between TAR and Percent Depth Dose	190	(2)
Conversion of Percent Depth Dose from One SSD to Another-the TAR Method	192	(3)
Calculation of Dose in Rotation Therapy	195	(1)
Scatter-Air Ratio	196	(4)
Dose Calculation in Irregular Fields-Clarkson's Method	197	(3)
A System of Dosimetric Calculations
Dose Calculation Parameters	200	(6)
Collimator Scatter Factor	201	(1)
Phantom Scatter Factor	201	(2)
Tissue-Phantom and Tissue-Maximum Ratios	203	(1)
Properties of TMR	204	(2)
Scatter-Maximum Ratio	206	(1)
Practical Applications	206	(10)
Accelerator Calculations	206	(1)
SSD Technique	206	(2)
Isocentric Technique	208	(1)
Cobalt-60 Calculations	209	(1)
Irregular Fields	210	(1)
SSD Variations within the Field	211	(1)
Computer Program	212	(1)
Asymmetric Fields	212	(4)
Other Practical Methods of Calculating Depth Dose Distribution	216	(6)
Irregular Fields	216	(1)
Point Off Axis	216	(2)
Point outside the Field	218	(1)
Point under the Block	219	(3)
Appendix to Chapter	222	(4)
Derivation of Sp	222	(1)
Derivation of TMR	222	(1)
Derivation of SMR	223	(3)
Treatment Planning I: Isodose Distributions
Isodose Chart	226	(3)
Measurement of Isodose Curves	229	(2)
Sources of Isodose Charts	230	(1)
Parameters of Isodose Curves	231	(3)
Beam Quality	231	(1)
Source Size, SSD, and SDD-The Penumbra Effect	231	(2)
Collimation and Flattening Filter	233	(1)
Field Size	233	(1)
Wedge Filters	234	(5)
Wedge Isodose Angle	235	(1)
Wedge Transmission Factor	236	(1)
Wedge Systems	236	(1)
Effect on Beam Quality	236	(2)
Design of Wedge Filters	238	(1)
Combination of Radiation Fields	239	(6)
Parallel Opposed Fields	240	(1)
Patient Thickness versus Dose Uniformity	241	(1)
Edge Effect (Lateral Tissue Damage)	242	(1)
Integral Dose	243	(1)
Multiple Fields	244	(1)
Isocentric Techniques	245	(5)
Stationary Beams	247	(1)
Rotation Therapy	247	(3)
Wedge Field Techniques	250	(4)
Uniformity of Dose Distribution	252	(1)
Open and Wedged Field Combinations	253	(1)
Tumor Dose Specification for External Photon Beams	254	(6)
Terminology	255	(1)
Target Volume	255	(1)
Treatment Volume	255	(1)
Irradiated Volume	255	(1)
Maximum Target Dose	255	(1)
Minimum Target Dose	256	(1)
Mean Target Dose	256	(1)
Median Target Dose	256	(1)
Modal Target Dose	256	(1)
Hot Spots	257	(1)
Specification of Target Dose	257	(1)
Stationary Photon Beams	257	(1)
Rotation Therapy	257	(1)
Additional Information	258	(2)
Treatment Planning II: Patient Data, Corrections, and Setup
Acquisition of Patient Data	260	(15)
Body Contours	260	(2)
Internal Structures	262	(1)
Transverse Tomography	262	(1)
Computed Tomography	263	(5)
Three-Dimensional Treatment Planning	268	(1)
Magnetic Resonance Imaging	269	(3)
Ultrasound	272	(3)
Treatment Simulation	275	(2)
Treatment Verification	277	(4)
Port Films	277	(1)
Electronic Portal Imaging	278	(3)
Corrections for Contour Irregularities	281	(5)
Effective SSD Method	281	(2)
Tissue-Air (or Tissue-Maximum) Ratio Method	283	(1)
Isodose Shift Method	283	(3)
Corrections far Tissue Inhomogeneities	286	(13)
Corrections for Beam Attenuation and Scattering	287	(1)
Tissue-Air Ratio Method	287	(1)
Power Law Tissue-Air Ratio Method	287	(1)
Equivalent Tissue-Air Ratio Method	288	(1)
Isodose Shift Method	289	(1)
Typical Correction Factors	289	(2)
Absorbed Dose within an Inhomogeneity	291	(1)
Bone Mineral	291	(2)
Bone-Tissue Interface	293	(1)
Soft Tissue in Bone	293	(1)
Soft Tissue Surrounding Bone	294	(4)
Lung Tissue	298	(1)
Air Cavity	299	(1)
Tissue Compensation	299	(8)
Design of Compensators	300	(4)
Two-Dimensional Compensators	304	(1)
Three-Dimensional Compensators	305	(1)
Moire Camera	305	(1)
Magnetic Digitizer	305	(1)
CT-Based Compensator Systems	305	(1)
Compensating Wedges	306	(1)
Other Applications	306	(1)
Compensator Setup	307	(1)
Patient Positioning	307	(8)
General Guidelines	307	(3)
The XYZ Method of Isocenter Setup	310	(1)
Simulation Procedure	310	(1)
Treatment Setup	310	(5)
Treatment Planning III: Field Shaping, Skin Dose, and Field Separation
Field Blocks	315	(8)
Block Thickness	316	(1)
Block Divergence	316	(1)
Field Shaping	317	(1)
Custom Blocking	317	(3)
Independent Jaws	320	(1)
Multileaf Collimators	320	(3)
Skin Dose	323	(9)
Electron Contamination of Photon Beams	323	(1)
Measurement of Dose Distribution in the Build-Up Region	323	(1)
Skin Sparing as a Function of Photon Energy	324	(1)
Effect of Absorber-Skin Distance	325	(1)
Effect of Field Size	326	(1)
Electron Filters	327	(2)
Skin Sparing at Oblique Incidence	329	(3)
Separation of Adjacent Fields	332	(14)
Methods of Field Separation	332	(2)
Geometric	334	(5)
Dosimetric	339	(1)
Orthogonal Field Junctions	339	(1)
Craniospinal Fields	339	(1)
Technique A	340	(1)
Technique B	341	(2)
Guidelines for Field Matching	343	(3)
Electron Beam Therapy
Electron Interactions	346	(4)
Rate of Energy Loss	347	(1)
Collisional Losses (Ionization and Excitation)	348	(1)
Radiation Losses (Bremsstrahlung)	348	(1)
Polarization	348	(1)
Stopping Power	348	(1)
Absorbed Dose	349	(1)
Electron Scattering	349	(1)
Energy Specification and Measurement	350	(2)
Most Probable Energy	351	(1)
Mean Energy	352	(1)
Energy at Depth	352	(1)
Determination of Absorbed Dose	352	(9)
Output Calibration	353	(1)
Ion Chamber	353	(1)
Phantom	353	(1)
Reference Depth and Field Size	354	(1)
Chamber Voltage	354	(1)
Effects of Chamber Polarity	354	(1)
Perturbation or Replacement Correction	354	(1)
Displacement Correction	355	(1)
Absorbed Dose Calculation	355	(1)
Depth Dose Distribution	356	(1)
Ionization Chambers	356	(1)
Silicon Diodes	356	(1)
Film	356	(4)
Phantoms	360	(1)
Characteristics of Clinical Electron Beams	361	(14)
Central Axis Depth Dose Curves	361	(4)
Isodose Curves	365	(1)
Field Flatness and Symmetry	366	(1)
Beam Collimation	367	(2)
Field Size Dependence	369	(2)
Electron Source	371	(3)
X-Ray Contamination	374	(1)
Treatment Planning	375	(15)
Choice of Energy and Field Size	375	(1)
Corrections for Air Gaps and Beam Obliquity	375	(7)
Tissue Inhomogeneities	382	(1)
Bone	382	(1)
Lung	382	(1)
Small Inhomogeneities	383	(4)
Use of Bolus and Absorbers	387	(1)
Problems of Adjacent Fields	387	(3)
Field Shaping	390	(9)
External Shielding	390	(1)
Measurement of Transmission Curves	391	(1)
Effect of Blocking on Dose Rate	392	(2)
Internal Shielding	394	(5)
Electron Arc Therapy	399	(5)
Calibration of Arc Therapy Beam	400	(1)
Treatment Planning	401	(1)
Beam Energy	401	(1)
Scanning Field Width	402	(1)
Location of Isocenter	402	(1)
Field Shaping	403	(1)
Isodose Distribution	404	(1)
Total Skin Irradiation	404	(1)
Translational Technique	404	(1)
Large Field Technique	405	(4)
Field Flatness	405	(1)
X-Ray Contamination	405	(2)
Field Arrangement	407	(1)
Dose Distribution	407	(2)
Modified Stanford Technique	409	(9)
Dual Field Angle	409	(2)
Calibration	411	(1)
In Vivo Dosimetry	412	(6)
Brachytherapy
Radioactive Sources	418	(10)
Radium	418	(1)
Decay	418	(1)
Source Construction	419	(1)
Source Specification	419	(1)
Exposure Rate Constant	420	(1)
Radon Hazard	421	(1)
Cesium-137	422	(1)
Cobalt-60	423	(1)
Iridium-192	423	(1)
Gold-198	424	(1)
Iodine-125	424	(1)
Palladium-103	425	(3)
Calibration of Brachytherapy Sources	428	(6)
Specification of Source Strength	428	(1)
Activity	428	(1)
Exposure Rate at a Specified Distance	428	(1)
Equivalent Mass of Radium	428	(1)
Apparent Activity	429	(1)
Air Kerma Strength	429	(1)
Milligram Radium Equivalent	430	(1)
Apparent Activity	430	(1)
Exposure Rate Calibration	431	(1)
Open-Air Measurements	432	(1)
Well-Type Ion Chambers	432	(2)
Calculation of Dose Distributions	434	(11)
Exposure Rate	434	(3)
Effect of Inverse Square Law	437	(1)
Absorbed Dose in Tissue	438	(2)
Modular Dose Calculation Models	440	(2)
Isodose Curves	442	(3)
Systems of Implant Dosimetry	445	(9)
The Paterson-Parker System	445	(1)
Planar Implant	445	(1)
Volume Implants	446	(1)
Paterson-Parker Tables	447	(1)
Determination of Implant Area or Volume	448	(1)
Orthogonal Radiographs	448	(2)
The Quimby System	450	(1)
The Memorial System	450	(1)
The Paris System	451	(1)
Computer System	451	(3)
Computer Dosimetry	454	(3)
Localization of Sources	455	(1)
Orthogonal Imaging Method	455	(1)
Stereo-Shift Method	455	(2)
Dose Computation	457	(1)
Implantation Techniques	457	(3)
Surface Molds	457	(1)
Interstitial Therapy	458	(1)
Intracavitary Therapy	459	(1)
Uterine Cervix	459	(1)
Uterine Corpus	460	(1)
Dose Specification: Cancer of the Cervix	460	(8)
Milligram-Hours	461	(1)
The Manchester System	461	(2)
Dose to Bladder and Rectum	463	(1)
The ICRU System	463	(2)
Absorbed Dose at Reference Points	465	(2)
Commentary	467	(1)
Remote Afterloading Units	468	(6)
Advantages	469	(1)
Disadvantages	470	(1)
HDR Versus LDR	470	(4)
Radiation Protection
Dose Equivalent	474	(1)
Effective Dose Equivalent	475	(1)
Risk Estimates	475	(1)
Background Radiation	476	(1)
Low-Level Radiation Effects	477	(1)
Effective Dose Equivalent Limits	478	(4)
Occupational and Public Dose Limits	479	(1)
Dose Limits for Pregnant Women	479	(2)
Negligible Individual Risk Level	481	(1)
Structural Shielding Design	482	(8)
Primary Radiation Barrier	483	(1)
Secondary Barrier for Scattered Radiation	484	(2)
Secondary Barrier for Leakage Radiation	486	(2)
Door Shielding	488	(1)
Protection against Neutrons	489	(1)
Protection against Radiation from Brachytherapy Sources	490	(2)
Storage	490	(1)
Source Preparation	491	(1)
Source Transportation	491	(1)
Leak Testing	491	(1)
Radiation Protection Surveys	492	(5)
Radiation Monitoring Instruments	492	(1)
Ionization Chamber	492	(1)
Geiger-Muller Counters	493	(1)
Neutron Detectors	494	(1)
Equipment Survey	495	(1)
Area Survey	496	(1)
Personnel Monitoring	497	(1)
NRC Regulations	497	(8)
License	497	(1)
Administrative Requirements	498	(1)
ALARA Program	498	(1)
Radiation Safety Officer	498	(1)
Radiation Safety Committee	498	(1)
Quality Management Program	498	(1)
Technical Requirements	499	(1)
Teletherapy	500	(2)
Training and Experience Requirements	502	(3)
Quality Assurance
Goals	505	(1)
Physics Staffing	505	(5)
Training	507	(1)
Qualifications	508	(1)
Roles and Responsibilities	508	(2)
Equipment	510	(3)
External Beam Units	510	(1)
Brachytherapy Sources	511	(1)
Simulator	512	(1)
Dosimetric Accuracy	513	(1)
Equipment Specifications	514	(1)
Acceptance Testing	515	(19)
Linear Accelerator	515	(1)
Radiation Survey	516	(1)
Jaw Symmetry	516	(1)
Coincidence	516	(1)
Collimator Axis, Light Beam Axis and Cross-Hairs	516	(1)
Light Beam with X-Ray Beam	516	(2)
Mechanical Isocenter	518	(1)
Collimator Rotation	518	(1)
Gantry Rotation	519	(1)
Radiation Isocenter	519	(1)
Collimator	519	(1)
Treatment Table	519	(3)
Gantry	522	(1)
Multiple Beam Alignment Check	522	(1)
X-Ray Beam Performance	523	(1)
Energy	523	(1)
Field Flatness	524	(2)
Field Symmetry	526	(1)
Electron Beam Performance	526	(1)
Energy	526	(1)
Flatness and Symmetry	526	(1)
Monitor Chambers	526	(1)
Wedges	526	(1)
Miscellaneous Checks	526	(1)
Simulator	527	(1)
Brachytherapy	527	(3)
Intracavitary Sources and Applicators	530	(1)
Source Identity	530	(1)
Source Uniformity and Symmetry	530	(1)
Source Calibration	530	(1)
Applicator Evaluation	530	(1)
Interstitial Sources	531	(1)
Remote Afterloaders	531	(1)
Source Positioning	532	(1)
Source Calibration	533	(1)
Commissioning	534	(3)
Linear Accelerator	535	(1)
Central Axis Depth Dose Tables	535	(1)
Isodose Curves	535	(1)
Monitor Unit Calculations	535	(1)
Treatment-Planning Computer System	535	(2)
Periodic Quality Assurance	537
Linear Accelerator	537	(2)
Cobalt-60 Unit	539	(1)
Simulator	540
Appendix	1	(1)
Index	1