the basic physics of radiation therapyPDF电子书下载

Ⅰ．SIMPLE MATHEMATICS OF RADIATION THERAPY 3

Proportion 3

Simple direct proportion 3

Algebraic or arithmetic proportion 3

Geometric proportion 5

Graphic proportion 5

Simple inverse proportion 7

Algebraic inverse proportion 7

Graphic inverse proportion 8

Inverse square proportion 9

Algebraic inverse square proportion 10

Geometric inverse square proportion 11

Graphic inverse square proportion 12

Mathematical law of decay 13

Decimal system and scientific notation 17

The slide rule 20

Ⅱ．MATTER AND ENERGY 27

Historical background 27

Ancient theories 27

Dalton＇s theory 27

Avogadro＇s law 28

Prout＇s hypothesis 28

Arrhenius＇ theory 29

Avogadro＇s number 29

States of matter 31

Structure of the atom 32

Historical background 32

Present concept 34

Atomic number 39

Mass number 39

Equivalence of mass and energy 41

Ⅲ．THE NATURE OF RADIATION 46

Definition 46

Types of radiation 46

Electromagnetic radiation 47

Quantum theory 49

X-rays 51

Production 51

X-ray spectra 52

Properties of x-rays 54

Bremsstrahlung (brems radiation) 55

Gamma-rays 56

Source 56

Properties 58

Energy 59

Radiation of particles 61

Alpha-particles 62

Beta-particles 68

Neutrons 71

Electrons 74

Positrons 74

Cosmic rays 75

Summary 76

Ⅳ．REACTIONS BETWEEN RADIATION AND MATTER 78

Photon interactions with matter 78

Transmission of photons 79

Unmodified or classical scattering 79

Photoelectric interaction with true absorption 80

Modified scattering 83

Pair production 85

Characteristic radiation 86

Interactions of particulate radiation with matter 91

Alpha-particles 91

Beta-particles 92

Positrons 92

Absorption of photon radiation 93

True absorption 93

Scattering 94

Inverse square law 95

The meaning of absorption curves 95

Attenuation of a heterogeneous x-ray beam 106

Ⅴ．X-RAY PRODUCTION AND CONTROL 109

Historical introduction 109

Principle of modern production of x-rays 111

Conditions necessary for the production of x-rays 113

Essential features of a therapy x-ray tube (100-250 Kv) 115

Valve tubes 119

Construction 120

Principle 120

Generating and control equipment 121

High voltage transformer 121

Voltage control devices 123

Autotransformer 123

Rheostat 124

Current control in x-ray tube 125

Control of current direction－rectification 126

Villard circuit 129

Constant potential circuit 131

Cables 133

High frequency x-ray generator 134

Ultra short distance therapy 136

Chaoul therapy unit 136

Philips therapy unit 139

General Electric Maximar-100 140

Ⅵ．QUANTITY OF X-RAYS AND GAMMA-RAYS 141

Historical introduction 141

Modern definition of the roentgen 143

Tissue exposure dose in roentgens 144

Measurement of the roentgen 145

The gamma-ray roentgen 148

Victoreen condenser-r-meter 149

Other types of dosimeters 155

Units of radiation dosage 156

Roentgen 156

Roentgen equivalent physical 157

Rad 158

Roentgen equivalent man 158

Factors affecting intensity of x-rays 159

Kilovoltage 159

Milliamperage 161

Time 161

Distance 161

Filtration 164

Factors affecting gamma-ray quantity 165

Ⅶ．X-RAY QUALITY 166

Factors 166

Analysis of x- ray beams 168

Modification of x-ray beams by filters 169

Clinical aspects of x-ray quality－half value layer 172

Other methods of specifying x-ray quality 179

Equivalent constant potential 179

Equivalent wavelength 180

Ⅷ．DOSAGE IN X-RAY THERAPY 182

Air dose 182

Calibration of an x-ray machine 182

Errors in dose calibration 184

Skin or surface exposure dose 186

Area of treatment field 188

Depth of irradiated part 189

Quality of the x-ray beam 191

Tissue or tumor dose 191

Absorbed dose 191

Central axis depth dose 193

Factors in depth dose percentage 196

Beam quality 196

Depth of lesion 201

Area of treatment field 202

Treatment distance 207

Exit dose 209

Isodose charts 211

Ⅸ．THERAPY PLANNING 214

Tumor localization and verification 214

Delimitation of field size 217

Cones 218

Diaphragms 219

Lead shields 220

Problem of adjacent or divided ports 221

Beam direction 223

Protractor 223

Pin-and-arc 225

Back pointer 226

Delivery of adequate radiation dosage 227

Crossfire radiation technic 227

Isodose curves in therapy planning 230

Composite isodose curves 233

Determination of dosage at critical points 238

Rotation therapy 244

Tumor-air ratio method 244

Transit dose method 252

Grid therapy 255

Sources of error in radiation therapy 257

Integral dose 259

Duties of the x-ray technician in radiotherapy 260

Establishment of rapport with patient 260

Assisting the radiologist 262

Ⅹ．RADIOACTIVE AND NUCLEAR PHYSICS 266

Definition 266

Historical background 266

Nuclides 268

Factors in nuclear stability 269

Neutron-proton ratio 269

Odd-even rules 270

Nuclear binding energy 270

Nuclear forces 271

Exchange forces 271

Types of nuclear disintegration 272

Alpha-decay 272

Beta-decay 273

Internal conversion 274

K-capture 275

Isomeric transition 275

Gamma-ray emission 276

Artificial radioactivity 276

Types of nuclear reactions 279

Alpha-particle bombardment 280

Neutron bombardment 280

Proton bombardment 282

Deuteron bombardment 282

Gamma-ray bombardment 283

The radioactive decay process 284

Displacement law 284

Radioactive decay scheme 286

Radioactive disintegration or decay constant 287

The unit of radioactivity 296

Specific radiation intensity，Iγ 298

Radioactive equilibrium 298

Ⅺ．SUPERVOLTAGE GENERATORS AND PARTICLE ACCELERATORS 301

Radium alpha-particles 301

Particle accelerators 302

Van de Graaff generator 302

Cyclotron 304

Synchrocyclotron 308

Betatron 310

Synchrotron 312

Linear accelerator 313

Nuclear reactor 317

Neutron physics 317

The fission reaction 319

Uranium fission 322

The nuclear reactor 323

Practical applications of nuclear reactor 328

Ⅻ．RADIUM AND RADON THERAPY 330

Historical survey 330

Radium 332

Decay and radiations of radium 332

Alpha-particles 333

Beta-particles 334

Gamma-rays 335

The radium series 336

Radioactive constants of radium 337

Disintegration constant 338

Half life 338

Average life 339

Radon 339

Source 339

Properties 340

Radioactive constants 341

Radioactive equilibrium 341

Gamma-ray dosage determination 347

Strength or activity of a radioactive source－the curie 349

Comparative dosage of radon and radium－determination of millicurie-hours 350

Determination of Iγ for radium 354

Absorbed dose－the rad 359

Types of radium applicators 361

Defects in radium needles 363

Gamma-ray therapy planning 364

Quimby system 366

Surface radium therapy 369

Quimby system 369

Paterson-Parker system 372

Cavitary radium therapy 380

Interstitial radium therapy 386

Paterson-Parker system 389

Martin system 399

Quimby system 401

Interstitial therapy with radioistopes 403

Cobalt-60 404

Iridium-192 404

Methods of checking accuracy of implant 405

ⅩⅢ．SURFACE BETA-RAY THERAPY 407

Natural beta-particle emitters 408

Radium series 408

Radon 409

Radium (D + E) 411

Artificial beta-particle emitting radionuclides 441

Strontium-90 411

Radiophosphorus 415

ⅩⅣ．SUPERVOLTAGE THERAPY 417

Telecurie therapy 417

Radium beam units 418

Cobalt-60 teletherapy equipment 421

Cesium-137 teletherapy equipment 425

Supervoltage x-ray equipment 428

Comparison with orthovoltage 430

Supervoltage treatment planning 439

Betatron therapy 439

ⅩⅤ．MEDICAL USE OF RADIOACTIVE ISOTOPES 444

Radioisotopes in medical diagnosis 445

Geiger-Müller tubes 447

Principle 448

Quenching 453

Construction of G-M counters 456

G-M counter circuits 458

Scintillation counters 458

Devices for counting detector pulses 462

Scalers 463

Count rate meter 466

Well counter 467

Statistics of counting 469

Background 469

Statistical error 470

Coincidence loss 474

General types of counting 477

Absolute counting 478

Comparative counting 480

Properties of radioisotopes 480

Decay constant 481

Half life 481

Average life 482

Decay curves 482

Units of dosage 485

Specific activity 485

Effective half life 487

Diagnostic use of radioisotopes 490

Radioactive iodine in thyroid gland function 490

Blood volume studies with I131 serum albumin 496

Localization of brain tumors with IHSA 498

Radiophosphorus (P32) in the diagnosis of inaccessible tumors 499

Radioactive chromium (Cr51) in red blood cell studies 501

Cobalt-60 labeled vitamin B12 in pernicious anemia (Schilling test) 502

Iron-59 in the study of anemias 504

Internal therapy with radioisotopes 505

Systemic use of radioisotopes 505

Absorbed dose from beta-emitters 507

Absorbed dose from gamma-emitters 509

Examples of radioisotopes in therapy 511

Radioactive iodine (I131) 511

Radiophosphorus (P32) 514

Radioactive chromic or zirconyl phosphate 521

Radiogold (Au198) 521

ⅩⅥ．RADIOBIOLOGY 524

Physical basis of radiobiology 524

The cell 530

Normal anatomy 530

Elementary genetics 532

Malignant cells 533

Mode of action of ionizing radiation 534

Observable radiation effects on cells 536

Radiation effects on cytoplasm 539

Effect of radiation on sensitive tumors 539

Direct effect 542

Indirect effect 542

Volume effect 543

Effect at a distance 543

Tissue recovery after irradiation 544

Tissue reactions in radiation therapy 552

Acute radiation syndrome 556

Modification of radiation injury 558

ⅩⅦ．PROTECTION IN RADIOTHERAPY 561

The maximum permissible dose 561

Determination of whole body exposure 566

Personnel monitoring 567

Laboratory surveying 569

X-ray protection up to 2 Mev 570

Radium protection 576

Protection from whole body exposure 576

Protection from local exposure 583

Hazards in the use of radioactive isotopes in Teletherapy 584

External radioisotope therapy 584

Hazards in the internal use of radioisotopes 587

Radioisotope hazards to the patient 587

Radioisotope hazards to personnel 590

External radioisotope hazards to personnel 591

Gamma-radiation 591

Beta-radiation 594

Exposure of hands to beta- or gamma-radiation 595

Internal radioisotope hazards to personnel 596

Laboratory design and facilities 599

Arrangement and location 599

Surface material 599

Ventilation 600

Shielding 600

Decay chamber 601

Laboratory monitoring 601

Disposal of radioactive wastes 602

Decontamination 603

Recommendations for nursing procedures 604

Special instructions with radioiodine 605

Special instructions with radiophosphrous 607

Special instructions with radiogold 608

Unsafe practices in handling radioisotopes 608

Bibliography 611

Supplementary References 617

Handbooks 618

Appendix 619

Central axis depth dose data (Tables A to F) 620

Useful physical data (Table G) 642

Useful equations (Table H) 643

The Greek alphabet (Table I) 646

Index 647