Monte Carlo Transport of Electrons and Photons

ISBN-13: 9781461283140 / Angielski / Miękka / 2011 / 656 str.

T. M. Jenkins; W. R. Nelson;A. Rindi

Opis

For ten days at the end of September, 1987, a group of about 75 scientists from 21 different countries gathered in a restored monastery on a 750 meter high piece of rock jutting out of the Mediterranean Sea to discuss the simulation of the transport of electrons and photons using Monte Carlo techniques. When we first had the idea for this meeting, Ralph Nelson, who had organized a previous course at the "Ettore Majorana" Centre for Scientific Culture, suggested that Erice would be the ideal place for such a meeting. Nahum, Nelson and Rogers became Co-Directors of the Course, with the help of Alessandro Rindi, the Director of the School of Radiation Damage and Protection, and Professor Antonino Zichichi, Director of the "Ettore Majorana" Centre. The course was an outstanding success, both scientifically and socially, and those at the meeting will carry the marks of having attended, both intellectually and on a personal level where many friendships were made. The scientific content of the course was at a very high caliber, both because of the hard work done by all the lecturers in preparing their lectures (e. g., complete copies of each lecture were available at the beginning of the course) and because of the high quality of the "students," many of whom were accomplished experts in the field. The outstanding facilities of the Centre contributed greatly to the success. This volume contains the formal record of the course lectures.

Spis treści

and Fundamentals.- 1. Overview of Photon and Electron Monte Carlo.- 1.1 Introduction.- 1.2 Some History.- 1.3 Photons, Electrons and Medical Physics.- 1.4 Interesting Electrons.- 1.5 The Ultimate (Radiotherapy) Problem.- 1.6 Computer Technology.- 1.7 The Appeal of Monte Carlo.- 2. Multiple-Scattering Angular Deflections and Energy-Loss Straggling.- 2.1 Introduction.- 2.2 Elastic-Scattering Cross Section.- 2.2.1 Factorization.- 2.2.2 Spin and Relativity Effects.- 2.2.3 Screening Effects.- 2.2.4 Characteristic Screening Angle.- 2.2.5 Calculations by the Partial-Wave Method.- 2.2.6 Comparisons of Elastic-Scattering Cross Sections.- 2.2.7 Molecular and Solid-State Effects.- 2.3 Calculation of Multiple-Scattering Deflections.- 2.3.1 Molière Multiple-Scattering Distribution.- 2.3.2 Goudsmit-Saunderson Multiple-Scattering Distribution.- 2.3.3 Contribution of Inelastic Collisions to Multiple Scattering.- 2.3.4 Number of Elastic Collisions and Mean Deflection Angle.- 2.3.5 Comparison of Multiple-Scattering Distributions.- 2.4 Energy-Loss Straggling.- 2.4.1 Landau’s Distribution: Applicability, Refinements.- 2.4.2 More Elaborate Treatment of Straggling.- 2.4.3 Energy-Loss Straggling in Water.- 3. Electron Stopping Powers for Transport Calculations.- 3.1 Introduction.- 3.2 Definition of Stopping Power.- 3.3 Continuous-Slowing-Down Approximation.- 3.4 Stopping-Power Formulas and Tables.- 3.5 Mean Excitation Energies.- 3.5.1 I-Values from Stopping-Power Data.- 3.5.2 I-Values from Photon Cross Sections.- 3.5.3 Survey of Mean Excitation Energies for Elements.- 3.5.4 Mean Excitation Energies for Compounds.- 3.6 Density-Effect Correction.- 3.7 Comparisons with Experiments.- 3.8 Stopping-Power Ratios.- 3.9 Stopping Powers at Low Energies.- 3.10 Concluding Remarks.- 4. Cross Sections for Bremsstrahlung Production and Electron-Impact Ionization.- 4.1 Introduction.- 4.2 Bremsstrahlung Production.- 4.2.1 Electron-Nucleus Bremsstrahlung.- 4.2.2 Electron-Electron Bremsstrahlung.- 4.2.3 Comparisons of Calculated and Measured Cross Sections.- 4.2.4 Radiative Stopping Power.- 4.2.5 Positron Bremsstrahlung.- 4.3 Electron-Impact Ionization.- 4.3.1 Cross-Section Formulas.- 4.3.2 Input Data.- 4.3.3 Illustrative Examples.- 5. Electron Step-Size Artefacts and PRESTA.- 5.1 Introduction.- 5.2 Electron Step-Size Artefacts.- 5.2.1 What Is An Electron Step-Size Artefact?.- 5.2.2 Path-Length Correction.- 5.2.3 Lateral Displacement.- 5.2.4 Boundary Crossing.- 5.3 PRESTA.- 5.3.1 The Elements of PRESTA.- 5.3.2 Constraints of the Molière Theory.- 5.3.3 PRESTA’s Path-Length Correction.- 5.3.4 PRESTA’s Lateral-Displacement Algorithm.- 5.3.5 Accounting for Energy Loss.- 5.3.6 PRESTA’s Boundary-Crossing Algorithm.- 5.3.7 Caveat Emptor.- 6. 20 MeV Electrons on a Slab of Water.- 6.1 Introduction.- 6.2 A Thin Slab.- 6.2.1 The CSDA Calculation.- 6.2.2 More Realistic Calculations.- 6.3 A Thick Slab.- 6.3.1 Typical Histories.- 6.3.2 Depth-Dose Curves.- 6.3.3 Fluence vs Depth.- 6.4 Conclusions.- The Eltran System.- 7. An Overview of ETRAN Monte Carlo Methods.- 7.1 Introduction.- 7.2 Monte Carlo Methods.- 7.2.1 Photon Transport.- 7.2.2 Electron Transport.- 7.3 Organization and Description of the Code System.- 7.3.1 Data Preparation.- 7.3.2. Monte Carlo Calculations.- 7.4 Future Improvements.- 8. ETRAN — Experimental Benchmarks.- 8.1 Introduction.- 8.2 Comparisons.- 8.3 Discussion.- 9. Applications of ETRAN Monte Carlo Codes.- 9.1 Introduction.- 9.2 Response of Photon Detectors for Spectrometry.- 9.2.1 NaI Detectors.- 9.2.2 High-Purity Ge Detectors.- 9.3 Space Shielding Calculations.- 9.4 Bremsstrahlung Beams for Radiation Processing.- 9.5 Liquid-Scintillation Counting of Beta Emitters.- The Integrated Tiger Series.- 10. Structure and Operation of the ITS Code System.- 10.1 Introduction.- 10.2 History of the TIGER Series.- 10.3 Structure of the ITS Code System.- 10.3.1 The Source Files.- 10.3.2 The UPEML Processor.- 10.4 Operation of the ITS Code System.- 10.4.1 Input.- 10.4.2 Output.- 10.5 Concluding Remarks.- 11. Applications of the ITS Codes.- 11.1 Introduction.- 11.2 Verification.- 11.2.1 Van de Graaff Deposition Profiles.- 11.2.2 Van de Graaff Electron Backscatter.- 11.2.3 Van de Graaff Electron Deposition in Film.- 11.2.4 Van de Graaff X-Ray Production and Dosimetry.- 11.2.5 Low-Energy Electron Backscatter.- 11.2.6 2-D Electron Energy Deposition in Water at Intermediate Energies.- 11.2.7 High-Energy 2-D Profiles.- 11.2.8 BGO Pulse-Height Distribution.- 11.2.9 Charge Profiles in Plastic.- 11.3 Verification/Corroboration.- 11.3.1 Radial Electron Beam Diode for Gas Laser Excitation.- 11.3.2 Helia.- 11.3.3 Proto II 6-Beam Overlap.- 11.3.4 REB/Multiple-Foil Interaction.- 11.3.5 18 Blades.- 11.3.6 REB Pumping of Noble-Gas Halide Laser.- 11.3.7 Gradient-B Drift Transport.- 11.3.8 Printed Circuit Boards.- 11.3.9 Voyager Electron Telescope.- 11.3.10 SPEED/Triaxial-Diode Flash X-Ray Source.- 11.3.11 Inverse Ion Diode.- 11.4 Predictions.- 11.4.1 Bremsstrahlung Radiation Environment of PBFA-II.- 11.4.2 PBFA-I, MITL, and Gamma-Ray Telescope Plots.- 11.4.3 RAYO: REB-Pumped Gas Laser in Rectangular Geometry.- 11.4.4 Sector X-Ray Converter with Gradient-B Transport.- 11.4.5 TIGER vs TIGERP Line Radiation.- 11.4.6 Falcon.- 11.5 Research.- 11.5.1 Time-Dependent Response of the Atmosphere to X-Ray Energy Deposition.- 11.5.2 Electric Fields in Materials.- 11.5.3 Hidden Lines.- 11.5.4 Self-Consistent Alfven Problem.- 11.6 Conclusion.- The EGS Code System.- 12. Structure and Operation of the EGS4 Code System.- 12.1 Introduction.- 12.1.1 History Prior to EGS3.- 12.1.2 The Development of EGS3.- 12.1.3 EGS4 — A Code Greatly Influenced by Medical Physics.- 12.2 General Description of EGS4 (and PEGS4).- 12.2.1 PEGS4 as a Development Tool.- 12.2.2 PEGS4 as a Preprocessor for EGS4.- 12.2.3 General Implementation of EGS4.- 12.2.4 Mortran3 Macros and EGS User Codes.- 12.3 Some Benchmark Comparisons.- 12.3.1 Conversion Efficiency of Lead for 30–200 MeV Photons.- 12.3.2 Large, Modularized NaI(Tl) Detector Experiment.- 12.3.3 Longitudinal and Radial Showers in Water and Aluminum at 1 GeV.- 12.3.4 Track-Length Calculations.- 12.4 Summary of EGS4 Capabilities and Features.- 12.5 EGS4 Graphics Capabilities.- 13. Experimental Benchmarks of EGS.- 13.1 Introduction.- 13.2 Detector Response Functions.- 13.2.1 Photon Spectrometers.- 13.2.2 Electron Detectors.- 13.3 Calculated Ion Chamber Response.- 13.4 Depth-Dose Curves.- 13.4.1 Photon Depth-Dose Curves.- 13.4.2 Electron Depth-Dose Curves.- 13.5 Bremsstrahlung Production.- 13.6 Conclusion.- 14. A Comparison of EGS and ETRAN.- 14.1 Introduction.- 14.2 Class I vs Class II Algorithms.- 14.3 Differences in Multiple Scattering.- 14.4 Electron Depth-Dose Curves.- 14.5 Low-Energy Treatment and Termination of Histories.- 14.6 Step Sizes and Boundary Crossing.- 14.7 Sampling Procedures.- 14.8 Timing.- 14.9 Miscellaneous.- Low-Energy Monte Carlo.- 15. Low-Energy Monte Carlo and W-Values.- 15.1 Introduction.- 15.2 Low-Energy Electron Monte Carlo Transport Model.- 15.3 Input Cross Section.- 15.4 Results Concerning Ionization Yields.- 15.5 Conclusion.- 16. Electron Track Simulation for Microdosimetry.- 16.1 Introduction.- 16.2 Outline of the Electron Track Simulation.- 16.3 Evaluation of the Electron Cross Section.- 16.4 Description of an Electron Track Simulation Monte Carlo Program (ETRACK).- 16.5 Results of Electron Track Simulation.- 16.6 Basic Physical Quantities Derived from Electron Track Structure.- 16.7 Patterns and the Proximity Function in Cell Nucleus.- 16.8 Calculation of the DSB Probability of DNA.- 16.9 The DSB Probability and RBE.- 16.10 Concluding Remarks.- 16.11 The Use of the Physical Random Number Generator, MIKY.- General Techniques.- 17. Geometry Methods and Packages.- 17.1 Mathematical Considerations.- 17.1.1 Intersection of a Vector with a Plane Surface.- 17.1.2 The PLANE1 Algorithm Available in EGS4.- 17.1.3 Intersection of a Vector with a Cylindrical Surface.- 17.1.4 The CYLNDR Algorithm Available in EGS4.- 17.2 Geometry Considerations in the EGS4 Code System.- 17.2.1 The EGS4 User Code Concept.- 17.2.2 Specifications for (and an Example of) HOWFAR.- 17.2.2 Auxiliary Geometry Subprograms Available with EGS4.- 17.2.4 Mortran3 and Macro Forms of the Geometry Routines.- 17.2.5 Other EGS4-Related Geometry Packages.- 17.3 Combinatorial Geometry.- 17.3.1 Constructing Bodies Using Combinatorial Geometry.- 17.3.2 An Example of a Complex MORSE-CG Geometry.- 17.4 Geometry Packages in ETRAN, ITS and FLUKA.- 17.4.1 ETRAN.- 17.4.2 ITS: The Integrated TIGER Series.- 17.4.3 The FLUKA Hadronic Cascade Code.- 18. Variance-Reduction Techniques.- 18.1 Introduction.- 18.1.1 Variance Reduction or Efficiency Increase?.- 18.2 Electron-Specific Methods.- 18.2.1 Geometry Interrogation Reduction.- 18.2.2 Discard Within a Zone.- 18.2.3 PRESTA!.- 18.2.4 Range Rejection.- 18.3 Photon-Specific Methods.- 18.3.1 Interaction Forcing.- 18.3.2 Exponential Transform, Russian Roulette, and Particle Splitting.- 18.4 Other Tricks.- 18.4.1 Sectioned Problems, Use of Pre-Computed Results.- 18.4.2 Geometry-Equivalence Theorem.- 18.4.3 Use of Geometry Symmetry.- 19. Electron Transport in $$\vec E$$ and $${\mathbf{\vec B}}$$ Fields.- 19.1 Introduction.- 19.2 Equations of Motion in a Vacuum.- 19.2.1 Special Cases: $$\vec E = Constant, \vec B = 0; \vec B = Constant, \vec E = 0, 423$$.- 19.3 Transport in a Medium.- 19.4 Application to Monte Carlo — Benchmarks.- Applications.- 20. Electron Pencil-Beam Calculations.- 20.1 Introduction.- 20.2 Point-Monodirectional Beams.- 20.3 Computational Details.- 20.4 Monte Carlo Codes for Pencil-Beam Calculations.- 20.5 Applications.- 20.5.1 Absorbed-Dose Distributions.- 20.5.2 Energy Distributions.- 20.5.3 Pencil Beams as “Benchmarks” for Treatment-Planning Algorithms.- 21. Monte Carlo Simulation of Radiation Treatment Machine Heads.- 21.1 Introduction.- 21.2 Monte Carlo Simulations of Linear Accelerator Heads.- 21.2.1 Electron Contamination.- 21.3 Simulation of 60Co Teletherapy Heads, 461 21.3.1 Electron Contamination.- 21.4 Summary.- 22. Positron Emission Tomography Applications of EGS.- 22.1 Principles of Positron Emission Tomography.- 22.2 Physical Processes in PET.- 22.2.1 Positron Emitters.- 22.2.2 Positron Range.- 22.2.3 Positron Annihilation.- 22.2.4 Scatter in Tissue.- 22.2.5 Interaction Within the Detector.- 22.3 The PET Camera.- 22.3.1 Scintillator Multicrystal Detector.- 22.3.2 Gas Detector.- 22.4 Use of Monte Carlo Codes in Tomograph Design.- 22.5 An Application: Use of EGS4 for the HISPET Design.- 22.5.1 The Converter Efficiency Code (UCCELL).- 22.5.2 Evaluation of the HISPET Performance (UCPET).- 22.5.3 Image Reconstruction from EGS4-Simulated Data Output.- 22.6 Summary.- 23. Stopping-Power Ratios for Dosimetry.- 23.1 Introduction.- 23.2 Fundamentals of Stopping-Power Ratios.- 23.3 The Need for Transport Calculations to Derive Electron Spectra.- 23.4 Monte Carlo Calculations of Electron Spectra.- 23.4.1 The Technique of Transport Down to the Monte Carlo Cutoff Plus a CSDA Calculation.- 23.5 Stopping-Power Ratios for Electron Beams.- 23.6 Stopping-Power Ratios for Photon Beams.- 24. Photon Monte Carlo Transport in Radiation Protection.- 24.1 Introduction.- 24.2 The Anthropomorphic Phantom.- 24.3 The Monte Carlo Photon Transport Model.- 24.3.1 Photon Interaction Model.- 24.3.2 Interaction Site Model.- 24.3.3 Bookkeeping Model.- 24.3.4 The Input Data.- 24.4 Results Concerning the MIRD Phantom.- 24.5 Operational Radiation Protection Quantities.- 24.6 ICRU-Sphere Quantities.- 24.7 Dose Distribution Geometry.- 24.8 Special Calculation Techniques.- 24.9 Results Concerning the ICRU Sphere.- 24.10 Influence of Electron Transport.- 24.11 Conclusion.- 25. Simulation of Dosimeter Response and Interface Effects.- 25.1 Introduction.- 25.2 An Interface Benchmark.- 25.3 Electron Steplength Variation.- 25.4 Ion-Chamber Response.- 25.4.1 Introduction.- 25.4.2 In-Air KERMA Calibration in 60Co Radiation.- 25.4.3 Other Ion-Chamber Simulations.- 25.5 Dose Distributions at Interfaces.- 25.5.1 A Benchmarking Situation.- 25.5.2 Interface Simulations Involving LiF.- 25.5.3 Aluminium/Gold.- 25.5.4 Electron Beams.- 25.6 Summary and Conclusions.- 26. Dose Calculations for Radiation Treatment Planning.- 26.1 Introduction.- 26.2 Conventional Methods of Dose Calculations.- 26.2.1 Equivalent-Pathlength Methods.- 26.2.2 Scatter-Integration Models.- 26.2.3 Electron Beams.- 26.3 Pencil-Beam-Convolution Method of Dose Calculation.- 26.4 Examples.- 26.5 “Differential Pencil-Beam” and “Dose-Spread-Array” Models.- 26.5.1 Characteristics of Differential Pencil Beams.- 26.5.2 Dose Computations with Differential Pencil Beams.- 26.5.3 Examples.- 26.5.4 Dose-Spread-Array Model.- 26.5.5 Electron Beams.- 26.6 Summary.- 27. Three-Dimensional Dose Calculations for Total Body Irradiation.- 27.1 Introduction.- 27.2 Photon-Transport Monte Carlo Model.- 27.3 60Co Gamma-Ray Pencil-Beam Calculation.- 27.4 Calculation of Tissue Air Ratio (TAR) for 60Co Gamma Rays.- 27.5 Calculation of Three-Dimensional Dose Distributions in Patients.- 27.6 Variance-Reduction Techniques.- 27.7 Three-Dimensional Dose Distribution in a Patient for TBI.- 28. High-Energy Physics Applications of EGS.- 28.1 Introduction.- 28.2 The EGS Code in Electromagnetic Calorimetry.- 28.2.1 The Electromagnetic Cascade Shower.- 28.2.2 Electromagnetic Calorimeters.- 28.2.3 EGS4 Simulation of EM Calorimeters in General.- 28.2.4 EGS4 Design of a Lead-Glass Drift Calorimeter.- 28.3 Coupling EGS with Hadronic Cascade Programs.- 28.3.1 Hadron Calorimetry.- 28.3.2 Photohadron Production with FLUKA87/EGS4.- 28.4 Accelerator Design Applications.- 28.4.1 Positron Target Design.- 28.4.2 Heating of Beam Pipes and Other Components.- 28.4.3 Synchrotron Radiation.- 28.5 Simulation of a Hydrogen Bubble Chamber.