Premium
Electron transport in photon and electron beam modeling
Author(s) -
Keall Paul
Publication year - 1997
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.598121
Subject(s) - monte carlo method , electron , physics , photon , superposition principle , dosimetry , computational physics , electron scattering , scattering , monte carlo method for photon transport , cathode ray , atomic physics , optics , dynamic monte carlo method , nuclear physics , quantum mechanics , mathematics , nuclear medicine , medicine , statistics , direct simulation monte carlo
To address the deficiencies of currently available dose calculation algorithms for radiotherapy planning, two dose calculation methods have been devised. The first method incorporates Fermi–Eyges multiple scattering theory into the primary dose calculation of the superposition method for external x‐ray beam radiotherapy. The inclusion of scattering theory into the superposition technique accounts for the density distribution between the primary photon interaction and energy deposition sites. The second method developed is the super‐Monte Carlo (SMC) method. SMC calculates dose by a superposition of pregenerated Monte Carlo electron track kernels. For x‐ray beams, the primary dose is calculated by transporting pregenerated (in water) Monte Carlo electron tracks from each primary photon interaction site. The length of each electron step is scaled by the inverse of the density of the medium at the beginning of the step. The scatter dose is calculated by superposition. SMC can also be applied to electron beam dose calculation. Pregenerated electron tracks are transported through media of varying density and atomic number. The perturbation of the electron fluence due to each material encountered by the electrons is explicitly accounted for. Dose distributions in a variety of phantoms show good agreement with Monte Carlo results. SMC is an accurate, three‐dimensional unified photon/electron dose calculation algorithm.