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Ant colony algorithm implementation in electron and photon Monte Carlo transport: Application to the commissioning of radiosurgery photon beams
Author(s) -
GarcíaPareja S.,
Galán P.,
Manzano F.,
Brualla L.,
Lallena A. M.
Publication year - 2010
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 - 10.1118/1.3456108
Subject(s) - monte carlo method , photon , variance reduction , algorithm , computer science , radiation transport , bremsstrahlung , radiosurgery , dosimetry , physics , isocenter , computational physics , optics , mathematics , imaging phantom , statistics , nuclear medicine , radiation therapy , medicine
Purpose In this work, the authors describe an approach which has been developed to drive the application of different variance‐reduction techniques to the Monte Carlo simulation of photon and electron transport in clinical accelerators. Methods The new approach considers the following techniques: Russian roulette, splitting, a modified version of the directional bremsstrahlung splitting, and the azimuthal particle redistribution. Their application is controlled by an ant colony algorithm based on an importance map. Results The procedure has been applied to radiosurgery beams. Specifically, the authors have calculated depth‐dose profiles, off‐axis ratios, and output factors, quantities usually considered in the commissioning of these beams. The agreement between Monte Carlo results and the corresponding measurements is within ∼ 3 % / 0.3 mm for the central axis percentage depth dose and the dose profiles. The importance map generated in the calculation can be used to discuss simulation details in the different parts of the geometry in a simple way. The simulation CPU times are comparable to those needed within other approaches common in this field. Conclusions The new approach is competitive with those previously used in this kind of problems (PSF generation or source models) and has some practical advantages that make it to be a good tool to simulate the radiation transport in problems where the quantities of interest are difficult to obtain because of low statistics.