Monte Carlo dose calculation in radiation therapy for different modelling of electron and photon transport

The goal of any Monte Carlo Dose Calculation is to deliver the result that is both accurate and sufficiently fast for routine radiotherapy treatment on a patient. Radiotherapy planning require compositions of the relevant accelerator components. In this work, we examined different manners for modelling of nuclear particles transport through material domains of accelerator configuration that are based on two numerical algorithm. First algorithm (marked as full-physics in MC simulation) describes all interactions incident photons or electrons and produced secondary electrons in all components, while second algorithm (marked as reduced-physics in MC simulation) decreases number of interactions when is estimated that is unacceptable nuclear particle free path in relate to distance from boundary of some noticed component in random chosen direction. In the case of reduced-physics, the CPU time is also decreased and saved is the accurate level of dose calculation in relate to full-physics nuclear particle tracking through identical geometry configuration and material domains. Examination of different modelling are carried out by Monte Carlo code FOTELP (RSIC Code package CCC-581). Software package FOTELP was developed to simulate the transport of photons, electrons and positrons by Monte Carlo method for numerical experiments in dosimetry, radiotherapy and nuclear medicine. This code is suitable for computing the absorbed energy in the layers of tissue and other significant material, for estimating radiation damage of materials, and other numerical experiments concerning the mentioned nuclear particles. Codes from this package perform calculations in 3D geometry with random spectra of nuclear particles having energy in the range from 1 keV to 100 MeV, and material region for which geometry can be described by planes and surfaces of second order. Last version of this code has a possibility that made nuclear particle transport simulation with both the full-physics and reduced-physics. On the base results of this MC simulations concluded is for which processes must be apply the modelling with reduced-physics at 3D radiotherapy planning. (author)