The Monte Carlo SRNA-VOX code for 3D proton dose distribution in voxelized geometry using CT data

Absorbed dose distribution in human eye simulated by FOTELP-VOX code and verified by volumetric modulated arc therapy treatment plan

This paper illustrates the potential of the FOTELP-VOX code, a modification of the general-purpose FOTELP code, combining Monte Carlo techniques to simulate particle transportation from an external source through the internal organs, resulting in a 3-D absorbed dose distribution. The study shows the comparison of results obtained by FOTELP software and the volumetric modulated arc therapy technique. This planning technique with two full arcs was applied, and the plan was created to destroy the diseased tissue in the eye tumor bed and avoid damage to surrounding healthy tissue, for one patient. The dose coverage, homogeneity index, conformity index of the target, and the dose volumes of critical structures were calculated. Good agreement of the results for absorbed dose in the human eye was obtained using these two techniques.

A simplified methodology to produce Monte Carlo dose distributions in proton therapy

The purpose of this study was to develop a simplified methodology that will produce Monte Carlo (MC) dose distribution for proton therapy which can be used as a clinical aid in determining the adequacy of proton plans produced from the treatment planning system (TPS). The Geant4 Monte Carlo toolkit was used for all simulations. The geometry of the double scatter nozzle in the simulation was a simplification of the treatment nozzle. The proton source was modeled as discrete energy layers, each with a unique energy distribution and weighting factor. The simplified MC system was designed to give the same dose distribution as the measured data used to commission the TPS. After the simplified MC system was finalized, a series of verification comparisons were made between it, measurements, and the clinically used TPS. Comparisons included the lateral profile of a stair‐shaped compensator that simulated a sharp lateral heterogeneity and depth‐dose measurements through heterogeneous materials. The simplified MC system matched measurements to within 2% or 2 mm for all commissioning data under investigation; moreover, the distal edge and lateral penumbra was within 1 mm of the measurements. The simplified MC system was able to better reproduce the measured profiles for a stair‐shaped compensator than the TPS. Both MC and TPS matched the measured depth dose through heterogeneous materials to within 2% or 2 mm. The simplified MC system was straightforward to implement, and produced accurate results when compared to measurements. Therefore, it holds promise as a clinically useful methodology to validate the relative dose distribution of patient treatment plans produced by the treatment planning systems.

PACS number: 87.55.K‐, 87.55.ne