Secondary Dose Verification of Radiotherapy Treatment Plans Using Monte Carlo Simulation | Original Article

ABSTRACT:

ABSTRACT

The study aims for independent secondary dose verification of radiotherapy treatment plans generated in a widely used Treatment Planning System (TPS) using a Monte Carlo (MC) simulated model of a medical linear accelerator (linac).MC simulation of a 6MV beam of a Clinac iX® linac was performed using the PRIMO MC simulation software (Version 0.3.64). An output phase-space file has been generated after simulating 5x108 primary photons histories. The simulation beam parameters were validated against measured beam data obtained from the linac. MC dose verification was conducted for ten brain tumour treatment plans. The MC simulation results were validated against Anisotropic Analytical Algorithm (AAA) and either dose reporting mode of the Acuros® XB (dose-to-water (AXB-Dw) dose-to-medium (AXB-Dm) algorithm implemented in a commercial TPS. The analysis was conducted using Dose Volume Histogram (DVH) parameters and Gamma analysis. No statistically significant differences (p³0.05) were observed for the planning target volume (PTV) DVH parameters for AAA and AXB-Dm algorithms against the MC simulated model. A statistically significant difference (p<0.05) was observed for AXB-Dw. Gamma analysis also shows similar differences for the PTV structure for AXB-Dw. MC simulation results of Clinac® iX linac using the PRIMO code show good agreement with measured data. The study demonstrates that the PRIMO Monte Carlo model of Clinac® iX medical linac generated can be used to verify radiation therapy treatment plans developed in a treatment planning system.