Comparision of electron beam dosimetry dose distributions obtained using Monte Carlo simulation methods with actual dosimetry

Aim of this study is comparing calculated dosimetric results from using Voxel Monte Carlo (VMC++) algorithm in Oncentra® treatment planning for 12 and 18 MeV electron energies and different fields under reference conditions, with actual dosimetry results.In the study, 12x12 cm2, 12x10 cm2, 12x8 cm2, 12x6 cm2, 10x10 cm2 and R=10 cm fields in accordance with standard 15x15 cm2 electron applicator were used. The reference conditions were defined for these fields in Oncentra® MasterPlan (brand of Nucletron) treatment planning system (TPS) and performed calculations with VMC++ algorithm. The calculated doses in the TPS were determined as 50.000 and 100.000 number of electrons history per cm2. In the second phase of the study, performed actual dosimetry results were compared with dosimetric results from TPS under reference conditions of the same fields. The differences of up to ±2% was obtained in this comparison. The highest and lowest levels of these differences were -2,30% and 0,13% for 12 MeV electron energy; 1,36% and -0,07% for 18 MeV electron energy; respectively.Our results in this study were found within the limits of ± 3% of clinical acceptance and accordance with literature. Big differences were observed in very small fields.Keywords: Electron beam dosimetry, Monte Carlo Simulation, Voxel Monte Carlo (VMC++).