Monte Carlo Simulation of 6MV Elekta Synergy Platform Linac photon beam using Gate/Geant4

The present work is devoted to develop a computational model using the Gate Monte Carlo software for the simulation of a 6MV photon beam given by Elekta Synergy Platform medical linear accelerator treatment head. The model includes the major components of the multileaf accelerator head and a homogeneous water phantom. Calculations were performed for a photon beam with several treatment fields size ranging from 5*5 cm2 to 30*30 cm2 at 100 cm distance from source. The simulation is successfully validated by comparison with experimental distributions measured at the Regional Hassan II Oncology Center. Good agreement between simulations and measurements was observed, with dose differences of about 1.6% and 1.8% for depth doses and lateral dose profiles, respectively. The gamma index comparisons were also performed where more than 98% of the points for all simulations passed the standard quality assurance criteria of 3mm/3%.