Monte Carlo simulation of errors in gantry angle and multi-leaf collimators on intensity modulated arc therapy radiation dose

This study aimed to investigate the impact of conventional linear accelerator errors in the gantry angle and multi-leaf collimators (MLCs) on the intensity-modulated arc therapy (IMAT) radiation dose for brain tumors. Seven typical planning datasets of patients with brain tumors were randomly selected and retreated using the IMAT conventional linear accelerator Varian 23EX. Random and system errors were introduced to modify these plans while maintaining the remaining treatment information. The dose-volume parameters of the target and critical organs were compared and analyzed. The results showed that for random single-sided MLCs errors, if a group of errors was moved outward by 2 mm, the planning target volume (PTV)-Dmean increased by approximately 2.7%. If one side of the MLCs expanded outward with MLC-1, MLC-2, and MLC-rnd, the mean deviations of PTV-Dmean were 1.12%, 2.15%, and 1.15%, respectively, and the Dmean deviations of the lenses were 5.25%, 9.97%, and 5.49%, respectively. The maximum deviation of P