Influence of statistical uncertainty on Monte Carlo dose calculation in volumetric modulated arc therapy for glioblastoma brain tumor

Volumetric modulated arc therapy (VMAT) is an advanced modality of radiotherapy treatment delivery by varying gantry speed and dose rate with reduced treatment time. Dose calculation accuracy in radiotherapy is an important and crucial factor to prevent mistreatment of radiation treatment delivery. Ideally, the dose calculation algorithm should be accurate and able to generate quality plan with less calculation time. Although Monte Carlo (MC) dose calculation algorithms are recognized as the most accurate dose computation algorithms among the commercially available algorithms for treatment planning, its inherent statistical uncertainty (SU), determines the accuracy of the dose calculation and calculation time. During VMAT treatment, the Monaco™ treatment planning system (TPS) has an option to choose different SU (%) up to 5% for MC dose calculations. So it is necessary to evaluate optimal acceptance level of SU (%) for different treatment each clinical sites