Second MU check and pretreatment verification
VMAT technique requires more beam intensity modulation, which usually results in a larger number of MUs. Moreover, uncertainties in using CT/MR/PET simulation, inhomogeneity corrections, and complex calculation algorithms such as convolution/superposition and Monte Carlo warrant the need of doing a second MU check to assure the accuracy of dose calculations.Next, plan delivery accuracy was measured using an ArcCHECK (Sun Nuclear Corporation, Melbourne, FL) phantom and the SNC‐Patient software (Ver 8.2) following a modified true composite setup as presented in the TG‐218 report of AAPM