Objective:To investigate the dosimetric performance of ArcCHECK system,to validate the designed plan before patients radiotherapy,to make sure patient gain accuracy dosimetry.Methods:34 VMAT treatment plans of nasopharyngeal carcinoma patients were performed with Pinnacle treatment planning system(TPS),and then these plans were exported to MOSAIQ system,treatment plans were transplanted into ArcCHECK phantom and recomputed.Calibrated Arccheck system,matrix and absolute dose Before validation.Usingbuild-in the ArcCHECK software to analyze th...