Abstract: The aim of the study is to assess the commissioning accuracy of Intensity-Modulated Radiation Therapy (IMRT) and RapidArc from a Varian TrueBeam linear accelerator, with a procedure guided by protocols established in American Association of Physicists in Medicine Task Group 119. Dosimetric accuracy has been verified in 6 MV photon beams in various testcases: a mock prostate, a mock head/neck, a multi-target, and a C-shape. Confidence Limits (CLs) were determined for both point dose measurements and gamma analysis to assess the agreement between planned and measured doses. The results indicated that CLs for both IMRT and Rapid Arc (RA) are within the acceptable limits according to TG-119, thus confirming the accuracy and reliability of the treatment planning system and dosimetry equipment. The aim of this study was to extend the scope of the TG-119 protocol to include RA delivery-a comprehensive evaluation of the accuracy of dosimetric commissioning for modern radiotherapy techniques.