Fig. 3

Differences in the mechanical parameters between those defined in the original VMAT plans and those recorded during the VMAT plan deliveries in the log files. MLC positional errors, gantry angle errors, and MU errors are shown for Trilogy (a) and TrueBeam STx (b). The units of the MLC errors, gantry angle errors, and MU errors are millimeters, degrees, and MUs, respectively