“…Due to their convenience and high temporal resolution, the use of machine log files as input data for linac and patient‐specific QA has been heavily investigated 19–55 . Log file–based patient‐specific QA usually involves the recalculation of the treatment plan with control points modified based upon log file data used as a representation of the “actual” delivery to be compared to the planned delivery 23–28,32,34–36,41–43,45–47,50–52,55 . A number of authors have cautioned about the nonindependence of log files from the systems under investigation and potential insensitivity of log files to MLC mis‐calibration or to faults in the MLC drive train and hence have suggested a need for separate MLC QA to assure log file accuracy 20,22,23,32,37,38,43,45,50 .…”