Test method

The IQM error sensitivity was evaluated by introducing deviations in 4 clinical H&N VMAT plans:

3, 5 and 10 % errors on total delivered MUs
and 3, 5 and 10 mm MLCs shift introduced with a Matlab  script.

The cumulative IQM checksum value was measured and the percentage difference was calculated with respect to the non-modified plan.

Test results

Both the MLC shift errors as well as the MU variations were detected by IQM.
IQM shows a linear response with dose (R2=0.9995).


IQM shows a good ability in detecting real-time errors and seems to be a good candidate to save time during the plan QA process.