Test purpose

Investigate the signal constancy of the IQM System for IMRT and VMAT plan QA.

Test method

The stationary and rotational dosimetric constancy of IQM was evaluated, using five field IMRT and single and double arc VMAT plans for prostate and head & neck (H&N) patients.

The plans were repeated three times for each measurement over several days to assess the constancy of IQM response.

Test results

Repeated IQM measurements of prostate and H&N IMRT deliveries showed 0.1 and 0.2% average standard deviation (SD) for cumulative comparison. The corresponding SDs for VMAT deliveries were 0.7, 1.3%,


IQM provides an effective means for real-time dosimetric verification of IMRT and VMAT treatment delivery.