Test purpose

Evaluate the long-term signal stability of the IQM system.

Test method

Each one 10cm x 10cm field for 6MV and 10MV, two IMRT QA plans as well as two VMAT Head&Neck plans were delivered on 160 days between October 2016 and February 2017.

Test results

The maximum deviation for all plans was found to be +/- 1% for all measurements. No systematic long-term trend has been determined.

Conclusion

IQM shows a good stability of the cumulative signal sufficient for clinical use.