Patient-specific quality assurance for IMRT delivery: A multicentre study

IMRT is a commonly used technique for radiotherapy. This is the first multicentre study conducted nationally for assessing the quality of IMRT delivery in participating centres by cross-checking local QA results with on-site measurements using novel MOSkin detector and a commercial two-dimensional planar detector. By using MOSkin, 40 measurement points were evaluated, with 18% (8 points) showing deviations of more than ±5% from the predicted dose, while 82% of the results were within the recommended tolerance level of ±5% for on-site and end-to-end IMRT/VMAT audits. Most centres passed the 95% points of the gamma criteria of 3%/3 mm for planar dose measurement, which is consistent with other similar studies and within the confidence limits recommended by AAPM TG119. By benchmarking their performance with the recommended tolerance levels for IMRT delivery, participating centres can improve their quality continuously. In conclusion, the study found that participating centres generally met the international guidelines for IMRT delivery standards. •The first multicentre IMRT dosimetry audit was carried out in Malaysia.•Institutional QA results were compared with MOSkin detector and a planar detector.•Point dose measurement showed 18% measurements with deviations of more than ±5%.•Most centres passed the 95% gamma passing criteria of 3%/3 mm.