RANZCR: Quality Corner

The Royal Australian and New Zealand College of Radiologists (RANZCR) Inside News June 2020

Making Sure That 50Gy is 50Gy

Delivering quality care to our cancer patients is a multi-disciplinary approach. As radiation oncologists, we are fortunate to be able to work with highly trained and qualified radiation professionals. While we conduct our day-to-day work in front of patients, there are a group of professionals who work tirelessly in the background to ensure that treatment is delivered with the accuracy and precision required. Among these professionals are those of the Australian Clinical Dosimetry Service (ACDS).

The ACDS is an independent dosimetry auditing program, providing quality assurance for radiation oncology facilities and patients. The ACDS covers 100 per cent of Australian radiotherapy facilities and selected New Zealand facilities. Facilities undergo yearly audits, ranging from machine output checks, through to end-to-end tests of the patient treatment pathway. The core component of the audits cover 3DCRT, IMRT, VMAT and SABR deliveries.

Additionally, the ACDS is continually developing audits to meet advancing radiotherapy technologies. The latest development by the ACDS has been audits to test both the MRand CBCT-based adaptive workflows, which have recently been clinically released in Australia.

ACDS' Rhonda Brown and Jessica Lye perform the Level III audit on the Elekta Unity MR-Linac.

After a year-long development, the team completed a Level Ib (output check) and a Level III (end-to-end test) audit on the Elekta Unity MR-Linac. Dosimetric accuracy in the adaptive workflows was tested using MR-visible plastic ‘tumours’, which changed shape and size between CT and treatment. The process was subsequently applied to the Varian Ethos adaptive CBCT solution.

The ACDS has also begun field trial audits for stereotactic radiosurgery (SRS). The cranial head phantom, ‘Max’, was custom designed by the ACDS for audits of complex SRS deliveries, in particular concurrent treatment of multiple metastases. Audit design was in consultation with TROG, to assist in credentialing for the OUTRUN and Local HER-O brain metastases clinical trials. The audit can be applied to SRS treatment on Conventional Linacs, Gamma Knife, Cyberknife, Tomotherapy and Halcyon systems, and has been completed at 5 facilities to date.

For more information on the ACDS you can visit their website:

www.arpansa.gov.au/our-services/ testing-and-calibration/calibration/ australian-clinical-dosimetry-service

Dr Jessica Lye Director ACDS, Medical Physicist, ACDS

Ms Maddison Shaw Clinical Operations Lead, Radiation Therapist, ACDS

Dr Albert Tiong RANZCR representative on the Clinical Advisory Group of the ACDS