S2364
Physics - Quality assurance and auditing
ESTRO 2026
guidelines (4) more frequently at Centre 2 (97%) than at Centre 1 (47%). Unacceptable cases were primarily due to the absence of a GTV or CTV, or a CTV that did not adequately cover the required areas.The prescribed dose complied with the protocol for 85% of plans at Centre 1 and 83% of plans at Centre 2. Dynamic treatment techniques were used for all plans at both centres; FFF beams were used for 80% (Centre 1) and 98% (Centre 2). Mean GTV and PTV covering doses were similar between the centres (Figure 2) and a comparable proportion of plans meeting the recommended dose coverage.
4197.2 Coles CE, Griffin CL, Kirby AM et al. Partial-breast radiotherapy after breast conservation surgery for patients with early breast cancer (UK IMPORT LOW trial): 5-year results from a multicentre, randomised, controlled, phase 3, non-inferiority trial. Lancet 2017; 390 (10099): 1048-1060.3 Krogh SL, Brink C, Lorenzen EL et al. A national repository of complete radiotherapy plans: design, Results, and experiences. Acta Oncol 2023; 62 (10): 1161-1168. Keywords: Partial breast irradiation (PBI), QA
Digital Poster 2532 Use of a distributed learning system for automated auditing of spine SABR
Elizabeth Claridge Mackonis 1,2 , Dane Lynch 3 , Lois Holloway 4,5 , Annette Haworth 2 , Nicholas Hardcastle 3,2 1 Radiation Oncology, Chris O'Brien Lifehouse, Sydney, Australia. 2 Institute of Medical Physics, University of Sydney, Sydney, Australia. 3 Physical Sciences, Peter MacCallum Cancer Centres, Melbourne, Australia. 4 Radiation Oncology, Liverpool and Macarthur Cancer Therapy Centres, Sydney, Australia. 5 Medical Physics, Ingham Institute for Applied Medical Research, Sydney, Australia Purpose/Objective: Safe and effective spine SABR requires adherence to established guidelines, but auditing of treatment processes is labour-intensive. We evaluated the feasibility of using the Australian Cancer Data Network (ACDN) for automating auditing of adherence to established guidelines for spine SABR. Material/Methods: Dosimetric and non-dosimetric data were extracted from treatment planning and oncology information systems (TPS/OIS) for spine SABR patients treated in 2023-2024 at two large radiation therapy centres aiming to assess 24 metrics. DICOM plan data were extracted using the ACDN infrastructure (1). TPS/OIS data was extracted via SQL into local ACDN datasets for subsequent analysis with PyDicer (2). Adherence of contouring, dosimetry and treatment technique to EviQ treatment protocol (3) was assessed. Results: The audit included 46 patients from Centre 1 and 47 from Centre 2 (of 107 eligible), with exclusions due to irregular structure naming, missing data, or conversion errors. Contouring, treatment plan dosimetry and technique data were obtained at both centres (Figure 1). All patients at Centre 2 and 85% at Centre 1 had a simulation CT slice thickness ≤ 2mm. The 2-week CT-to-treatment interval was met for only 26% of patients at Centre 1 and 23% of patients at Centre 2, with a median time of 22 and 21 days respectively. Target contours adhered to consensus
Figure 1: The data accessed for this audit.
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