ESTRO 2024 - Abstract Book

S4882

Physics - Quality assurance and auditing

ESTRO 2024

[17] Giglioli FR, Garibaldi C, Blanck O, et al. Dosimetric Multicenter Planning Comparison Studies for Stereotactic Body Radiation Therapy: Methodology and Future Perspectives. Int J Radiat Oncol Biol Phys. 2020;106(2):403-412. [18] Parenica HM, Mavroidis P, Jones W, et al. VMAT Optimization and Dose Calculation in the Presence of Metallic Hip Prostheses. Technol Cancer Res Treat. 2019;18:1533033819892255. [19] Pawałowski, B., Ryczkowski, A., Panek, R. et al. Accuracy of the doses computed by the Eclipse treatment planning system near and inside metal elements. Sci Rep 12, 5974 (2022). [20] 19a] Blanck O, Ipsen S, Chan MK, et al. Treatment Planning Considerations for Robotic Guided Cardiac Radiosurgery for Atrial Fibrillation. Cureus. 2016;8(7):e705.

2374

Mini-Oral

Early experience with IAEA/WHO postal dose audits for high energy electron beams

Godfrey Azangwe, Alexis Dimitriadis, Pavel Kazantsev, Egor Titovich, Krzysztof Chelminski, Mauro Carrara, Jamema Swamidas

International Atomic Energy Agency, Dosimetry and Medical Radiation Physics, Vienna, Austria

Purpose/Objective:

To report the dosimetry audit results of electron beam output in reference conditions, a new service, within IAEA/WHO dosimetry audit programme, and compare to similar audit results from Co-60 and high energy photon beams.

Material/Methods:

The IAEA/WHO postal dose audit service 1 for Co-60 beams in operation, since 1969 while audits for high energy photon beams were introduced in 1991. The service for high energy electron beams 2 was introduced in 2021 and is currently limited to institutions with newly commissioned electron beams. During the audit, participants were requested to irradiate the radiophotoluminescent dosimeters (RPLDs) at at z ref (or at z max as an option) as defined by TRS 398 3 , using 10×10 cm 2 field size and the clinical source-to-surface (SSD) distance. The audit results in terms of ratio of the dose stated by the hospital (D_STATED) against the dose determined from the RPLD (D_RPLD) were analysed for Co-60, high energy photon and electron beams. The mean and the standard deviation of results were computed for each beam type and each region for the period 2021-2023. The results of the analysis for the new electron service were further examined to assess the potential impact of having a formal process of recognition of Clinically Qualified Medical Physicist(s) (CQMPs) in the audited institution.

Results:

During the review period, a total of 614 institutions from 92 IAEA Member States participated in the audits. Of these, 86 institutions participated with Co-60 beams, 73 with high energy electron beams and 503 with high energy photon beams. Institutions participated in audits for all beam types with some participating with one or multiple beams. For