ESTRO 2025 - Abstract Book

S3697

Physics - Quality assurance and auditing

ESTRO 2025

Conclusion: myQA iON demonstrates good potential as a PSQA tool for proton therapy, providing accurate and efficient dose verification across various treatment plans. Further studies are needed to address its limitations in handling complex anatomical regions and to ensure its safe integration into clinical practice.

Keywords: PSQA, independent dose calculation, proton therapy

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Digital Poster QA-2030: a revised view on QA procedures on medical systems and patient treatment process in The Netherlands Leo van Battum 1 , Marion Essers 2 , Bas Gobets 3 , Stan Heukelom 1 , Jeroen van de Kamer 4 , Phil Koken 1 , Thijs Perik 4 , Hendrik Piersma 5 , Richard Tiggelaar 1 , Jochem Wolthaus 6 1 1) Dept. of Radiation Oncology, AmsterdamUMC, Amsterdam, Netherlands. 2 Radiotherapy, 2) Dr. Verbeeten Institution, Tilburg, Netherlands. 3 3) Dept. of Radiation Oncology, LeidsUMC, Leiden, Netherlands. 4 4) Dept. of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands. 5 Radiotherapy, 5) Radiotherapeutic Institution Friesland, Leeuwarden, Netherlands. 6 6) Dept. of Radiation Oncology, UMCUtrecht, Utrecht, Netherlands Purpose/Objective: Radiotherapy systems and techniques are rapidly evolving and becoming more and more complex, requiring additional quality assurance (QA) policies. Current radiotherapy machine and patient-specific quality assurance measurements (mQA and PSQA) generally are based on concepts disregarding statistical analysis of quality control (QC) data, improved technology and internally system safety checks. I.e. nowadays a rationale often is missing about the mQA and PSQA while efficiency and effectivity in QA work is questionable. A revision of the Dutch QA philosophy is needed, driven too by online adaptive treatment. This also includes a redefinition of the roles and responsibilities of the staff involved in the QA. Material/Methods: Three nationwide meetings were organised to discuss the current mQA and PSQA. Involved were all stakeholders: medical physics experts, medical physics assistants, linac engineers and various vendors of linac and QA equipment. A national survey was conducted in advance to determine the actual state. The meetings included presentations on QA techniques, the rationale behind specific QA practices and how to control crucial risk factors. Two methods are under consideration in risk factor analysis. First, the prospective failure mode effect analysis (FMEA) concerning technology and processes analysing the consequences of each action not performed as required (e.g. AAPM TG100 [1]). Second, the treatment as “a chain of process steps” (NCS 25 approach [2]), in which each step has to satisfy quality output indicators or, if not, blocks that chain. Combining those two, allows harmonizing the treatment process chain across institutions. Results: The survey showed that no serious issues were identified during routine verification using secondary dose calculations or PSQA. Therefore, all institutes are interested in reducing the number of these measurements, meanwhile realizing these type of PSQA probably should only be performed during linac- and planning system acceptance and for newly introduced techniques. Strategies to optimize the QA level to “as low as reachable achievable” are in progress. A national QA2030 proposition document was created about organisation and work-to do [3]. An upcoming report on Linac QA (NCS33 [4]) will also be based on risk analysis. Conclusion: Initial national steps have been taken to review QA for radiotherapy in The Netherlands. Involving all staff with specialized knowledge and vendor expertise is crucial to streamline revised QA procedures. The risk analysis