ESTRO 2025 - Abstract Book

S2581

Physics - Detectors, dose measurement and phantoms

ESTRO 2025

respectively. Of 85 plans having mD measurements, this resulted in 79 plans (92.9%) and 81 plans (95.3%) adhered to the TG-218 tolerance and action limits for mD measurements.

Conclusion: Implementing TG-218 guidelines in PSQA framework for Vertebra SABR has improved the process control and safety of dose delivery. The vast majority of treatment plans met TG-218 specified limits, confirming the robustness and effectiveness of our current PSQA processes.

Keywords: Spine SABR, phantom design, TG-218 implementation

References: [1] Berk K, Kron T, Hardcastle N, Yeo AU. Efficacious patient-specific QA for Vertebra SBRT using a high-resolution detector array SRS MapCHECK: AAPM TG-218 analysis. J Appl Clin Med Phys . 2024; 25:e14276 [2] Miften, M., Olch, A., Mihailidis, D., Moran, J., Pawlicki, T., Molineu, A., Li, H., Wijesooriya, K., Shi, J., Xia, P., Papanikolaou, N. and Low, D.A. (2018), Tolerance limits and methodologies for IMRT measurement-based verification QA: Recommendations of AAPM Task Group No. 218 . Med. Phys., 45: e53-e83 [3] Sanghangthum T, Suriyapee S, Kim G-Y, Pawlicki T. A method of setting limits for the purpose of quality assurance. Phys Med Biol. 2013; 58: 7025–7037

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Digital Poster Identifying the Origins of Possible Nonlinear Scintillator Response Under Ultra-High Dose Rate Electron Beams Daline Tho, Sam Beddar Radiation Physics, MD Anderson, Houston, USA Purpose/Objective: The Exradin-W2 (Standard Imaging, Middleton, WI, USA), previously studied under electron UHDR beams, has shown signs of saturation at high pulse repetition rates (PRF) and dose per pulse (DPP). This study investigates the