S2386
Physics - Quality assurance and auditing
ESTRO 2026
Purpose/Objective: Reliable treatment planning is essential to ensure consistent and safe delivery of regional hyperthermia. This study presents an experimental validation of the HyperPlan® treatment planning system for the core BSD phased-array applicators used in deep regional hyperthermia: Sigma-30, Sigma-60, and Sigma-Eye. Material/Methods: To assess the predictive accuracy of HyperPlan®, specific absorption rate (SAR) distributions in realistic clinical configurations were validated by comparing simulated results with experimental measurements obtained from published studies or new phantom experiments, depending on data availability. For the Sigma-60, SAR profiles published by Sullivan [1] served as reference data, while for the Sigma-30, measurements reported by Nadobny et al. [2] were used. For the Sigma-Eye, a dedicated experimental campaign was performed at Charité – Universitätsmedizin Berlin to fill the lack of published SAR datasets for this applicator. Solver accuracy was additionally benchmarked against Sim4Life using controlled electromagnetic test scenarios. The HyperPlan® graphical interface enables detailed applicator and phantom setup within a clinically oriented workflow (Fig. 1).
Figure 2. Impact of errors on PTV D99% Conclusion:
This work identified important failure modes for single-isocentre multi-target SRS treatments. Overall, MLC positional changes have the greatest impact. This work highlighted that not all plans respond in the same way to the same error, reinforcing the importance of accurate patient specific quality assurance (PSQA). An outstanding challenge is to choose tolerances appropriate to the individual PSQA device and analysis tools. References: [1] Glenn, M.C., Peterson, C.B., Followill, D.S., Howell, R.M., Pollard-Larkin, J.M., Kry, S.F., 2020. Reference dataset of users’ photon beam modeling parameters for the Eclipse, Pinnacle, and RayStation treatment planning systems. Med. Phys. 47, 282–288. https://doi.org/10.1002/mp.13892 Keywords: Delivery errors, SRS, PSQA Digital Poster Highlight 3784 Experimental Validation of HyperPlan® for BSD Phased-Array Hyperthermia Systems Anna Chiara Giovannelli 1 , Jacek Nadobny 1 , Franziska Hartmann 2 , Günter Futschik 2 , Dominik Gerster 1 , Nikolai Beck 2 , Steffen Eisenhardt 2 , Daniel Zips 1 , Pirus Ghadjar 1 1 Department of Radiation Oncology and Radiotherapy, Charité – Universitätsmedizin Berlin, Berlin, Germany. 2 /, Dr. Sennewald Medizintechnik GmbH, Munich, Germany
Results: HyperPlan® accurately reproduced the expected SAR focal locations and spatial distributions for all applicators. Both central and off-center steering conditions were correctly modelled, with simulated focal positions and intensity profiles in excellent agreement with experimental measurements. Median relative errors (Fig.2) were 2.1 % for Sigma-60, 0.9 % for Sigma-30, and 4.6 % for Sigma-Eye, all well below the 20 % quality-assurance threshold [3]. Solver accuracy tests showed deviations within 8 %, and correlation coefficients exceeded 0.95 across all configurations, confirming strong agreement between measured and simulated SAR distributions. The independent Sigma-Eye measurements provided the first quantitative SAR validation for this applicator, closing the experimental evidence gap within the BSD applicator family.
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