ESTRO 2025 - Abstract Book

S2899

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2025

Results:

The VENUS Shell™ allowed skin dose optimization in all configurations, even with magnetic fields. For “SkinBody5mm,” volumes receiving >20Gy remained below 220cm³, with negligible 40Gy exposure, ensuring safety for moderate-severe late toxicities [2]. Mean dose differences (TLD vs. planned) were 3.1 ± 2.3%. Median (range) dose increases due to the shell were 19% (6–24%) in-field and 0.4% (-1.1–1.9%) out-of-field. These results were confirmed with the measurements in the slab geometry. In the worst-case scenario, with a beam orthogonal to the phantom surface, the presence of the shells increase the dose on the central axis at 3mm and 5mm depth in the phantom by 18% and 10% at 6MV respectively (Fig.2). Conclusion: The VENUS Shell™ is accurately accounted for by various planning systems, algorithms, and clinical treatment machines. While minor increases in skin dose were observed, these remain within safe limits that are unlikely to lead to increased toxicity, confirming the device's suitability for improving patient positioning in prone radiotherapy.

Keywords: Breast cancer, In-phantom dosimetry, skin dose

References: 1. Dipasquale G. et al., Validating pErsoNalized 3D-printed Unique breaSt SHELLs for radiotherapy (VENUS SHELL) Radiother Oncol, 2023; 182, S1034, 2023 2. Cicchetti A. et al., Skin dose-volume predictors of moderate-severe late effect after whole breast radiotherapy. Radiother Oncol 2024 194: 110183