ESTRO 2025 - Abstract Book

S3041

Physics - Image acquisition and processing

ESTRO 2025

consistently outperformed others for all datasets. Notably, registrations that better preserved rigidity did not have degraded image similarity (not shown). The BRE further varied strongly between bones (Figure 1), with long, thin bones violating the rigidity preservation more severly than short, rounded ones. Based on our data, we propose bone-specific inspection thresholds to use in case of patient-specific validations (Figure 1). The BRE calculation required on average 2.6 seconds, excluding automatic segmentation.

Conclusion: The BRE is an automatic, interpretable, fast, and easy-to-implement metric for DIR performance, that varies widely across algorithms. It provides a useful complementary metric for patient-specific validation, especially in time sensitive applications.

Keywords: Deformable image registration, quality assurance

3367

Digital Poster Photon-Counting CT: preliminary analysis on its potential benefits for radiotherapy applications Valerio Pisoni 1,2 , Manuela Henein 2 , Raffaele Villa 2,3 , Sara Trivellato 3 , Nicoletta Paruccini 3 , Kanatbek Karauzokov 4 , Gianluca Montanari 3 , Elena De Ponti 2,3 , Alessandro Loria 5 , Antonella Del Vecchio 5 , Moreno Zanardo 6 , Elvis Tresova 6 , Pietro Spagnolo 6 , Stefano Arcangeli 1,2 1 Department of Radiation Oncology, Foundation IRCCS San Gerardo dei Tintori, Monza, Italy. 2 School of Medicine and Surgery, University of Milano Bicocca, Milano, Italy. 3 Medical Physics Department, Foundation IRCCS San Gerardo dei Tintori, Monza, Italy. 4 Master of Advanced Studies in Medical Physics, ICTP International Centre for