ESTRO 2025 - Abstract Book

S3199

Physics - Intra-fraction motion management and real-time adaptive radiotherapy

ESTRO 2025

Conclusion: The tracking accuracy of XLT is strongly dependent on the CNR between the tumour and lung tissue densities, with a recommended threshold CNR of at least 17. This index may aid in patient selection prior to treatment planning, enhancing predictions of successful XLT tracking outcomes.

Keywords: Synchrony, fiducial-free, contrast-noise-ratio

References: B. Yang et al. (2021) Comparison of modeling accuracy between Radixact® and CyberKnife® Synchrony® respiratory tracking system. Biomed. Phys. Eng. Express 7 (2021) 067001 Nakayama et al. (2017). Clinical log data analysis for assessing the accuracy of the CyberKnife fiducial-free lung tumor tracking system. Pract. Radiat. Oncol. , 8 (2), e63–e70 Yang et al. (2017) Target margin design for real-time lung tumor tracking stereotactic body radiation therapy using CyberKnife Xsight Lung Tracking System. Sci Rep . 2017 Sep 7;7(1):10826. Jung et al. (2015). Verification of accuracy of CyberKnife tumor-tracking radiation therapy using patient-specific lung phantoms . Int. J. of Radiat. Oncol. Biol. Phys , 92 (4), 745–753.

444

Digital Poster OPEN Trial: Intrafraction motion analysis of 3-point and 5-point OPEN facemasks vs. closed facemasks using both SGRT and CBCT Ciaran Malone 1 , Samantha Ryan 1 , Jill Nicholson 1,2 , Rosin O'Maolalai 1 , Rebecca O'Donovan 1 , Orla McArdle 1 , Frances Duane 1,2 , John Armstrong 1 , Lorna Keenan 1 , Aisling Glynn 1 , Ruth Woods 1 , Brendan McClean 1,3 , Sinead Brennan 1,2 1 Department of Radiation Oncology, St.Luke's Radiation Oncology Network, Dublin, Ireland. 2 Applied Radiation Therapy Trinity, Discipline of Radiation Therapy, Trinity St.James’s Cancer Institute, Trinity College Dublin, Dublin, Ireland. 3 Department of Physics, UCD, Dublin, Ireland Purpose/Objective: This analysis, part of the OPEN Phase III trial, aimed to evaluate intrafraction motion in head and neck (H&N) cancer patients using different facemask designs during radiotherapy. The study specifically compared intrafraction motion