ESTRO 2025 - Abstract Book

S3316

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

ESTRO 2025

Material/Methods: For 11 prostate cancer patients, undergoing 5x7.25Gy MRIgRT at the UMC Utrecht, 3D cine MRI data was acquired during radiation delivery via a balanced turbo-field echo (bTFE) acquisition sequence with a 9.36 s temporal resolution, resulting in 43-72 images-per-fraction. Time-synchronized dose maps allowed associating a partial dose distribution to each acquired image. Additionally, the planned dose and clinically approved contours were available. The 3D cine MR images were registered to the first dynamic in their respective series, with the resulting deformations being used for dose accumulation. To investigate the differences between the algorithms, several clinically relevant DVH parameters -V95% for the CTV and D1CC for the rectum and bladder- were calculated and paired sign statistical testing was performed.

Results: