ESTRO 2024 - Abstract Book

S4161

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

ESTRO 2024

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Digital Poster

MR-based real-time bowel tracking for radiotherapy

Saskia L.C. Damen, Astrid Van Lier, Cornel Zachiu, Bas W. Raaymakers

UMC Utrecht, Radiotherapy, Utrecht, Netherlands

Purpose/Objective:

Image-guided radiotherapy (IGRT) in the pelvis currently aims towards hypo-fractionated treatment regimens, increasing delivered dose levels per fraction compared to conventional treatments. In pelvic radiotherapy, the small bowel is one of the most radiosensitive organs at risk (OAR), for which long-term radiation effects occur in 90% of the patients [1]. This makes monitoring of the absorbed radiation dose imperative. The introduction of the MR-Linac makes it possible to track OARs in real-time. However, imaging and tracking individual bowel loops remains a challenge due to peristaltic and respiratory motion combined with the bulk motion of chime (leading to intensity changes over time). Thus, the goal of this research is to synergistically optimize MRI image acquisition and motion estimation of the small bowel, to allow tracking of individual bowel loops during treatment, opening the door to more accurate dose tracking and safe multi-isocenter radiotherapy.

Material/Methods:

Image acquisition