ESTRO 2025 - Abstract Book

S3267

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

ESTRO 2025

Conclusion: Our study shows that distance from the anal verge significantly influences the magnitude of intrafraction motion in AP and CC direction in SCRT rectal cancer patients. For mid-upper rectal tumors (> 5 cm from anal verge), the margin could be decreased in AP and CC direction.

Keywords: Rectal cancer, online adaptive RT, PTV margins