ESTRO 2025 - Abstract Book

S3255

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

ESTRO 2025

Conclusion: The target dose coverage may be maintained by beam gating and baseline shift re-planning at the expense of a reduced treatment delivery efficiency during radioablation of pancreatic tumours using only a 2 mm PTV margin on a 1.5 T MRI-Linac. A decent compromise is obtained using 4 mm for both gating and drift window size.

Keywords: Beam gating, pancreatic cancer, MR-linac

References: [1] Grimbergen G, et al. Gating and intrafraction drift correction on a 1.5 T MR-Linac: clinical dosimetric benefits for upper abdominal tumors. Radiother Oncol. 2023:109932. [2] Bernchou U, et al. Impact of abdominal compression on intra-fractional motion and delivered dose in magnetic resonance image-guided adaptive radiation ablation of adrenal gland metastases. Phys Med. 2023;114:102682. [3] Grimbergen G, et al. Treatment planning for MR-guided SBRT of pancreatic tumors on a 1.5 T MR-Linac: A global consensus protocol. Clinical and Translational Radiation Oncology. 2024.