ESTRO 2025 - Abstract Book

S3338

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

ESTRO 2025

Figure 2 . Target homogeneity index (D2 - D98) and D98. Log plan results are based on log file data, while TPS plan results reflect the planned dose.

Conclusion: This study introduces a 4D photon dose reconstruction framework to assess dose accuracy in lung cancer patients with significant respiratory motion. The results demonstrate notable discrepancies between delivered and planned doses, particularly in patients with larger motion, with deviations exceeding 5%. These findings highlight need for enhanced motion compensation strategies to improve treatment accuracy and /or treatment adaptation.

Keywords: Log file, RayStation, 4D dose reconstruction

References: 1. Meijers A, Knopf AC, Crijns APG, et al. Evaluation of interplay and organ motion effects by means of 4D dose reconstruction and accumulation.. Radiother Oncol. 150:268–74 (2020). 2. Meijers A, Jakobi A, Stützer K, et al. Log file-based dose reconstruction and accumulation for 4D adaptive pencil beam scanned proton therapy in a clinical treatment planning system: Implementation and proof-of-concept Med Phys. 46:1140–9 (2019).