ESTRO 2025 - Abstract Book

S3320

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

ESTRO 2025

patient were generated with the same optimization approach. A total of eleven plans per patient were evaluated in terms of dose to the heart, lungs and esophagus and the resulting NTCPs.

Results: On average, the greatest dose reduction to the mean dose of the lungs, heart, and esophagus was observed in the 0%, 40%, and 70% phases, respectively. Mean lung dose decreased by 0.7 Gy, with a maximum of 1.7 G; mean heart dose decreased by 0.4 Gy, with a maximum of 1.4 Gy; and mean esophagus dose decreased by 0.9 Gy, with a maximum of 6.0 Gy. Figure 1 shows the relative dose differences for each phase in comparison to the (surrogate) clinical plan, highlighting OAR dose reductions through phase-targeted planning. Figure 2 shows the resulting NTCP model predictions, with ΔNTCP values demonstrating reduced complication probabilities using phase-targeted approaches. The optimal breathing phases to reduce radiation pneumonitis, two-year treatment related mortality, and dysphagia are 0%, 40%, and 70%, respectively.