ESTRO 2025 - Abstract Book

S3501

Physics - Optimisation, algorithms and applications for ion beam treatment planning

ESTRO 2025

Conclusion: Discrete PAT plans demonstrate the capability to increase plan quality with respect to state of the art MFO robust optimization. The dose reduction outside the target is significant with no reduction of the quality of nominal dose distribution. Robustness analysis showed no significant differences even if the dose gradients are steeper with PAT. LET d comparisons showed that, with this new delivery technique, the radiobiological risk in the cerebral tissue will not be enhanced if a LET d -dependent RBE model is used. The clinical workload of monitoring anatomical changes in PAT is comparable to MFO plans. With a proper choice of arc parameters, the delivery times can be kept similar or lowered with respect to the current clinical delivery times. This comparison was the basis for the first discrete proton arc clinical treatments at our centre in October 2024.

Keywords: Proton ARC, optimization, arc delivery

2451

Proffered Paper Probabilistic IMPT planning with realistic setup and range uncertainties improves OAR sparing or target coverage in neuro-oncological patients Jenneke I. de Jong 1,2 , Steven J.M. Habraken 3,2 , Jesús Rojo-Santiago 1,2 , Danny Lathouwers 4 , Zoltán Perkó 4 , Sebastiaan Breedveld 1 , Mischa S. Hoogeman 1,2