ESTRO 2025 - Abstract Book

S3547

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

ESTRO 2025

Results: All 3DRM plans showed a drastic reduction in delivery time per beam compared to IMPT: from 89.0±27.3s to 1.15±0.19s for LA-LungCa, from 38.3s±21.9 to 0.62s±0.41 and for SBRT-LungCa and from 22.77s to 0.86s for the phantom. Figure 1c shows the different 3DRM plans both collimated and uncollimated with similar minor differences.

Figure 2a,2b show the limited differences in plan quality between the conventional IMPT plans and the 3DRM plans in terms of conformity to the target volume and dose gradient towards surroundings. Collimated and uncollimated plans only show minor differences when comparing CI (Fig. 2a). Simulation of interplay effects for IMPT during free breathing shows dose degradation for phantom plan (ΔD99%=-5%). With a beam-on time of <1 sec 3DRM enables a free-breathing end-of-exhale gated delivery to encounter breathing motion.