ESTRO 2025 - Abstract Book

S3528

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

ESTRO 2025

measured doses with relative deviations of less than 2.5%. The tracking device (see fig. 1) and a dedicated MR-micro coil for high resolution images were integrated in the planning workflow (see fig. 2). Clip detection and gaze angle optimization are integral parts of plan optimization within RayOcular (RSL, Stockholm). Using a dedicated alignment QA procedure, a positioning reproducibility of the treatment couch and brass collimator center below 0.2mm could be achieved mimicking stereotactic setups.

Figure 1

Figure 2

Conclusion: A new versatile system for treatment of ocular tumors in a non-dedicated room was successfully developed resulting in similar beam-, geometric and dosimetric quality compared to dedicated eye treatment rooms. Further improvements aim at reducing the required beam-on times to < 1 minute. The system has been fully certified and first clinical experiences are currently made.

Keywords: uveal melanoma, non-dedicated beam, proton therapy

References: Figure 1: The tracking device attached to the treatment couch and mask system together with the holder for the brass collimator attached to our vertical beam line. Figure 2: CT and MR image including overlayed eye-model adapted to the patient anatomy used for treatment planning.