ESTRO 2024 - Abstract Book

S4587

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

ESTR0 2024

Smaller couch angles for non-coplanar arcs did not significantly impact SABR Spine plan quality when compared to coplanar techniques. However, further research using a patient-specific algorithm for VMAT planning could lead to improved results.

Keywords: Non-coplanar, SABR Spine

References:

Paddick, I., 2000. A simple scoring ratio to index the conformity of radiosurgical treatment plans. Neurosurg, 93(3), pp. 219-222.

Simms, J., Rowbottom, C. & Dawson, R., 2022. A quasi-optimal non-coplanar 4pi-VMAT solution for treating head & neck cancers. Radiotherapy & Oncology ESTRO, 170(1), p. 484.

Smyth, G., Evans, P. M., Bamber, J. C. & Bedford, J. L., 2016. Recent developments in non-coplanar radiotherapy. British Institute of Radiology, Volume 92.

Yu, V. et al., 2016. Significant Cord and Esophagus Dose Reduction by 4p Non-Coplanar Spine Stereotactic Body Radiation Therapy and Stereotactic Radiosurgery. International Journal of Radiation Oncology Biology Physics, Volume 96.

295

Mini-Oral

Probabilistic consistency of voxel-wise robustness evaluation in IMPT for neuro-oncological patients

Jenneke I. de Jong 1,2 , Jesús Rojo-Santiago 1,2 , Steven J.M. Habraken 3,2 , Danny Lathouwers 4 , Zoltán Perkó 4 , Sebastiaan Breedveld 1 , Mischa S. Hoogeman 1,2 1 Erasmus MC Cancer Institute, Radiotherapy, Rotterdam, Netherlands. 2 HollandPTC, Medical Physics & Informatics, Delft, Netherlands. 3 Leiden University Medical Center, Radiation Oncology, Leiden, Netherlands. 4 Delft University of Technology, Radiation Science and Technology, Delft, Netherlands

Purpose/Objective:

At our center, dose is evaluated using the voxel-wise minimum (VWmin) dose distribution of 28 scenarios, in line with the Dutch robustness evaluation protocol. Although calibrated against PTV-based photon plans, the approach does not allow for insight into probabilistic outcomes, potentially leading to interpatient variation in delivered dose and suboptimal tradeoffs in treatment planning.

To investigate this interpatient variation, for 20 neuro-oncological patients, we analyze the probability distributions of the dose delivered to the CTV. Hereafter, we explore the potential of scaling treatment plans based on these