ESTRO 2024 - Abstract Book

S4680

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

ESTR0 2024

Increasing the power level for compiling the radiation spectra into a RQM seems to significantly increase the model performance compared to a linear weighing method employed by conventional metrics like LET d or LET t . This suggests that particles with very high LET values, which receive a much higher weight with increasing the power level, are predominantly responsible for the increased RBE observed for protons. This study suggests that moving away from linear weighting in RQM construction in favor of non-linear approaches enhances the accuracy of RBE models. The increased RBE observed for protons can be primarily attributed to particles with high LET values, emphasizing the significance of considering non-linear effects in proton therapy. There are also ongoing patient evaluations, with the aim to find if the novel metrics also performs better for clinically observed RBE effects.

Keywords: LET, RBE

References:

1: Ilicic K, Combs SE, Schmid TE. New insights in the relative radiobiological effectiveness of proton irradiation. Radiation oncology. 2018 Dec;13(1):1-8.

2: Kalholm F, Grzanka L, Toma ‐ Dasu I, Bassler N. Modeling RBE with other quantities than LET significantly improves prediction of in vitro cell survival for proton therapy. Medical Physics. 2023 Jan;50(1):651-9.

3: Guan F, Geng C, Ma D, Bronk L, Kerr M, Li Y, Gates D, Kroger B, Sahoo N, Titt U, Grosshans D. RBE model-based biological dose optimization for proton radiobiology studies. International journal of particle therapy. 2018 Jun 1;5(1):160-71. 4: Patel D, Bronk L, Guan F, Peeler CR, Brons S, Dokic I, Abdollahi A, Rittmüller C, Jäkel O, Grosshans D, Mohan R. Optimization of Monte Carlo particle transport parameters and validation of a novel high throughput experimental setup to measure the biological effects of particle beams. Medical physics. 2017 Nov;44(11):6061-73. 5: Bronk L, Guan F, Patel D, Ma D, Kroger B, Wang X, Tran K, Yiu J, Stephan C, Debus J, Abdollahi A. Mapping the relative biological effectiveness of proton, helium and carbon ions with high-throughput techniques. Cancers. 2020 Dec 5;12(12):3658.

6: Abolfath R, Peeler CR, Newpower M, Bronk L, Grosshans D, Mohan R. A model for relative biological effectiveness of therapeutic proton beams based on a global fit of cell survival data. Scientific reports. 2017 Aug 21;7(1):8340.

2311

Digital Poster

Treatment plan robustness in IMPT for esophageal cancer: every millimeter counts.

Eva van Weerd 1 , Anne Lisa Wolf 1 , Steven J.M. Habraken 2,1 , Yvonne L.B. Klaver 1,2 , Mischa S. Hoogeman 1,3