ESTRO 2024 - Abstract Book

S4622

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

ESTR0 2024

Conclusion:

Within the homogenous craniopharyngioma patient group, there were, on average, no significant differences seen in terms of D1% and D0.01cc to the selected OARs. This is most likely due to two main causes: the simple symmetric beam configuration that was adopted because of the reciprocal target-OARs localization, and the mitigation techniques used in the conventional plan to prevent high LET deposition near the OARs, found as an adequate alternative when no LETd-based optimisation is available for craniopharyngioma proton treatments. However, because of their LET-dependence, the dosimetric discrepancies here analyzed rise when alternative variable RBE models are utilized for plan evaluation, suggesting caution in plan evaluation when fixed RBE calculation is adopted.

Keywords: LET-optimization, paediatrics, Variable RBE Models

References:

1 Paganetti H. Range uncertainties in proton therapy and the role of Monte Carlo simulations. Phys Med Biol. 2012 Jun 7;57(11):R99-117. doi: 10.1088/0031-9155/57/11/R99.

2 McNamara AL, Schuemann J, Paganetti H. A phenomenological relative biological effectiveness (RBE) model for proton therapy based on all published in vitro cell survival data. Phys Med Biol. 2015 Nov 7;60(21):8399-416. doi: 10.1088/0031-9155/60/21/8399.

3 McMahon SJ, Paganetti H, Prise KM. LET-weighted doses effectively reduce biological variability in proton radiotherapy planning. Phys Med Biol. (2018); Nov 9;63(22)

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