ESTRO 2024 - Abstract Book

S4598

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

ESTR0 2024

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511

Mini-Oral

Enhanced IMPT dose fall-off by optimised integration of Bragg peaks and transmission pencil beams

Wens Kong 1 , Merle Huiskes 2 , Steven J.M. Habraken 2,3 , Eleftheria Astreinidou 2 , Coen R.N. Rasch 2,4 , Ben J.M. Heijmen 1 , Sebastiaan Breedveld 1 1 Erasmus MC Cancer Institute, Erasmus University Medical Center, Department of Radiotherapy, Rotterdam, Netherlands. 2 Leiden University Medical Centre, b. Department of Radiation Oncology, Leiden, Netherlands. 3 c. HollandPTC, Department of medical physics and informatics, Delft, Netherlands. 4 c. HollandPTC, Department of Radiation Oncology, Delft, Netherlands

Purpose/Objective:

In intensity-modulated proton therapy (IMPT), the Bragg peaks (BPs) from each beam are positioned in and around the target volume, resulting in a steep dose fall-off at the distal target end. Typically, the lateral dose fall-off is less steep due to deep tumour positions or usage of rangeshifters. High-energy pristine transmission pencil beams (TPBs) with the BPs behind the patient exhibit a sharp lateral penumbra at the target level. In this study we hypothesised that by combining IMPT BPs with TBPs (denoted ‘IMPT&TPB’), dose distributions in head-and-neck cancer patients could be improved in terms of OAR dose compared to conventional IMPT with BPs only.

Material/Methods:

Our SISS-MCO system for fully-automated IMPT treatment planning [1], embedded in Erasmus- iCycle, was extended for the combined optimisation of IMPT BPs and TPBs. It employs automated multi-criteria optimisation (MCO) to