ESTRO 2024 - Abstract Book


Physics - Dose calculation algorithms

ESTRO 2024

reconstructed MC dose distributions was found to be notably strong. For three specific fields, an average agreement was 99.4%±0.7%, 99.1%±0.5%, and 98.4%±0.8%, respectively. These results further support the accuracy and reliability of the beam model and the projection of monitored machine parameters to the isocenter plane and its ability to accurately predict dose distributions.

Fig. 1. 3D gamma history over the nine treatment fractions for head and neck case. Gamma distributions are calculated separately for each field based on the ProBeam treatment delivery log files.


Our results showed that independent MC dose calculations offered by myQA iON are a promising approach to improve PSQA process in proton therapy. The high level of agreement observed in the gamma passing rates indicates that the beam model is well configured and can potentially be used in the clinical workflow. Moreover, the results demonstrate that the utilization of Monte Carlo dose calculations not only streamlines the PSQA process but also eliminates the need for additional in-beam measurements, resulting in a more efficient and time-saving approach. The integration of the MC dose engine into the myQA iON platform not only simplifies the implementation process but also enhances the level of independence in plan verification. Log-based dose reconstruction combined with analysis of the actual delivered spot, enables further reinforcement of monitoring the delivered dose. The clinical implementation of the myQA iON software offers an efficient and automated approach to performing PSQA, further enhancing the overall quality assurance process in proton therapy. This is the first demonstration of log-file based PSQA implementation for ProBeam proton therapy systems vers. 4.1. The implementation will provide means for an efficient PSQA solution in the context of adaptive proton therapy workflows.

Keywords: Monte Carlo, PSQA, Treatment Log Files


A. Meijers, G. Guterres Marmitt, K. Ng Wei Siang, A. van der Schaaf, A. Knopf, J.A. Langendijk, S. Both. Feasibility of patient specific quality assurance for proton therapy based on independent dose calculation and predicted outcomes . Radiotherapy and Oncology 2020;150:136-141. G. Guterres Marmitt, A. Pin, K. Ng Wei Siang, G. Janssens, K. Souris, M. Cohilis, J.A. Langendijk, S. Both, A. Knopf, A. Meijers. Platform for automatic patient quality assurance via Monte Carlo simulations in proton therapy. Physica Medica 2020;70:49-57.

M. Cohilis, L. Hong, G. Janssens, S. Rossomme, E. Sterpin, J.A. Lee, K. Souris. Development and validation of an automatic commissioning tool for the Monte Carlo dose engine in myQA iON . Physica Medica 2022;95:1-8.

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