ESTRO 2024 - Abstract Book

S3479

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2024

Keywords: robustness, mixed-beam RT, dynamic trajectory RT

References:

[1] Mueller S, Manser P, Volken W, Frei D, Kueng R, Herrmann E, et al. Part 2: Dynamic mixed beam radiotherapy (DYMBER): Photon dynamic trajectories combined with modulated electron beams. Med Phys 2018;45:4213–26. https://doi.org/10.1002/mp.13085. [2] Mueller S, Guyer G, Risse T, Tessarini S, Aebersold DM, Stampanoni MFM, et al. A hybrid column generation and simulated annealing algorithm for direct aperture optimization. Phys Med Biol 2022;67:075003. https://doi.org/10.1088/1361-6560/ac58db.

[3] Fix MK, Frei D, Volken W, Terribilini D, Mueller S, Elicin O, et al. Part 1: Optimization and evaluation of dynamic trajectory radiotherapy. Med Phys 2018;45:4201–12. https://doi.org/10.1002/mp.13086.

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Digital Poster

Assessing the fraction of dose originating from the penumbra region for plans of varied complexity

Emmanouil Terzidis 1,2 , Fredrik Nordström 2,1 , Magnus Gustavsson 2 , Anna Karsson 3 , Julia Götstedt 3,1 , Anna Bäck 1,2

1 Institute of Clinical Sciences, Department of Medical Radiation Sciences, Gothenburg, Sweden. 2 Medical Physics and Biomedical Engineering, Therapeutic Radiation Physics, Gothenburg, Sweden. 3 Medical Physics and Biomedical Engineering, Medical Physics and Biomedical Engineering, Gothenburg, Sweden

Purpose/Objective:

The absorbed dose delivered to the patient that originates from a penumbra region have larger uncertainties compared to the dose delivered from the center of the treatment field. 1,2 The magnitude of these uncertainties could be important input when evaluating absorbed dose to organs at risk (OARs) and target volumes. The aim of this work was to examine the fraction of penumbra dose in three-dimensions (3D) for volumetric modulated arc therapy (VMAT) plans of different complexities.

Material/Methods:

A C# software was developed in our department, able to calculate the fraction of penumbra dose in relation to the total dose in each voxel and visualize it as a 3D distribution (penumbra map). Twelve treatment plans of previously treated patients have been selected to represent different types of treatment geometry and different treatment sites (prostate, head & neck, lung and gynecological cancer). The clinical plan used for the actual treatment of the patient was reoptimized in Eclipse TPS (Varian Medical Systems, Palo Alto, CA), to create one plan