ESTRO 2025 - Abstract Book

S350

Brachytherapy - Physics

ESTRO 2025

verifying total treatment times, number of catheters, or source activity, nor does it calculate at a single point. This software performs a calculation over the entire 3D volume and compares it with what has been calculated in the TPS.

Material/Methods: The software has been developed using open-source programming language Python along with some of its also open-source libraries. The software includes tables for anisotropy factors and distance factors for the calculations. To achieve acceptable and practical calculation times, various kernels addressing different geometric situations were generated in advance. For the calculation, only the RTDose, RTStruct, and RTPlan files need to be provided. Images are not required since the calculation in HDR is always performed in water; the images serve as a guide for painting and visualization. Results: The results obtained show a high concordance with the doses exported from the planner in all cases and geometries. Once the user has the result, they can display different visualizations in addition to isodoses, such as dose differences, for example. Numerically, by default, the values of D2, D50, and D95 are calculated, but the user can add other calculations for both dose and volume and include them in the final report. Finally, a report is generated with the name of the user who created it.

Conclusion: A tool is provided for dosimetric verification of all HDR patients, offering the option to verify treatments directly in the treatment room, for example, during real-time planning of prostate treatments.

Keywords: Verification, Dosimetry