ESTRO 2025 - Abstract Book

S263

Brachytherapy - Gynaecology

ESTRO 2025

factor between irradiations, the type of dose volume histogram (DVH) parameters, conversion to equivalent doses in 2 Gy (EQD2) or not, and the availability of (3D) imaging data or only values (DVH or dose), reported in the patient chart. Second, we have conducted a systematic review on the reported accuracy of different dose addition scenarios for all relevant pelvic organs at risk. Results: The decision tree is depicted in Figure 1. Following the digital lookup table based on the decision tree for a specific case, gives an overview of both the reported results as the full papers of the available literature as a reference. The systematic literature of 343 papers identified 47 articles reporting on dose addition accuracy for the dose volume parameters and organs listed in Table 1. We included data for all pelvic malignancies and did not limit to gynecological studies only. Data included repeat CT, repeat CBCT and re-irradiation. Compared to algebraic addition, doses calculated using deformable registration were generally lower, varying between a few percent to 12% or up to several Gy. Figure 1.