ESTRO 2025 - Abstract Book

S351

Brachytherapy - Physics

ESTRO 2025

3589

Digital Poster Experimental verification of new Valencia applicator library models using a diamond detector Maria Persson 1 , Apostolos Raptis 1 , Mohammed Ghazal 1 , Bob van Veelen 2 , Yury Niatsetski 2 , Åsa Carlsson Tedgren 1,3,4 1 Nuclear medicine and medical physics, Karolinska University hospital, Stockholm, Sweden. 2 Physics and Advanced Development, Elekta, Veenendaal, Netherlands. 3 Oncology Pathology, Karolinska Institute, Stockholm, Sweden. 4 Medicine Health and Caring Sciences, Linköping University, Linköping, Sweden Purpose/Objective: To report on the experimental commissioning of new applicator library-models of Valencia applicators that could be added to the Oncentra brachytherapy treatment planning system (TPS). TG43-based dose calculation cannot be used to calculate the dose distribution around these metallic applicators, but the vendor provides atlas data allowing the users to calculate correct treatment time depending on prescription dose and depth. Material/Methods: Dose calculation: Applicator models of 20 mm (VH2) and 30 mm (VH3) Valencia surface applicators (defining geometry, material) were placed on top of a large water phantom constructed in the TPS. The model-based dose calculation algorithm of the TPS,ACE 1) , was used in high accuracy mode to calculate the dose distribution. Figure 1. Experimental verification: The applicators were positioned on the surface of a large water phantom. Depth dose curves and profiles (cross line, in line) were measured using a microdiamond detector calibrated in 60 Co beam quality 2) . Figure 2.