ESTRO 2025 - Abstract Book

S353

Brachytherapy - Physics

ESTRO 2025

3595

Digital Poster Dosimetric characterization of an innovative flexible resin material (Ultracur3D®FL 300) for skin brachytherapy 3D printed applicators Francesca Itta 1 , Elisabetta Verdolino 1 , Eleonora Paulicelli 1 , Domenico Becci 1 , Claudia Ciraci 1 , Antonio Bruno 1 , Giovanna De Zisa 1 , Eliana Piccarreta 2 , Simone Carrozzoli 3 , Nicola Ferrara 4 , Annarita Marsella 5 , Domenico Mola 1 1 Medical Physics department, S.G. Moscati Hospital, Taranto, Italy. 2 Crea3D, Crea 3D, Ruvo di Puglia, Italy. 3 DEE, Politecnico di Bari, Bari, Italy. 4 Dipartimento Interateneo di Fisica, Politecnico di Bari, Bari, Italy. 5 Radiotherapy department, S.G. Moscati Hospital, Taranto, Italy Purpose/Objective: In skin cancer HDR brachytherapy the use of personalized 3D-printed applicators is becoming an emerging choice. Especially for treatment in challenging anatomical sites, the use of flexible materials is crucial to ensure proper 3D printed applicator fitting capabilities.The aim of this work is to dosimetrically evaluate an innovative highly flexible material the Ultracur3D® FL 300. Rectangular applicator structure (1cm thickness) with a central catheter path (1.5 mm radius) has been designed (Autodesk Fusion) and 3D printed with three different materials: Ultracur3D® FL 300 (1.07 g/cm^3, shore 40 A, Liquid Crystal Display 3D Printer), standard TPU 85A with 100% infill factor (1.082 g/cm^3, shore 85 A, Fused Filament Fabrication 3D printer) and foamy TPU (0,709 g/cm^3, shore 40 A, Fused Filament Fabrication 3D printer). Treatment plan has been optimized using Oncentra TPS (TG-43 formalism), setup of Fig1.a, and delivered with Flexitron (Elekta) for each different applicator material (FL 300, TPU, foamy TPU). Planar dose measurements were performed with calibrated Gafchromic films placed 1cm below central catheter path (Fig.1.b). We compared measured and calculated dose distribution using gamma passing rate with criteria of 3%/2mm (Film QA Pro). Material/Methods:

Figure 1: 3D printed applicator material dosimetric characterization (a) setup and (b) dose distribution TPS calculated

Results: FL 300 applicator was acceptably approximated as homogeneous water equivalent material, infact computed vs measured planar dose distribution showed 97.4% gamma passing rate.