ESTRO 2025 - Abstract Book

S280

Brachytherapy - Gynaecology

ESTRO 2025

manufactured using selective laser sintering with PA-12, of which safety was demonstrated through evaluations (3a c). Applicator and treatment planning files generation could be completed within an hour, while manufacturing and sterilisation are achievable within one working week.

Conclusion: The patient-tailored ARCHITECT applicator was developed in a systematic process in accordance with regulatory requirements. Integration in our clinical workflow seems feasible.

Keywords: Patient-tailored applicator, MDR, 3D printing

4510

Digital Poster Analysis of TRAK/Volume Metrics and Dose Coverage in Interstitial Brachytherapy for Cervical and Uterine Cancers Alek Rapchak, Austin Skinner, William Godwin, Daniel McDonald, Sean Roles, Jean Peng Radiation Medicine, Medical University of South Carolina, Charleston, USA Purpose/Objective: Total Reference Air Kerma (TRAK) metrics are often used to compare HDR to LDR implants but not used effectively for all interstitial implants [1]. We seek to investigate the correlation between the ratio of TRAK normalized to the target volume (TRAK/Vol) and dose coverage metrics (D90%) in interstitial brachytherapy for cervical and uterine cancers. We aim to find a single metric to evaluate the quality of dose coverage. Material/Methods: Retrospective data from 50 patient plans treated with HDR interstitial brachytherapy were analyzed. Plans were scored for quality on a scale of 0 to 5, with a point accrued for achieving benchmarks including V90 > 90%, V90 > 95%, V100 > 90%, V100 > 95%, and V200% < 20 cc. Plans receiving 4-5 points were deemed good plans, 2-3 were acceptable and 0-1 were not good. All plans met guidelines for Organs at Risk (OARs) and were excluded in this study. Key metrics included TRAK/Vol, and D90%. Comparisons between these parameters and plan quality scores were assed to determine quality of planning. TRAK/Vol and D90% values were categorized into six bins (0-5) based on scores, and mean values were plotted.