S79
Brachytherapy - Gynaecology
ESTRO 2026
Conclusion: Despite shared planning philosophies, relevant differences remain in actually obtained dose distributions, highlighting need for further standardization in delineation and treatment planning. Keywords: Inter-centre variability, Treatment planning
Visual comparison revealed modest differences in intrauterine and needle loading, visualized as a heatmap showing a pixel-wise SD of up to 2.3 Gy (Figure 1). Catheter usage varied slightly between centres, with intrauterine applicator contributions varying by 8% (SD), total-needle contributions by 3.6%, and single-needle contributions by 1%.Across all re- evaluations, variation in total EQD2 values could be considered large enough to be clinically relevant (ranges up to 15Gy). The median (SD; range) values in Gy for planning aims were as follows: GTVres-D98%: 100.6 (2.6, 95.8-105.7); CTVHR-D90%: 93.3 (4.3, 84.7- 99.6); CTVHR-D98%: 84.7 (3.4, 77.5-88.5); CTVIR-D98%: 61.2 (1.2, 58.2-62.4); Bladder-D2cm3: 76.8 (3.4, 70.5- 81.7); Bowel-D2cm3: 57.4 (2.6, 53.0-61.7); Rectum- D2cm3: 52.7 (1.8, 49.9-56.4); Sigmoid-D2cm3: 61.1 (2.0, 59.3-65.8); ICRU rectovaginal point: 62.3 (2.3, 60.2-66.5). Most variation stemmed from delineation: CTVHR and CTVIR maximum volume difference was 10.4 cm3 and 19.3 cm3, respectively.
Proffered Paper 4060
Patient-tailored 3D printed versus conventional applicators: Plan comparisons for locally advanced cervical cancer brachytherapy Sharline van Vliet - Perez 1 , Robin Straathof 1 , Henrike Westerveld 1 , Huda Abusaris 1 , Raymond de Boer 1 , Jan- Willem Mens 1 , Linda Rossi 1 , Nick van de Berg 2 , Jenny Dankelman 3 , Linda Wauben 3 , Ben Heijmen 1 , Inger- Karine Kolkman-Deurloo 1 , Remi Nout 1 1 Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands. 2 Gynecological Oncology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands. 3 BioMechanical Engineering, Delft University of Technology, Delft, Netherlands Purpose/Objective: Patient-tailored 3D-printed ARCHITECT brachytherapy (BT) applicators were developed to improve treatment outcome for locally advanced cervical cancer (LACC) patients, particularly in patients with extensive or asymmetric tumors [1]. This study compares dosimetry, geometry and plan quality between ARCHITECT and conventional intracavitary/interstitial applicators.
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