S155 reduction in D ₀ . ₁ cm ³ . The benefit was most pronounced in smaller prostates. Target coverage was preserved (V ₁₀₀ ≈ 92 %, D ₉₀ ≈ 103 %).
Brachytherapy - Urology
ESTRO 2026
3 Surgery clinic, Clinical–hospital center Zemun, Belgrade, Serbia
Purpose/Objective: Brachytherapy plays an important role in prostate cancer management and can be applied using various treatment regimens. We aimed to evaluate the implementation and clinical experience of MRI–based HDR prostate brachytherapy at the Institute for Oncology and Radiology of Serbia. Material/Methods: Clinical implementation began in April 2019, with the first procedure successfully performed at our Institute. Between April 2019 and August 2025, the technique was applied in several clinical settings: as a boost following EBRT, as salvage therapy for local recurrence after definitive radiotherapy, as second–line salvage after surgery and salvage EBRT, and as primary treatment in selected patients.The procedure included transrectal ultrasound–guided needle placement under epidural or general anesthesia, followed by MRI acquisition, needle reconstruction, delineation of target volumes and OARs, treatment planning, plan evaluation, radiation delivery, and needle removal. Patients received one or two applications, with the number of fractions and prescribed dose individualized according to patient characteristics and established protocols.Dose–volume parameters for target volumes and OARs, as well as perioperative morbidity, were evaluated. Planning aims for prostatic CTV were: D90 > 100%, V100 > 90%, and V150 < 40%. OAR constraints were D2cc < 80% for rectum and D10 < 125% for urethra. Results: A total of 61 MRI–guided HDR prostate brachytherapy procedures were performed in 39 patients: 17 as boost (19 applications), 17 as salvage (32), 3 as second–line salvage (6), and 2 as monotherapy (4). Seventeen patients underwent a single application, while 22 patients received two. Median prescribed dose per fraction was 13 Gy (range 10–17.5 Gy).CTV D90 and V100 aims were achieved in 93% of procedures (57/61), and V150 in 77% (47/61). Median CTV D90, V100, and V150 were 107.6% (range 83.8– 113.8), 95.0% (range 80.8–99.1), and 37.4% (range 29.1–48.7), respectively. OAR constraints were met in 98% of procedures (60/61), both for rectum and urethra.
Conclusion: Hydrogel spacer application before HDR-BT
significantly reduces rectal dose while maintaining optimal prostate dose coverage. The dosimetric advantage is especially relevant in smaller prostates and in patients receiving combined EBRT + HDR-BT, supporting the routine integration of hydrogel spacers to minimize rectal toxicity risk. Keywords: prostate cancer, HDR-Brachytherapy, Hydrogel
Digital Poster 623
Implementation of MRI–based HDR Prostate Brachytherapy—Experience of the Institute for Oncology and Radiology of Serbia Predrag S Petra š inovi ć 1,2 , Mladen Marinkovi ć 1,2 , Perica Jocki ć 3 , Sandra Vu č kovi ć 1 , Milan Marki ć evi ć 1 , Bojan Todorovi ć 1 , Danica Jestrovi ć 1 , Igor Mari ć 1 , Vuka č Vujanac 1 , Aleksandar Rankovi ć 1 , Marko Jovanovi ć 1 , Marko Radovi ć 1 , Mirjana Mikovi ć 1 , Aleksandar Toma š evi ć 1,2 , Suzana Stojanovi ć Rundi ć 1,2 1 Clinic for radiation oncology, Institute for oncology and radiology of Serbia, Belgrade, Serbia. 2 Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
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