ESTRO 2025 - Abstract Book

Brachytherapy - Gastro-intestinal, paediatric brachytherapy, miscellaneous

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ESTRO 2025

< 0.001 vs. HDR and eBT). Electronic BT yielded a significantly better OAR dose sparing compared to SBRT. Radiation exposure to the healthy liver was significantly lower with eBT (V9.1Gy 13.8 [3.4–41.6] cm 3 ) and HDR (49.2 [12.7– 116.8] cm 3 ) when compared with SBRT (98.8 [54.3–303.7] cm 3 ; p < 0.001 for both; Fig. 2). Figure 2

Conclusion: Minimally invasive eBT provides a new potential approach in the context of unresectable liver metastases. Combining the advantages of both modalities, a multi-dwelling eBT approach as in HDR might further reduce treatment times and optimize target volume coverage while maintaining excellent OAR doses. Future prospective investigations are requiredto further define its role within well-established liver-directed therapies.

Keywords: liver metastases, SBRT, electronic brachytherapy

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Digital Poster IORT in brain metastasis surgery results in less radionecrosis than postoperative external beam radiotherapy with equal oncological outcome. Klaus-Henning Kahl 1 , Ehab Shiban 2,3 , Susanne Gutser 4 , Maria Emanuel Neu 1 , Christoph J. Maurer 5 1 Klinik für Strahlentherapie und Radioonkolgie, University Hospital Augsburg, Augsburg, Germany. 2 Klinik für Neurochirurgie, University Hospital Augsburg, Augsburg, Germany. 3 Klinik für Neurochirurgie, Medizinuische Universität Lausitz - Carl Thiem, Cottbus, Germany. 4 Stabsstelle für medizinische Physik, University Hospital Augsburg, Augsburg, Germany. 5 University hospital Augsburg, Klinik für diagnostische und inverventionelle Radiologie und Neuroradiologie, Augsburg, Germany Purpose/Objective: In the treatment of brain metastases (BM), whole brain radiotherapy after resection of brainmetastases has been replaced by fractionated stereotactic radiotherapy (fSRS) of the resection cavity due neurocogintive favorable outcome. Intraoperative radiotherapy (ioRT) theroretically offers a beneficial treatment profile in the treatment of resected BM. Whether this is reflected in postoperative outcome remains little investigated. Aim of this study is to compare time parameters of treatment as well as outcome, local control and the rate of radionecrosis (RN) in patients that underwent resection of BM with adjuvant fSRS compared with ioRT in a single center setting. Material/Methods: We performed a retrospective single center analysis comparing patients receiving either fSRS after BM resection or ioRT between 2013 and 2021 in University Augsburg Medical Center with respect to RN, overall survival and local control. Time point of analyis was 15.10.2024. Treatment protocols: