ESTRO 2025 - Abstract Book

S3127

Physics - Inter-fraction motion management and offline adaptive radiotherapy

ESTRO 2025

For HN patients (Figure 1, first column), the mean DSC of all OARs is 0.97 (SD:0.01, OAR mean range: 0.95-0.99), and the mean HD of all OARs is 2.1mm (SD:0.64mm, OAR mean range: 1.63mm-3.04mm), where two outliers had large HD of 6.5mm and 8.0mm for Oral Cavity and Larynx respectively (Figure 2). For prostate patients (Figure 1, second column), the mean DSC of all OARs is 0.92 (SD:0.08, OAR mean range: 0.78-0.98), and the mean HD of all OARs is 2.99mm (SD:1.73mm, OAR mean range: 2.59 mm-3.60 mm.) The lower DSC in prostate patients is from the Penile Bulb and Urethra because of small volumes resulting from the cropping of the field of view. Conclusion: The results indicated insignificant differences between propagated contours from DIR-org and DIR-adj. Rare (2 in 30 HN sessions) large disagreements (up to 8mm) in low-contrast OARs should be noted. Future work will include additional sites and deep learning-based DIR algorithms .

Keywords: Image registration, CBCT, adaptive radiotherapy

References: 1. L. Kuo, Y. C. Hu, S. B.G. Lim, P. Zhang, M. Aristophanous, M. K. Savacool and L. I. Cervino. Development of an Adapting Density Calibration Curve Method for Dose Calculation on Ethos HyperSight CBCT: Medical Physics, 51(10), Oct 2024, page 7753.

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Digital Poster Gantryless adaptive MR-guided proton therapy outperforms MR-LINAC in an in silico study with hepatocellular carcinoma patients Franciska Lebbink 1,2 , Emilie Alvarez Andres 1,3 , Anna Kornek 1,3 , Annika Lattermann 1,3 , Chiara Valentini 1,3 , Esther G.C. Troost 1,3,4 1 OncoRay – National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany, Germany. 2 National Center for Tumor Diseases (NCT/UCC), Dresden, Germany, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany. 3 Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany. 4 Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology – OncoRay, Dresden, Germany