S2602
Radiobiology - Radiobiological modelling
ESTRO 2026
disease, with the pericardium being the most frequently affected structure. Pericardial disease following radiotherapy may present as pericarditis and/or pericardial effusion. Pericardial effusion is the most commonly observed form of pericardial disease. Although studies using mouse models have been conducted for several decades, the biological mechanisms of RIHD remain unclear. This study aimed to develop a mouse model of RIHD-associated pericarditis to elucidate its underlying mechanisms. Material/Methods: We developed a novel radiation shielding device that allows partial cardiac irradiation in mice. The hearts of BALB/cJ mice were locally irradiated with 50 Gy in a single fraction. Twelve mice were assigned to each of the irradiated and control groups. Cardiac ultrasonography was performed at 0, 10, 20, 30, 35, and 40 weeks after irradiation to assess pericardial effusion. At 40 weeks after irradiation, the mice were euthanized, and heart tissue specimens were collected for histological analysis. The heart tissue specimens were stained with hematoxylin and eosin (H&E), Elastica Sirius Red (ESR), CD3, and CD68. The thickest portion of the pericardium was measured. Statistical analysis was performed using SPSS version 29.0 for Windows. Kaplan–Meier survival curves were constructed and compared between groups. The Mann–Whitney U test was used to compare two groups. Results: In the irradiated group, 3 of 12 mice died within 40 weeks after irradiation. No deaths occurred in the control group. Histological analysis of heart tissue in the irradiated group revealed pericardial thickening and inflammatory cell infiltration. A subset of the inflammatory cells was identified as macrophages based on CD68 ⁺ /CD3 ⁻ staining. In the irradiated group, the median pericardial thickness at the thickest region was significantly greater than that in the control group (55.70 μ m vs. 14.02 μ m, p < 0.001). In the irradiated group, pericardial effusion was detected by cardiac ultrasonography in 3 of 10 mice at 35 weeks and in 7 of 9 mice at 40 weeks after irradiation. Pericardial effusion was not observed before 35 weeks after irradiation. Conclusion: In this study, pericardial effusion, pericardial thickening, and inflammatory cell infiltration were observed only in the irradiated group of mice, findings suggestive of pericarditis. We successfully developed a mouse model of RIHD-associated pericarditis. Keywords: Cardio-oncology, Mouse, Radiation heart disease Digital Poster 3204 Effects of interaction potentials on oxygen depletion in simulations of water radiolysis Robin Erdmann 1 , Larissa Derksen 2 , David Weishaar 1 , Fabian Meister 3 , Uli Weber 1,4 , Kilian-Simon Baumann 1,2 1 Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany. 2 Marburg Ion-Beam Therapy Center (MIT), Department of Radiotherapy and Radiation Oncology, Marburg University Hospital, Marburg, Germany. 3 Department of Physics, Philipps-Universität Marburg, Marburg, Germany.
Conclusion: GRWU can be a valuable time-efficient tool for DW-MRI simulations in complex substrates for characterisation of tumour microstructure in radiotherapy planning. GRWU is currently used in simulation frameworks to stratify radiotherapy patients, in similar fashion to what was done by [1] and [2]. References: [1] G. Buizza et al., Med Phys, vol. 48, no. 3, pp. 1250–1261, Mar. 2021, doi: 10.1002/mp.14689.[2] L. Morelli et al., Med Phys, vol. 50, no. 5, pp. 2900–2913, May 2023, doi: 10.1002/mp.16202.[3] P. A. Cook et al., 2005, http://www.cs.ucl.ac.uk/research/medic/camino.[4] J. Rafael-Patino et al., Front Neuroinform, vol. 14, Mar. 2020, doi: 10.3389/fninf.2020.00008.[5] L. Kerkelä et al., J Open Source Softw, vol. 5, no. 52, p. 2527, Aug. 2020, doi: 10.21105/joss.02527.[6] M. G. Hall and D. C. Alexander, IEEE Trans Med Imaging, vol. 28, no. 9, pp. 1354–1364, 2009, doi: 10.1109/TMI.2009.2015756. Keywords: tumour microstructure, DWI simulation, Monte Carlo Digital Poster Highlight 3096 development of a mouse model of pericarditis associated with radiation-induced heart disease yoshitaka suzuki, Yutaka Toyomasu, Akinori Takada, Kazuki Omori, Hajime Sakuma, Yoshihito Nomoto Radiology, Mie University Hospital, Tsu, Japan Purpose/Objective: The increasing number of cancer survivors has drawn attention to radiation-induced heart disease (RIHD). RIHD includes pericarditis, acute coronary syndrome, arrhythmia, heart failure, and valvular
4 Biophysics Division, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
Purpose/Objective: Radiobiological simulations that aim to predict indirect DNA damage rely on an accurate modelling of the chemical stage. The presence of molecular oxygen alters this stage by introducing further reaction channels that increase the production of reactive oxygen species (ROS) and thus affect the indirect DNA damage yield. This study investigates the effect of a refined model for the simulation of the
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