ESTRO 2025 - Abstract Book

S2696

Physics - Dose calculation algorithms

ESTRO 2025

Results: The dose rate obtained for the validation simulation was 0.114 Gy/min, which is in good agreement with published reference data [3]. The average dose rate in our set-up was 0.603 Gy/min and 0.599 Gy/min with and without the gamma and beta particles emitted by 241 Am considered. The dose distribution was inhomogeneous across the cells, likely due to the similar diameter of the source and cell well opening and short source to surface distance (Figure 2).

Conclusion: It is important to consider the source diameter, source to surface distance, and metallic components when irradiating cells with 241 Am. The contribution of gamma and beta particles emitted by 241 Am is negligible. Our software allows for an accurate dosimetry of the custom cell irradiation set-up, which delivers a high dose rate to cells. Dose homogeneity to the cells should be improved.

Keywords: Radiobiology, Alpha Radiation, Monte Carlo

References: 1. Kim, Young-Seung, and Martin W Brechbiel. “An overview of targeted alpha therapy.” Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine vol. 33,3 (2012): 573-90. 2. Beaton, Lindsay A et al. “Development and characterization of an in vitro alpha radiation exposure system.” Physics in medicine and biology vol. 56,12 (2011): 3645-58. 3. GEANT4: A simulation toolkit. S. Agostinelli, and others. Nucl. Instrum. Meth., (2003) DOI: 4. Nishri, Yossi et al. “Diffusing alpha-emitters radiation therapy in combination with temozolomide or bevacizumab in human glioblastoma multiforme xenografts.” Frontiers in oncology vol. 12 888100. 27 Sep. 2022.

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Digital Poster Accuracy of MU calculation in small MLC fields with Acuros and Enhanced Leaf Modeling Antonella Fogliata 1 , Antonella Stravato 2,3 , Marco Pelizzoli 1 , Francesco La Fauci 1 , Pasqualina Gallo 1 , Andrea Bresolin 1 , Luca Cozzi 1 , Stefano Tomatis 1 , Marta Scorsetti 1,4 , Giacomo Reggiori 1 1 Radiosurgery and Radiotherapy Department, IRCCS-Humanitas Research Hospital, Milan, Italy. 2 Medical Physics Dept, A.O. San Giovanni-Addolorata, Rome, Italy. 3 International Medical University in Rome, UniCamillus, Rome, Italy. 4 Department of Biomedical Sciences, Humanitas University, Milan, Italy