ESTRO 2020 Abstract book

S121 ESTRO 2020

first commissioning results of IDEAL/GATE-RTion for scanned proton and carbon ion beams. Material and Methods DICOM input files (CT, Plan, Dose and Structure) are imported into IDEAL and run on a dedicated cluster of modular capacity (currently equipped with 48 cores). Commissioning work is divided into 1D beam delivery (depth-dose profiles, spot sizes, and nuclear halo), 2D (spot maps, output factors) and 3D (targets of various shapes and complexity: square, cylinder, L-shape, etc.). TEDD (a Toolkit for the Evaluation of DICOM Doses) was developed to analyze 1D/2D/3D beam delivery parameters. Proton and carbon ion beam models were generated and validated in terms of energy and optical properties and then calibrated in dose. 3D commissioning of IDEAL is performed using TEDD. IDEAL recomputed treatment plan doses are evaluated with TEDD against measurements performed in water using a 3D-block featured with 24 pin-point ionization chambers. Results The proton beam model was found to be within clinical tolerances of 0.5 mm in range and 10% in spot size in the air-gap from the nozzle exit to the isocenter. So far, 26 targets of various shapes were simulated in water for protons. Averaged dose differences were always better than +/-3% and mostly within 1% or 2%. These plans included field sizes from 3 to 20 cm, target volumes from 0.03 to 2 liters and more, with and without range shifter and were centered between 3 and 31 cm depth. Overall, more than 2000 pin-point measurements were analyzed. An example is provided in Figure 1.

Conclusion As of today, proton commissioning is on-going and promising preliminary results have been obtained. More complex plans including inhomogeneities and various phantom geometries and compositions will be analyzed. In parallel, carbon ion commissioning will start by the end of 2019 and preliminary results will be obtained early 2020. To our knowledge, this work is the first attempt of transferring general purpose MC codes such as GATE/Geant4 into a CE certified IDC product, making this project very unique. OC-0218 Approximate modeling for dose calculations in Diffusing Alpha-emitters Radiation Therapy L. Arazi 1 , M. Dumančić 1 , Y. Keisari 2 , I. Kelson 3 1 Ben-Gurion University of the Negev, Nuclear Engineering Unit- Faculty of Engineering Sciences, Beer-Sheva, Israel ; 2 Tel Aviv University, Department of Clinical Microbiology & Immunology- Sackler Faculty of Medicine, Tel Aviv, Israel ; 3 Tel Aviv University, School of Physics and Astronomy- Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv, Israel

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