ESTRO 2025 - Abstract Book

S3062

Physics - Image acquisition and processing

ESTRO 2025

Figure 1. Single tracker configuration of the ion radiography setup in the experimental room at HIT (bottom panel). Schematic view of the anthropomorphic abdominal phantom (upper right panel). Single energy proton radiograph of the anthropomorphic abdominal phantom (upper left panel). Results: Protocols for low-intensity beam extraction and data acquisition for single-event proton and helium radiography and computed tomography (CT) at HIT have been established for the clinical scanner prototype. Spatial resolution of 1 lp/mm for dual trackers and 4 lp/mm for a single tracker was demonstrated for protons and helium ions. Single-event proton and helium radiographs of a custom motion phantom were obtained for the first time at a synchrotron-based facility. The frame rate of 2 fps was achieved for a field size of 10 cm × 10 cm. Conclusion: The initial phase of the HELIOS project, the adaptation of the clinical proton radiography prototype to the HIT beamline, has been successfully completed. The experimental datasets for proton and helium radiographs and CT represent satisfactory imaging quality for both single- and dual-tracker setup configurations. The next steps in the project will be the development of algorithms to suppress carbon fragments in mixed helium-carbon beams and the optimization of small-field helium radiography for quasi-real-time imaging applications. References: 1. DeJongh EA, DeJongh DF, Polnyi I, Rykalin V, Sarosiek C, et al. Technical Note: A fast and monolithic prototype clinical proton radiography system optimized for pencil beam scanning. Med Phys. 2021; 48(3):1356-1364. doi: 10.1002/mp.14700. 2. Hardt JJ, Pryanichnikov AA, Homolka N, DeJongh EA, DeJongh DF, et al. The potential of mixed carbon-helium beams for online treatment verification: a simulation and treatment planning study. Phys Med Biol. 2024; 69(12). doi: 10.1088/1361-6560/ad46db. 3. Stengl C, Panow K, Arbes E, Muñoz ID, Christensen JB, et al. A phantom to simulate organ motion and its effect on dose distribution in carbon ion therapy for pancreatic cancer. Phys Med Biol. 2023; 68(24). doi: 10.1088/1361 6560/ad0902. Keywords: proton imaging, ion imaging, image-guidance