Layout optimization and comparison of a Carbon-ion gantry based on different mechanical structures

Carbon ion therapy is one of the most effective radiotherapy methods for cancer treatment, offering superior dose conformality compared to conventional radiation therapies. The combination of carbon ion treatment with a gantry further enhances treatment effectiveness and safety. When designing a gantry, the magnet aperture must consider both the beam envelope and the beam position errors all along the gantry beamline. These errors may arise from magnetic field errors, imperfect magnet alignment, construction inaccuracies and mechanical design choices. A well-matched optics guarantees a low beam envelope; however, this does not always correspond to an optimization of the space occupied by the beam after introducing error sources and related corrections. Thus, a novel methodology that integrates optics and mechanical studies has been developed. By combining mechanical deformation analyses and optics correction optimization algorithms, this study provides a comprehensive solution for the HITRIplus carbon ion gantry design. A detailed analysis of the impact of two different design options for the supporting system of the SC magnets is provided.