Vacca F, Amrein P, Klüter S, Röll S, Debus J, Ladd M, Fiedler T. Design of Magnet Configurations for a 0.55 T Superconducting MRI System for MRI-Guided Upright Particle Therapy. In: Proceedings of the Cape Town - 2026 ISMRM-ISMRT Annual Meeting and Exhibition, Cape Town, South Africa. Program #564-02-012.