RayStation has been chosen as the treatment planning system for a new carbon-ion therapy facility which is under construction at Yamagata University Hospital in northern Japan. The order represents the first RayStation carbon ion installation in Japan. Carbon ion therapy is an advanced form of radiation therapy that precisely targets cancer cells with minimal damage to surrounding tissue. The technique uses a carbon ion beam, accelerated up to 70% of the speed of light. Carbon ion beams are highly effective in destroying cancer cells, and the technique can be effective for cancers that are resistant to X-rays. An additional advantage is that the treatment period often is shorter than for other forms of radiation therapy. RayStation was selected jointly by Yamagata University Hospital and Toshiba, which is supplying the treatment delivery system. The decision was motivated by RayStation's outstanding functionality and comprehensive support for this cutting-edge treatment technique. The RayStation installation will include modules for carbon pencil beam scanning with robust biological optimization (using both the MKM and LEM models), deformable registration, dose tracking and adaptive therapy. The facility expects to treat its first patients by early 2020. Toshiba's treatment delivery system will comprise two treatment rooms, a fixed-port room and a 360-degree rotating compact superconducting gantry. The facility will be the most compact carbon ion installation in the world, and one of the few integrated into a general hospital.