Leo Cancer Announces Pioneering Proton Therapy Advancement at Stanford Medicine
Leo Cancer Care marked a significant milestone at Stanford Medicine Cancer Center with the inaugural clinical use of its upright proton therapy system, Marie®, on June 4, 2026. This distinctive compact proton therapy and upright patient positioning system aims to enhance the delivery of cancer treatments by integrating with the Mevion S250-FIT™ Proton Therapy System, facilitated by RayStation from RaySearch. This breakthrough represents the fruition of ten years of development in applying upright radiotherapy in clinical settings.
Historically, proton therapy has required large, dedicated facilities due to bulky rotating gantries. Marie® offers an alternative by rotating patients relative to a stationary proton beam, enabling installation of these systems in existing radiotherapy vaults. This innovation effectively reduces the required installation space by more than 90 percent, from over 29,000 square feet to approximately 1,700 square feet.
Addressing the needs of pediatric patients, who are particularly sensitive to radiation, the system provides enhanced precision in targeting treatment. It is envisioned to render proton therapy more accessible to healthcare facilities that lack the infrastructure for conventional systems. By facilitating accessible proton therapy, Marie® could significantly reduce travel burdens for families, as the nearest treatment facilities are often far from patients' homes.
The system design emphasizes patient comfort and a more human-centric approach to radiotherapy by offering treatments in the more natural standing or sitting position familiar to everyday life. This upright approach promotes interactions between patients and clinical teams, which can be crucial for younger patients, and is further supported by an interactive game, StatueQuest, developed for pediatric patients. Feedback from early use indicates positive patient experiences, with reports of comfortable breathing and ease of positioning.
Stephen Towe, CEO of Leo Cancer Care, emphasized the transformational potential of this technology, stating, "This milestone represents an important moment not only for Leo Cancer Care, but for the future direction of radiation oncology. For decades, proton therapy has delivered remarkable clinical benefits but has remained limited by the scale, complexity, and infrastructure demands of traditional systems. By enabling treatment in an upright position using a fixed-beam approach, we are helping redefine how proton therapy can be delivered — making it more compact, more flexible, and potentially accessible to far more patients around the world."
Stanford Medicine's deployment of the Marie® system also allows for ongoing evaluation of its practical application in terms of patient workflow, immobilization, and treatment planning. This promising advance opens avenues for broader adoption of compact proton therapy systems, facilitating partnerships with institutions globally as Leo Cancer Care continues its collaborations with Mevion Medical Systems.