Marie® by Leo Cancer Care Makes History at Stanford Medicine — World First in Compact Upright Proton Therapy

The first patient treated was a child. The milestone marks the moment upright proton therapy moves from innovation to adoption — and reflects exactly what Leo Cancer Care built Marie® to achieve

Following the landmark first treatment at Stanford Medicine Cancer Center Care June 4, Leo Cancer Care today announces the role of its Marie® upright patient positioning and imaging platform in enabling the world's first compact upright proton therapy patient treatment. Delivered using the Mevion S250-FIT™ Proton Therapy System and powered by RayStation from RaySearch, the milestone is the culmination of a decade of development.

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The treatment room at Stanford Medicine Cancer Center, Palo Alto, California, housing the Marie® upright patient positioning platform by Leo Cancer Care (center foreground) integrated with the Mevion S250-FIT™ Proton Therapy System. The circular rotating platform enables a patient seated in the Marie® chair to rotate 360 degrees in relation to a fixed proton beam — replacing the large rotating gantries required by traditional proton therapy systems. This compact configuration, which requires approximately 1,700 square feet compared with over 29,000 square feet for conventional proton therapy facilities, was used on June 4, 2026 to complete the world's first compact upright proton therapy patient treatment. The Marie® system is powered by RayStation from RaySearch. Photo: Steve Fisch / Stanford Medicine

From Innovation to Adoption

Leo Cancer Care was built on a straightforward belief: that people living with cancer deserve a treatment experience designed around them — not around the machine. That belief drove the development of Marie®, and the first clinical deployment of this combined compact proton therapy and upright positioning approach is its proof point. Upright radiotherapy is not a new concept; Leo Cancer Care has spent a decade ensuring that its potential becomes a clinical reality, and that the lessons of the past inform the breakthroughs of the future.

The momentum behind that journey had already drawn significant attention. In October 2025, Forbes headlined their coverage of Leo Cancer Care: "How A High-Tech Chair Could Revolutionize Cancer Radiation Therapy" — noting that the system's compact design reduces the space required for proton therapy by more than 90 percent, from over 29,000 square feet to approximately 1,700 square feet. The latest milestone is the clinical validation of that prediction.

For children, whose developing bodies are particularly sensitive to radiation, proton therapy's ability to target treatment with greater precision can be especially significant. Yet for most families, proton therapy has simply not been an option. Traditional systems require large rotating gantries and dedicated purpose-built facilities, placing them out of reach for the vast majority of cancer centres worldwide. For a child requiring weeks of daily treatment, the nearest facility may be hundreds of miles away — a distance that carries a very human cost.

The Marie® platform addresses this by rotating the patient in relation to a fixed proton beam rather than rotating a large gantry around them. This can enable proton therapy systems to be installed within existing radiotherapy vaults — expanding the reach of this treatment to places it has never been before.

The More Human Way to Deliver Radiotherapy

Marie® was designed from a simple starting point: what does the person in treatment actually need? The upright position is where we spend two-thirds of our lives — standing, sitting, moving. Treating patients in that natural position is not a rejection of conventional radiotherapy; it is an expansion of what radiotherapy can be. Less daunting. More comfortable. More human.

Marie® is being explored for its potential to improve patient comfort and enable faster patient set-up. The upright approach enables eye-to-eye interaction between patients and clinical teams throughout the treatment process — something that has not previously been possible within a radiotherapy setting, and which takes on particular significance when the patient is a child.

To further support younger patients, Leo Cancer Care has developed StatueQuest, a unique interactive adventure game designed for pediatric patients — one more expression of the company's belief that every part of the treatment experience should be designed with the person at its centre.

Preliminary evaluations of upright positioning have indicated strong patient acceptance, with participants reporting comfortable breathing, ease of positioning, and a preference for the upright treatment experience.

Marie® features a 360-degree rotating patient positioning system with integrated upright CT imaging, enabling proton therapy to be delivered with initial image guidance directly at the treatment position. At Stanford Medicine, Marie® is integrated with the Mevion S250-FIT™ system to create a compact proton therapy configuration that supports installation within existing radiotherapy vaults.

"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."

— Stephen Towe, CEO, Leo Cancer Care

What's Next

The Stanford Medicine installation represents the first clinical deployment of this combined compact proton therapy and upright positioning approach. The site is exploring treatment delivery with patients positioned upright, alongside continued evaluation of workflow, immobilisation, and planning flexibility. As additional patients are treated, the human story at the heart of this milestone will only deepen.

The commercial implications extend well beyond a single installation. By enabling proton therapy deployment within existing radiotherapy vaults, Leo Cancer Care's approach dramatically lowers the capital threshold that has historically confined proton therapy to a small number of specialist centres — opening it to a significantly larger addressable market of institutions that could never previously have considered it.

Following this milestone, Leo Cancer Care will continue working with clinical and technology partners to support further installations and ongoing research into upright radiotherapy delivery. The collaboration between Leo Cancer Care and Mevion Medical Systems is expected to support broader adoption of compact proton therapy solutions across additional centres globally.

ABOUT LEO CANCER CARE

It's estimated that we spend two-thirds of our lives upright, standing, sitting, or moving in our natural position. At Leo Cancer Care, we are committed to challenging the conventions of radiation oncology by reintroducing upright treatment to radiotherapy practice.

Our Marie® suite of upright positioning and imaging solutions was created with two complementary goals: transforming the patient experience and expanding access to advanced radiotherapy. By shifting from machine rotation to patient rotation, Leo Cancer Care enables more compact treatment environments while allowing patients to remain in a more natural and comfortable position.

This approach supports improved patient interaction, potential motion reduction, and more flexible treatment delivery, while also helping healthcare providers overcome infrastructure and cost barriers associated with traditional systems.

Leo Cancer Care is proud to be working alongside leading healthcare institutions and industry partners to support the evolution of radiotherapy — enabling more accessible, sustainable, and patient-centered cancer treatment worldwide.

NOTES TO EDITORS

Stanford Medicine first patient story: https://med.stanford.edu/news/all-news/2026/06/proton-therapy.html
Forbes coverage, October 2025 (Amy Feldman): https://www.forbes.com/sites/amyfeldman/2025/10/16/how-a-high-tech-chair-could-revolutionize-cancer-radiation-therapy/

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