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Learn More About Proton Therapy
Learn More About Proton Therapy

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Mevion Introduces New MEVION S250-FIT Proton Therapy System

This new compact system can fit in existing LINAC vaults, making proton therapy more accessible and affordable than ever before.

LITTLETON, Mass., October 21, 2022 – Mevion Medical Systems, the leading provider of compact proton therapy systems for use in radiation treatment for cancer patients, today introduced its new product, the MEVION S250-FIT Proton Therapy System™.

Enabled by the world’s smallest self-shielded proton accelerator from Mevion, the MEVION S250-FIT will be the first and only full proton therapy system that can fit in an existing LINAC vault. The system will feature industry-leading HYPERSCAN® Pencil Beam Scanning for Intensity Modulated Proton Therapy (IMPT), dual-energy large bore diagnostic CT at treatment position for IGRT and adaptive therapy, and FLASH research capabilities. It is also designed to support fast access to emerging technologies like ARC therapy.

Thanks to the compact size, the FIT™ system will further reduce the cost and complexity of proton therapy. As the name suggests, FIT will enable a Fast deployment of an Integrated design and bring the Transforming power of proton therapy to more cancer centers.

The MEVION S250-FIT Proton Therapy System™

The MEVION S250-FIT Proton Therapy System™

“The MEVION S250-FIT is a true quantum leap for proton accessibility. Fitting high-quality proton therapy inside a LINAC vault has always been a major goal in bringing the cost of proton closer to conventional X-ray, and as such, providing more access to this important therapy," said Jay Loeffler, MD, Chair Emeritus of Mass General Hospital and Co-Chair of Mevion’s Clinical and Technical Advisory Board.

“I have seen the clinical benefits of proton therapy for the past 20 years, especially for pediatric patients, and the idea that proton therapy could be accessible to all pediatric patients has always been my dream. I am so excited to hear of this innovation. This product could be a game changer,” said Nancy Tarbell, MD, a world-renowned pediatric radiation oncologist, and CC Wang Professor emerita at Harvard Medical School and Mass General Hospital.

The FIT system will be developed in partnership with Leo Cancer Care, a medical device company based in Middleton, Wisconsin, with offices in Europe and North America. Leo Cancer Care is focused on bringing a “more human” approach to delivering radiation therapy and utilizes upright positioning to improve patient experience, clinical effectiveness, and access to radiotherapy.

“Mevion Medical Systems has a proven 18-year track record of technological innovation. We are excited to be disrupting the industry once again by shrinking proton therapy even more and by making this coveted technology much more accessible to patients who need it the most. Imagine the potential of bringing proton therapy to your cancer center within a year and having it fully integrated with other radiation modalities,” said Tina Yu, PhD, CEO and President of Mevion Medical Systems. “Leo Cancer Care’s upright patient positioning system complements Mevion’s core technologies very well. They share our vision of democratizing proton therapy. We look forward to a long and rewarding partnership with Leo Cancer Care.”

“Leo Cancer Care, like Mevion, has been focusing on the patient experience. Together, Leo and Mevion agreed we wanted to take proton therapy where we never thought it could go, and together we will be achieving what was once thought impossible. In working with Mevion, we will be able to scale down proton therapy in size and cost so that it can be within reach of patients who will benefit from it most,” said proton therapy champion and veteran entrepreneur Rock Mackie, PhD, Board Chairman and Co-Founder of Leo Cancer Care.

Mevion will officially debut the MEVION S250-FIT Proton Therapy System at ASTRO’s 64th Annual Meeting in San Antonio, TX. Attendees are invited to join the unveiling at Mevion’s booth 566 at 2 PM CDT on October 23 and learn more about the system throughout the exhibition from October 23 – 25.

*The MEVION S250-FIT Proton Therapy System, FLASH therapy, online adaptive therapy, and ARC therapy are not yet available for clinical use. 

About Mevion Medical Systems

Since 2004, Mevion Medical Systems has been the leading provider of compact proton therapy systems for cancer care. Dedicated to advancing the design and accessibility of proton therapy worldwide, Mevion is the first company to innovate this new single-room platform and continues to further the science and application of proton therapy. Mevion’s series of products, including the flagship MEVION S250i and MEVION S250-FIT* with HYPERSCAN pencil beam scanning, represent the world’s smallest proton therapy systems that eliminate the obstacles of size, complexity, and cost that exist with other proton therapy systems. Mevion is headquartered in Littleton, Massachusetts, with a presence in Europe and Asia. For more information, please visit

*The MEVION S250-FIT Proton Therapy System is not yet available for clinical use

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Jingyi Wang

Mevion Medical Systems