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Learn More About Proton Therapy
Learn More About Proton Therapy

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The upgraded room is scheduled to be put into service in 2022.

LITTLETON, MA JUNE 17, 2021 / BUSINESSWIRE / -- Mevion Medical Systems today announced the upgrade of the MEVION S250 Proton Therapy System at the S. Lee Kling Proton Therapy Center at Siteman Cancer Center, Barnes-Jewish Hospital, and Washington University School of Medicine in St. Louis, MO, to a MEVION S250i Proton Therapy System with HYPERSCAN Pencil Beam Scanning and FLASH capabilities. Originally installed and treating patients since 2013, the MEVION S250 was the first compact proton therapy system in the world.

“This upgrade strengthens our commitment to provide the most up-to-date proton technology to cancer centers and their patients,” said Tina Yu, CEO of Mevion. "We are delighted to continue a collaboration with our longest clinically operational collaborator for many years to come.”

The S. Lee Kling Proton Therapy Center features two independent Mevion proton therapy systems, each with its own dedicated compact accelerator. The system upgrade will enable the center to offer Mevion’s industry leading HYPERSCAN Pencil Beam Scanning on both systems. HYPERSCAN enables faster and sharper delivery of therapeutic radiation to tumors while sparing healthy tissue. FLASH*, a non-invasive, ultra-high dose rate technique delivering treatments in less than one second, may dramatically improve the cancer-fighting benefits of therapeutic radiation by shortening treatment courses and lessening side effects.

The purchase agreement with Barnes-Jewish Hospital was signed in December 2020 and received Certificate of Need Approval in March 2021. The upgraded room is scheduled to be put into service in 2022.

As the leading supplier of compact proton therapy systems in the United States, Mevion has been selected by more leading cancer centers, including NCI-Designated Cancer Centers, and has treated over 6,000 patients worldwide. Mevion’s leading-edge clinical capabilities, combined with its compact, affordable design, and industry-leading ramp-up time, have changed the landscape of proton therapy.

*FLASH Therapy is currently under preclinical research and is not yet available for commercial sale or 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 was the first company to innovate this new single-room platform and continues to further the science and application of proton therapy. Mevion’s flagship product, the MEVION S250i Proton Therapy System with HYPERSCAN pencil beam scanning, is the world’s smallest proton therapy system that eliminates the obstacles of size, complexity, and cost that exists with other proton therapy systems. Mevion is headquartered in Littleton, Massachusetts, with a presence in Europe and Asia. For more information, please visit

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