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Learn More About Proton Therapy
Learn More About Proton Therapy

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Siteman Cancer Center Expands Proton Therapy Center with Second Mevion Proton System

Construction has begun on the new vault that will be equipped with the Mevion HYPERSCAN Pencil Beam Scanning System

LITTLETON, Mass., October 22, 2018 - Mevion Medical System announces that construction is underway for a second proton therapy system at Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine in St. Louis. This new vault will be equipped with the MEVION S250i Proton Therapy SystemTM with HYPERSCAN Pencil Beam Scanning (PBS)TM  technology.

“We are extremely proud to be selected to provide a second system to Siteman Cancer Center,” said Tina Yu, Ph.D., chief executive officer of Mevion Medical Systems. “We see this as a reflection of the dedication and hard work of our team to provide the best possible solutions to cancer centers and patients. At Mevion we pride ourselves on bringing innovative new solutions to make proton therapy a reality for more patients, and that is what we are doing here at Siteman.”

In 2013, Siteman Cancer Center became the first in the world to treat a patient with a Mevion compact proton therapy system. Siteman treats adult cancer patients with proton therapy, as well as pediatric cancer patients from St. Louis Children’s Hospital, also located on the Washington University Medical Campus. Last year, Siteman celebrated the treatment of its 500th proton therapy patient.

Since then, the S. Lee Kling Proton Therapy Center has grown and is now expanding with a second Mevion system located directly next to the first. This will be the first cancer center with two Mevion systems. Several other sites are following this approach, having planned a second room at the time of the first to accommodate expansion as needed

The MEVION S250i with HYPERSCAN Pencil Beam Scanning is pictured above.

The new system will be equipped with Mevion’s HYPERSCAN Pencil Beam Scanning technology. This technology improves on older scanning technologies particularly due to Mevion’s Adaptive ApertureTM , a novel proton multi-leaf collimator (pMLC), which gives clinicians the most conformal treatments. Additionally, Siteman Cancer Center is leveraging the open platform capabilities of the Mevion system to incorporate the latest imaging modalities. Siteman will be equipping its room with both a ceiling rail mounted cone beam CT system and diagnostic CT on rails system for advanced treatment modalities.

“We envision that the second proton therapy system will enable us to more precisely treat cancers located near critical structures, such as the brain tumors near the eyes and optic structures, spinal cord or the heart,” said Dr. Jeffrey Bradley, “That’s because this advanced form of proton therapy technology is based on pencil-beam scanning, in which a single, narrow proton beam is aimed directly at the tumor and adjusted for intensity. Such precision helps spare surrounding healthy tissues and reduce the risk of treatment-related complications.”

The new proton therapy system at Siteman Cancer Center is scheduled to open to patients in early 2020.

Uptick in Global Adoption

The proton therapy market continues to grow based the segment of modern, economically responsible, compact systems which Mevion invented. The new MEVION S250i™ system continues to be the system of choice for leading cancer centers. Two more hospitals are targeting openings for HYPERSCAN systems in late 2018 and a new system was just recently announced in Utah.

More information about the MEVION S250i system with HYPERSCAN Pencil Beam Scanning will be available at the Mevion booth 2844 at the 2018 Annual American Society for Radiation Oncology (ASTRO) meeting in San Antonio, Texas from Sunday October 21st through 23rd. Come learn why Mevion is the leader in compact proton therapy and see demonstrations of the economic feasibility, new proton room planning, as well as HYPERSCAN treatment planning demonstrations performed in conjunction with RaySearch Labs.

About Mevion Medical Systems®

Mevion Medical Systems, Inc. is a leading provider of proton therapy systems for use in radiation treatment for cancer patients. Mevion is based in Littleton, Massachusetts, with presence in Europe and China. For more information, please visit

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