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Mercy St. Louis Begins Treatment with Mevion Compact Proton Therapy System

The first patient received treatment on July 5th

LITTLETON, Mass., July 7, 2022 – Mevion Medical Systems, the leading provider of compact proton therapy systems for use in radiation treatment for cancer patients, announced today that the first patient was treated at the David C. Pratt Cancer Center at Mercy Hospital St. Louis on July 5th with the MEVION S250i Proton Therapy System®.

The new Mercy Proton Therapy Center is one of only 40 treating centers in the U.S. Thanks to the compact size of the MEVION S250i, Mercy was able to integrate the addition into the existing radiation oncology department, enabling the hospital to share existing resources and maintain a full continuum of care for patients.

A ribbon-cutting event was held on June 30 with members from Mercy and Mevion Medical Systems.

 Mercy Proton Therapy Center Begins Treatment with Mevion System

Leaders gathered to cut the ribbon on the new Mercy Proton Therapy Center. Left to right: Dr. David Meiners, Mercy St. Louis President; Steve Mackin, Mercy President and CEO; Tina Yu, Mevion CEO and President; Dr. Robert Frazier, Division Chief of Radiation Oncology at Mercy St. Louis; Joe Pecoraro, Mercy St. Louis Executive Director of Oncology Services; John Timmerman, Mercy St. Louis Vice President of Operations.

“We know patients have choices when it comes to cancer care and when they choose Mercy, we want them to know they have access to all the options for care,” said Dr. Robert Frazier, division chief of radiation oncology at Mercy Hospital St. Louis. “Each patient is unique so no two treatment plans will be the same. At the David C. Pratt Cancer Center, we now have all the most advanced radiation therapy technologies, both Cyberknife and proton therapy, making sure we offer what’s best for each individual during their cancer therapy.”

The center features Mevion’s industry-leading HYPERSCAN® pencil beam scanning technology and Adaptive Aperture® pMLC. The powerful duo delivers faster and more precise, therapeutic doses of radiation to tumors while preserving surrounding healthy tissue and organs at risk, making proton therapy an ideal treatment choice for tumors near sensitive parts of the body such as the head and neck, spinal cord, breasts, esophagus, prostate, lung, bone, gastrointestinal, stomach, colon and bladder.

The MEVION S250i system at Mercy also integrates the CBCT imaging system and the C-RAD Catalyst PT surface-guided tracking system, enabling a cutting-edge Image-Guided Proton Therapy configuration for high-precision patient positioning and intra-fraction motion management.

“We congratulate Mercy for starting treatment with the Mevion proton therapy system,” said Tina Yu, chief executive officer and president of Mevion Medical Systems. “Mevion is proud to be a part of Mercy’s dedication to offering this state-of-the-art cancer treatment in St. Louis and the surrounding area.”

Mevion is the system provider for 60% of the clinical single-room proton centers in the U.S. and has treated over 7,000 patients worldwide.

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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About Mercy

Mercy, one of the 25 largest U.S. health systems, serves millions annually with nationally recognized quality care and one of the nation’s largest Accountable Care Organizations. Mercy is a highly integrated, multi-state health care system including more than 40 acute care, managed and specialty (heart, children’s, orthopedic and rehab) hospitals, convenient and urgent care locations, imaging centers and pharmacies. Mercy has 900 physician practices and outpatient facilities, 3,400 Mercy Clinic physicians and advanced practitioners, as well as more than 40,000 co-workers serving patients and families across Arkansas, Kansas, Missouri and Oklahoma. Mercy also has clinics, outpatient services and outreach ministries in Arkansas, Louisiana, Mississippi and Texas.


Jingyi Wang

Mevion Medical Systems