January 26, 2012 — Mevion Medical Systems announced that it has closed a $45 million investment from ProQuest Investments and its existing investors, including Caxton Heath Life Sciences, Venrock and CHL Medical Partners. Mevion is the manufacturer of the Mevion S250 proton therapy system. The capital will be used to accelerate the manufacturing and worldwide deployment of the Mevion S250.
Proton beam radiation therapy permits more precise dose targeting by complete proton absorption at predictable tissue depth, allowing the treatment of target volumes adjacent to critical structures without inadvertent dose to sensitive structures. The availability of proton therapy has remained very limited, however, due to the enormous cost, large footprint and technical complexity of traditional proton systems. Powered by a TriNiobium Core, the Mevion S250 significantly reduces the cost, size and complexity to levels similar to other modern X-ray radiation therapy devices, and brings accessibility, affordability and practicality to proton therapy.
The Mevion S250 proton therapy system has yet to be cleared by the U.S. Food and Drug Administration (FDA) for clinical use.
For more information: www.mevion.com
April 10, 2026 
