LITTLETON, Mass. — Mevion Medical Systems said Tuesday that its MEVION S250-FIT proton therapy system has received CE Marking under the European Union’s Medical Device Regulation, clearing the way for the system to be marketed and used clinically across EU member states.
The approval follows completion of the conformity assessment process under Regulation (EU) 2017/745 and builds on the system’s U.S. FDA 510(k) clearance, which was granted in September 2025. Company officials said the milestone significantly expands global access to compact proton therapy technology.
The MEVION S250-FIT is designed to fit inside a standard radiation therapy vault, allowing hospitals and cancer centers to deploy proton therapy using existing infrastructure. By eliminating the need for purpose-built bunkers, the system aims to reduce the cost, construction complexity, and timelines that have historically limited broader adoption of proton therapy.
“With both FDA clearance and CE Marking now in hand, the MEVION S250-FIT is positioned to transform how proton therapy is delivered worldwide,” said Tina Yu, Ph.D., CEO and President of Mevion Medical Systems. “For European health systems that have long recognized the clinical benefits of proton therapy but faced significant infrastructure and financial barriers, the S250-FIT offers a fundamentally new approach that brings high-quality proton therapy directly into existing treatment environments.”
According to the company, the system incorporates its HYPERSCAN pencil beam scanning platform for intensity modulated proton therapy, enabling highly conformal dose delivery with rapid energy layer switching. It also includes an Adaptive Aperture proton multi-leaf collimator and is designed to support DirectARC proton arc therapy for faster, VMAT-like treatment delivery.
The platform integrates a large-bore diagnostic CT scanner aligned to the treatment isocenter, supporting advanced image-guided and adaptive radiation therapy workflows. An upright patient positioning system is intended to increase flexibility in patient setup and may offer clinical advantages for certain tumor sites. The system is also described as FLASH research ready.
Mevion said the CE Mark comes amid growing global momentum for the S250-FIT platform. The company has signed contracts with nine institutions worldwide and announced installations and partnerships with several major U.S. medical centers. The architecture also builds on the earlier MEVION S250i platform, which has been in clinical operation at a proton therapy center in the Netherlands since 2018.
With the new European approval, Mevion said cancer centers across the EU can now evaluate the S250-FIT as a practical option for establishing or expanding proton therapy programs without undertaking large-scale construction projects.
