Proton Pencil Beam Scanner Installed at US University Hospital

The first installation of a novel, advanced, proton-therapy pencil beam scanning system that provides a new standard of Intensity Modulated Proton Therapy (IMPT) for cancer treatments, has taken place in a university hospital in the US.

The new standard combines fast energy-modulation with a sharp lateral penumbra, and is intended to improve treatment options for cancer patients.


The Mevion Medical Systems MEVION S250i with HYPERSCAN system was installed at the MedStar Georgetown University Hospital. A second system will be installed in a Netherlands’ clinic, and another in a cancer center in Florida, in the US.

The system uses Mevion Medical System’s proton multi-leaf collimator called Adaptive Aperture, a low-profile system designed specifically for the new MEVION S250i scanner. The system provides layer-by-layer beam collimation and can achieve collimated effective spot sizes of one to three millimeters, for all energies. The new system can be used to scan a typical lung tumor within two seconds or less, eliminating patient motion artifacts.

The MEVION S250mx is a scalable proton therapy solution for two to four-room designs that provide redundancy and 100% uptime. The MEVION S250i system with HYPERSCAN and Adaptive Aperture is currently pending clearance by the US FDA for clinical use.

President and CEO of Mevion Medical Systems, Joseph K. Jachinowski, said, "Mevion is proud to be working with MedStar Georgetown to achieve this milestone, and to be making proton therapy accessible to the Washington D.C. area. HYPERSCAN with Adaptive Aperture represents a real paradigm shift for the entire industry. This is the only proton system able to precisely shape each energy layer and deliver those layers at speeds up to 50 times faster than other systems. The results are highly conformal proton dose distributions that can be automatically adapted as treatment progresses."