More than 100 guests explored how compact proton therapy systems are built and experienced upright positioning firsthand.

The day before the ASTRO 2026 exhibit hall opened, Mevion welcomed more than 100 guests to its headquarters in Littleton, Massachusetts. Visitors moved through the manufacturing floor and treatment demonstration areas in groups, taking different routes through ten stops that connected treatment planning, accelerator construction and patient positioning.

Planning and Imaging

RaySearch Laboratories demonstrated treatment planning for Mevion systems, showing how the planning software and machine work together to deliver a treatment. Another stop explored imaging and the development of adaptive workflows to account for changes in patient anatomy.

Upright Positioning Firsthand

Guests tried the MEVION S250-FIT’s upright positioning system and spoke with therapists who use it every day. Leo Cancer Care’s Marie® positioner supports patients in positions ranging from fully seated to perched. Pediatric demonstrations included a forward-facing positioning concept for craniospinal treatment and a car-seat-style chair already used at Stanford. Our Meet the Experts Theater recap explores the clinical experience behind that work.

On the Manufacturing Floor

The manufacturing floor gave visitors a close look at the superconducting technology behind Mevion’s compact accelerators. Kilometers of conductor strand go into the magnets. Their strong magnetic field keeps protons moving in tight orbits, helping reduce the accelerator’s size to roughly 1.8 meters diameter. Seeing the components and assembly work made the engineering behind compact proton therapy tangible.

In the pre-integration manufacturing bay, guests saw a MEVION S250 series accelerator taking shape. They also learned how a system connects to a building through a single point for power and a single point for chilled water. These details connected the manufacturing work to a question raised that morning at the symposium: how to bring proton therapy into an existing radiation oncology department.

Beam Delivery

The HYPERSCAN Direct Beam delivery demonstration explained how rapid energy changes move the beam through successive treatment layers. Adaptive Aperture, Mevion’s proton multi-leaf collimator, shapes the dose edge to limit exposure to surrounding healthy tissue. Visitors also learned about the system’s ultra-high dose-rate capabilities for FLASH research, an area still under development for clinical use.

The Treatment Room

In the FIT demonstration room, visitors saw how beam delivery, patient positioning and imaging come together. The control room showed how therapists manage those functions and monitor patients during treatment. Supporting equipment can be arranged in different configurations, with routing developed around each facility’s space, structural, shielding and access requirements.

From Manufacturing to Treatment

From superconducting conductor to upright patient positioning, the tour connected the work on the manufacturing floor with the demands of delivering treatment. It gave guests a closer understanding of how the components, software and clinical workflows come together in a compact proton system.