S250-FIT Proton Beam Radiation Therapy Device (S250-FIT)

The MEVION S250-FIT is a proton beam radiation therapy system that delivers therapeutic proton radiation to patients with localized tumors and other radiation-susceptible conditions, particularly those above the mid-chest or carina when the patient is in a fully seated position. The device uses a 230 MeV superconducting synchrocyclotron with pencil beam scanning modality and includes an optional 2D oblique X-ray imaging subsystem for patient alignment verification.

The subject device is identical to its predicate in all core specifications: 230 MeV synchrocyclotron, 30-230 MeV usable energy, pencil beam scanning, 2 Gy/min dose rate, ±0.1 g/cm² spot range accuracy, and boron-carbide ceramic range shifter plates. The only difference is the addition of an optional 2D Oblique X-Ray imaging system for secondary patient positioning verification, which does not modify the primary treatment delivery method or allow deltas to the upright positioner.

Testing followed IEC 60601-1 (medical electrical equipment safety), IEC 60601-1-2 (EMC), IEC 60601-2-68 (X-ray image-guided radiotherapy), IEC 60601-2-54 (X-ray equipment), IEC 60825-1 (laser safety), IEC 62304 (software development), ANSI/AAMI SW96:2023 (cybersecurity), IEC 62366-1 (human factors), and relevant FDA guidance documents on software, cybersecurity, and human factors.

The subject device is substantially equivalent because both the subject and predicate devices have identical intended use, the same core technical specifications and beam delivery characteristics, and the optional 2D imaging subsystem does not raise new safety or effectiveness questions as it provides only secondary verification without affecting primary treatment delivery or clinical outcomes.