# K172848: MEVION S250i Proton Beam Radiation Therapy Device

- Pathway: 510(k) (Traditional)
- Applicant: Mevion Medical Systems
- Decided: Dec 27, 2017 after 99 days
- Product code: LHN (System, Radiation Therapy, Charged-Particle, Medical)
- Device class: 2
- Regulation: 21 CFR 892.5050
- Recalls of this device: 5 (0 Class I)
- Data: FDA decisions to Oct 25, 2026; recalls to Oct 12, 2026

## Lineage
Longest line of descent: 7 generations back to K872369 (1988). 15 ancestors in all.
2 later devices descend from it; 1 cites it directly.
0 of 18 devices in its family (counting itself) have a Class I recall.

## Predicates on the family tree (from the FDA summary)
- K120676: S-250 Proton Beam Radiation Therapy System, Mevion Medical Systems (2012) Summary page 7.
- K152224: Proton Therapy System - Proteus 235 (Proteus One, Proteus Plus, Proteus TK2), Ion Beam Application S.A. (2016) Summary page 8.

## Most influential descendants
- K250986: S250-FIT Proton Beam Radiation Therapy Device (S250-FIT) (2025), 1 descendant of its own
- K253406: S250-FIT Proton Beam Radiation Therapy Device (S250-FIT) (2026), 0 descendants of its own

## Recalls of this device
- Feb 1, 2022 · Class II · Z-0827-2022: Malfunction of the hand pendant controlling movement of the therapy couch and nozzle may result in unintentional motion. Patient injury is possible if they come in contact with the nozzle or other obj
- Oct 19, 2020 · Class II · Z-0485-2021: Treatment beam information disappears on Treatment Console screen while beam delivery continues potential for harm to a patient could occur
- May 15, 2020 · Class II · Z-2406-2020: Couch Correction moves sent after using a 3D CT scan are partially lost if the previous correction sent or recorded had some of the Couch Correction checkboxes turned off
- Oct 1, 2018 · Class II · Z-0705-2019: Treatment is allowed to continue (via partials) in situations where dDose1 interlock has tripped
- Jun 29, 2018 · Class II · Z-2746-2018: QFix has advised Mevion Medical Systems that they are identifying unauthorized combinations of QFix Couch Tops with non-QFix devices in clinical use. The kVue Oen Touch latch consists of a precision l

## Indications for use
The MEVION S250i is intended to deliver proton radiation therapy treatment to patients with localized tumors or other conditions susceptible to treatment by radiation.

Source page: https://510kreport.com/device/K172848
Methodology: https://510kreport.com/methodology