Use cautionMedical device recall · FDA · Published October 19, 2020
Mevion S250i/S250 Proton Therapy System: Treatment Beam Info Disappears During Use
Mevion recalls S250i and S250 proton radiation treatment systems due to risk of missing treatment beam information during patient therapy, potentially causing harm.
Treatment beam information disappears on Treatment Console screen while beam delivery continues potential for harm to a patient could occur
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Contact the company
📍Recalling firmMevion Medical Systems, Inc.300 Foster St · Littleton, MA 01460-2017
✎ GovInfoNow plain-language explainer
Mevion is recalling its S250i and S250 proton radiation treatment systems because the treatment console may show disappearing beam information while delivering radiation, which could harm patients. This issue affects specific units with serial numbers listed in the recall notice. Read more at govinfonow.com/recall/64076-mevion-s250i-s250-proton-therapy-system-treatment-beam-info-disappears.
“Mevion S250i/S250 Proton Therapy System: Treatment Beam Info Disappears During Use.” GovInfoNow, updated August 19, 2026. https://govinfonow.com/recall/64076-mevion-s250i-s250-proton-therapy-system-treatment-beam-info-disappears. Based on FDA recall #Z-0485-2021 (https://api.fda.gov/device/enforcement.json?search=recall_number:%22Z-0485-2021%22&limit=1).
The FDA announced on 2020-10-19 that Mevion Medical Systems, Inc. is recalling its MEVION S250i and MEVION S250 Proton Radiation Treatment Systems due to a hazard where treatment beam information disappears from the console screen while delivery continues. According to the FDA, this malfunction could potentially harm patients.
How to tell if you have it
MEVION S250i, MEVION S250; Proton Radiation Treatment System
UPC 00864366000100
UPC 00864366000124
The hazard
The treatment beam information disappears on the Treatment Console screen while beam delivery continues, creating a potential for harm to a patient. The record does not report specific incidents or injuries.
Context
GovInfoNow's records show Mevion Medical Systems, Inc. has had five other recalls since 2018-06-29, including the 2022-02-01 Mevion S250 Hand Pendant Recall for unintentional motion risk and the 2020-06-23 Mevion S250 Proton Therapy System Recall for sharp screen risks. Other recent recalls of similar products include the IBA Proton Therapy System PROTEUS 235 Recall (2026-02-03) and the Hitachi Proton Beam Therapy System Recall (2026-02-06).
How to tell if you have this one
Check for serial numbers starting with MEVION S250-0001 through MEVION S250-0008. The unique device identifiers (UDIs) listed in the recall include specific date codes that match the affected units.
Brand
Mevion
Product
MEVION S250i, MEVION S250; Proton Radiation Treatment System
Category
Medical device
Based on the official FDA remedy
What to do — step by step
Check Serial Numbers
Verify your system's serial number against the list of affected units: MEVION S250-0001 through MEVION S250-0008.
Where it went and when
Where it was distributed
Distributed nationwide and abroad; the notice names 4 states.
Named in the notice
Covered by “nationwide”
Not listed
FDA distribution: “Worldwide distribution - US Nationwide distribution including in the states of DC, FL, MO, NJ, OK and the country of Netherlands.” States read from FDA’s own wording; “not listed” means the notice does not name it.
Named in the notice: District of Columbia, Florida, Missouri, New Jersey, Oklahoma.
Recall timeline
FDA terminated this recall 10 months after the firm started it.
1Firm started the recall
2FDA classified it Class II
3Published in FDA’s Enforcement Report
4FDA terminated the recall
Dates from the agency record only; steps without a date are left out.
The facts (hazard, remedy, dates, manufacturer) are pulled from the official FDA recall record. The plain-language summary and step-by-step checklist are written by GovInfoNow to make the official notice easier to act on — they don’t replace it.
Official source: FDA Recall #Z-0485-2021 (October 19, 2020) — FDA publishes no per-recall page; this is the official machine-readable enforcement record. Search FDA recalls for Z-0485-2021 to see it in context.
Plain-language summary written by qwen3:4b on August 19, 2026, from the official record above. Not reviewed by a person — if it conflicts with the FDA notice, the notice is correct. Report an error on this page.
GovInfoNow is an independent service and is not a government agency. We republish official FDA recall data; we don’t issue, amend or administer recalls.