Z-1529-2016Class II

MEVION S250 for Proton Radiation Therapy

Name: Z-1529-2016 MEVION S250 for Proton Radiation Therapy
Creator: Mevion Medical Systems, Inc.
Published: 2016-03-15
License: https://open.fda.gov/license/

Mevion Medical Systems, Inc. / initiated 2016-03-15 / Terminated / root cause: design

FDA source

Mevion Medical Systems, Inc. began a recall of MEVION S250 for Proton Radiation Therapy on 2016-03-15. FDA classified it as Class II and gives the reason as "Possibility of Gantry Motion with Aperture or Compensator only partially inserted. An Aperture may fall out during Gantry motion. It is possible that it can hit a patient and cause traumatic injury or death". As of 2026-09-10, the recall status on record is Terminated, and MDM tags the root cause as design.

Recall record

Recall number: Z-1529-2016
Classification: Class II
Status: Terminated
Initiated: 2016-03-15
Posted: 2016-04-20
Terminated: 2017-08-24
Recalling firm: Mevion Medical Systems, Inc.
Product: MEVION S250 for Proton Radiation Therapy
Product code: LHN System, Radiation Therapy, Charged-Particle, Medical
Reason for recall: Possibility of Gantry Motion with Aperture or Compensator only partially inserted. An Aperture may fall out during Gantry motion. It is possible that it can hit a patient and cause traumatic injury or death.
Root cause tag: design
FDA root cause: Device Design
Action: Customer notification letters were sent to customers on March 15, 2016, by certified mail, return receipt requested, as well as by email. The letter explains the problem, description of potential harm, and the cause containment, and mitigation. The cause of the malfunctioning sensors was discovered to be a non-conforming limit switch assembly. A Mevion Field Service Engineer will immediately inspect all such parts in the field for similar non-conformance, and replace those parts if necessary. In addition, a new periodic preventive maintenance check will be performed to individually test each of the redundant sensors at all sites. In the interim period, on a daily basis, until the inspection, repair, and the preventive maintenance check is completed at any site, Mevion Field Service will check that the Applicator Door interlock sensors are working properly. Mevion will also update the inspection procedure for incoming parts to ensure that any non-conformance is identified early in the manufacturing process.
Quantity in commerce: 5
Distribution: US nationwide distribution to MO, OK, FL, and NJ.
Product codes and lots: S250-0002

Enforcement reports

One row per recalled product line

FDA enforcement reports joined to recall event Z-1529-2016
Recall number	Class	Status	Voluntary or mandated	Report date	Classified
Z-1529-2016	Class II	Terminated	Voluntary: Firm initiated	2016-04-27	2016-04-20

Product code LHN

K120676Class IIS-250 Proton Beam Radiation Therapy SystemMevion Medical Systems / cleared 2012-06-04

MDM coverage of this record lists here, newest first.

About this record

Sourced from the FDA device recall database and the FDA enforcement reports, both ingested from openFDA. The recall record supplies the product, the reason and the product code; the enforcement report supplies the classification. The two datasets are exported by FDA on different days, and the date above is the older of the two, so nothing on this page is newer than it says.

MDM adds the root cause tag, derived from FDA’s own root cause text, and the cross-links to the product code, the clearances named on the record and MDM coverage. Where a recall has not been joined to an enforcement report, no classification is shown.

Data as of 2026-09-30, the FDA export date for this dataset. Page last changed 2026-09-05. View this recall on fda.gov (opens on fda.gov)