MEVION S250 for Proton Radiation Therapy

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.

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.