Proteus 235, ProteusPLUS or Proteus ONE produces and delivers a proton beam for the treatment of patients with localized tumors and other conditions susceptible to treatment by radiation.

When switching from Pencil Beam Scanning treatment mode to Uniform Scanning treatment mode, the tuning setpoints of the scanning magnets are not always taken into account when the proton beam is requested. The mismatch between the setpoint and feedback leads to an error message. Depending on user action, two scenarios are possible: 1. The user resumes the treatment field without analyzing the cause for the error message. This may lead to under-irradiation. 2. The user reboots the Scanning Magnets Power Supply Electronic Unit. This may lead to delay in patient treatment and the patient may need to be re-aligned, which leads to an additional X-ray dose.

On January 26, 2018, the firm sent Field Safety Notices to all its consignees by email or delivered personally, alerting them of the issue. The notice recommended that users not resume pauses in Uniform Scanning more than twice without informing on-site firm personnel. The firm also recommended rebooting the Scanning Magnets Power Supply Electronic Unit if the issue occurs. The recalling firm stated it would implement an upgrade of the Scanning Magnet Power Supply Electronic Unit at all affected sites by June 30, 2018. Consignees were instructed to sign and return a copy of a notice read confirmation within 10 working days. Recalling firm Helpdesk Contact: +32 2 507 20 81 (available 24/7)