The device has a control unit (230) arranged within a hermetically sealed housing. A conductive element comprising electrode, antenna and coil, is coupled in preset format. The MRT interference fields are detected by detection unit connected to control unit and conductive element. The induced voltage from conductive element is converted into optical signals, by electro-optical converter (210) of detection unit. The MRI-safe state is switched when optical signal threshold or predetermined periodic occurrence of optical signals is exceeded.
