An imaging medical device includes a detector including an active material which is serviceable in a state of thermodynamic equilibrium, a primary power supply designed to supply the imaging medical device with power in an operating state, and an ancillary power supply designed to maintain a thermodynamic equilibrium in the active material of the detector in a non-operating state of the imaging medical device to keep the detector in a state of readiness. A method for operating such an imaging medical device is disclosed, wherein in the operating state, the imaging medical device is supplied with power via the primary power supply, and wherein in the non-operating state, a thermodynamic equilibrium is maintained in the active material of the detector, with power supplied by the ancillary power supply. The detector is thereby kept in a state of readiness.