In a method and system for monitoring the power state of an x-ray emitter and/or an x-ray detector, the x-ray emitter is operated according to a set of test parameters, so as to emit x-rays that strike at least a portion of the detector region of the x-ray detector. At least one value characterizing the operation of the x-ray emitter and/or the x-ray detector is determined, and this detected parameter is compared with a comparable reference parameter value. The power state of the x-ray emitter and/or the x-ray detector is determined based on deviation of the detected parameter from the reference parameter.