The invention relates to an X-ray tube, especially a microfocus X-ray tube (2), comprising means (18) for orienting an electron beam (10) towards a target (4). A control device (20) is used to control the means for orienting the electron beam (10) towards the target (4) in such a way that the electron beam (10) scans the target (4), in addition to a measuring device (22) for measuring the intensity of the target current which flows to different scanning sites when the target (4) is scanned by the electron beam (10), or a measuring variable dependent on the target current, and an evaluation device (24) for associating each measured value of the target flow with the corresponding scanning site. Said X-ray tube enables the easy and economical implementation of a method for checking the operability of the target (4).