The present invention involves an angiography device for examining vessels of patients having an x-ray emitter and an associated detector, having an image processing unit, an image display unit, a control unit, a collision computer and sensors. The sensors, which are fastened to the angiography device, are designed to scan the outer dimensions of the patient prior to the actual examination and during the examination. The data obtained in this way can be fed into a memory of the collision computer and the system is controllable by a software of the collision computer such that the movement of the system when the system and patient become too close can be automatically slowed down or completely stopped by means of a the control unit.