The invention relates to an interventional medical diagnosis or therapy system comprising: an imaging device, which is embodied for recording 3D images of an object under examination, with a control unit and an image processing unit; an at least two-axis robot arm, having means for yield control of the robot arm and a robot control unit for control of the robot arm; an instrument holder, which is connected to the robot arm, for holding an instrument; a position detection device, by means of which the position of the instrument is able to be detected for the robot control unit. The robot arm is embodied to yield to system-external force effects or to follow a system-external guidance.