1. A process for determining the actual position of a structure of an object to be examined ( 1 ) in a coordinate system, whereby a CT scanner is employed which uses CT technology, having a first coordinate system, the CT coordinate system, related to said CT scanner, and a coordinate measuring instrument (MI) is employed which is either a tactile or an optical coordinate measuring instrument or a multisensor coordinate measuring instrument or an ultrasonic coordinate measuring instrument, having a second coordinate system, the MI coordinate system, related to said coordinate measuring instrument, whereby a) the coordinates of the object to be examined ( 1 ) are determined in the MI coordinate system, b) a target position of the structure within the object to be examined ( 1 ) is predefined, c) after the execution of steps a) and b), the target position is determined in the MI coordinate system, d) and, using the result of step c), the object to be examined ( 1 ) is positioned in such a way that the target position of the structure comes to lie within the volume detected by the CT scanner.