A method for determining the location, in a coordinate system, of a target position for an invasive medical procedure on a patient. An entry mark that defines the coordinate system and indicates an entry position for the procedure is affixed to the patient. A site marker, which can be identified in a radioscopy image, is fixed in a known relative location in the coordinate system. At least two 2D radioscopy images of the patient, which both depict the respective site marker and the target position, are recorded from different recording directions. The location of the target position in the coordinate system is determined from the representation of the target position and from the representation of the site marker in the 2D radioscopy images and from the relative location of the site marker in the coordinate system.