A method for overlaying a 3D volume image of a CT recording system and a 2D projection image of an angio recording system of an X-ray diagnostic facility including a rotatable gantry. The method includes providing a 3D volume image of an examination object reconstructed from a data record of the CT recording system and recording a 2D projection image of the examination object using the angio recording system. The method also includes determining a projection direction of the recorded 2D projection image in relation to the 3D volume image, based on the geometric arrangement between the recording systems. The method still further includes simulating a 2D projection image from the 3D volume image for the determined projection direction and matching the recorded 2D projection image and the simulated 2D projection image. The method includes overlaying the recorded 2D projection image and the 3D volume image, based on the matching.
