At an imaging site an imaging device (14) generates an image of a subject (4) and an imaging light markers generation device (6) generates light markers at locations on a surface of the subject before an interventional procedure is performed. At an interventional site an interventional light markers generation device (17) generates light markers at the locations on the surface of the subject (4) and a localization device (25, 27) determines the position of a catheter during the interventional procedure. A position determination unit (29) then determines the position of the catheter within the pre-interventional image based on the position of the catheter determined by the localization device and provided spatial relations between the devices used for generating the image and the light markers and for localizing the catheter. This allows showing the position of the catheter within the pre-interventional image without necessarily using x-rays.
