The invention relates to a device for merging a 2D radioscopy image with an image obtained from a 3D image data record, having a memory unit that stores the 2D radioscopy image and the 3D image data record, a segmentation unit that segments an inner surface of a hollow organ from the 3D image data record, a registration unit that registers the 2D radioscopy image with the 3D image data record, a back-projection unit that back-projects the pixels of the 2D radioscopy image onto the segmented surface, taking account of the projection geometry of the 2D radioscopy image and the registration, and an image merger unit that generates a virtual endoscopy view of the surface from the segmented surface using the back-projected pixels. The device primarily allows 2D radioscopy images to be superimposed during interventional procedures with a fly display of the interior of an interesting organ.