A system for navigating an interventional device within a tubular structure of an object; comprising: an X-ray image acquisition device; a processing unit; and an interface; wherein the X-ray image acquisition device is adapted to acquire 2D X-ray fluoroscopy image data in one projection geometry of a region of interest of the tubular structure; wherein said 2D X-ray fluoroscopy image data comprise a 2D X-ray image, wherein only one projection is provided for the 2D X-ray image; wherein the interventional device lies within a segment of the tubular structure throughout the navigational procedure; wherein the processing unit is adapted to detect the interventional device in the 2D X-ray image; to determine the 2D position of the interventional device in the 2D X-ray image; to register the 2D X-ray image with a previously acquired 3D dataset of the region of interest of the tubular structure; to map the determined 2D position of the interventional device to a position in the 3D dataset; to extract local 3D parameters of the tubular structure at the position of the interventional device; and to generate navigational information on behalf of the determined 3D position of the interventional device and the extracted local 3D parameters; wherein the processing unit is adapted to register the 2D X-ray image such that a spatial orientation and position of a 3D volume of the 3D data set corresponds to a spatial orientation and position of the tubular structure of the object of interest based on the 2D X-ray fluoroscopy image data; and wherein, to extract the local 3D parameters, the processing unit is adapted to determine the orientation of a surrounding tubular structure in the 3D dataset of the region of interest of the tubular structure; and to determine the orientation (218, 222, 522) of the interventional device in relation to the surrounding tubular structure; wherein the processing unit is adapted to convert the navigational information into graphical advisory information; wherein the graphical advisory information comprises an orientation indicator being an orientation vector and/or a depth indicator indicating the depth of the tubular structure; wherein the processing unit is adapted to transform the 2D X-ray image data into enhanced 2D image data by superimposing the graphical advisory information with a 2D X-ray image; and wherein the interface is adapted to provide the navigational information in form of the enhanced 2D image data for displaying to the user. an X-ray image acquisition device; a processing unit; and an interface; wherein the X-ray image acquisition device is adapted to acquire 2D X-ray fluoroscopy image data in one projection geometry of a region of interest of the tubular structure; wherein said 2D X-ray fluoroscopy image data comprise a 2D X-ray image, wherein only one projection is provided for the 2D X-ray image; wherein the interventional device lies within a segment of the tubular structure throughout the navigational procedure; wherein the processing unit is adapted to detect the interventional device in the 2D X-ray image; to determine the 2D position of the interventional device in the 2D X-ray image; to register the 2D X-ray image with a previously acquired 3D dataset of the region of interest of the tubular structure; to map the determined 2D position of the interventional device to a position in the 3D dataset; to extract local 3D parameters of the tubular structure at the position of the interventional device; and to generate navigational information on behalf of the determined 3D position of the interventional device and the extracted local 3D parameters; wherein the processing unit is adapted to register the 2D X-ray image such that a spatial orientation and position of a 3D volume of the 3D data set corresponds to a spatial orientation and position of the tubular structure of the object of interest based on the 2D X-ray fluoroscopy image data; and wherein, to extract the local 3D parameters, the processing unit is adapted to determine the orientation of a surrounding tubular structure in the 3D dataset of the region of interest of the tubular structure; and to determine the orientation (218, 222, 522) of the interventional device in relation to the surrounding tubular structure; wherein the processing unit is adapted to convert the navigational information into graphical advisory information; wherein the graphical advisory information comprises an orientation indicator being an orientation vector and/or a depth indicator indicating the depth of the tubular structure; wherein the processing unit is adapted to transform the 2D X-ray image data into enhanced 2D image data by superimposing the graphical advisory information with a 2D X-ray image; and wherein the interface is adapted to provide the navigational information in form of the enhanced 2D image data for displaying to the user.