An assisting apparatus for assisting a user in moving an insertion element to be inserted into an object to a target element within the object being a living being, wherein the target element is an inner part of the living being, the assisting apparatus comprising: - a target element image providing unit for providing a target element image showing the target element, wherein the target element comprises at least one opening, - a target element representation generating unit for generating a target element representation (38; 48) representing the at least one opening of the target element within the object in its three-dimensional position and three-dimensional orientation and with its size based on the target element image, wherein the target element representation generating unit is adapted to generate a target element representation comprising at least one ring representing the at least one opening of the target element within the object in the three-dimensional position, the three-dimensional orientation and size of the at least one opening of the target element, wherein the target element representation generating unit is adapted to segment the target element within the provided target element image for generating the target element representation, - a tracking unit for tracking a three-dimensional position of the insertion element within the object, while the insertion element is moved to the target element, wherein the tracked insertion element has at least one opening, - means to determine at least one ring representing the at least one opening of the insertion element, and - a display for displaying the at least one ring of the target element representation and the at least one ring representing the at least one opening of the insertion element, wherein the target element image providing unit and the tracking unit are registered with respect to each other. - a target element image providing unit for providing a target element image showing the target element, wherein the target element comprises at least one opening, - a target element representation generating unit for generating a target element representation (38; 48) representing the at least one opening of the target element within the object in its three-dimensional position and three-dimensional orientation and with its size based on the target element image, wherein the target element representation generating unit is adapted to generate a target element representation comprising at least one ring representing the at least one opening of the target element within the object in the three-dimensional position, the three-dimensional orientation and size of the at least one opening of the target element, wherein the target element representation generating unit is adapted to segment the target element within the provided target element image for generating the target element representation, - a tracking unit for tracking a three-dimensional position of the insertion element within the object, while the insertion element is moved to the target element, wherein the tracked insertion element has at least one opening, - means to determine at least one ring representing the at least one opening of the insertion element, and - a display for displaying the at least one ring of the target element representation and the at least one ring representing the at least one opening of the insertion element, wherein the target element image providing unit and the tracking unit are registered with respect to each other. <EOS>