A method for determining the position of a stent within a body, comprising the steps of: providing a 3D dataset of voxels representing a 3D image containing the stent; determining a starting position for the determination of the stent position; determining the axis of symmetry of the stent in the 3D dataset; determining a second dataset representing at least one image containing the stent in its present position; and determining the positional offset of the stent by image fusion using the 3D dataset and the second dataset and by penalizing a rotation around the axis of symmetry as compared to the starting position.