1. A method for assisting a physician track a point in a non-rigid body organ of a subject in real time, said method comprising the steps of: a) receiving a 3D image data set of the non-rigid body organ in a first position and computing a 3D model of the body organ; b) receiving a real-time fluoroscopy image from a fluoroscopy unit, said fluoroscopy image showing a reference mark in the non-rigid body organ; and c) deforming the 3D model of the non-rigid body organ to match the body organ of the subject in a second position and based on the reference mark, said second position corresponding to the position of the body organ and subject in real time.