1. A method, comprising; registering a first coordinate system of a fluoroscopic imaging system and a second coordinate system of a magnetic position tracking system; displaying a three-dimensional (3D) magnetic position tracking map of an organ of a patient, which is produced by the magnetic position tracking system; calculating, based on aligned coordinates of the registered first and second coordinate systems, a 3D volume that would be irradiated by the fluoroscopic imaging system according to a direction in which the fluoroscopic imaging system is pointing; and marking the calculated 3D volume on the 3D magnetic position tracking map.