A method includes registering a first coordinate system of a fluoroscopic imaging system and a second coordinate system of a magnetic position tracking system. A three-dimensional (3D) map of an organ of a patient, which is produced by the magnetic position tracking system, is displayed. A 3D volume that would be irradiated by the fluoroscopic imaging system is calculated using the registered first and second coordinate systems. The calculated 3D volume is marked on the 3D map.