A method includes registering a first coordinate systemof a fluoroscopic imaging system and a second coordinatesystem of a magnetic position tracking system. Athree-dimensional (3D) map of an organ of a patient, which isproduced by the magnetic position tracking system, isdisplayed. A 3D volume that would be irradiated by thefluoroscopic imaging system is calculated using theregistered first and second coordinate systems. Thecalculated 3D volume is marked on the 3D map.