Simulated camera data of 161.6 MeV proton beam(s): (a) camera data from the side view, px, and (b) from the head-on view, pz, of a single proton beam. (c) camera data from the side view, px, and (d) from the head-on view, pz, of the 69 161 MeV proton beams in a prostate treatment plan.