Distance-driven binning for proton CT filtered backprojection along most likely paths

We propose to account for curved most likely paths of protons in proton CT using an approximate adaptation of filtered backprojection algorithms. The protons are first binned in several proton radiographies at different distances to the source of protons. The adequate radiography is then used during backprojection depending on the distance to the source. The efficiency of the distance-driven binning on spatial resolution is demonstrated on a Monte Carlo simulated phantom with a circular trajectory and a cone-beam of protons.