  Proton Computed Tomography (CT) is a prototype imaging modality for the
reconstruction of the Relative Stopping Power of a patient, for more accurate
calculations of the dose distributions in proton therapy dose planning. The
measurements needed for the reconstruction of a proton CT image are: i) each
initial proton vector incident on the imaged object, ii) each proton vector
incident on the front face of the detector and iii) the stopping depth of each
proton in the detector. In this study, a track reconstruction algorithm is
adapted for a planned pixel-based particle-tracking range telescope for proton
CT, called the Digital Tracking Calorimeter (DTC). The algorithm is based on
the track-following scheme, in which a growing track searches for deeper-laying
activated pixels, while minimizing the accumulated angular change. The
algorithm is applied to Monte Carlo-simulated output of the DTC, showing that
the DTC is able to reconstruct the tracks and find the depths of up to several
hundred simultaneous proton tracks.
