Tracking synthetic particle paths generated in GATE with multi-positron emission particle tracking (MPEPT)

Multi-Positron Emission Particle Tracking (MPEPT) is able to reconstruct the position of point-sources in a PET scanner to a high degree of accuracy. Experimental and simulated trajectories of activated point-sources are compared herein to validate the GATE model of our PET scanner, and test MPEPT performance. The trajectory followed by one point-source of activity 370000 Bq is simulated in GATE, and experimentally measured for velocities 0.18, 0.22. and 0.45 cm/s moving along the major axis of the detector bore. The average difference between the prescribed and predicted point-source positions is found to be approximately 0.3 mm. However, the number of Lines of Response (LOR) reported by GATE for the 370000Bq source is larger than the number of LOR measured in the experiments. Additional testing of the accuracy of MPEPT is provided by the simulation of 20 point-sources of 20 Bq each placed around the surface of a sphere of radius 40 mm and moving radially inward to a radius of 20 mm at a constant velocity of 1E-6 m/s. Pointsource trajectories for the GATE simulation are compared to trajectories reconstructed from the GATE generated LOR using MPEPT. The average difference between prescribed and predicted point-source position is found to be approximately 0.72 mm.