DOI PET detectors with scintillation crystals cut as triangular prisms

For depth of interaction (DOI) encoding on a PET detector, we propose to use scintillation crystals, each cut as a triangular prism. Demonstration of the method for the 3-layer and 2-layer DOI encodings was carried out with two shapes of Lu2xGd2(1−x)SiO5 (LGSO) crystals: an equilateral triangle of 3.0 mm length per side and a isosceles right triangle of 3.0 mm length for two sides in their horizontal cross section. The height of each crystal prism was 10.0 mm. The former and latter crystal shapes were arranged in 3-layer and 2-layer DOI array, respectively, and their performances were evaluated by coupling the array to a position sensitive photomultiplier tube (PS-PMT). By Anger-type calculations of the PS-PMT signals, we obtained 2-dimensional position histograms in which responses of the crystals in all layers were represented. Both DOI detectors showed promising results for crystal identification and energy performances.