DOI- and TOF-capable PET array detector using double-ended light readout and stripline-based row and column electronic readout.

Abstract

We investigate a highly multiplexing readout for depth-of-interaction (DOI) and time-of-flight PET detector consisting of an N×N crystals whose light outputs at the front and back ends are detected by using silicon photomultipliers (SiPM). The front N×N SiPM array is read by using a stripline (SL) configured to support discrimination of the row position of the signal-producing crystal. The back N×N SiPM array is similarly read by an SL for column discrimination. Hence, the detector has only four outputs. We built 4×4 and 8×8 detector modules (DM) by using 3.0×3.0×20 mm3 lutetium-yttrium oxyorthosilicates. The outputs were sampled and processed offline. For both DMs, crystal discrimination was successful. For the 4×4 DM, we obtained an average energy resolution (ER) of 14.1%, an average DOI resolution of 2.5 mm, a non DOI-corrected coincidence resolving time (CRT), measured in coincidence with a single-pixel reference detector, of about 495 ps. For the 8×8 DM, the average ER, average DOI resolution and average CRT were 16.4%, 2.9 mm, and 641 ps, respectively. We identified the intercrystal scattering as a probable cause for the CRT deterioration when the DM was increased from 4×4 to 8×8.