Development of a LGSO detector using a tapered fiber for a high-resolution animal PET

A LGSO detector using tapered fiber was developed for a high-resolution positron emission tomography (PET) for small animals. The goal of the resolution of the animal PET is less than 1 mm. The detector consists of LGSO scintillators, a straight fiber optical plate (straight fiber), a tapered fiber optical plate (tapered fiber), and a position sensitive photo-multiplier tube (PSPMT). The tapered fiber that improves the spatial resolution magnifies the scintillation image of the LGSO block. The straight fiber is used for arranging the detector without any gaps between detectors. First, we measured the light output of a sub-millimeter LGSO scintillator that is used for the detector block. We also tested the light losses for LGSO scintillator when we use the straight fiber as well as tapered fiber between scintillator and PMT. Without the straight fiber, 4×4 LGSO block of 0.7 mm×0.7 mm×8 mm was resolved in 2 dimensional distribution. With the straight fiber of 60 mm, the resolution of 2 dimensional distribution became worse but still had reasonable resolution. With these results, we confirmed that the LGSO block of less than 1 mm will be possible with the proposed configuration for a high-resolution animal PET.