Design and construction of a multi-slice, depth-of-interaction MR-compatible PET

We are now developing a multi-slice depth-of interaction (DOI) MR-compatible PET system The MR compatible PET system is for imaging small animals such as mouse or rat. The PET system employs previously reported concept of the DOI block detectors made of scintillators, optical fibers, and multi-channel position sensitive photo-multiplier tubes (PSPMTs). The scintillator was changed from LSO to MLS. The size of a single MLS was enlarged to 2.5 mm×3.5 mm×3.5 mm to increase the system sensitivity. Eight MLSs were combined to form a DOI block detector and connected to four optical fibers via light guides. Thirty two sets of block detectors were arranged in a circular ring of which diameter is 51 mm. Full sets of the DOI block detectors were fabricated and arranged in the ring. Position histograms showed reasonable separations for all block detectors. The MR compatible PET system will have 3 imaging slice, two layers DOI detection capability, and spatial resolutions of around 2 mm FWHM in transaxail and axial directions.