A new High-Resolution Imaging System (HiRIS2) detector for preclinical SPECT imaging

The aim of the work is to describe a new high-performance scintigraphic detector, derived from our previous work based on a Position Sensitive Photomultiplier Tube (PSPMT) with 256 output anodes. This detector is suitable for direct integration into multi-modality imaging systems. Indeed, the detector has been developed in order to be integrated into a pre-clinical system. The detector is based on an H9500 Hamamatsu PSPMT coupled to an LYSO pixelated scintillator and a low-energy tungsten collimator with parallel square holes. In order to limit the overall size of the device, a dedicated compact electronics has been developed. The device design was performed using Monte Carlo transport calculations to aid the development. Our results show a detector performance suitable for application on small animals. The intrinsic spatial resolution was experimentally determined to be about 1.6 mm. The measured energy resolution was 16% at 140 keV and the maximum recorded sensitivity was 76 cps/MBq. In addition, the results agree quite well with those of Monte Carlo simulations. We have successfully improved the performance of our previous detector design in order to integrate the new device into a complex system focused on pre-clinical imaging.