Development of the SiliSPECT Small-Animal Imager

Abstract

SiliSPECT, a multi-pinhole, multi-detector SPECT system, was designed to image targeted regions of rodents at sub-300 micron resolution with stationary data acquisition. High spatial resolution is achieved with thick silicon double-sided strip detectors (DSSDs) and 250 micron pinhole apertures. Each of the two camera heads contain two stacked DSSDs, which collect four multi-pinhole projection images simultaneously, enhancing the total detection efficiency and permitting reconstruction based on the synthetic collimator method. The DSSDs were evaluated for imaging low-energy photons, such as the emissions from iodine-125. Trigger uniformity was improved with an iterative trim adjustment algorithm. Detection efficiency, dead time, charge-sharing, and other detector characteristics were measured. The system sensitivity, resolution, multiplexing and magnification of the full system were assessed. A calibration method was implemented to estimate the geometrical parameters of the system. SiliSPECT was fully characterized and readied for tomographic imaging studies.