Design of a Multi-Technology Pre-Clinical SPECT System

All imaging techniques have fundamental trade-offs as a consequence of the physics that govern the image-forming technique in combination with limitations imposed by the detector technology. In SPECT systems that trade-off is between energy resolution, spatial resolution, field of view, and sensitivity. SPECT detectors would ideally have large area and stopping power, excellent energy and spatial resolution, as well as high count-rate capability. To date, no single detector combines all of these attributes. Nor is there a single collimation strategy that is effective under all circumstances. In prior theory work, we have shown that image quality, as defined by objective task performance measures, can in principle be improved by combining multiple detector and collimator strategies in the same system [3]. In this work, we present a design for a pre-clinical imager combining an intensified quantum imaging detector (iQID) and a CdTe crossed-strip semiconductor detector. The iQID scintillation detector can achieve excellent spatial resolution while also delivering high sensitivity, but with limited energy resolution. This compliments the semiconductor detector's ability to achieve excellent energy and spatial resolution, but at limited count rates and with a smaller detector area. By jointly reconstructing data sets acquired concurrently, we seek to produce a SPECT system that has high energy and spatial resolution without sacrificing sensitivity or field of view. In this work we present the design considerations in building this multi-technology SPECT system.