[Spatial Resolution and Uniformity of a Full-ring CZT SPECT/CT System: Comparison with a Conventional Anger-type SPECT/CT Instrument].

Purpose: StarGuide (GE HealthCare, Haifa, Israel) is a full-ring SPECT/CT system based on Cadmium Zinc Telluride (CZT) technology. In this study, we aimed to compare the image quality of this CZT-based SPECT/CT to a conventional Anger-type SPECT/CT system (NM/CT 870 DR, 870DR; GE HealthCare).

Methods: Tomographic sensitivity was calculated by recording the total number of counts detected during tomographic acquisition for a point source. We evaluated spatial resolution and image uniformity on each system using the full width half maximum (FWHM) of line sources and root mean square uniformity (%RMSU) of pool phantom, respectively. The voxel size of the StarGuide SPECT images was 2.46×2.46×2.46 mm, compared to 4.42×4.42×4.42 mm on 870DR. These projection data were reconstructed using 3D-OSEM with a resolution recovery technique (RR). We compared 3 different algorithms: non-correction (NCRR), scatter correction (SCRR), and attenuation correction and scatter correction (ACSCRR).

Results: Tomographic sensitivity of StarGuide and 870DR were estimated at 200.0 counts・s・MBq and 193.3 counts・s・MBq, respectively. Spatial resolution at the center of the FOV was estimated at 2.6 mm for StarGuide and 5.4 mm for 870DR with ACSCRR. Likewise, the %RMSU was 21.7 for StarGuide and 24.6 for 870DR.

Conclusion: The full-ring CZT SPECT/CT system has a superior spatial resolution and better image uniformity than the conventional Anger-type SPECT instrument, whereas tomographic sensitivity remains similar.