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

Abstract

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 mm³, compared to 4.42×4.42×4.42 mm³ 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^-1・MBq^-1 and 193.3 counts・s^-1・MBq^-1, 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.