CZT Detectors-Based SPECT Imaging: How Detector and Collimator Arrangement Can Determine the Overall Performance of the Tomograph

A technical comparison is described between two SPECT systems, one dedicated to cardiovascular studies and one general-purpose, to evaluate the advantages and disadvantages of their use in an organ-specific clinical setting. The comparison was made between a dedicated cardiac SPECT (Alcyone, Discovery NM 530c, GE Healthcare) scanner and a general-purpose one (Discovery NM/CT 670 CZT, GE Healthcare). The two scanners differ in terms of hardware, mainly in the arrangement of the detectors and collimators, which are the main components of SPECT. A standard NEMA phantom was used to characterize the energy resolution, spatial resolution, and sensitivity for the two systems. Then, using a custom-made cardiac phantom, more specific indices were computed to evaluate the quality of cardiac images, such as signal-to-background noise ratio (SBNR), tissue-background contrast-to-noise ratio (TBCNR), and uniformity. Finally, the same indices were computed for clinical images acquired with the two systems from 11 subjects. Alcyone showed superior performance for dedicated cardiac imaging; however, its excellent qualities are aimed only at the study of the heart and only at patients with a low body-mass index, unlike Discovery NM/CT 670 CZT, which can be used for every anatomic district area and for every type of patient.

Automated summary

A comparison was made between a dedicated cardiac SPECT system and a general-purpose SPECT system, evaluating their hardware differences and image quality through specific indices. The dedicated cardiac SPECT system showed superior performance in cardiac imaging, but was only suitable for patients with a low body mass index; whereas the general-purpose system could be used for various anatomical regions and patient types.