Head-to-head Comparison Of A Conventional Or CZT-based SPECT/CT With A Next Generation Multidetector CZT-based SPECT/CT System

Introduction: <InvalidTag charset="UTF-8" />Conventional Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) systems use an anterior and posterior detector head which rotate around the patient. The StarGuide is a next generation 3D-ring SPECT/CT system based on Cadmium Zinc Telluride (CZT) technology (GE Healthcare, Haifa, Israel). The scanner is equipped with 12 high-resolution CZT detectors which swivel around the patient enabling acquisition closer to the patient and also focused scanning modes. This novel SPECT/CT technology is under clinical evaluation in our facility in order to improve image quality, acquisition time and speed, and usability. In this prospective study, we aimed to compare the image quality of this multidetector general purpose CZT-based SPECT/CT to a conventional dual head SPECT/CT system based on NaI- (Discovery NM/CT 670, ‘D670’) or CZT (NM/CT 870CZT, ‘870CZT’) detectors.

Methods: <InvalidTag charset="UTF-8" />Forty-six patients were consecutively enrolled in this prospective study. All participants underwent two SPECT/CT scans: First on either the D670 or 870CZT scanner followed by the StarGuide using different radioisotopes (⁶⁷Ga, ^99mTc, ¹¹¹In, ¹²³I, ¹⁷⁷Lu) for their respective clinical indication. The scan duration of conventional SPECT/CT systems was nearly identical to StarGuide: 20±11.58 (range 4 – 6) vs. 20±11.68 (range 4 – 62) minutes, respectively (P=0.40). Image quality was evaluated by two experienced nuclear medicine physicians using a 5-point Likert scale (1 non-diagnostic, 2 suboptimal image quality, 3 acceptable image quality, 4 good image quality, 5 excellent image quality).

Results: Twenty-one participants were scanned on the D670 with a mean Likert score of 3.73 ± 0.60 (range 3 – 5) while 25 patients were imaged on the 870CZT with a mean Likert score of 4.18 ± 0.52 (range 3 – 5). All patients subsequently underwent imaging with the StarGuide showing a mean Likert score of 4.70 ± 0.50 (range 3 – 5). In the intra-participant comparison between D670 and StarGuide, the StarGuide scanner showed a significantly better image quality (P=0.000) as well as in the comparison between 870CZT and StarGuide (P=0.000).

Conclusions: The CZT-based multidetector SPECT/CT StarGuide showed significantly better image quality not only in comparison to conventional NaI-based SPECT/CT but also to CZT-based two head detectors. Larger studies with dedication to each radioisotope are needed to confirm these preliminary results.

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