Nucl Med Mol Imaging.  2019 Feb;53(1):57-63. 10.1007/10.1007/s13139-018-0559-0.

Comparative Cardiac Phantom Study Using Tc-99m/I-123 and Tl-201/I-123 Tracers with Cadmium-Zinc-Telluride Detector-Based Single-Photon Emission Computed Tomography

• Niimi T
• Nanasato M
• Sugimoto M
• Maeda H

• KMID: 2446886
• DOI: http://doi.org/10.1007/10.1007/s13139-018-0559-0

Abstract

OBJECTIVE
A recently introduced single-photon emission computed tomography (SPECT), based on cadmium-zinc-telluride (CZT) detectors (D-SPECT), supports high energy resolution for cardiac imaging. Importantly, the high energy resolution may allow simultaneous dual-isotope (SDI) imaging (e.g., using Tc-99m and I-123). We quantitatively evaluated Tc-99m/I-123 SDI imaging by D-SPECT in comparison with conventional T1-201/I-123.
MATERIALS AND METHODS
Energy resolution was measured as a percentage of the full width at half maximum(FWHM) for Tc-99m, I-123, and Tl-201. The impact of cross-talk and reconstructed image contrast were quantified by measuring the contrast-to-noise ratio (CNR), and the transmural defect contrast in the left ventricle wall (C TD) induced by a difference in energy, for combinations of Tc-99m/I-123 or Tl-201/I-123, using an RH-2 cardiac phantom. Corresponding measurement was also carried out in Anger SPECT (A-SPECT).
RESULTS
The energy resolution of the D-SPECTsystem was 5.4%/5.1%for Tc-99m/I-123 and 5.4%/5.3%for Tl-201/I-123, which was approximately two times higher than the A-SPECT. No notable difference was confirmed in the CNRs of the two systems, but T1-201/I-123 showed overall higher value than Tc-99m/I-123. Compared to A-SPECT, C TD of D-SPECT significantly increased with both Tc-99m/I-123 and T1-201/I-123 (p < 0.05). In DSPECT, the combination of Tc-99m/I-123 had a slightly better C TD than T1-201/I-123. In addition, C TD of Tc-99m/I-123 was improved with scatter correction at both nuclides (p < 0.05), but in Tl-201/I-123, no significant improvement was confirmed in I-123 (p > 0.05).
CONCLUSION
D-SPECT was considered to be capable of performing high-quality SDI imaging using Tc-99m/I-123.

Keyword

CZT detector; Energy resolution; Simultaneous dual-isotope SPECT; Cardiac imaging

MeSH Terms

Anger
Heart Ventricles
Tomography, Emission-Computed*
Tomography, Emission-Computed, Single-Photon