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 / 대한핵의학회잡지

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 (CTD) 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, CTD 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 CTD than T1-201/I-123. In addition, CTD 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.

Application of 18F-FDG/99mTc-MIBI dual-isotope SPECT and gated myocardial imaging in early diagnosis of diabetes-induced myocardial damage / 实用医学杂志

Objective To explore the diagnostic value of 18F-FDG/ 99mTc-MIBI dual-isotope SPECT and gated myocardial imaging in early diagnosis of diabetes-induced myocardial damage. Methods 32 patients with diabetes and 26 healthy volunteers received 18F-FDG/ 99mTc-MIBI dual-isotope SPECT and gated myocardial imaging for assessing myocardial ischemia, viability status, and cardiac function. Results Myocardial perfusion abnormalitieswere observed in 47 regions on myocardial perfusion imagingin 21 of 32 (65.6%)patients with diabetes, showing perfusion/metabolism mismatched and suggesting viable myocardium. All the volunteers were normal on DISA. As compared with the normal control group, the positive rate of DISA in diabetic patients was significantly higher (P < 0.01). Left ventricular ejection fraction (LVEF) was (54.3 ± 7.2%) and (67.3±4.9%) respectively, the difference was statistically significant (P < 0.05). Conclusions 18F-FDG/ 99mTc-MIBI dual-isotope SPECT and gated myocardial imaging can assess myocardial ischemia ,viability and cardiac function in diabetic patients, and it is helpful for the early diagnosis of cardiac damage in patients with diabetes mellitus.