First assessment of simultaneous dual isotope (¹²³I/^99mTc) cardiac SPECT on two different CZT cameras: A phantom...

We studied the impact of simultaneous dual-isotope acquisition on ¹²³I/^99mTc mismatch assessment using two CZT cameras (DNM 530c, GE Healthcare and DSPECT, Biosensors International).

We used an anthropomorphic torso phantom (respectively filled with a solution of ¹²³I alone, ^99mTc alone, and a mixture of ¹²³I and ^99mTc) and its cardiac insert with two defects mimicking two matched and mismatched defects. Mismatch extent and reconstructed image contrast were evaluated.

The acquisition mode (single vs dual) significantly impacted (i) ^99mTc (but not ¹²³I) reconstructed segmental activities using both camera (P < .001), and (ii) image contrast (using ¹²³I and DNM 530c, P < .0001; and using both ¹²³I and ^99mTc with DSPECT, P < .0001). However, the defect and mismatch size were not impacted by the type of acquisition. With both DNM 530c and DSPECT, Lin's concordance correlation coefficient and Bland-Altman analysis demonstrated an almost perfect concordance and agreement between single- and simultaneous dual-isotope segmental activity (¹²³I and ^99mTc).

This study found no impact of the acquisition mode (single vs dual) or the type of camera (DSPECT vs DNM 530c) on ¹²³I and ^99mTc defect size and mismatch, providing a new step toward simultaneous dual-isotope acquisition for combined innervation and perfusion assessment.