TY - JOUR T1 - Gated <sup>99m</sup>Tc-Tetrofosmin and <sup>18</sup>F-FDG Studies: A Comparison of Single-Acquisition and Separate-Acquisition Protocols JF - Journal of Nuclear Medicine Technology JO - J. Nucl. Med. Technol. SP - 175 LP - 178 VL - 30 IS - 4 AU - Robert A. Pagnanelli AU - Michael W. Hanson AU - Timothy Turkington AU - R. Edward Coleman AU - Salvador Borges-Neto Y1 - 2002/12/01 UR - http://tech.snmjournals.org/content/30/4/175.abstract N2 - 18F-FDG is a well-established tracer for evaluating myocardial viability, as is 99mTc-tetrofosmin (TET) for evaluating myocardial perfusion. Dual-isotope single-acquisition (DISA) studies using a 99mTc perfusion agent and 18F-FDG have been performed to evaluate myocardial viability. The purpose of this investigation was to determine whether there is a difference in the results of gated SPECT DISA, compared with gated SPECT DIDA (dual-isotope dual-acquisition) studies using 99mTc-TET/18F-FDG and a high-energy collimated dual-head SPECT system. Methods: We prospectively studied 13 patients with depressed left ventricular function using both acquisition protocols. Summed rest scores were calculated for both 99mTc and 18F-FDG studies using a 12-segment model and a 5-grade severity score. Images were evaluated by a single reader who did not know whether the images were acquired separately or simultaneously. Results: The concordance of DISA and DIDA protocols for 99mTc-TET when allowing no difference in the SRS was 57%, or 89 of 156 segments. The concordance of DISA and DIDA protocols for 18F-FDG was 86%, or 134 of 156 segments. The concordance of segments determined to be viable versus nonviable was 92%, or 143 of 156 segments. Ejection fraction measurements obtained by gated 99mTc-TET studies correlated strongly with those obtained by gated 18F-FDG studies. Conclusion: A high concordance for 18F-FDG studies was shown between gated DISA and gated DIDA. A lower concordance was shown between gated DISA and gated DIDA studies using 99mTc-TET, most likely because of downscatter from 18F into the 99mTc window. An excellent concordance was demonstrated between the 2 techniques for viability assessment. The gated 99mTc-TET/18F-FDG DISA protocol can be both a reliable and an efficient way to evaluate myocardial function, perfusion, and viability. ER -