PET Imaging with 62Cu-ETS in a human clinical trial at the university of wisconsin - madison

Copper(II) bis(thiosemicarbazone) compounds show promise for clinical use in the measurement of tissue blood flow with positron emission tomography(PET). ⁶²Cu-PTSM has been extensively evaluated as a myocardial and general purpose flow agent. Although an effective agent, it exhibits albumin binding in human plasma which limits its performance in high blood flow imaging. A new agent, ⁶²Cu-ETS, exhibits no such species differentiation of albumin binding. In this study, ten healthy human volunteers were subjected to ⁶²Cu-ETS PET imaging to obtain percent injected dose values for major organs, including the blood, brain, kidneys, liver, lungs, and myocardium, by measuring count densities within defined regions of interest (ROI's) around the general anatomical structure and dividing by the injected dose, correcting for losses at the injection site. These results were then compared to an analogous ⁶²Cu-PTSM PET imaging study completed previously utilizing the same imaging methods. For effective comparison, data for the ⁶²Cu-PTSM study was reanalyzed using the same ROI procedure as was performed on the ⁶²Cu-ETS study. ⁶²Cu-ETS shows similar myocardial uptake compared to ⁶²Cu-PTSM, but kidney uptake is two fold higher than resting myocardium compared with only 1.3 fold for ⁶²Cu-PTSM. Hence ⁶²Cu-ETS shows high promise for the important application of hyperemic myocardial flow measurement as well as renal imaging. An additional advantage of ⁶²Cu-ETS is that liver uptake which can interfere with myocardial imaging is reduced by about 2 fold relative to that of ⁶²Cu-PTSM.