Effect of pertechnetate source and age on the radiochemical purity of technetium Tc 99m exametazime.

The radiochemical purity of technetium Tc 99m exametazime preparations was evaluated by comparing pertechnetate sources and sodium pertechnetate Tc 99m ages. Vials of exametazime were prepared using sodium pertechnetate Tc 99m that was obtained from two brands of generators and up to five hours after elution. Radiochemical purity was determined by using instant thin-layer chromatography. Substantial variability in radiochemical purity existed within and between lots of exametazime. There was little difference in radiochemical purity between the two brands of generator and among the various ages of eluant. The radiochemical purity was not significantly affected by the source or age of sodium pertechnetate Tc 99m used in this study.