Biokinetics in normal human volunteers of a new brain perfusion tracer, 99mTc ECD

This report describes the tracer distribution in 12 normal individuals (8 cases with complete biodistribution studies and 4 cases with detailed study of cerebral tracer distribution). Tracer uptake in the brain of forementioned complex is fast and results in a retention of about 5% of the dose. The washout is slow with halftime values between 4 to 6 hours. High resolution SPECT demonstrates the flow related intracerebral tracer distribution with high gray/white matter ratios. The ratio brain uptake versus soft tissues uptake is sufficiently high. The blood clearance and the disappearance from other organs is fast resulting in a low body background activity. The excretion is predominantly renal. Liver and gastrointestinal tract were also visible. The lung extraction is low and clears rapidly. Forementioned human experiments indicate that 99mTc ECD appears to be an excellent tracer substance for routine SPECT imaging of the cerebral perfusion. (orig./MG)