Autoradiographic comparison of thallium-201 diethyldithiocarbamate, isopropyliodoamphetamine and iodoantipyrine as cerebral blood flow tracers.

We investigated [201Tl]diethyldithiocarbamate (DDC) as a tracer for local cerebral blood flow (LCBF). Awake male rats were given intravenous infusions of a mixture of DDC and reference tracer(s): [123I]isopropyliodoamphetamine (IMP) and/or [14C]iodoantipyrine (IAP). LCBF values for DDC, IMP, and IAP were measured using simultaneous multiple radionuclide autoradiography and quantitative digital image analysis. Patterns of local cerebral blood flow (LCBF) obtained with DDC were intermediate compared to IMP and IAP, although they were more similar to those of IMP. DDC and IMP underestimated LCBF in some white matter and adjacent structures, while IAP underestimated LCBF values in high flow regions. We conclude that DDC uptake generally reflects local cerebral blood flow and that it can therefore be used as a cerebral perfusion tracer in humans using SPECT imaging.