Cerebral blood flow imaging with thallium-201 diethyldithiocarbamate SPECT

Thallium-201 diethyldithiocarbamate ([201TI]DDC) was studied in humans as an agent for cerebral blood flow imaging. Brain uptake proved to be complete 90 sec after injection with no appreciable washout or redistribution for hours. Intracarotid injection suggested an almost 100% extraction during the first passage. Whole-body distribution studies demonstrated a brain uptake of 4.3% of the dose compared with 0.9% for [201TI]chloride. No differences were found in the distribution of [201TI]DDC versus [201TI]chloride in other organs. After the injection of 3 mCi 201TI, good quality single photon emission computed tomographic (SPECT) images of the brain were obtained with both a rotating gamma camera and a multidetector system. In ischemic brain disease, perfusion defects were easily demonstrated. We conclude that [201TI]DDC is a suitable radiopharmaceutical for SPECT studies of cerebral blood flow.