Measurement of Tc-99m-radiopharmaceutical biolocalization by autoradiography

Autoradiography (ARG) is a powerful tool for assessing the in vivo regional concentrations of radiolabeled compounds in organs at different times after administration. This widely applied technique provides excellent resolution and the opportunity to digitize the ARG images for quantitation of localized radiopharmaceutical concentrations. Applications of ARG technology for assessing the region uptake of radiopharmaceuticals in brain in small animals have been particularly valuable. For example, the regional cerebral uptake (rCU) ARG patterns of Tc-99m-d,1-hexamethyl-propylene amine oxime (Tc-99m-d,1-HM-PAO) have excellent resolution. These ARG studies showed that the rCU of this chelate is related to regional cerebral blood flow. The concentration of Tc-99m-d,1-HM-PAO in grey matter relative to white matter, however, is lower than the actual relative flows in these brain tissues