[en] We have compared [Tc-99m] sodium pertechnetate with Tc-99m glucoheptonate in 52 patients studied for various brain lesions. Flow studies as well as delayed scans were performed in all. Especially in primary and metastatic lesions of the posterior fossa, the diagnostic yield was improved by the delayed glucoheptonate (GH) scans. In contrast, no advantage of GH over pertechnetate could be detected in the study of infarcts or other ischemic lesions. Various hypotheses are discussed to explain the observed differences in behavior between the two tracers