ULTRASTRUCTURAL BASIS FOR DIFFERENT PERTECHNETATE UPTAKE PATTERNS BY VARIOUS HUMAN-BRAIN TUMORS

[The uptake of 99Tc pertechnetate by tumor tissue is the basis for visualization of brain tumors by scintigraphy.] Patterns of pertechnetate uptake were correlated with ultrastructural properties of the endothelial wall in 14 human brain tumors. In tumors with reduced uptake of the radionuclide, intercellular tight junctions were observed whereas absence of intercellular tight junctions was characteristic of all tumors with an increased uptake of pertechnetate. In some tumors with increased uptake, fenestrated endothelial wall was seen while in others a nonfenestrated wall was evident. Intercellular junctions and not fenestrations evidently affect the permeability of brain tumors to pertechnetate.