Simple analytic method of 11C-flumazenil metabolite in blood.

UNLABELLED 11C-Flumazenil ((11)C-FMZ) is useful to estimate central benzodiazepine receptors by PET. The binding potential (BP) can be calculated with dynamic PET and continual blood sampling. Because conventional metabolite analysis of plasma samples is complicated and time consuming, a simple method is required to obtain an input function. In this article, a whole blood solvent extraction method was evaluated using data of 13 subjects. METHODS The plasma solvent extraction method was estimated in comparison with the thin-layer chromatography (TLC) method. Then, the whole blood solvent extraction method was evaluated in comparison with the plasma solvent extraction method. RESULTS Metabolite data analyzed by the plasma extraction method were well correlated with those by the TLC method (r = 0.99). The BP was calculated using both the whole blood extraction data and the plasma extraction data. No difference was observed in all brain regions. CONCLUSION This simple whole blood solvent extraction method can be applied to clinical BP estimation using (11)C-FMZ.

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