NIMH DIRP Molecular Imaging Branch - Section on PET Imaging

See next figure for extension of this paradigm to human subjects.
Background. Many ¹⁸F-labeled radiotracers are metabolized by defluorination. [¹⁸F]fluoride is generated and avidly absorbed by bone. High uptake of [¹⁸F]fluoride in skull can obscure images of the underlying neocortex. Defluorination typically occurs via the hepatic cytochrome P450 enzyme CYP2E1. Miconazole (Tinactin®) is known to be an inhibitor of CYP2E1. We found that miconazole treatment of rats almost completely blocked defluorination and bone uptake of [¹⁸F]fluoride. We are now performing comparable studies in humans.

Legend. PET scans of the head acquired between 50 and 60 min after intravenous injection of rat with [¹⁸F]fluoride ion (A), [¹⁸F]FCWAY (B), miconazole nitrate (15 mg/kg i.v.) and then [¹⁸F]FCWAY (C), miconazole nitrate (30 mg/kg i.v.) and then [¹⁸F]FCWAY (D), miconazole nitrate (60 mg/kg i.v.) and then [¹⁸F]FCWAY (E).

Reference.
D.N. Tipre, S.S. Zoghbi, J.-S. Liow, M.V. Green, J. Seidel, M. Ichise, R.B. Innis, and V.W. Pike. PET imaging of brain 5-HT_1A receptors in rat in vivo with [¹⁸F]FCWAY and improvement by successful inhibition of radioligand defluorination with miconazole. J. Nucl. Med. 47: 345-353, 2006. (PDF File)