Skip to main content
An official website of the United States government
Government Funding Lapse
Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.

The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit cc.nih.gov.

Updates regarding government operating status and resumption of normal operations can be found at opm.gov.

fluorine F 18-5-fluoro-2-deoxycytidine

A radioconjugate composed of a fluorinated pyrimidine analog, linked to the radioisotope fluorine F 18 with potential imaging activity using positron emission tomography/computed tomography (PET/CT). Upon administration of fluorine F 18-5-fluoro-2-deoxycytidine ([F-18]-FdCyd), the FdCyd moiety is phosphorylated by deoxycytidine kinase to 5-fluoro-2’-deoxycytidylate (FdCMP) and deaminated by deoxycytidylate (dCMP) deaminase, an enzyme overexpressed by tumor cells, to 5-fluoro-2-deoxyuridine monophosphate (FdUMP). Eventually, FdUMP is metabolized to the triphosphate forms 5-fluoro-2′-deoxycytidine-triphosphate (FdCTP) and fluorodeoxyuridine triphosphate (FdUTP). FdCTP and FdUTP inhibit DNA methyltransferase (DNMT) and DNA methylation, and induce DNA strand breaks, respectively. FdCyd is coadministered with tetrahydrouridine (THU), an inhibitor of cytidine/deoxycytidine deaminase, which prevents FdCyd breakdown and increases its efficacy. The fluorine F 18 moiety can be imaged upon PET/CT, thereby allowing for the evaluation of the biodistribution of FdCyd and its uptake by tumor cells.
Synonym:[F-18]-5-fluoro-2'-deoxycytidine
fluorine F 18 5-fluoro-2-deoxycytidine
Abbreviation:[F-18]FdCyd
Search NCI's Drug Dictionary