Sodium fluoride /ˌsoʊdiəm ˈflʊəraɪd/ is an inorganic chemical compound with the formula NaF.A colorless solid, it is a source of the fluoride ion in diverse applications. Sodium fluoride is less expensive and less hygroscopic than the related salt potassium fluoride.n medical imaging, fluorine-18 -labelled sodium fluoride (USP, sodium fluoride F18) is one of the oldest tracers used in positron emission tomography (PET), having been in use since the 1960s.