Production of [ 18F]fluoride from fluorocarbons by the 19F(γ,n) 18F reaction

Abstract

We have measured the amount of 18F from the photonuclear reaction 19F(γ,n) 18F which can be recovered as no-carrier-added [ 18F]fluoride by aqueous extraction of fluorocarbons irradiated with bremsstrahlung. Aqueous extraction yields range from 11 to 68% depending on the type of fluorocarbon used. With proper choice of the target compound, extraction yields in the order of 100 mCi of 18F or more are readily obtained. However, for use in nuclear medicine the method has certain disadvantages: (1) the [ 18F]fluoride recovered by extraction may contain some of the organic target compound as well as other recoil products labelled with 18F; (2) because of radiation decomposition of the target compound ( G ≈ 1) the amount of stable 19F − formed gives rise to specific activities not higher than 37 GBq (1 Ci) of 18F per 1 to 4 × 10 −2 mol of fluoride, too low for certain applications.