NCA [18F]fluoride ion was obtained through the 18O(p,n)18F nuclear reaction by irradiating [18O]water (95 atom%) for 90–120 min with a proton beam (14.1 MeV; 20 mA) produced by a PETrace cyclotron (GE, Milwaukee, WI). Cyclotron-produced aqueous [18F]fluoride ion was dried azeotropically in the presence of appropriate base (Cs2CO3, K2CO3 or KF) with or without K 2.2.2 (in 1.5 molar excess of metal ion if used), under microwave-enhanced conditions [32].