Proton irradiation of [O-18]O-2: Production of [F-18]F-2 and [F-18]F-2+[F-18]OF2

The production of F-18 electrophilic reagents via the O-18(p,n)F-18 reaction has been investigated in small-volume target bodies made of aluminum, copper, gold plated copper and nickel, having straight or conical bore shapes. Three irradiation protocols-single-step, two-step and modified two-step-were used for the recovery of the F-18 activity. The single-step irradiation protocol was tested in all the target bodies. Based on the single step performance, aluminum targets were utilized extensively in the investigation of the two step and modified two-step irradiation protocols, With an 11-MeV cyclotron and using the two-step irradiation protocol, >1Ci [F-18]F-2 was recovered reproducibly from an aluminum target body, Probable radical mechanisms for the formation of OF2 and FONO2 (fluorine nitrate) in the single-step and modified two step targets are proposed based on the amount of ozone generated and the nitrogen impurity present in the target gases, respectively.