title: Vacuum ultraviolet photon-mediated production of [18F]F2.
abstract: The chemistry of F2and its derivatives are amenable to facile aliphatic or aromatic substitution, as well as electrophilic addition. The main limitation in the use of [18F]F2for radiopharmaceutical synthesis is the low specific activity achieved by the traditional methods of production. The highest specific activities, 55 GBq/μmol, for [18F]F2have been achieved so far by using electrical discharge in the post-target production of [18F]F2gas from [18F]CH3F. We demonstrate that [18F]F2is produced by illuminating a gas mixture of neon/F2/[18F]CH3F with vacuum ultraviolet photons generated by an excimer laser. We tested several illumination chambers and production conditions. The effects of the initial amount of [18F]F-, amount of carrier F2, and number of 193-nm laser pulses at constant power were evaluated regarding radiochemical yield and specific activity. The specific activity attained for [18F]F2-derived [18F]NFSi was 10.3 ± 0.9 GBq/μmol, and the average radiochemical yield over a wide range of conditions was 6.7% from [18F]F-. The production can be improved by optimization of the synthesis device and procedures. The use of a commercially available excimer laser and the simplicity of the process can make this method relatively easy for adaptation in radiochemistry laboratories.
authors.affiliation: Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland.
authors.forename: Anna
authors.initials: A
authors.lastname: Krzyczmonik
authors.affiliation: Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Keller
authors.affiliation: Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Kirjavainen
authors.affiliation: Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland.|Department of Chemistry, University of Turku, Turku, Finland.
authors.forename: Sarita
authors.initials: S
authors.lastname: Forsback
authors.affiliation: Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Turku, Finland.|Department of Chemistry, University of Turku, Turku, Finland.|Accelerator Laboratory, Åbo Akademi University, Turku, Finland.
authors.forename: Olof
authors.initials: O
authors.lastname: Solin
mesh_terms: D005374:Filtration; D005461:Fluorine / Q000737:chemistry*; D005462:Fluorine Radioisotopes / Q000737:chemistry*; D007834:Lasers; D017785:Photons; D011854:Radiochemistry / Q000295:instrumentation / Q000379:methods*; D014466:Ultraviolet Rays; D014618:Vacuum
chemical_list: D005462:Fluorine Radioisotopes; D005461:Fluorine
keywords: PET; [18F]F2; [18F]NFSi; electrophilic 18F; excimer laser; fluorine-18; radiochemistry; specific activity