title: Radionuclide impurities in proton-irradiated [18O]H2O for the production of 18F-: activities and distribution in the [18F]FDG synthesis process.
abstract: Proton- and neutron-induced activation products in the components of a high-pressure [(18)O]H(2)O target vessel used for the production of (18)F(-) in a medical cyclotron have been identified using high resolution gamma spectrometry. The activities leached from the target vessel into the [(18)O]H(2)O during irradiation, and the distribution of the identified radionuclide impurities in the various cartridges and solutions used in the [(18)F]FDG synthesis process have been measured and are discussed from the perspective of waste disposal. The results indicate that, at the energies and beam currents employed, only a few, relatively short-lived radionuclides are present in the irradiated [(18)O]H(2)O, and that the activities involved (<10 kBq in each case) are well below typical exemption limits. Activities of beta-emitting (3)H in irradiated [(18)O]H(2)O, produced via the (18)O(p,(3)H)(16)O reaction, have also been determined using liquid scintillation spectrometry. Measured activity concentrations, in the range 150-180 kBq g(-1), are consistent with those reported by other workers. Analyses of the synthesised [(18)F]FDG confirm the radiochemical purity of the product, both for (3)H and for gamma-emitting radionuclides in the energy range 25-1650 keV.
authors.affiliation: School of Physics, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Louise
authors.initials: L
authors.lastname: Bowden
authors.forename: Luis León
authors.initials: LL
authors.lastname: Vintró
authors.forename: Peter I
authors.initials: PI
authors.lastname: Mitchell
authors.forename: Ruairi G
authors.initials: RG
authors.lastname: O'Donnell
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Seymour
authors.forename: George J
authors.initials: GJ
authors.lastname: Duffy
mesh_terms: D017357:Cyclotrons; D005462:Fluorine Radioisotopes / Q000737:chemistry*; D019788:Fluorodeoxyglucose F18 / Q000138:chemical synthesis*; D010103:Oxygen Isotopes / Q000737:chemistry*; D011522:Protons; D011868:Radioisotopes; D019275:Radiopharmaceuticals / Q000138:chemical synthesis; D013051:Spectrometry, Gamma; D014867:Water / Q000737:chemistry*
chemical_list: D005462:Fluorine Radioisotopes; D010103:Oxygen Isotopes; D011522:Protons; D011868:Radioisotopes; D019275:Radiopharmaceuticals; D014867:Water; D019788:Fluorodeoxyglucose F18