title: The natBr(p,x) (73,75)Se nuclear processes: a convenient route for the production of radioselenium tracers relevant to amino acid labelling.
abstract: A possible route for the production of no-carrier-added (n.c.a.) 73Se (T(1/2) = 7.1 h) and 75Se (120 d) is introduced. D,L-2-Amino-4-([73Se]methyl-seleno) butanoic acid (D,L-[73Se]selenomethionine) with an overall radiochemical yield of > 40% could be prepared via a 3-step polymer-supported synthesis after successful separation of 73Se from KBr targets. Excitation functions for the natBr(p,x) (72,73,75)Se processes were measured from threshold up to 100 MeV utilizing pellets of pressed KBr. Targets were irradiated at the NAC cyclotron with proton beams having primary energies of 40.4, 66.8 and 100.9 MeV. The calculated 73Se yield (EOB) for 1 h irradiation in 1 microA of beam at the optimum proton energy range of 62-->42 MeV is 81.4 MBq (2.2 mCi), and the calculated 75Se yield (EOB) for the overall range 62 MeV-->threshold for the same irradiation conditions is 0.97 MBq (0.026 mCi).
authors: National Accelerator Centre, Faure, South Africa. mifa@lanl.gov
authors: M
authors: M
authors: Fassbender
authors: D
authors: D
authors: de Villiers
authors: M
authors: M
authors: Nortier
authors: N
authors: N
authors: van der Walt
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis; D001966:Bromine; D017357:Cyclotrons; D007202:Indicators and Reagents; D007553:Isotope Labeling / Q000379:methods*; D012644:Selenium Radioisotopes; D012645:Selenomethionine / Q000138:chemical synthesis*
chemical_list: D000596:Amino Acids; D007202:Indicators and Reagents; D012644:Selenium Radioisotopes; D012645:Selenomethionine; D001966:Bromine