Positron emission intensities in the decay of 64 Cu , 76 Br and 124 I

The relatively long-lived positron emitters Cu (t1/2 = 12.7 h), Br (t1/2 = 16.2 h) and I (t1/2 = 4.18 d) are finding increasing applications in positron emission tomography (PET). For precise determination of their positron emission intensities, each radionuclide was prepared via a charged particle induced reaction in a “no-carrier-added” form and with high radionuclidic purity. It was then subjected to γ -ray and X-ray spectroscopy as well as to anticoincidence beta and γγ -coincidence counting. The positron emission intensities measured were: Cu (17.8±0.4)%, Br (58.2±1.9)% and I (22.0±0.5)%. The intensity of the weak 1346 keV γ -ray emitted in the decay of Cu was determined as (0.54±0.03)%. Some implications of the precisely determined nuclear data are discussed.