Standardization of Ga-67 by 4 pi gamma (NaI) and 4 pi beta-gamma coincidence methods

摘要

The nuclide Ga-67 is widely used in nuclear medicine for diagnostic purposes. It decays with a half-life of 3.259 days to Zn-67, a stable nuclide. The decay mode is electron capture with several branches followed by gamma- de-excitation. One of the excited levels of Zn-67 with energy 93 keV has a half-life of 9.1 mus, which makes its absolute standardization by coincidence methods difficult. Two methods were used to standardize a solution of this nuclide: (a) 4pi-EC(PPC)-gamma(NaI) coincidence counting with efficiency extrapolation to infinite dead time and (b) high-efficiency 4pigamma counting with a well-type NaI detector. (C) 2003 Elsevier Ltd. All rights reserved.