Standardization of ~(99m)Tc and ~(99)Mo by the use of a 4(pi)(beta)-4(pi)(gamma) counter

摘要

Technetium-99m is widely used for many diagnostic investigations in nuclear medicine, thus the standardization of this nuclide is important. In classical 4(pi)(beta)-gamma coincidence counting of ~(99m)Tc, the steep slope of the efficiency function and the large extrapolation range may cause a large measurement uncertainty. In order to overcome these difficulties, we apply the 4(pi)(beta)+4(pi)(gamma) sum counting technique for the standardization. Furthermore, we adopt both the 4(pi)(beta)-4(pi)(gamma) coincidence counting method and the 4(pi)(beta)+4(pi)(gamma) sum counting technique for the standardization of its parent nuclide ~(99)Mo. High efficiencies for both nuclides were easily achieved by the use of our 4(pi)(beta)-4(pi)(gamma) counter. All the results were consistent with the reference value obtained by the conventional method obtained by NMIJ.