Absolute standardizations of 99mTc and 57Co by 4π electron-gamma liquid scintillation coincidence counting for SIRTI and SIR comparisons. (April 2018)

• Record Type: Journal Article
• Authors: Rooy, M.W. van; Staden, M.J. van; Simpson, B.R.S.; Lubbe, J.
• Is Part Of: Applied radiation and isotopes. Volume 134(2018:Apr.)
• Page Start: 245
• Page End: 251
• Publication Date: 2018-04
• Subjects: Liquid scintillation coincidence counting -- Extrapolation technique -- Technetium-99m -- Cobalt-57 -- SIRTI -- SIR; Radiology -- Periodicals; Radiation -- Industrial applications -- Periodicals; Nuclear chemistry -- Periodicals; Internet resource; Periodical; 660.298
• DOI: 10.1016/j.apradiso.2017.07.042
• Languages: English
• ISSNs: 0969-8043

Abstract

Abstract: The radionuclides 99m Tc and 57 Co were standardized via absolute liquid scintillation counting techniques. We provide the first technical report on the absolute standardization of 99m Tc using 4 π (LS) e - γ coincidence counting. The low detection efficiency of low-energy conversion electrons translates into a large efficiency extrapolation range. A simulation indicated that the γ -ray interacting with the liquid scintillator introduces curvature to the count rate vs. efficiency relationship, the approximation of the functional form used for extrapolation providing the main measurement uncertainty for 99m Tc. A detection efficiency analysis for both radionuclides is presented. Results from the standardizations, and SIRTI and SIR comparison exercises are reported. Highlights: Absolute standardizations of 99m Tc via 4 π (LS) e - γ and 57 Co via 4 π (LS)( e, X )- γ coincidence counting. Preparation at NMISA for SIRTI and SIR comparisons of 99m Tc and 57 Co, respectively. First technical report on the standardization of 99m Tc via liquid scintillation coincidence counting. Count rate vs. efficiency simulation for 99m Tc.