Exploration of Quality Control Methods for Nuclear Purity Detection of Conventional Positron Radionuclides
Objective To explore the application of half-life assay in the purity determination and analysis of medical positron nuclides(18F,11C,13N).Methods A cyclotron was used to accelerate proton bombardment of heavy oxygen water,nitrogen oxygen mixture,and ethanol(20 mmol/L)target water,respectively,to produce aqueous solutions of 18F,11C,and 13N positron nuclide samples.The radioactivity of the sample aqueous solution was measured every 10,2,and 2 min for 18F,11C,and 13N nuclides,and the number of radioactivity measurements was 5.According to the linear fitting formula of radioactive nuclide decay,the half-life T1/2 of the nuclide was calculated.The radionuclide purity of the sample was determined by γ-energy spectrometer.Results The results showed that the half-lives of three positron nuclides calculated by the half life measurement method was similar to that of the γ-spectrometer method,and the half-lives of radioactive nuclides in 18F,11C,and 13N samples were(110.07±0.53),(19.62±0.77),and(10.02±0.94)min,respectively,calculated using the half-life measurement method.The purity of 18F,11C,and 13N nuclides in the corresponding samples determined by the energy spectrometer was 100%,and their physical half-lives were 109.77,20.39,and 9.97 min.Conclusion The half-life determination method has the feasibility of determining the purity of medical radioactive nuclides,which is worth promoting and applying.