常规正电子放射性核素的核纯度检测质控方法探究

Exploration of Quality Control Methods for Nuclear Purity Detection of Conventional Positron Radionuclides

目的探讨半衰期测定法在医用正电子(^(18)F、^(11)C、^(13)N)核素纯度测定和分析中的方法。方法通过回旋加速器加速质子分别轰击重氧水、氮氧混合气及乙醇(20 mmol/L)靶水,分别产生^(18)F、^(11)C、^(13)N正电子核素样品水溶液。^(18)F、^(11)C、^(13)N核素分别每间隔10、2、2 min测量样品水溶液放射性活度,放射性活度测定次数为5次。根据放射性核素衰变的线性拟合公式,计算核素半衰期T_(1/2)。通过γ能谱仪测定对应样品水溶液,鉴定样品放射性核素纯度。结果由半衰期测定法计算可得3种正电子核素的半衰期与γ能谱仪法测定得半衰期结果相近,^(18)F、^(11)C、^(13)N样品的放射性核素半衰期分别为(110.07±0.53)、(19.62±0.77)、(10.02±0.94)min。通过γ能谱仪测定对应样品的^(18)F、^(11)C、^(13)N核素纯度均为100%,其物理半衰期分别为109.77、20.39、9.97 min。结论半衰期测定法具有测定医用放射性核素纯度的可行性,值得推广应用。

Objective To explore the application of half-life assay in the purity determination and analysis of medical positron nuclides(^(18)F,^(11)C,^(13)N).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^(18)F,^(11)C,and^(13)N positron nuclide samples.The radioactivity of the sample aqueous solution was measured every 10,2,and 2 min for^(18)F,^(11)C,and^(13)N nuclides,and the number of radioactivity measurements was 5.According to the linear fitting formula of radioactive nuclide decay,the half-life T_(1/2) of the nuclide was calculated.The radionuclide purity of the sample was determined byγ-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 theγ-spectrometer method,and the half-lives of radioactive nuclides in^(18)F,^(11)C,and^(13)N samples were(^(11)0.07±0.53),(19.62±0.77),and(10.02±0.94)min,respectively,calculated using the half-life measurement method.The purity of^(18)F,^(11)C,and^(13)N 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.