CS-30回旋加速器辐照天然锌靶制备高核纯67Ga

    Simple and Feasible Method for 67Ga Production on CS-30 Cyclotron With High Purity

    • 摘要: 67Ga是一种经典的单光子显像核素,因其衰变过程中同时发射俄歇电子也具有一定的治疗潜力。利用加速器辐照天然锌靶通过natZn(p, xn)67Ga核反应可获得67Ga,但现有分离方法与流程尚需要进一步优化。通过硫酸锌体系电镀制备出品质良好的锌靶,靶厚大于70 mg/cm2。在CS-30回旋加速器中,用21 MeV的质子束流轰击电镀制备的天然锌靶,束流强度为50 μA。基于磷酸三丁酯(TBP)萃淋树脂,通过模拟实验、示踪实验与放射化学分离实验建立了从辐照锌靶溶液中获取高核纯67Ga的分离工艺。整个分离过程可在2 h内完成,放射性回收率大于90%,67Ga核纯度高达99.9%以上,通过natZn(p, xn)67Ga反应得到67Ga的产率为13 MBq/(μA•h)。所建立的从天然锌靶中制备高放射性核纯度67Ga的方法,不仅简单可行,也对加速器制备68Ga具有参考价值。

       

      Abstract: 67Ga is a classical single photon imaging nuclide, which also has therapeutic potential due to its simultaneous emission of auger electrons. At present, 67Ga is mainly prepared by enrichment of Zn target. 67Ga can also be obtained by natZn(p, xn)67Ga nuclear reaction, but the existing separation methods and processes need to be further optimized. In this study, a simple and feasible method for the preparation of high radionuclidic purity 67Ga from natural zinc target was studied. Zinc target with good quality was prepared by zinc sulfate system with target thickness >70 mg/cm2. To determine the best separation scheme of Ga, the simulated separation experiment of non-radioactive elements using 60% tributyl phosphate(TBP) resin was carried out. The distribution coefficients of Ga3+, Zn2+, Cu2+, Ni2+ and Co2+ ions in w=60% TBP resin under the action of 0.05, 0.10, 0.50, 1.00, 2.00, 4.00, 6.00 and 8.00 mol/L HCl were determined. We found that NH4Cl solution has good elution performance and can elute the adsorbed gallium. After eluting with 6.00 mol/L HCl, then eluted with 0.10, 0.30, 0.50, 0.75, 1.00 mol/L NH4Cl solution. The recovery of Ga was calculated respectively. According to the actual situation, the simulated solution was prepared and verified according to the experimental conditions obtained. 6.00 mol/L HCl and 0.50 mol/L NH4Cl were selected as the eluent. The results show that 60% TBP extraction resin has good separation effect. In order to verify the effectiveness of our separation method, a simulation separation experiment with trace amounts of radioactive Ga is conducted. The results of 68Ga tracer experiments are as good as those of non-radioactive experiments. The natural zinc target prepared by electroplating was bombarded with a beam of 21 MeV protons at 50 μA on the CS-30 cyclotron. The separation and purification process of high radionuclidic purity 67Ga from irradiated zinc target solution was established based on TBP extraction resin. According to the isotopic composition of zinc target material, the presence of trace amounts of 64Ga, 65Ga, 66Ga, 67Ga, 68Ga is estimated. However, after 5 days of decay, no short half-life nuclides(64Ga, 65Ga, 68Ga) have appeared, but a trace amount of 66Ga is still present in the product. The separation process is simple and efficient. The whole separation process can be completed within 2 hours. The radioactive recovery rate is greater than 90%. The radionuclidic purity is more than 99.9%. The yield of 67Ga obtained by natZn(p, xn)67Ga reaction is 13 MBq/(μA•h). This method also has reference value for the preparation of 68Ga by accelerator.

       

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