Researchers at the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS) have conducted a study on production of ²¹¹At, which is an excellent radionuclide being investigated for use in targeted alpha therapy(TAT). 

At present, the production of ²¹¹At is mainly based on accelerator irradiation, which is generated by nuclear reaction ²⁰⁹Bi(α,2n) and separated into dry method. The whole process has obvious advantages such as high efficiency, high product purity and very few radioactive waste. 

Researchers at IMP have successfully developed the separation process of medical isotope ²¹¹At. The results showed that the ²¹¹At products with high specific activity and high nuclear purity (> 99.999 %) could be obtained within 30 minutes by dry distillation separation process, and the total yield of ²¹¹At was up to 78.5 %. The quality analysis of ²¹¹At product was analyzed by ICP-MS and HPGe-γ detector, and the content of Bi, Cu, Zn and Al was lower than 100 ng/GBq.  

Meanwhile, when the incident particle energy is lower than 28.5 MeV, the N(²¹⁰At)/N(²¹¹At) ratio was lower than 10^-5, and the content of the extremely toxic nuclide ²¹⁰Po (²¹⁰At decay) is below the occupational intake stipulated by the International Commission on Radiological Protection, which is fully suitable for the labeling study.   

Furthermore, collaborated with Sichuan University, researchers successfully realized the labeling of ²¹¹At-nimotuzumab through N-succinimidyl-3-(trimethylstannyl) benzoate. The labeling rate was 94.8%, and the radiochemical purity reached 96.5%. And the test results of in vitro stability also turned out well. 

Based on this research, a set of simple and efficient separation methods was established, which laid a good foundation for the subsequent production and application of ²¹¹At in China.  

This work was financially supported by Competitive projects of the special fund for the guidance of the innovation and development of science and technology, Gansu Province.   

The study has been published in Acta Chimica Sinica.  

 Figure1. The cover 

 Figure 2. Production of targeted therapeutic nuclide ²¹¹At