Production of the Alpha-Particle Emitting Radionuclide Astatine-211 at the Texas A&M Cyclotron Institute
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The need of a stable production of At-211 is necessary to continue research in alpha-particle targeted radionuclide therapy. Our objectives were to establish the production of Astatine-211 at Texas A&M Cyclotron Institute, optimize the production methods to reduce the generation of contaminants and maximize At-211 production, and assess the radiological safety aspects of At-211 production. The production of the alpha-particle emitting radionuclide At-211 was performed at the Texas A&M Cyclotron Institute using the K500 superconducting cyclotron following the production reaction Bi-209(α, 2n)At-211 using a thick bismuth target of 500 μm. We carried out two irradiation experiments where the initial energy of the alpha-particle beam, 80 MeV, was degraded using multiple copper and aluminum foils to 27.8 and 25.3 MeV, respectively. The end of beam time was 4 hours for both experiments. The resulting At-211 yields were 36.0 and 12.4 MBq/μA-h, respectively. Several impurities were produced using the 27.8 MeV, which included At-210 and Po-210. However, when the 25.3 MeV beam was used, the impurities At-210 and Po-210 were resolved and other contaminants were minimized to less than 0.8% of At-211 yield. The production yields were in accordance to previous published results. From the success of these initial experiments, additional steps were taken to produce At-211 in excess quantities for distillation purposes. In order to obtain viable quantities of At-211, the gross yield needed to be increased due to losses that are incurred during distillation and radioactive decay. The ability to produce high yields of this isotope required a redesign of the target and use of the K150 cyclotron using a higher beam intensity.
Bhakta, Viharkumar Satish (2011). Production of the Alpha-Particle Emitting Radionuclide Astatine-211 at the Texas A&M Cyclotron Institute. Master's thesis, Texas A&M University. Available electronically from