Automation of nuclear chemistry processes leads to more efficient production of astatine for cancer therapy
Researchers developed a remotely controlled device for the safe and efficient purification of astatine using liquid phase chemistry
image: Concept of the automated system for remote dissolution of the irradiated bismuth target and astatine recovery in nitric acid media.
Credit: Conceptual design by Evgeny Tereshatov, Texas A&M University/Graphic Design by Nathan Clark, Office of Science, Communications and Public Affairs
The Science
Astatine-211 (At-211) is one of a handful of promising alpha emitting radioisotopes for cancer therapy. Its short 7.2-hour half-life means that it must be handled quickly to minimize losses due to radioactive decay. In this research, scientists designed and tested an automated device for producing At-211. The device is able to remotely dissolve an irradiated target and extract At-211 from a solution by using a separation technique called extraction chromatography. This device minimizes the dose of radioactivity to workers producing the At-211. It also reduces the time needed to prepare samples for shipment to less than 20 minutes.
The Impact
The emission of alpha particles near tumor cells is a promising tactic in cancer treatment. These particles damage a tumor while causing only limited damage to surrounding cells. In comparison, beta particles travel much farther and so, cause more damage beyond the targeted cells. At-211 is one of nine alpha-emitting radioisotopes that researchers have clinically studied. The fast and efficient new chemical At-211 production procedure is the result of using the principles of process automation, which helps to simplify and accelerate routine production of this valuable radioisotope. The approach fully automates all chemical processing steps, resulting in minimized dose to personnel and high reproducibility. This compact device can significantly increase availability of the promising At-211 radioisotope for research centers, hospitals, and patients.
Summary
At-211 (7.2-hour half-life) has limited availability worldwide. For example, there are only five centers in the United States capable of its production. This radioisotope is available through the Department of Energy Isotope Program. The Texas A&M K150 cyclotron is capable of routine production of medically relevant quantities of At-211 and can deliver it to nearby facilities using overnight shipment options. The facility is part of the DOE Isotope Program University Isotope Network.
In this study, a team of researchers designed and tested an automated device aimed at remote dissolution of an irradiated bismuth target followed by extraction chromatography column separation of At-211 from unwanted impurities. The automated device can use as many as 10 independent columns, allowing to it divide the At-211 production activity. For convenience, each column containing At-211 can be shipped to the desired destination facilities. This allows researchers to implement their own chemical protocols. The time required for complete target dissolution and At-211 purification is as long as 20 minutes with a very high 95% elution yield.
Funding
This work was supported by Department of Energy Office of Science and its Isotope Program managed by the Office of Isotope R&D and Production, Texas A&M University, and the Texas A&M System National Laboratories Office through a collaboration with Los Alamos National Laboratory, the Texas A&M Nuclear Solutions Institute.