What Is Astatine Used For?
Astatine (At) has no established industrial, commercial, or household uses, because of its extreme scarcity and the short half-lives of its radioactive isotopes, which limit production, handling, and long-term use. However, it is being researched for potential applications in cancer treatment, primarily in the field of targeted alpha therapy (TAT), which delivers alpha-emitting radioisotopes directly to tumor cells. In this context, the isotope astatine-211 (At-211) has been investigated for potential use in treating certain blood-borne cancers and is also being explored in early-stage research for possible additional medical applications, including the treatment of Alzheimer disease.
Astatine-211 has been studied for use in TAT because its short half-life, about 7.2 hours, allows it to decay rapidly without producing long-lived radioactive decay products, thereby limiting the exposure of nontargeted, healthy tissue to toxic radiation. This isotope undergoes rapid radioactive decay because its nucleus is highly unstable, having an odd number of protons and neutrons, which forces it to quickly emit alpha particles to reach a more stable state. Astatine is a halogen that is found in trace amounts as a decay product of heavier elements. It is one of the rarest naturally occurring elements—amounting to less than 1 gram in Earth’s crust at any given time. For these reasons, At-211 must be synthesized in specialized facilities using cyclotrons. In this process, bismuth targets are irradiated with alpha particles to generate small, carefully controlled quantities of the isotope.
At-211 emits alpha particles, which deposit a high amount of energy over a very short distance and can lethally damage double-stranded DNA molecules in cancer cells. Because these particles typically travel only about 50–100 micrometers—roughly the diameter of a few cells—research has centered on delivering the isotope directly to malignant cells while limiting damage to surrounding tissue. Such studies have focused on blood-borne malignancies, such as leukemia, lymphoma, myelodysplasia, and myeloma, which often originate in the bone marrow.
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The practical use of At-211 in medicine is constrained by its short half-life, which limits the time available for production, purification, radiolabeling, and delivery. However, scientists have developed automated systems that employ extraction chromatography to purify At-211 rapidly, significantly reducing preparation time and minimizing decay losses. In 2025 the U.S. Department of Energy’s National Isotope Development Center reported the first successful long-distance shipment of a labeled astatine-211 compound, demonstrating the feasibility of distributing purified radioisotopes to distant research and clinical facilities.