c&en, chemical & engineering news, august 13, 2020.

Astatine is the rarest naturally occurring element on Earth. It resists easy chemical classification. In reactions, it sometimes acts like a halogen, sometimes like a metal.

But astatine isn’t just a chemical curiosity. Groups around the world are investigating the Isotope astatine-211 as a potential cancer treatment.

Astatine-211 can be produced from an inexpensive, non-enriched bismuth target; it can be attached to small molecules or antibodies; and it has lower side-effect risks than some other therapeutic Isotopes. Early clinical studies are showing promise for cancer therapy and pre-transplant immunoablation.