radioactivity

At-211's short half-life also means it quickly loses its radioactivity, making it less toxic than longer-lived radiopharmaceuticals.

The heart of a nuclear reactor seethes with deadly radioactivity.

“And there’s been a lot of reasons for why this process takes so long. But, from a radiological perspective, the actual residual radioactivity at the site is pretty modest.”

A becquerel is defined as a small unit of radioactivity.

As well as radioactivity, chemical exposure could also be a problem for anyone nearby.