X-ray shows the pellets located across the kitten's body, legs and face. The 7-month-old kitten was rescued in Ypsilanti, Michigan. Courtesy of the Humane Society of Huron Valley ...

The TSA notes that animals should never be put through an airport's X-ray tunnel. Dogs and cats, for example, can either be screened privately in a separate room or walk with a traveler through ...

But the smallest amount to date that can be X-rayed is an attogram, or roughly 10,000 atoms. That's because the X-ray emission of a single atom is just too weak to be detected—until now.