There have been quite a few photographic lenses containing radioisotopes: https://camerapedia.fandom.com/wiki/Radioactive_lenses https://camerapedia.fandom.com/

There have been quite a few photographic lenses containing radioisotopes: https://camerapedia.fandom.com/wiki/Radioactive_lenses https://camerapedia.fandom.com/wiki/Radioactive_lenses A few years ago I sent an Olympus Zuiko 55mm 1.2 to a friend in Russia. It has thorium in its glass elements. The lens didn't arrive for weeks and he started worrying whether it was lost on the way. He then was summoned by the customs authority to make a statement on the radioactive material he was importing. Turns out, during import they take a radioactivity reading on a container full of packages. This lens alone was radioactive enough to trigger the alarm for the container, and they had to make multiple readings (like in the puzzle with the coins of different weight) to find the radioactive package. In the end, I think he had to give up the lens.