And it would be bloody useless
as it wouldn't show up on the X-rays.
( The Mock TurtIe ™ --- Thinks you are a cunt, on, Fri 12 Jan 2007, 20:17, archived)

The Barium sulphate molecules are just big enough =)
Anyway, if it was Beryllium then you wouldn't need x-rays.
( Rev. Cleo still alive, Fri 12 Jan 2007, 20:20, archived)