Latest info on Polonium-210 is that it is 1 billion times more radioactive than uranium, 250 billion times more poisonous than cyanide, was discovered by Marie Currie and named after her homeland of Poland, is made in a particle accelerator (each reaction creates only enough to fit onto the head of a pin), it's only known use (apart from as a poison, although this case is - as far as we know - unprecidented) is as an accelerator in nuclear reactors, a speck smaller than the eye could see would be enough to kill him instantly, so imagine how small a dose he has been given, it is carried in bodily fluids, especially saliva and sweat, and something like 100 people are believed to have been affected by the radiation he emmited in hospital, especially his wife and young son. Also, it has been available recently on the British black market. Be afraid...be very afraid.