I still remember the demo in third year physics at school where the alpha radiaiton source was held in front of a piece of paper and the detector immediately went quiet. Oh useful to know I thought.......
IMHO this has been way over milked by the media. Unless I was being remarkably and uncharacteristically intimate with a Russian spy I am confident that I am not about to pop my clogs of radiation poisoning. However the media heard "Radiation" and went into full public scare mongering frenzy as they are too dim to know that Alpha radiation and Gama radiation (the stuff from Plutonium etrc) are VERY different animals. Gamma will kill you stone dead. Alpha will be stopped by your skin. UNLESS you are ingeniously forced to eat it in which case it will kill you as surely as ............say rat poison.
However I'm sure that if rat poison were found to have been carried on a BA767 without permission we would not be grounding aircraft and talking to the BBC.