Bust that makes rather unsuitable as a terrorist weapon. Terrorism needs an instant and spectacular even to be effective - a building falling down, scores of bodies, blood gushing etc. If the effect of a plutonium "dirty bomb" will take place 50 years later - it simply won't do.
However, it works quite effectively as a terrorist scare tactic. Just imagine the fascist Repug propaganda telling the gullible US-ers that they will get cancer from terrorists 50 years form now....
Wojtek