One, al-Qaeda have the knowhow to build radiological bombs.

José Padilla: arrested in 2002 on suspicion of planning to detonate a radiological bomb.

"Do you think Adara plans to use a radiological bomb at the peace summit?"

Pu-238 could conceivably be used in a radiological or dirty bomb to exploit the significant public fear of plutonium.

A radiological bomb, one that would take a while to decontaminate after it went off.

Other weapons, including chemical poisons and radiological "dirty bombs," will terrorize more than kill.

Not enough to make much of a radiological bomb, but we think they're planning something like it.

But some experts have said terrorists might try to make a so-called radiological bomb by combining conventional explosives with radioactive material like spent nuclear fuel.

The government says he was planning to detonate a radiological bomb in America.

Such events raise concerns that terrorists could have obtained materials for a radiological bomb and exposed nearby residents to radioactive contamination.