“Putin may be ordering up some more Polonium. Soros ought have a Geiger counter when he eats out”.
An ordinary Geiger counter won’t work.
That is true.
But once Litvinenko's doctors figured out what was wrong with him three days before he died, Scotland Yard had little trouble tracing polonium contamination all the places Litvinenko and his assassins had been. And they were able to trace it back across Europe to Mother Russia.