On 17 Nov 2009 at 21:19, William Donzelli wrote:
  Yes, but most of those other substances are not
useful, or no more
 useful that the normal mix of isotopes found in nature. B10 is (or
 was, I think they use something else these days), even if it is a one
 trick pony. 
I wonder what the price of a microgram of U235 is currently?
Doing a little reading, I see the that use of B10 is as a neutron
capture agent.    It apparently has a role in some experimental
nuclear medicine (Google BNCT for "Boron Neutron Capture Therapy").
Cheers,
Chuck