Cobalt 60 and mutations?

Does anyone know the name of a company that will irradiate seeds with the isotope Cobalt 60? It doesn't have to be C-60, any gamma source will work. Also, a link to any foreign country will do, as well as college professors or someone in nuclear medicine. One of the little doohickeys they use to inspect welding would also work if you could calculate the 'grey units'. I'd buy the C-60 but Homeland Security wouldn't understand. RScott