If you get a chance read The Body Electric by, I think it's Bender. He's a bone doctor and researcher-- he developed a way to help bad breaks heal with electric signals which is widely used today. The problem is not the thermal effects or the radiation itself- the problem is that the body uses a lot of electrical signalling internally, and a lot of the effects relate to frequency and resonance more than just intensity, and it is not well understood. Since it is not well understood and a lot of money is at stake, it is even less well understood-- business agendas come into play, and the science becomes an economic battlefield.