Hi Patsy,
The OCF site has good information about different types of radiation. Take a look at:
http://www.oralcancerfoundation.org/facts/radiation.htm

Because proton radiation therapy is so precise, as Brian noted, it may not be the correct treatment in your situation. You really need the advice of a radiation oncologist experienced in treating head and neck cancers.

You didn't mention whether your husband is getting treatment at a comprehensive cancer center. Please make sure that you go to such a center for treatment. Best, Sheldon