I want to be a bone marrow donor, but I don't know if I can?

I have always wanted to donate my bone marrow. I have many friends who have had a bone marrow transplant – and it saved their lives. I want to be able to do this for someone, but I’m not sure I can… I am a cancer survivor but I have been in remission for 10+ years. I am 18 and I am very thin and have had blood transfusions (for this reason cannot donate blood). I have had chemo and radiation. Does anyone know the requirement for bone marrow donation or if my situation disqualifies me from it?