Radiation Poisoning Remedies

my daughter who is now 15 years old rec'd radiation treatment on her head for a brain tumor. can you tell me if there is anything that can be done to help her hair grow back. some hair has grown back, but very thin and there is stll a big area where no hair has grown back. is there something she can take to regrow her hair? If not, i am considering hair transplant for her. i would appreciate an answer from ted or anyone out there who has been in this same situation.