Proton Beam Radiotherapy for Medulloblastoma and Pineoblastoma

* Before beginning radiation therapy, participants will have scans done in order to prepare for the radiation treatment. Doctors will use information gathered from these scans to plan the best way to deliver radiation to the tumor. * The following procedures will be performed either before or during the radiotherapy: Hearing exam; neurocognitive exam; blood tests and cerebral spinal fluid test. * Not everyone who participates in this study will receive the same amount of proton radiation therapy. The length of time and amount of radiation received will depend upon the condition of the participant's disease. Radiation treatment will be given once a day, 5 days a week (Monday-Friday). The overall treatment course will be approximately 6 weeks.