Proton Beam Radiotherapy for Medulloblastoma and Pineoblastoma

There are two types of external radiation treatments (proton beam and photon beam). As part of the participant's treatment, they will receive radiation to the entire central nervous system (CNS); this is known as craniospinal irradiation (CSI). In the past, photon radiation therapy has been used for CSI. In this study we will be examining the effects of proton beam radiation therapy. Studies have suggested that this kind of radiation can cause less damage to normal tissue than photon radiation therapy. The physical characteristics of proton beam radiation let the doctor safely deliver the amount of radiation delivered to the tumor that is normally delivered through standard therapy but spare more normal tissue in the process.

* 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.