Inclusion Criteria:

- Histologically confirmed germ cell tumor or elevated AFP or B-HCG in the setting of
radiographic disease consistent with a germ cell tumor. Disease must be confined to
the central nervous system.

- Participants do not need to have measurable disease. Most patients will not have
measurable disease at the time of treatment.

- 3 years of age or older and 25 years of age or older a the time of diagnosis because
this study evaluates this disease entity in the pediatric population which may differ
from the adult population.

- Life expectancy of greater than 12 months.

- ECOG performance status of 0, 1 or 2

- Baseline MRI of the brain and spinal axis with gadolinium and prior to any
chemotherapy is required. If surgical resection is performed a post-operative MRI is
required. If the patient receives chemotherapy prior to radiation, a
post-chemotherapy MRI of the brain is required. If spinal involvement was seen on
initial MRI and prior to chemotherapy, a MRI of the spine is required after
chemotherapy and prior to radiation.

- Serum and lumbar CSF must be obtained to evaluate for alpha fetoprotein (AFP) and
beta human chorionic gonadotropin (HCG). This is needed to stratify patients into
pure GCT and NGGCT.

- Women of child-bearing potential and men must agree to use adequate contraception
prior to study entry and for the duration of study participation.

Exclusion Criteria:

- Patients will be ineligible if any prior therapeutic radiation therapy > 200 cGy has
been delivered to the central nervous system.

- Patients will be ineligible if chemotherapy was completed greater than 1 year from
the planned start date of radiation therapy or if the patient is referred for
radiation therapy after a relapse following a regimen with chemotherapy alone.

- Individuals with a history of a different malignancy are ineligible except for the
following circumstances: Disease-free for at least 5 years and are deemed by the
investigator to be at low risk for recurrence of that malignancy. Individuals
diagnosed and treated within the past 5 years for cervical cancer in situ and basal
cell or squamous cell carcinoma of the skin.

- Pregnant females