Motexafin Gadolinium and Radiation Therapy in Treating Young Patients With Pontine Glioma

Inclusion Criteria: * Diagnosis of intrinsic pontine glioma (brain stem glioma) * Clinical and radiographic (MRI) evidence of tumors that diffusely involve the brain stem (i.e., tumors that intrinsically \[\> 50% intra-axial\] involve the pons or pons and medulla, pons and midbrain, or entire brain stem) allowed * Tumor may contiguously involve the thalamus or upper cervical cord * No more than 1 lesion/mass present at diagnosis * Karnofsky performance status (PS) 60-100% (age \> 16 years) OR Lansky PS 60-100% (age ≤ 16 years) * Life expectancy ≥ 8 weeks * Absolute neutrophil count ≥ 1,000/mm³ * Platelet count ≥ 100,000/mm³ (transfusion independent) * Hemoglobin ≥ 10 g/dL (RBC transfusions allowed) * Creatinine clearance or radioisotope glomerular filtration rate ≥ 70 mL/min OR creatinine normal for age/gender (0.4-1.7 mg/dL) * Bilirubin ≤ 1.5 times upper limit of normal (ULN) * ALT \< 1.5 times ULN * No known glucose-6-phosphate dehydrogenase (G6PD) deficiency * If family history suggestive of congenital hemolytic anemia, patient must be screened for G6PD with G6PD activity test prior to study entry * No biliary obstruction * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No prior definitive therapy for this specific tumor * No prior cranial radiotherapy * Concurrent steroids and anticonvulsants allowed * No concurrent proton therapy * No concurrent intensity-modulated radiotherapy * No concurrent anticancer chemotherapy * No concurrent immunomodulating agents