Motexafin Gadolinium in Treating Patients With Glioblastoma Multiforme Who Are Undergoing Radiation Therapy to the Brain

DISEASE CHARACTERISTICS: Histologically confirmed supratentorial grade IV astrocytoma Glioblastoma multiforme Previously untreated disease Measurable and contrast-enhancing tumor by MRI after incomplete resection/biopsy PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 60-100% Life expectancy: Not specified Hematopoietic: WBC at least 3,000/mm^3 Absolute granulocyte count at least 1,500/mm^3 Platelet count at least 100,000/mm^3 Hemoglobin at least 10 g/dL Hepatic: Bilirubin no greater than 2.0 mg/dL SGOT/SGPT no greater than 4 times upper limit of normal (ULN) Alkaline phosphatase no greater than 4 times ULN PT/APTT normal Renal: Creatinine no greater than 1.5 mg/dL Cardiovascular: No uncontrolled hypertension Other: Mini mental state exam score at least 15 No history of glucose-6-phosphate dehydrogenase deficiency or porphyria No other malignancy within the past 5 years except curatively treated basal cell or squamous cell skin cancer, carcinoma in situ of the cervix, or carcinoma in situ of the breast No serious infection No other medical illness that would preclude study participation No allergy to MRI contrast (e.g., motexafin gadolinium) Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for up to 2 months after study PRIOR CONCURRENT THERAPY: Biologic therapy: No prior biologic therapy or immunotherapy for this disease, including any of the following: Immunotoxins Immunoconjugates Antisense therapy Peptide receptor antagonists Interferons Interleukins Tumor-infiltrating lymphocytes Lymphokine-activated killer cell therapy Gene therapy Chemotherapy: No prior chemotherapy for this disease Endocrine therapy: Must be on a stable corticosteroid regimen (i.e., no increase within 5 days prior to treatment on this protocol) No other prior hormonal therapy for this disease Radiotherapy: No prior radiotherapy for this disease Surgery: See Disease Characteristics Recovered from prior surgery Other: No other concurrent investigational agents