Neurocognitive Outcomes After Whole Brain Radiation Therapy for Hematologic Malignancies

PRIMARY OBJECTIVE: I. Record patients' cognitive outcomes after whole-brain radiation therapy (WBRT) for hematologic malignancies using standard-of-care neurocognitive function testing. SECONDARY OBJECTIVES: I. Assess patients' quality-of-life after WBRT for hematologic malignancies, based on a validated questionnaire. II. Explore magnetic resonance imaging (MRI) changes in the brain after WBRT for hematologic malignancies, based on standard-of-care imaging studies. III. Study the role of Memantine in patients' cognitive outcomes during and after WBRT for hematologic malignancies, based on standard-of-care use, utilizing standard-of-care neurocognitive function testing. OUTLINE: Patients undergo neurocognitive function assessments, complete questionnaires over 8-10 minutes and undergo standard of care MRI at baseline (within 4 weeks before the first day of WBRT), 2, 6, 12 months after RT completion, then annually for 5 years.