Inclusion Criteria:  Patients must be age >= 18 years Patients must be planned for fractionated radiotherapy that will be delivered over at least 5 weeks and that will expose the brain to radiation Patients must have Karnofsky performance status (KPS) >= 80 Patients must be able to obtain an MRI scan with gadolinium contrast Female patients of childbearing age must not be pregnant as determined with a serum beta human chorionic gonadotropin (HCG) no greater than 14 days prior to study registration, or breast-feeding. (The exclusion is made because gadolinium may be teratogenic in pregnancy). Pregnancy tests are part of standard of care routine if a patient is receiving radiation treatment Patient must be fluent enough in English to complete neurocognitive testing Education of >= 12 years (high school graduate or equivalent) by patient self-report Patient is able to complete an in-person and electronic neurocognitive assessments (i.e. is alert and has the ability to comprehend and complete the assessments) Patient has no history of psychiatric or medical conditions that would result in an inability to complete serial neurocognitive tests, severe claustrophobia, prior cerebrovascular event(s), degenerative neurological diagnoses (e.g., dementia, Parkinson's, multiple sclerosis [MS]) or severe psychiatric illness (e.g., schizophrenia) that may impact neurocognitive and imaging assessments  Exclusion Criteria:  Prior radiation to the brain Concurrent chemotherapy Psychiatric or medical conditions that would result in inability to complete serial neurocognitive tests Severe claustrophobia requiring sedative medications for the MRI Prior cerebrovascular event(s) or degenerative neurological diagnoses (e.g., dementia, Parkinson's, MS) Contraindication to gadolinium-based contrast administration for MRI (i.e. allergy to gadolinium or severe chronic kidney disease defined by estimated glomerular filtration rate [eGFR] < 30 mL/min/1.73 m^2, as per institutional policy)