• Histologic proof or unequivocal cytologic proof solid tumor malignancy. This may be obtained from either the primary or any metastatic site

• Mini Mental State Examination (MMSE) ≥24

• Age≥ 18 years

• Karnofsky Performance Status (KPS) ≥70

• Patient does not have metastases to the genu

• Patient must be scheduled to undergo treatment with whole brain radiation therapy (WBRT) to manage the brain metastases

• Patients of childbearing potential (male or female) must practice adequate contraception due to possible harmful effects of radiation therapy on an unborn child

• Patient must have the ability to understand and the willingness to sign a written informed consent document

• All patients must be informed of the investigational nature of this study and must be given written informed consent in accordance with institutional and federal guidelines

• Patient must have a minimal life expectancy of at least 6 months

• Patients receiving prior stereostatic radiosurgery (SRS) for brain metastases are eligible