The purpose of this study is to evaluate the efficacy of parotid sparing in reducing measurable xerostomia (dry mouth) in patients undergoing whole brain radiotherapy. This is primarily a two-arm, single-blind, randomized study of parotid sparing whole brain radiation therapy (WBRT), with a third observational arm of patients who were identified after radiation had already started or who refused randomization but were willing to be followed for quality of life assessment. Qualifying patients who are interested in participating in the trial will be asked to complete an anonymous screening baseline xerostomia questionnaire. If their raw score on this questionnaire meets eligibility criteria, they will be offered enrollment on the study. Patients identified prior to radiation start will be offered enrollment into the interventional randomization arm, with the observation arm offered to those who refuse randomization. Patients identified after radiation has already started, but within 5 days of the first day of radiation, will be offered enrollment into the observational arm. Questionnaires completed by patients who consent to the trial will be assigned patient information (de-anonymized) and serve as their baseline quality of life data. After baseline assessment, subjects will be asked to complete the same questionnaire again at the end of treatment, as well as two weeks, one month, three months, and six months after treatment completion.