Cancer which spreads to the brain (brain metastases) is a common and significant problem. Historically, whole-brain radiotherapy has been used to treat these patients but has a negative effect on cognition. Radiosurgery is an alternative treatment with potential for fewer cognitive side effects. The impact of radiosurgery alone on the cognitive function of patients with multiple brain metastases is not well studied. We propose a pilot study at the Winnipeg Centre for Gamma Knife Surgery to examine this issue.