There is evidence from previous studies (including Radiation Therapy Oncology Group (RTOG) 0933) that hippocampal avoidance during whole brain radiotherapy using IMRT may decrease toxicity in the form of memory loss. Patients who had brain metastases within the region of hippocampal avoidance were not eligible for enrollment on RTOG 0933. In contrast, this study will include this group of patients since IMRT will be used to not only deliver higher doses to visible brain metastases even though they are located within the hippocampal avoidance region, but also to avoid the hippocampus itself. This approach may help to preserve memory function. Additionally, while temporary (and sometimes permanent) alopecia results from conventional whole brain radiation, IMRT spares the skin and possibly decreases the rate of hair loss. Dose to the scalp will be limited to as low as possible in order to decrease the risk of permanent alopecia in this study.