Sean Collins, MD, PhD, joined the Georgetown Lombardi Comprehensive Cancer Center in July of 2006 as an attending physician in radiation oncology. Dr. Collins completed both an internship in surgery and a residency in radiation oncology at Georgetown University Hospital. His area of expertise is prostate cancer, for which he treats patients using the CyberKnife, a technology that allows for the targeting of radiation therapy. Dr. Collins is a physician-scientist which means he also conducts laboratory research. The focus of this work is to discover small molecules that will sensitize prostate tumors to radiation, improving efficacy of CyberKnife treatments and to develop methods for locating cancer within the prostate.