This research is studying a new investigative imaging instrument called a nonlinear microscope (NLM). A nonlinear microscope can produce images similar to an ordinary pathologist's microscope, but without first processing tissue to make slides. This study will determine if a NLM can be used to evaluate tissue during lumpectomy surgery for breast cancer in order to reduce the probability that standard pathologic examination of the specimen after the end of the operation will find close or positive margins, thus possibly requiring the patient to have additional breast surgery.