This study will apply optical spectroscopy to intraoperative margin assessment during surgery for breast cancer. We hypothesize that a combination of fluorescence spectroscopy and diffuse reflectance spectroscopy will reliably detect involved surgical margins. Twenty patients with ductal carcinoma in-situ will undergo a standard lumpectomy followed by scanning with a sterile optical spectroscopy probe. Frozen sections from the surgical cavity will be used to evaluate the margins. Optical spectroscopy data will be categorized as benign or malignant using a statistical algorithm and the results will be compared with the frozen and permanent section results.