The prognosis for many carcinomas is dependent on the extent of surgical resection. At present, the ability to perform a complete resection with negative margins is limited by the investigator's ability to palpate and visualize the tumor and its borders. In many cases, a more radical resection than necessary is performed in order to provide assurance that negative margins are achieved. This approach may also increase complication rates, as well as short- and long-term morbidity. It is desirable to improve visualization of primary tumors and occult metastases in real time, during surgery. The use of fluorescent probes that recognize cancer-specific antigens, in conjunction with a clinical imaging system, is under investigation.