Intraoperative radiation therapy (IORT) is the delivery of radiation at the time of surgery. It is performed in conjunction with a surgeon. The surgeon removes the tumor if possible. Then a large dose of radiation is given directly to the tumor bed (the area from which the tumor has been removed) or to the tumor directly. This allows a larger dose of radiation to be given than with standard external radiation as some of the non-cancerous tissue is moved out of the way.