Intra-operative radiation therapy (IORT) is the use of radiation therapy during a surgical procedure. IORT is one solution for giving high radiation doses to a tumor while sparing the nearby normal tissues. During the surgical procedure while the wound is open, the surgeon shows the radiation oncologist the areas of the tumor bed where tiny fragments of tumor may remain. The sensitive normal tissues are moved out of the radiation field, and then radiation oncologist directs a single high dose of radiation to the area most at risk for residual disease. At UCSF, we have 2 machines for delivery of IORT. One machine (Mobetron), located in the operating room at the Parnassus campus, is used for tumors such as sarcomas, neuroblastoma, recurrent pelvic malignancies, and recurrent head and neck cancer. The other IORT machine (IntraBeam), located in the operating room at the Mt. Zion campus, is used to treat breast cancer at the time of lumpectomy. IORT may be used alone, but is frequently complemented by additional external beam radiation therapy after a patient has healed from surgery.