While most radiation treatments are delivered from outside the body, radiation can also be delivered internally, directly targeting the tumor. With this form of radiation, known as brachytherapy, small radioactive “seeds” are placed during an outpatient surgical procedure. The seeds stay in the body permanently, continually exposing the tumor to radiation over a period of many weeks or months. This allows higher doses of radiation to be delivered than what can safely be achieved with external beam radiation. Brachytherapy is particularly useful for prostate cancer, where the target (prostate) is near other organs (rectum and bladder) that cannot tolerate high dose radiation. Studies have shown that this approach results in higher cure rates for certain forms of prostate cancer than what can be achieved with external beam radiation therapy.