This technique is done less often. It uses higher doses of radiation that are left in place for a short time. Hollow needles are placed through the skin between the scrotum and anus and into the prostate. Soft nylon tubes (catheters) are placed in these needles. The needles are then removed but the catheters stay in place. Radioactive iridium-192 or cesium-137 is then placed in the catheters, usually for 5 to 15 minutes. Generally, about 3 brief treatments are given over 2 days, and the radioactive substance is removed each time. After the last treatment the catheters are removed. For about a week after treatment, you may have some pain or swelling in the area between your scrotum and rectum, and your urine may be reddish-brown.
External beam radiation (also known as traditional or whole breast radiation therapy) uses external beam radiation, like that of a regular x-ray, but the beam is highly focused and targets the cancerous area for two to three minutes. This form of treatment usually involves multiple appointments in an outpatient radiation center — as many as five days a week for five or six weeks. Certain situations may require a slightly higher dose of radiation over a shorter course of treatment, usually three to four weeks (called accelerated radiation.)