Temporary (high dose rate, or HDR) brachytherapy
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.
These treatments are usually combined with external beam radiation given at a lower dose than if used by itself. The advantage of this approach is that most of the radiation is concentrated in the prostate itself, sparing nearby normal tissues.