Radiation therapy can also cause hair loss in the pelvic area. The loss may be temporary or permanent, depending on the amount of radiation used. Radiation therapy causes impotence in some men. This does not occur as often with internal radiation therapy as with external radiation therapy, since internal radiation therapy is not as likely to damage the nerves that control erection. There is also a slight risk of long-term incontinence of urine and rectal problems with external radiation.
Some patients receive both kinds of radiation therapy.
The implant may be temporary or permanent. When a temporary implant is removed, there is no radioactivity in the body. The amount of radiation in a permanent implant is not generally dangerous to other people, but patients may be advised to avoid prolonged close contact with others for a period of time. This will be used to calculate the exact number of seeds for complete coverage and accurate placement. Usually 40 to 100 seeds are implanted in the prostate gland.