For those considering radiation as the way to treat localized prostate cancer, an alternative to external beam radiation is brachytherapy -- the delivery of radiation directly to the prostate from dozens of tiny radioactive seeds implanted into the prostate gland.

This approach has the advantage of delivering a high dose of radiation to tissues in the immediate area, while minimizing damage to healthy tissues such as the rectum and bladder.

Seeds made of radioactive palladium or iodine are delivered through the thin-walled needles into the prostate, according to a computer-generated pattern, to conform to the shape and size of each man's prostate. Placement of the needles is guided by ultrasound of CT.

The implantation procedure generally take an hour or two under local anesthesia with the patient typically going home the same day. The seeds remain in the body permanently, The seeds emitting radiation for several weeks.

Because the experience with brachytherapy is relatively recent, long-term results are not yet known. But the National Cancer Institute says that at 5 years, more than 90 percent of prostate cancer patients treated with brachytherapy remain free of disease.

While a brachytherapy patient can expect a few weeks of incontinence, the approach appears to cause few long-termcomplications such as prostatitis or urinary incontinence. Sexual impotence occurs in about 15 percent of men under age 70 and 30 to 35 percent of men over age 70.