Cathe Barr didn't wear shorts for almost a decade because of an unsightly varicose vein on her right thigh. But when the vein began to cause a burning pain in her leg nad prevented her from kneeling at church, she sought medical advice.

Two doctors suggested the most common treatment: "vein stripping" - an invasive procedure requiring a general anesthetic and a four-week recovery. But he 49-year-old Chicago law-firm administrator took the advice of a third doctor. He suggested a new "closure" procedure that uses radio-frequency heat to collapse veins.

The technique, which uses devices approved in March 1999 by the Food and Drug Administration, requires only a local anesthetic and a small incision that doesn't need stitches. Minutes after treatment, Ms. Barr took a 30-minute walk. "Before, one leg looked like it belonged to an 80-year-old woman," says Ms. Barr. "It is so much more comfortable now."

The new therapy so far is only done by about 25 doctors in the U.S. But proponents say it's a promising alternative for the estimated 10% to 20% of the population suffering from varicose veins, a sometimes painful condition in which veins in the leg bulge grotesquely. The condition can result from weight gain, pregnancy, excessive standing and hereditary factors.

Varicose veins are most often caused by a faulty saphenous vein - the one that, when healthy, is used in coronary bypass operations. Over time, the vein can become stretched and dilated, preventing its valves from closing. Blood that usually flows up to the heart starts backing up, filling the vein and causing its tributary veins to bulge. Skin problems, ankle ulcers, and swelling and heaviness in the leg also can result.

Getting rid of varicose veins often first requires treatment of the saphenous vein. Ligation involves making an incision in the groin and pinching the vein closed. In vein stripping, a rod is threaded through the vein from the groin to just below the knee, where the vein is then ripped out, often causing a long recovery, bruising and tenderness. Smaller varicose veins are sometimes treated with sclerotherapy, in which a solution is injected into the vein to collapse it. It requires several treatments. Veins also are removed with a phlebectomy, in which the vein is pulled through an incision by a hooking tool.

Often after these procedures, varicose veins come back. Studies have shown recurrence rates as high as 40%; 20% of varicose vein operations are re-treatments, according to a 1999 article in the Journal of Vascular Surgery. As a result, doctors say, most people with varicose veins don't seek treatment. Indeed, of an estimated 25 million sufferers, just 150,000 vein strippings were performed in the U.S. last year.

"Patients say, 'Nope, I'll just wear support hose for a while until something easier comes up," says Robert A. Weiss, assistant professor of dermatology at Johns Hopkins University, Baltimore, who has treated about 40 patients with the closure procedure.

The closure technique was developed by VNUS Medical technologies, Sunnyvale, Calif. Ultrasound is used to view the saphenous vein, while a catheter containing electrodes is inserted through a nick below the knee and threaded up the vein to the groin. Radio-frequency energy is then used to heat the vein wall, causing it to collapse. The catheter is slowly pulled out to heat the length of the vein, sealing it shut. The body will redirect blood flow through other veins. About 60% of patients also receive a phlebectomy to remove smaller varicose veins.

Mark Marzano, an interventional radiologist at Vein Care Associates, Barrington, Ill., has performed closure on 42 patients, and says he is pleased with how quickly they recover. "I've had patients go dancing the next day," he says.

The closure procedure, like other treatments for varicose veins, carries risks. Early studies found 15% of patients suffered some temporary numbness or tingling in the leg. In a study of 390 procedures, three patients developed blood clots, although all were successfully treated. Early in the study, eight patients, accounting for less than 3% of the procedures, developed skin burns. Now, doctors who perform the procedure use ultrasound to determine if the vein is unusually close to the skin surface, and inject fluid to prevent burning in those areas.

The new procedure works only for those whose underlying problem is a faulty saphenous vein, which excludes 20%-30% of varicose vein sufferers.

Doctors aren't certain of long-term recurrence rates because the technology is so new. Six months to one year after treatment, 83% of the patients in one study group said they no longer had symptoms and another 10% reported substantial improvement. Doctors say early results suggest the treatment will produce success rates better then ligation and comparable to stripping.

The treatment typically costs between $2,000 and $2,500. Not al insurance companies cover it. VNUS Chief Executive Brian Farley says seven medical journals are expected to publish studies over the next year, which may prompt greater acceptance.

Nan Norman, a 51-year-old fitness instructor from Myrtle Beach, says a ligation in 1982 and more than 25 sclerotherapy treatments failed to cure a varicose vein in her right thigh. After reading about closure treatment on the Internet, she was treated by Dr. Weiss in October. The heaviness she felt in her leg has disappeared, as has slight swelling in her calf and ankle. "My legs are in front of everybody all the time," Ms. Norman says. "I've been more or less biding my time waiting for this technology."