Endovenous chemical thermal ablation is a treatment for venous insufficiency and varicose veins that uses a laser or high-frequency radio waves to close a defective vein. In this procedure, your doctor will locate the vein using ultrasound and insert a catheter into the vein, usually just below the knee. Then a salt water solution and an anesthetic will be injected into the vein, followed by laser or radio-frequency waves. You will be given local anesthesia for this procedure, and you can expect to return home the same day. Most people need a week or two to fully recover.