High Intensity Focused Ultrasound (HIFU) is a non-invasive procedure to treat varicose veins and venous reflux disease using ultrasound. It is totally non-invasive treatment which works with ultrasound energy being beamed from a transducer applied to the skin above the vein. HIFU heats the target vein to temperatures proven to cause permanent closure of a leaking varicose vein by fibrosis. It does not require cannulation of the vein, and indeed nothing is inserted into the target vein at all.