Ultrasound is a modality that uses high frequency sound waves to stimulate the immune system. This cuts down healing time to help you get better sooner. It is applied using a round-headed wand put in direct contact with the skin. Ultrasound gel is used on all surfaces of the head in order to reduce friction and assist in the transmission of the ultrasonic waves. Depending on the setting, the waves can penetrate anywhere from 1 to 5 cm under the skin’s surface.