ULTRASOUND Ultrasound equipment generates high-frequency sound waves that are transferred to a specific body area via a round-headed probe. The sound waves travel deep into tissue (e.g. muscles), creating gentle heat. The therapist usually applies a hypoallergenic gel to the skin, which creates a friction-free surface. Using gentle, circular motions with the probe, the therapist administers the treatment, which lasts several minutes. Ultrasound can also be used in phonophoresis. This treatment involves the application of a topical anti-inflammatory. The anti-inflammatory medication can be mixed with the ultrasound gel and applied to the area using the probe. The ultrasonic sound waves force the medication to migrate into the tissues reducing inflammation.