Therapeutic ultrasound may have two types of benefit: Thermal effects and non thermal effects. Thermal effects are due to the absorption of the sound waves. Non thermal effects are from cavitation, microstreaming and acoustic streaming. Cavitational effects result from the vibration of the tissue causing microscopic air bubbles to form, which transmit the vibrations in a way that directly stimulates cell membranes. This physical stimulation appears to enhance the cell-repair effects of the inflammatory response.
Therapeutic ultrasound is sometimes recommended for muscle as well as joint pain.
Ultrasound has been used in various drug delivery applications to enhance the delivery of pharmaceuticals to target tissues. Ultrasound has been shown to facilitate the delivery of drugs across the skin, promote gene therapy to specific tissues, deliver chemotherapeutic drugs into tumours and deliver thrombolytic drugs into blood clots. In addition, ultrasound has also been shown to facilitate the healing of wounds and bone fractures.