Ultrasound Therapy

Enhanced drug uptake using acoustic targeted drug delivery (ATDD).[/caption]

Therapeutic ultrasound refers generally to any type of ultrasonic procedure that uses ultrasound for therapeutic benefit. This includes HIFU, lithotripsy, targeted ultrasound drug delivery, trans-dermal ultrasound drug delivery, ultrasound hemostasis, cancer therapy, and ultrasound assisted thrombolysis. It may use focused ultrasound (FUS) or unfocused ultrasound.

Ultrasound is a method of stimulating the tissue beneath the skin’s surface using very high frequency sound waves, between 800,000 Hz and 2,000,000 Hz, which cannot be heard by humans.

There is little evidence that active ultrasound is more effective than placebo treatment for treating patients with pain or a range of musculoskeletal injuries, or for promoting soft tissue healing.

Relatively high power ultrasound can break up stony deposits or tissue, accelerate the effect of drugs in a targeted area, assist in the measurement of the elastic properties of tissue, and can be used to sort cells or small particles for research.

  • Focused high-energy ultrasound pulses can be used to break calculi such as kidney stones and gallstones into fragments small enough to be passed from the body without undue difficulty, a process known as lithotripsy.
  • Cleaning teeth in dental hygiene.
  • Focused ultrasound sources may be used for cataract treatment by phacoemulsification.
  • Ultrasound can ablate tumors or other tissue non-invasively. This is accomplished using a technique known as High Intensity Focused Ultrasound (HIFU), also called focused ultrasound surgery (FUS surgery). This procedure uses generally lower frequencies than medical diagnostic ultrasound (250–2000 kHz), but significantly higher time-averaged intensities. The treatment is often guided by Magnetic Resonance Imaging (MRI); the combination is then referred to as Magnetic resonance-guided focused ultrasound (MRgFUS).
  • Enhanced drug uptake using acoustic targeted drug delivery (ATDD).
  • Delivering chemotherapy to brain cancer cells and various drugs to other tissues is called acoustic targeted drug delivery (ATDD). These procedures generally use high frequency ultrasound (1–10 MHz) and a range of intensities (0–20 W/cm2). The acoustic energy is focused on the tissue of interest to agitate its matrix and make it more permeable for therapeutic drugs.
  • Ultrasound has been used to trigger the release of anti-cancer drugs from delivery vectors including liposomes, polymeric microspheres and self-assembled polymeric.
  • Ultrasound is essential to the procedures of ultrasound-guided sclerotherapy and endovenous laser treatment for the non-surgical treatment of varicose veins.
  • Ultrasound-assisted lipectomy is Liposuction assisted by ultrasound.

There are three potential effects of ultrasound. The first is the increase in blood flow in the treated area.[citation needed] The second is the decrease in pain from the reduction of swelling and edema[citation needed]. The third is the gentle massage of muscle tendons and/ or ligaments in the treated area because no strain is added and any scar tissue is softened[citation needed]. These three benefits are achieved by two main effects of therapeutic ultrasound. The two types of effects are: thermal 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 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.