Ultrasound works by sending sound waves through the body. Doctors can recommend ultrasound therapy to treat pain. It may work best alongside other treatments.

Many people know ultrasound as an imaging tool that allows doctors to see inside the body.

It can also be therapeutic, promoting tissue healing and treating pain.

Both imaging and therapeutic ultrasound procedures use certain sound waves. The biological effects that result depend on the frequency of those sound waves.

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Ultrasound uses a round-headed transducer probe to produce sound waves that enter the body. Transducers can both send and receive sound waves.

Diagnostic ultrasound utilizes sound waves to produce images doctors can use for patient assessment. Therapeutic ultrasound uses sound waves to interact with body tissue and modify it in some way, such as:

  • pushing or moving tissue
  • heating tissue
  • dissolving clots
  • delivering medication to precise locations in the body

Studies indicate that therapeutic ultrasound has a variety of applications, including treating pain.

A 2020 clinical trial found that continuous, low-intensity ultrasound resulted in significant pain reduction for people with myofascial pain in the shoulder and neck. Myofascial pain is referred musculoskeletal pain that appears in a confined area.

A 2020 review found that ultrasound therapy reduced knee and shoulder pain. It noted that research strongly supports its use for knee pain but that more research is necessary to create guidelines for clinicians.

The review authors indicated that ultrasound might be more effective with other treatments rather than done in isolation.

Can it treat other conditions?

Ultrasonic therapy may benefit people with other conditions.

Joint stiffness can improve because the thermal effect can increase collagen stretchiness, improving joint mobilization.

Cancer patients may even benefit from therapeutic ultrasound. A 2015 review found that using ultrasound resulted in cancer cell death in four areas of cancer therapy:

  • sonodynamic therapy
  • antivascular ultrasound therapy
  • ultrasound-mediated gene delivery
  • ultrasound-mediated chemotherapy

Ultrasound can also treat:

Read about conventional versus complementary therapy here.

There are two ways in which practitioners use therapeutic ultrasound.

Diathermy

Diathermy is the practice of creating heat beneath the skin for therapeutic purposes. Body tissues absorb the sound wave energy, resulting in molecular vibration, which converts the sound energy into heat.

Target areas include deep muscles, subcutaneous tissues, and joints.

Diathermy can treat:

Diathermy may also improve the effectiveness of radiotherapy and chemotherapy.

Cavitation

Cavitation refers to the way ultrasound waves create pressure changes in tissue fluids. Bubbles form and then burst, creating changes to nearby tissue. Doctors commonly use cavitation to break down fat cells.

Cavitation can treat conditions such as:

  • Cancer: Doctors use focused ultrasound on cancer cells to break them down and make them more receptive to treatment.
  • Diabetes: Doctors use cavitation to enhance wound healing for people with diabetes. It may help prevent cardiac problems that can result from diabetes.
  • Cardiovascular disease: Doctors may also use ultrasound cavitation to treat varicose veins, blood clots, calcified arteries, and veins.
  • Kidney disease: Doctors use cavitation to break down kidney stones.

Therapeutic ultrasound is a noninvasive procedure that can take place in a clinical setting such as a doctor’s or therapist’s office.

In addition to relieving pain, ultrasound therapy can also:

Learn about high intensity focused ultrasound facials here.

Ultrasound is noninvasive and doctors generally regard it as safe. Unlike X-rays, ultrasound does not produce ionizing radiation.

The Food and Drug Administration (FDA) warns that ultrasonic therapy is not safe for everyone and suggests a person tell their practitioner if they:

Although ultrasound therapy is generally safe, the wand should not be kept in one place for too long at certain frequencies. Patients should notify the practitioner immediately if they experience any discomfort.

The ultrasound transducer works using skin contact. A person having this procedure must either wear loose clothing that can be pushed aside or change into a hospital gown.

The ultrasound technician applies hypoallergenic gel to the skin over the target area. The gel helps to conduct the sound waves from the transducer.

The technician then places the end of the transducer on the gel and moves it across the skin while applying gentle pressure.

Treatments are usually short, lasting 5–10 minutes.

Ultrasound can do more than generate diagnostic imaging. It can also promote healing and treat pain.

Therapeutic ultrasound uses sound waves to create heat and movement in body tissue. It can treat various conditions, often in conjunction with other treatments.

Ultrasound is generally safe, but there may be risks for certain people. Anyone considering this procedure should speak with a clinician about any pre-existing health conditions.