Ultrasound Therapy


What Is Ultrasound Therapy Or Therapeutic Ultrasound? What Are Its Types?

This therapy involves the application of Ultrasound waves above the range of human hearing in order to treat various types of injuries. The application of Ultrasound Therapy helps in increasing the blood flow of a localized area in order to reduce the swelling and inflammation in that area. It is also used to enhance the healing of a bone fracture.

It is generally categorized into 2 types:

1. Thermal Ultrasound Therapy

  • This therapy involves the continuous transfer of sound waves resulting in small vibrations in the deep tissue molecules. These vibrations increase heat and friction in the molecules. This heating effect results in increases in the metabolism of the tissue cells resulting in the healing of the soft tissues.
  • The local rise in the temperature could be used to accelerate healing. It is generally used in cases of Myofascial painmuscle strain or sprain, scars, or adhesion.

2. Mechanical Ultrasound therapy

  • This therapy uses single vibration of sound waves to penetrate tissue. It actually causes the expansion and contraction in the tiny gas bubbles of the soft tissues which then helps to reduce the inflammation, reducing tissue swelling and thus decreasing pain in the tissue.
  • It is generally used if you have Pain and Swelling such as with Carpal Tunnel Syndrome,

Ultrasound may be used in a continuous mode where the treatment head continuously produces ultrasonic energy or pulsed where the treatment head continuously produces ultrasonic energy or pulsed where the periods of ultrasound are separated by periods of silence.

What Are The Treatment Parameters Of Ultrasound Therapy Or Therapeutic Ultrasound?


The unit of intensity when using ultrasound is the watt.

Space averaged intensity where the average intensity over a specified area is given, e.g. watts per square centimeter (Wcm-2).

Time-averaged/space-averaged intensity can be used when the ultrasound is being applied in a pulsed mode and gives the average intensity over the whole treatment time (per second for a specified area Wcm-2).

Pulsed mark: space ratio

When ultrasound is applied in its pulsed mode, the ratio of the time on to time off should be expressed. This is the mark: space ratio, the mark being the time ultrasound is on space being the silence, both being measured in milliseconds eg  2: 8, 1: 7.

Reflection of ultrasound

Air does not transmit ultrasonic waves, so in ultrasonic treatment, great care is taken to avoid leaving air between the treatment head and the patient, to minimize reflection. Though there will always be some reflection at each interface that the ultrasound beam encounters. This gives rise to acoustic impedance. When the acoustic impedance is low, the transmission is high, and vice versa.

Transmission of ultrasound

If the ultrasound beam encounters an interface between two media and is transmitted, it may be refracted. As refraction does not occur when the incident waves travel along the normal, treatment should be given with the majority of waves traveling along with the normal, whenever possible.

Attenuation of ultrasound

Attenuation is the term used for the gradual reduction in the intensity of the ultrasonic beam once it has left the treatment head. Two major factors contribute to attenuation.


Ultrasound is absorbed by the tissues and converted to heat at that point. This constitutes the thermal effect of ultrasound.


This occurs when the normally cylindrical ultrasonic beam is deflected from its path by reflection at interfaces, bubbles, or particles in its path. The overall effect of these two is such that the ultrasonic beam is reduced in intensity the deeper it passes. Therefore, when treating deep structures consideration needs to be given to the frequency and intensity of ultrasound chosen.

Ultrasonic fields

The depth of penetration and intensity of the ultrasonic beam is the division of the beam into a near and a far-field. The near and far-fields arise because the wavefronts from different parts of the source have to travel different distances and consequently there is interference between adjacent fronts. At some points, the interference is constructive at other points the interference is destructive. The extent of the near field is of significance in that it is more intense than the far-field and may have a more profound effect in the treatment of certain conditions. The frequency of the ultrasound and radius of the transducer may need to be considered when treating tissues at a depth greater than 6.5cm.

Coupling media

Ultrasonic waves are not transmitted by air, thus some couplant that does transmit then must be imposed between the treatment head (transducer) and the patient's skin. No couplant affords perfect transmission and only a percentage of the original intensity is transmitted to the patient. Air reflects the ultrasonic beam back into the treatment head and thus produces standing waves that might damage the crystal. The treatment head is never left switched on when not in contact with a transmission medium.


How Does Ultrasound Therapy Or Therapeutic Ultrasound Work?

Ultrasound therapy basically involves the use of a metallic probe. The procedure begins with the application of gel either on the head of the probe or directly to the skin. This gel basically helps the sound waves to penetrate into the skin evenly. After the gel is applied, this probe is then continuously moved over the selected area for over 5 to 10 min. The intensity or the power of an Ultrasound is adjusted as per the desired effect. Some people may feel a mild pulsing during this therapy while others may feel a slight warmth in the selected area.

Ultrasound Therapy has got numerous benefits as it can be used for a vast range of issues. However its most commonly used for:

  • Heating and relaxing the muscles in order to alleviate the pain.
  • Increasing the blood flow i.e. lymph (lymph: a fluid that carries white blood cells throughout the body) to enhance the healing process not only of muscles but also joints and ligaments.
  • Softening of any existing scar tissue.
  • A low-intensity Pulsed Ultrasound (LIPUS) is used for fracture repair.
  • Management of the Knee Osteoarthritis (OA)

What Are The Conditions Treated By Ultrasound Therapy Or Therapeutic Ultrasound?

The most common conditions that can be treated using Ultrasound therapy are:

TENDONITIS / TENDINITIS:                                                                                                                     

It is a general term that is used to define the inflammation of the tendon tissue that connects the muscle to the bone. This is the most common cause of soft-tissue pain. It can occur at any age but it is more common in adults who do a lot of sports. Old-age people are also prone to it as the tendons tend to lose their elasticity and become weaker with age. Its common types are:

Other conditions that can be treated with Therapeutic Ultrasound are:

What Are The Limitations Of Ultrasound Therapy Or Therapeutic Ultrasound?

Ultrasound Therapy is a very low-risk, non-invasive procedure. But there are certain times where and when it should be avoided like,

  • It is not applied to people who have cardiovascular issues.
  • It is not applied over the abdomen, pelvic regions, or lower back in pregnant or menstruating women.
  • It is not applied over broken skin or healing fractures.
  • It is not applied around the eyes, breasts, or sexual organs.
  • It is not applied over the areas with plastic implants, cardiac pacemakers.
  • It is not applied over or near the areas with malignant tumors.
  • It is not applied cannot be used in acute sepsis.
  • It is not applied over spina bifida or after laminectomy.
  • It is not applied to the radiated area for at least six months after irradiation.

Ultrasound Physiotherapy should not be used without a prescription from a doctor/physiotherapist & administration should be done by a physiotherapist unless allowed by a medical doctor.

Ultrasound Therapy Physiotherapy Nearby

Select your City to find & connect with our experts regarding Physiotherapy for Ultrasound Therapy