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ULTRASOUND

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Ultrasound refers to mechanical vibrations which are essentially the same as sound waves but of a higher frequency.

Frequencies of a few megahertz that are typically used therapeutically:

From the range from 0.5-5MHz

  1. Production of Ultrasound

  2. Piezo-electric effect

For a 1MHz machine a vibrating frequency of one million per cycles is needed. This is achieved using either a quartz or barium titanate crystal. These crystals deform when subjected to varying potential difference.[1]

 

Physical and Physiological effects of Ultrasound

 

Thermal effects

Hyperemia - Temprature raised up to 40 - 45°C, which leads to -

  1. Reduction of pain

  2. Reduction of muscle spasm

  3. Promote healing process by increased cellular metabolism and consequently, the cellular activity

 

Non Thermal effects

  1. Cavitation

  2. Standing waves

  3. Acoustic streaming

  4. Micromassage

 

Therapeutic Uses

  1. Fracture healing

  2. Articular cartilage repair

  3. Wound healing

  4. Soft tissue injuries

  5. Pain relief

  6. Changing the extensibility of the scar tissue

  7. Diagnosis of stress fracture

 

Principles of Applications

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Couplant

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  1. Water bag, Gel/Gel pad, Plastic/Rubber bag with some water, Body part immersed in water with te treatment head

  2. Adequate tramission of ultrasonic  energy to the tissues depends on having a couplant that provides a good match of acoustic  impedence between the metal of the transduce head and the skin.

 

Continuous movement of the treatment head

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Method of application

  1. Direct contact application

  2. Water Immersion application

  3. Water bag application

 

Contraindications and Risks

  1. Tumors

  2. Pregnant uterus

  3. Epiphyseal plates

  4. Implants

  5. Spread of infection

  6. Vascular problems

  7. Radiotherapy

  8. Specialized tissue (Eyes, Gonads, Lungs and Gut)

  9. Anesthetic areas

 

Phonophoresis

It is also known as sonophoresis or ultrasonophoresis, is the movement of drugs through skin in to the subcutaneous tissues under the influence of ultrasound. [2]

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​REFERENCES

  1. Angela Forster,NigelPalastanga, Clayton’s Electrotherapy, Theory and Practice, 9th Edition.

  2. Val Robertson, Alex Ward, Electrotherapy Explained, Principles and Practice, 4th Edition.

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