D- Ultrasonic wave Heating
These waves are different from electromagnetic waves . It produces mechanical vibration inside tissue. It is the same as the sound waves but it has much higher frequencies about I MHz with power of several watts per centimeter. It can move the tissue particles backward and forward with high frequency, in doing so it can increase the kinetic energy consequently it heats the tissue.
Ultrasound can be produced by special transducers placed in direct contact with the skin. It is used for relieving tightness and scarring occurring in jointdisease. It can dispose more heat in bones, as bones are better absorber for ultrasonic energy than soft tissue. It is also used in deep therapy.