Ultrasound is applied using a round-headed wand or probe that is put in direct contact with the patient’s skin.
Ultrasound gel is used on all surfaces of the head in order to reduce friction and assist in the transmission of the ultrasonic waves.
Therapeutic ultrasound is in the frequency range of about 0.8-3.0 MHz.
The waves are generated by a piezoelectric effect caused by the vibration of crystals within the head of the wand/probe.The sound waves that pass through the skin cause a vibration of the local tissues.This vibration or cavitation can cause a deep heating locally though usually no sensation of heat will be felt by the patient.
In situations where a heating effect is not desirable, such as a fresh injury with acute inflammation, the ultrasound can be pulsed rather than continuously transmitted.