Therapeutic ultrasound: temperature increase at different depths by different modes in a human cadaver.

A specific increase in temperature is necessary to achieve a temperature-mediated therapeutic impact by ultrasound in rehabilitation. In order to obtain a physical basis for a definite temperature rise at a certain depths in the human body a human cadaver study in situ was conducted. A set of 16 experiments was carried out with an ultrasound frequency of 1 and 3 MHz. For each frequency the pulsed and continuous mode of energy delivery were compared at a variable intensity of 0.5, 1.0, 1.5 and 2.0 W/cm2. The ultrasonic energy was delivered in direct contact to the cadaver at the posterior crural compartment of the leg in a static manner. Temperature was monitored with a 1-minute interval during an insonation of 10 minutes. Results revealed that theoretical physical predictions concerning tissue heating by therapeutic ultrasound could not always be consolidated and that thermal therapeutic effects for deeper conditions are not obvious to be achieved by ultrasonic therapy.