Method and experiment of noninvasive temperature estimation by ultrasound echo pulses

According to wave group decomposition theory, a method of segmenting the time-frequency diagram of the WDF (Wigner Distribution Function) to extract the available spectral component amplitude of the reflected pulses, which is related to the sound speed difference between neighboring layers, has been proposed to resolve the temperature profile of the layered medium. With this approach and the corresponding computer program, the temperature distribution inside excised liver tissue along the direction of the insonified ultrasound beam perpendicular to the interfaces of the layers was calculated from the sampling data of echo pulse series practically acquired through the use of an A-scanner and an appropriate A/D converter. The comparison of the calculated result with real temperature distribution shows that good agreement may be obtained with an error less than 0.5/spl deg/C.