Ultrasonic diagnostic apparatus based on variations of acoustic characteristic

摘要

Disclosed is an ultrasonic diagnostic apparatus for detecting variations of an acoustic characteristic to obtain the fluctuation of temperature within a body to be examined. The ultrasonic diagnostic apparatus includes an ultrasonic transducer (10; 80, 81; 90, 92) for transmitting an ultrasonic wave and receiving the reflected ultrasonic wave which is in then converted into an electric signal. The signal is phase-detected (14, 15) in accordance with a plurality of gate intervals or a plurality of window intervals to detect a phase difference therebetween. The relative variation of velocity distribution shown before and after heating of the body is obtained on the basis of the phase variation resulting from the variation of the ultrasonic drive frequency.