ULTRASONIC-IMAGING OF INTERNAL VIBRATION OF SOFT-TISSUE UNDER FORCED VIBRATION

Aiming at estimation of the viscoelastic properties of soft tissues, an imaging system that can display both the amplitude and phase maps of internal vibration in soft tissues for forced low-frequency vibration is proposed. In this method, low frequency sinusoidal vibration of frequency under several hundred Hz is applied from the surface of the sample and the resulting movement in it is measured from the Doppler frequency shift of the simultaneously transmitted probing ultrasonic waves. Basic experiments are carried out by using 3.0-MHz ultrasonic waves. The two-dimensional (2-D) maps of the amplitude and phase of internal vibration are shown and the velocities of vibration are measured for some samples as well as in vivo. © 1990, IEEE.