1985 年 41 巻 12 号 p. 857-863
It has been well-known in radar technology that the intensity of echoes scattered by a random medium can be evaluated quantitatively in term of a backscattering coefficient. In order to apply this concept to ultrasonic pulse echo techniques, the influence due to the aperture length of window must be compensated since in ultrasonics the broad band pulse is used so as to increase the resolving power of the system. Thus the measurement of backscattering coefficient must be dependent on the window length as well as the duration of ultrasonic pulse. In this paper the influence of these factors on the measurement of backscattering coefficient is analyzed under the assumptions of Gaussian function for the window, the pulse and the correlation function of tissue. And then the results are generalized to give a formula for in vivo measurement of backscattering coefficient for arbitrary window functions. Finally the availability of the formula is shown in the experiments where a sponge is used as the random medium.