EFFECT OF SOUND FIELD ON ATTENUATION COEFFICIENT MEASUREMENT AND ITS CORRELATION.

In the conventional method, where the ultrasound attenuation coefficient is determined from the echo signal reflected from inside of the subject, it is assumed that the incident and the reflected waves propagate as plane waves. This paper regards the subject as a set of scatterers and shows that the attenuation coefficient determined by the plane wave assumption contains an error. The method considered is the determination of the attenuation coefficient from the difference of power spectra of the echo signals reflected from different depth, and the effect of the sound field produced by the transducer is also included. The error can be evaluated by the shape function determined by the geometry of the transducer. Consequently, the error term from the attenuation coefficient obtained by the plane wave approximation.