IN-VITRO ULTRASONIC-ATTENUATION STUDIES IN LIVER AND KIDNEY TISSUE OFGOAT

A quantitative method for analysing echographic signals for characteri zation of biological tissues is presented. Using cathode ray oscillosc ope and spectrum analyser to acquire radio frequency (rf) echo signals from different state of the tissues, it is possible to estimate the f requency dependent attenuation coefficient. We have investigated the u se of Time Fourier analysis to provide an estimation of the echographi c spectrum as a function of tissue state. It permits tracking of the d epth dependence of the local round trip transfer function. It has been shown that the depth dependence of the spectral centroid allows simpl e determination of frequency dependent attenuation. The spectral runni ng moments of the Time Fourier analysis are correlated to the attenuat ion slope. In the present studies we have investigated liver, and kidn ey. Typical values of attenuation slope in the case of liver and kidne y are found to be 0.53+/-0.039 and 0.69+/-0 074 dB/cm/MHz respectively which are close to the values by other workers.