Abstract

Ultrasonic Doppler Imaging of Nonlinear Elastic Shear Properties of Biological Tissue Phantoms

E.Timanin, E.V.Eremin (Institute of Applied Physics RAS, Nizhny Novgorod, Russia)

e-mail: eugene@appl.sci-nnov.ru

On the base of the ultrasonic pulsed Doppler technique the software-hardware complex has been built for imaging the forced vibration displacements within phantoms of biological tissues. A set of algorithms of quadrature Doppler signals processing is included into the complex. One of them provides the reconstruction the full signal of vibratory displacement along the ultrasonic beam in the sample volume on the Doppler signals. The spectral processing is applied then to reconstructed displacement signal. Possibilities are provided by the complex software to record the magnitude distributions of the first and the second harmonicas of this signal in the sample along the ultrasonic beam. A set of experiments has been conducted on the uniform gelatine-based cylindrical phantoms of biological tissue. The "not uniform" distributions are registered of displacement magnitudes on the main frequency of vibrations, corresponding to the excited modes of cylindrical sample, and the "uniform" distributions are registered of relative displacement magnitudes on the second harmonica. These results demonstrate the possibility of heterogeneity imaging of tissues (in nonlinear elastic shear properties) against the background of spottiness of vibrations on the main frequency. Experiments are being planned now on tissue mimicking phantoms with definitely not uniform distributions of shear elastic parameters.

Section : 5