Narrow Results

Tissue elasticity and viscosity are always associated with pathological changes. As a new imaging method, ultrasound vibro-acoustic imaging is developed for quantitatively measuring tissue elasticity and viscosity which have important significance in early diagnosis of cancer. This paper developed an ultrasound vibro-acoustic imaging research platform mainly consisting of excitation part and detection part. The excitation transducer was focused at one location within the medium to generate harmonic vibration and shear wave propagation, and the detection transducer was applied to detect shear wave at other locations along shear wave propagation path using pulse-echo method. The received echoes were amplified, filtered, digitized and then processed by Kalman filter to estimate the vibration phase. According to the phase changes between different propagation locations, we estimated the shear wave speed, and then used it to calculate the tissue elasticity and viscosity. Preliminary phantom experiments based on this platform show results of phantom elasticity and viscosity close to literature values. Upcoming experiments are now in progress to obtain quantitative elasticity and viscosity in vitro tissue.

In this paper, the mathematical model of distribution of the injected compound in biological liquid flow has been described. It is considered that biological liquid contains a few phases such as water, peptides and cells. The injected compound (for example, photosensitizer) can interact with peptides and cells. At the time, viscosity of the biological liquid depends on pathology present in organism. The obtained distribution of the compound connects on changes of its fluorescence spectra which are registered during fluorescent diagnostics of tumors. It is obtained that the curves do not have monotonic nature. There is a sharp curves decline in the first few seconds after injection. Intensivity of curves rises after decreasing. It is especially pronounced for wavelength 590nm and 580nm (near the “transparency window” of biological tissues). Time of inflection point shifts from 8.4s to 6.9s for longer wavelength. However, difference between curves is little for different viscosity means of the biological liquid. Thus, additional pathology present in organism does not impact to the results of in vivo biomedical investigations.