Girnyk S. Physical mechanisms of interaction of ultrasound with biological structures and its models.

The model of bilayer lipid lecithine-cholesterol membrane, water solution of gelatine as the phantom of a biological tissue and muscle tissue in vitro. The purpose of work was research of nonlinear effects of influence of ultrasound on biological structures and their models. Methods of research: measurement of electroconductivity of BLM, ultrasonic Doppler method of registration of shear displacement in tissue. Theoretical and practical results, novelty: ultrasound of therapeutic intensity results in change of diffusion mode on boundary phase division. The specified effect is caused by excitation of microflows. The ultrasonic Doppler registration of induced shear deformations of viscoelastic medium is carried out. The dynamic of relaxation of shear deformations in tissue phantoms and tissue in vitro was investigated. The features of formation of acoustic fields are determined and the spatial distribution of shear deformations is investigated which arise due to propagation of induced shear waves. Visualization of non-uniform elastic inclusion with the help of ultrasonic Doppler method for the first time is carried out. The results can be used for revealing both localization tumors and developing of the equipment for ultrasonic diagnostics with the purpose of early differentiation of pathological changes in soft tissue. Region of application - biophysics, medical physics, oncology and physiology.