Search academic texts

Information × Registration Number 0305U003274, 0103U004220 , R & D reports Title Investigation of local shifting disturbance in biological tissues phantoms popup.stage_title Експериментальне дослідження методу допплерівської діагностики та вдосконалення ультразвукової допплерівської системи для реєстрації індукованих зсувних збурень Head Tovstjak V.V., Registration Date 04-03-2005 Organization Kharkov national university named after V.N. Karazin popup.description2 The purpose of the work is to create the array of biological tissues phantoms with different viscoelastic features and also to define their mechanical characteristics with independent methods. Experimental investigation of phantoms viscoelastic features by registration of induced shear disturbance is to be carried out. It has been designed the ultrasound system for estimation of displacements induced in biological soft tissues and acoustical phantoms of soft tissue. The principles, structure and algorithms of Doppler system channel operating at frequency 7,5MHz are described. The system uses the phase method of measurement based on the handling of consecutives signals of ultrasound Doppler tissue response. The achieved measurement preciseness was demonstrated using the combined electromagnetic imitator, that contains the gel staff, and gel based acoustical phantom. The present study revealed the significant dependence of displacement magnitude and strain relaxation on phantom elasticity and viscosity.It has been shown that simultaneous analysis of temporal behavior and magnitude of shear strain induced by the radiation force of focused ultrasonic beam gives the necessary data for quantitative estimation of tissue viscosity and shear modulus due to the known functional dependencies of displacements on these parameters. As a result the simplest calibration procedure of acoustic radiation force based methods is performed and algorithm for separate reconstruction of tissue elasticity and viscosity is proposed. These findings were tested, in particular, using the data obtained for specially prepared phantoms containing calf liver and muscle tissue in vitro. The observed complex character of shear strain relaxation and noises in some tissue phantoms and tissues in vitro reduces the preciseness of viscoelastic properties estimation. Product Description popup.authors popup.nrat_date 2020-04-02 Close