The Research On Ultrasonic And Magneto-electric Imaging Method Based On Low-frequency Vibration

Electrical and mechanical properties of biological tissue have important values for the early diagnosis of diseases.The clinical requirement has promoted the development of frontier technologies of medical imaging such as electrical conductivity imaging and elasticity imaging.This study proposed an innovative dual-mode functional imaging method which combines acoustic and magneto-electric imaging methods on the basis of ultrasonography.The basic principle of the imaging method is to place a biological tissue in a static magnetic field,and excite the tissue by a low frequency vibration to produce internal vibration.The vibration has two effects:(1)the motion of charged ions has the phenomenon of electric charge separation influenced by Lorentz force in static magnetic field;(2)vibration induces the propagation of shear wave.The conductivity and elasticity properties of the tissue can be obtained by the surface electrodes and the ultrasonic pulse echo method,respectively.The main work of this thesis includes: the theoretical and methodology research,the dual mode imaging experiment platform construction and preliminary experimental studies on phantoms.In the theoretical and method research part,this thesis introduces the principle of the dual mode imaging method based on low frequency vibration in details,and derives the equation of the shear wave velocity and the conductivity distribution.In the construction of experimental platform and experimental research part,this thesis introduces the experimental platform construction and the function of each component in the platform.The feasibility of the platform was verified using the QA phantom.Then some preliminary experiments were performed which synchronously detected the elasticity and conductivity edge of the custom-made phantom.In the last part of this thesis,an analysis on the application prospects of the proposed method and a summary of all the work related to this thesis are provided.Some suggestions for the future work are discussed.