Modeling Changes in Electrical Properties of Tissues Under Low Intensity Focused Ultrasound

Electrical impedance tomography (EIT) is a functional imaging technology, which can reconstruct the distribution image of electrical parameters that can reflect the physiological and pathological changes of tissues. By using acoustoelectric (AE) effect, ultrasonic modulated electrical impedance tomography (UMEIT) can obtain additional effective information on the basis of traditional EIT and improve the spatial resolution of the reconstructed image. Understanding the physical mechanism of AE effects in tissues is very important for further application and optimization of this effects. It is assumed that focused ultrasound (FUS) is applied to tissues in the form of acoustic radiation force (ARF), which causes elastic deformation of the focused area and changes the dielectric constant, and a theoretical model is established. Based on this model, simulation was carried out to discuss the influence of acoustic radiation force, initial dielectric constant and Young's modulus of materials on the AE effect signal. The experiment of tissue simulation phantom with different electrical and elastic properties is realized.