J0206-2-1 Numerical study on the focus control in high intensity focused ultrasound through an inhomogeneous media

Abstract

Although nowadays widely spread for imaging and treatments uses, HIFU techniques are still limited by the distortion of the wave front due to refraction and reflection over the inhomogeneous media inside the human body. CT-scan Time Reversal (TR) procedure has risen as a promising candidate for focus control. A finite difference time domain parallelized code is used to provide simulations of TR-enhanced propagation through elements of the human body and implement a simple algorithm to address the issue of grating lobes, or pressure secondary peaks due to natural diffraction of phased array and enhanced by medium heterogeneity. Using an iterative, progressive process combining secondary sound sources and independent signals summation, the primary peak is strengthened while secondary peaks are increasingly obliterated. This method supports the feasibility of precise modification and enhancement of the pressure profile in the targeted area through Time Reversal based solutions.