FDTD simulation of transcranial focusing using ultrasonic phase-conjugate arrays

Focusing ultrasonic fields onto selected targets within the body with good accuracy and sufficient intensity to allow controlled necrosis of a region of tissue is a topic of great interest in medical acoustics. Several techniques have been demonstrated through simulation and laboratory experiment to achieve promising results [1, 2, 3]. The purpose of the present paper is to demonstrate the use of acoustic phase conjugation, or more narrowly in this context, time reversal as a valid focusing technique in biological tissue, which does not require a priori knowledge of the inhomogeneous propagation medium’s properties. Another goal of this paper is to demonstrate the effectiveness of the finite-difference time-domain (FDTD) method for the simulation of linear acoustic propagation in an inhomogeneous propagation medium