The Simulation of Temperature Field for HIFU Phased Array Transducer

High intensity focused ultrasound (HIFU) phased array transducer can obtain variable focus and multiple focus for the variable timetable of ultrasound launched by different elements. In this study, the approximation of Westervelt formula, associated with Pennes heat conduction equation, through a model of 3D breast tissues, is reported for analyzing the differences of the temperature field between the plane phased array transducer and the spherical-section phased array transducer with a numerical method of Finite Difference Time Domain (FDTD).The effect of frequency and ultrasound power densities (USPD) on the temperature field of spherical-section phased array are also studied. The results demonstrated that the spherical-section phased array transducer can reduce the temperature of skin effectively, and cause less damage to skin. While the therapy frequency increases, the treated region decreases. In addition, the higher USPD are, the bigger the focal region is, but the focal distance does not change so much.