Simulation of nonlinear acoustic field and thermal pattern of phased-array high-intensity focused ultrasound (HIFU)

HIFU becomes an effective and noninvasive modality of solid tumor/cancer ablation. Angular spectrum was used in the wave propagation from phased-array HIFU transducer, and diffraction, attenuation and the nonlinearity were accounted by second order operator splitting scheme. Bioheat equation was used to simulate the subsequent temperature elevation and lesion formation. Good agreement was found between our acoustic pressure waveform and distribution and those of KZK from a concave transducer. Furthermore, the multiple foci synthesis has much less nonlinear effect, which affects the heating rate but not the lesion size. In summary, our approach could simulate the performance of phased-array HIFU with high accuracy and efficiency to optimize the treatment planning.