P5E-9 A Fast Field Simulation Method for Longitudinal Ultrasound Wave Propagation and Transmission in Homogeneous and Layered Media

A fast Rayleigh-Sommerfeld integral-based method was presented in this paper to speed up acoustic field simulation using a modified summation scheme. Partitioning source aperture with uniform large patches instead of simple sources, the modified summation scheme outperformed the conventional simple source based approach by both reducing the number of source-field interaction pairs and reusing the beam directivity of a single source patch. This modified scheme, along with Snell's law, could also facilitate wave transmission simulation in layered media. Using the fast method with patches of one wavelength dimension, the axial and lateral intensity distribution of a circular piston and a spherical cap transducer were calculated at least 20 times faster than did the conventional approach and retained numerical accuracy in near and far fields, with 2% and 5% root mean square error (RMSE) of their theoretical counterparts, respectively. Numerical examples of transmitted beam in a tissue-mimicking medium further demonstrated the efficiency and accuracy of the method. The modified scheme achieved at least 4 times computational time speed-up and had no more than 5% RMSE in comparison with the conventional approach. The fast field simulation method should be useful in transducer design and beam-forming investigation in therapeutic ultrasound applications and other scenarios where efficiency of transmitting acoustic field simulations is critical.