Capabilities and features of the “HIFU beam” nonlinear modeling tool for axially symmetric acoustic fields generated by focused therapeutic transducers in layered media

The goal of this introductory talk is to present an overview of the software termed “HIFU beam” that has been designed for simulating HIFU fields generated by axially symmetric single-element transducers and annular arrays in flat-layered media that mimic biological tissues. Numerical models include the Khokhlov–Zabolotskaya–Kuznetsov (KZK) and one-way Westervelt equations with thermoviscous absorption as well as power-law absorption to capture frequency-dependent effects. The numerical algorithms include combinations of time- and frequency-domain finite-difference schemes to simulate formation of high-amplitude shocks at the focus. The software comprises a MATLAB toolbox combined with a user-friendly graphical interface and binary executable compiled from FORTRAN source code; it is available for Windows operating systems only. Simulation examples representing typical cases of ultrasound transducers, focusing conditions, and propagation in layered media are presented to illustrate software features for High Intensity Focused Ultrasound (HIFU) applications. The software tool “HIFU beam” is freely available and can be downloaded, along with a detailed help file, from the website http://limu.msu.ru. The software can help to predict nonlinear HIFU pressures generated by existing transducers and help in the design of transducers for achieving specified acoustic outputs. [Work supported by RSF 20-12-00145, NIH R01EB7643, and R01EB25187.]