Contact: Joshua Soneson, PhD
HITU_Simulator v2.0 predicts many important characteristics of continuous wave, high-intensity therapeutic ultrasound (HITU) beams and their heating effects. This is done by integrating a high-order parabolic approximation of the axisymmetric Westervelt equation, also known as the wide-angle Khokhlov-Zabolotkaya-Kuznetsov (WAKZK) equation, from the frequency-domain perspective. This results in a spatial distribution of pressure of each harmonic, taking into account beam diffraction, interference effects, power-law frequency-dependence of attenuation and the corresponding phase velocity dispersion, the fraction of energy loss that is converted to heat, the nonlinear effects of higher harmonic generation/wavefront steepening, and the corresponding augmented heat generation due to shocked waveforms. From these pressure fields the temporal average intensity and power density are calculated. The power density is then used as a source for the bioheat transfer (BHT) equation, which is integrated to determine the temperature and thermal dose fields.
The software is user-friendly, fast, light on system resources, and runs on Matlab, the popular technical computing platform. Many changes have been incorporated to improve the performance and features of its predecessor, HIFU_Simulator, including the ability to simulate a wider range of axisymmetric fields from shallow-focus to unfocused beams. The user may specify as many tissue layers as required. Spatial averaging is used to mimic the effects of hydrophone measurements of the pressure field. The graphical output is more flexible. And as always the software developer is available to provide technical assistance.
HITU_Simulator v2.0 is open source and available for free download from GitHub: https://github.com/jsoneson/HITU_Simulator