Numerical study of the effect of ultrasound frequency on temperature distribution in layered tissue

• We simulated the propagation of high intensity focused ultrasound in tissue.
• We predicted the temperature of tissue during the HIFU surgeries by solving the bio-heat equations.
• We analyze the effect of changes in intensity and frequency of HIFU and the effect of these on temperature rising.
• We obtain the best range of frequency and intensity of HIFU surgery.

The high intensity focused ultrasound (HIFU) technology can produce therapeutic benefits in deep-seated tissues of interest, selectively and noninvasively. In order to control the treatment process, it is important to recognize the heat generation in biological tissue and the parameters that have an effect on temperature rising. This study investigates the influence of frequency and source intensity on temperature distribution during high-intensity focused ultrasound (HIFU). A nonlinear full wave equation model is simulated to compute the pressure field. Additionally, the absorbed coefficient of tissue is added to the nonlinear equations to simulate accurately the wave propagation in tissue with high absorbed coefficient. In addition, temperature distribution was solved by the Pennes bio-heat equation. Conclusively, frequencies in the range of 1–1.5 MHz are prescribed to have maximum heat absorption in the focal region.