Variations of temperature distribution and lesion formation induced by tissue inhomogeneity for therapeutic ultrasound

Abstract

High intensity focused ultrasound (HIFU) has shown potential applications in therapeutic medical fields. This work reported both theoretical and experimental investigations on the influence of tissue inhomogeneity on the temperature distribution and tissue lesion formation using the phase screen model. The inhomogeneous tissue is considered as a combination of a homogeneous medium and a phase aberration screen. Numerical simulations were performed by using the nonlinear acoustic equation and bio-heat transfer equation. Four polyethylene (PE) plates with various standard deviations were made to mimic the inhomogeneity induced by human body abdominal. Temperature rise and lesion formation induced by HIFU were measured and compared with the numerical calculations. Results indicate that the standard deviation is associated with the focusing capability and temperature field observably. This study provides a theoretical and experimental basis for the development of precise HIFU treatment plan.