Calculation of Temperature Rise in Multi-layer Biological Tissue Based on Large Aperture Concave Sphere Focused Ultrasonic Transducer.

Introduction: The large aperture concave spherical focused ultrasonic transducer has stronger acoustic focusing effect and can obtain good temperature rise effect. The purpose of this study was to explore the effect of different frequency, duty cycle and inner radius parameters on temperature rise of multi-layer biological tissue. Material and Methods: The simulation model of high-intensity focused ultrasound (HIFU) irradiated multilayer biological tissue was constructed. By changing the irradiation frequency, duty cycle and inner radius of large aperture concave spherical focused ultrasonic transducer, the sound field and temperature field of multilayer biological tissue were simulated and calculated by using Westervelt nonlinear acoustic wave equation and Pennes biological heat conduction equation, respectively. Results: The intensity of sound field increased with the increase of frequency, while it decreased with the increase of inner radius, but the duty cycle almost had no effect on the intensity of sound field. The focal temperature increased with the increase of frequency and duty cycle, but decreased with the increase of inner radius. Conclusion: By selecting appropriate parameters of transducer, the optimum temperature rise in the target area of biological tissue can be obtained by using a large aperture concave spherical focused ultrasonic transducer. [ABSTRACT FROM AUTHOR]