Finite element analysis for acoustic and temperature characteristics of a piezoelectric HIFU transducer at 10 MHz

A high intensity focuses ultrasound (HIFU) is one of the emerging technologies in the biomedical field. The piezoelectric HIFU transducer is a device that utilizes the thermal energy generated by high ultrasound energy. Recently an operating frequency of the HIFU transducer is to expand above a 7 MHz. In this study, the acoustic pressures and temperature distributions in the tissue that generated by the HIFU transducer at 10 MHz were calculated with the finite element method. In addition, the pressure focusing characteristics of the device were analyzed. The geometrical variables are the piezomaterial thickness, lens shape, water height, and film thickness. The results shown that the acoustic pressure increased and saturated gradually when the height/radius (H /RL) ratio of the lens increased. Moreover, the focal area was gradually decreases with H /RL ratio of the lens. In case of the optimized HIFU transducer, the maximum pressure and temperature were analyzed about 19 MPa and 65 C respectively. And the -3 dB focused distances in the axial and lateral direction are around 2.3 mm and 0.23 mm respectively.