中文摘要：

目的高强度聚焦超声（HIFU）肿瘤治疗过程中，HIFU换能器形成的声场分布是决定其治疗效果的关键因素之一，为了提高HIFU肿瘤治疗的安全性和可靠性，需要对HIFU换能器形成的声场进行预测。方法采用时域有限差分（FDTD）法数值仿真水体内形成的声压分布与实验测量结果对比的研究方法，分析讨论了HIFU换能器在不同激励功率、不同激励频率下的声压分布。结果随着激励功率的增加，焦点处声压变大，焦点位置基本不变；在共振频率下焦点的声压值最大，随着频率减小焦点位置向远离换能器一侧移动。结论仿真结果与实验结果相一致，可以通过仿真方法对声场进行预测。

英文摘要：

Objective In the treatment of tumor with high intensity focused ultrasound （HIFU）, the acoustic pressure distribution determines the safety and reliability of HIFU. It is necessary to predict the acoustic field produced by HIFU transducer. Methods To analyze the acoustic pressure distribution of HIFU generated by different excitation frequency and variable incentive power, comparison was made between the acoustic pressure simulated by finite difference time domain （FDTD） method and the ones measured by experiments. Results The results showed that the pressure at focal point increased with the increasing of excitation power, while the change in the focal length was negligible. The focal point moved towards the transducer with the frequency increasing until the maximum sound pressure was gained at the resonant frequency （RF） Conclusion The simulation results are consistent with the experiment results, indicating that the acoustic fields can be predicted by simulation.