高强度聚焦超声脑肿瘤治疗焦域温度均匀分布调控的数值仿真研究

Numerical simulation of the focal region modulation to realize uniform temperaturedistribution during high-intensity focused ultrasound brain tumor therapy

在高强度聚焦超声(HIFU)脑肿瘤治疗过程中需严格控制治疗温度。本研究通过调控相控换能器激励信号实现了焦域温度均匀分布的目的。首先,本文利用志愿者头部计算机断层扫描(CT)数据和82阵元相控换能器建立开颅HIFU治疗脑肿瘤的三维数值仿真模型,通过叠加聚焦于两个设定目标点的信号并调控两信号间激励时间差和幅值,研究其对HIFU焦域温度分布及焦域形状大小的调控。研究结果表明,两目标点间距离在一定范围内通过调节两激励信号的激励时间差和幅值可以实现焦域内温度均匀分布,同时可调控焦域形状和体积大小。本文研究的仿真结果或可为HIFU安全有效地应用于临床治疗提供理论方法和参考。

The temperature during the brain tumor therapy using high-intensity focused ultrasound (HIFU) should be controlled strictly.This research aimed at realizing uniform temperature distribution in the focal region by adjusting driving signals of phased array transducer.The three-dimensional simulation model imitating craniotomy HIFU brain tumor treatment was established based on an 82-element transducer and the computed tomography (CT)data of a volunteer's head was used to calculate and modulate the temperature distributions using the finite difference in time domain (FDTD)method.Two signals which focus at two preset targets with a certain distance were superimposed to emit each transducer element.Then the temperature distribution was modulated by changing the triggering time delay and amplitudes of the two signals.The results showed that when the distance between the two targets was within a certain range,a focal region with uniform temperature distribution could be created.And also the volume of focal region formed by one irradiation could be adjusted.The simulation results would provide theoretical method and reference for HIFU applying in clinical brain tumor treatment safely and effectively.