Realtime control of multiple-focus phased array heating patterns based on noninvasive ultrasound thermography.
Realtime control of multiple-focus phased array heating patterns based on noninvasive ultrasound thermography.
复制标题
DOI：
10.1109/tbme.2011.2162105
复制
发表时间：
2012-01
期刊：
影响因子：
--
通讯作者：
Ebbini ES
中科院分区：
文献类型：
--
作者：
Casper A;Liu D;Ebbini ES
提出了一种实时生成和控制多焦点超声相控阵加热模式的系统。该系统采用 1 MHz、64 元件阵列和驱动电子设备，能够对加热模式进行精细的空间和时间控制。该驱动程序与商用扫描仪上实现的实时 2D 温度成像系统集成。温度控制点的坐标以及温度设定点和控制器参数在扫描仪的 B 模式引导图像上定义。每个点的温度由独立的比例、积分和微分 (PID) 控制器控制，该控制器确定该点的焦点强度。应用最佳多焦点合成在控制点生成所需的加热模式。当每个控制点达到所需温度时，控制器动态地重新分配来自共享电源的焦点之间的可用功率。此外，在每个控制点都实施了抗饱和补偿，以提高系统动态性。模拟组织模型的体外实验证明了控制器在短时间（2 – 5 秒）和更长的多焦点 HIFU 曝光下的鲁棒性。控制点附近的热电偶测量证实了通过无创反馈获得的温度变化的动态。
A system for the realtime generation and control of multiple-focus ultrasound phased-array heating patterns is presented. The system employs a 1-MHz, 64-element array and driving electronics capable of fine spatial and temporal control of the heating pattern. The driver is integrated with a realtime 2D temperature imaging system implemented on a commercial scanner. The coordinates of the temperature control points are defined on B-mode guidance images from the scanner, together with the temperature set points and controller parameters. The temperature at each point is controlled by an independent proportional, integral, and derivative (PID) controller that determines the focal intensity at that point. Optimal multiple-focus synthesis is applied to generate the desired heating pattern at the control points. The controller dynamically reallocates the power available among the foci from the shared power supply upon reaching the desired temperature at each control point. Furthermore, anti-windup compensation is implemented at each control point to improve the system dynamics. In vitro experiments in tissue-mimicking phantom demonstrate the robustness of the controllers for short (2 – 5 sec) and longer multiple-focus HIFU exposures. Thermocouple measurements in the vicinity of the control points confirm the dynamics of the temperature variations obtained through noninvasive feedback.