基元控制的方式优化自聚焦换能器聚焦声场的研究

Optimization of the focused acoustic field of self-focusing transducer by element control

根据HY2900聚焦超声治疗系统聚焦换能器采用6基元自聚焦方式的特点,通过对6基元聚焦换能器排序及数量的控制,达到了避让特定部位的目的。采用亥姆霍兹-基尔霍夫积分计算并用HY2900声场测量软件测量换能器在脱气水中声场的分布。对6基元换能器排序进行定义,结合水听器控制基元数及排序。在对换能器基元全驱动,关闭1、6基元,关闭1、2、6基元,关闭1、3、5基元的四种状况下测量聚焦换能器途径声场及焦平面声场分布。研究发现焦点上10 mm声场分布平面直接反映换能器基元数及随排序的改变换能器聚焦声途径的变化,可通过对换能器基元排序及数量的控制,优化其途径声场分布。

According to the characteristics of the focusing transducer using 6-element self-focusing mode in HY2900 focused ultrasound tumor treatment system, through sorting and quantity control of the transducer, the system is able to control the focused acoustic field to avoid special parts. The sound field distribution of the transducer in deaerated water is measured by Reyleigh＇s integral calculation and the software HY2900. The order of 6-element transducer is defined, and the number of controlled elements and their order are determined. The sound field distributions on the focal plane and on the plane at 10 mm above the focal point are measured in four different conditions： transducer elements all driven, closing the 1, 6 element, closing the 1, 2, 6 element, closing 1, 3, 5 element. It is found that the acoustic distribution plane at 10 mm above the focal point directly reflects the number and the order of transducer elements causing the change of transducer focusing path. The optimization of the acoustic field distribution can be achieved by controlling the order and number of the focusing transducer elements.