用于动物实验的阵列式超声脑刺激器

Array ultrasound brain stimulator for animal experiments

目的:设计用于动物实验的阵列式超声脑刺激器,以解决单换能器无法校正散焦以及焦点不可控的问题。方法:刺激器采用16路的阵列换能器,每一路都有独立的匹配电路和驱动,延时电路和脉冲发生电路都集成在FPGA,并与上位机控制界面相连。然后,用水听器测量延时时间,并根据相位补偿原理校正和操纵焦点。最后用水听器扫描测量声场分布,以检测焦点校正和偏移的情况。结果:声场测试结果表明散焦得到校正,焦点声压提高了23%,旁瓣声压均比主瓣低6 dB以上,-6 dB焦域尺寸为d_(x)=3 mm、d_(y)=3 mm、d_(z)=14 mm。操纵焦点从原点O左右上下各偏移了2 mm。结论:阵列式超声脑刺激器具有校正焦点和操纵焦点偏移的功能,为超声脑刺激研究提供了一个有用工具。

Objective To design an array ultrasonound brain stimulator for animal experiments for solving the problem that a single transducer cannot realize defocus correction and focus manipulation.Methods A 16-channel array transducer was used in the simulator,and each channel had an independent matching circuit and driver.Delay circuit and pulse generation circuit were integrated on FPGAand connected to the control interface of the host computer.Then,delay time was measured with a hydrophone,and the focus was corrected and manipulated according to phase compensation principle.Finally,the sound field distribution was scanned with a hydrophone to assess the focus correction and focus offset.Results The sound field test results showed that the defocus was corrected.Moreover,the focus sound pressure was increased by 23%;and the side lobe sound pressure was more than 6 dB lower than the main lobe;and the size of the-6 dB focal zone was d_(x)=3 mm,d_(y)=3 mm,d_(z)=14 mm.The focus was manipulated to realize focus offsets from the origin O to the left,right,up and down by 2 mm.Conclusion The proposed array ultrasound brain stimulator has the functions of defocus correction and focus manipulation,and it provides a useful tool for the study on ultrasound brain stimulation.