Development Of Ultrafast Ultrasonic Imaging System Based On Plane Wave

Medical ultrasound imaging is widely used in clinical diagnosis because of its advantages such as radiation-free,high speed and low cost.At the same time,with the development of electronic technology and the innovation of principle and method,ultrasound imaging has made great progress,which can provide more accurate and more auxiliary reference for clinical diagnosis.However,the traditional ultrasonic imaging usually adopts the way of electronic scanning,which needs to be transmitted many times to focus on a frame,so the imaging speed is slow.Dozens of frames per second are not slow for the human eye,but with the emergence of real time elastography technology,functional brain imaging,super resolution imaging,they need hundreds of thousands of frames per second repeat overlay,higher requirements for imaging speed are put forward.Each element of the ultrasonic transducer is excited at the same time in plane wave ultrasonic imaging system,the whole imaging area needs to be transmitted only once,and a complete image can be obtained at one time,so the imaging speed is greatly enhanced.Based on the theory of plane wave imaging,a new scheme of ultrafast ultrasonic imaging system based on plane wave is proposed in this paper.The speed of ultrasonic imaging is increased from dozens of frames per second to more than one thousand frames per second creatively,and the image quality can be upgraded by compounding coherently the images obtained with several plane waves of different angles,through engineering research and development,the plane wave imaging method is transformed into a plane wave imaging system.The main contents of this paper are the hardware circuit design and programmable logic development of the system,and the system can realize 128 channel excitation and 128 channel acquisition at the same time.Logic control selects FPGA to perform efficiently and accurately,it also can adjust different working modes flexibly by receive instructions and parameters from host computer software in real time,the necessary pre-processing such as FIR has been done before uploading ultrasonic echo data to the host computer software for imaging display.In addition to introducing the design details of the functional modules of the system,the joint debugging of software and hardware is completed.In the echo receiving module,the signal gain is adjustable from-4dB to 54 dB,each channel analog to digital conversion rate up to 65 MSPS,12 bit conversion accuracy;In the ultrasonic excitation module,it also supports multi angle plane wave emission,the excitation frequency is adjustable from 1M to 35 M,and the excitation voltage is ±64V;USB3.0 high-speed communication with the host computer for data transmission,the highest measured speed of more than 300MByte/s.The system is verified by standard phantom,experimental results shows that the system can achieve high frame rate ultrafast ultrasonic imaging,it lays a solid foundation for real time elastography technology,functional brain imaging,super resolution imaging in the next step.