Ultrasonic medical imaging system using capacitive micromachined transducer array

超声成像几乎占所有临床成像方法的25%，有两个战略方向：制造低成本、便携的设备，易于在偏远地区部署并帮助远程诊断，以及在高端现场设计高分辨率3D和4D(即实时3D)声学成像系统，这需要具有大量换能器的2D阵列来产生和接收超声波。虽然目前的压电换能器通常被用作超声成像系统的前端，但缺乏与电子设备的芯片级集成以及相对较高的成本是阻碍这两个方向发展的障碍。利用新存在的CMOS-MEMS集成技术的潜力，本方案旨在开发一种医学成像系统，该系统使用一组电容式微机械超声换能器(CMUT)作为前端，在芯片级与CMOS电子器件集成。MEMS(微机电系统)技术使超声传感器的制造成为可能，这种传感器的工作频率比大多数压电器件更高，具有宽带宽和大动态范围。短期内，目标是在项目持续时间内设计和测试与电子电路集成的线性CMUT阵列，并将其连接到现有的超声设备；第二次设计迭代将针对2D集成CMUT阵列。一个较长期的目标是设计一种适用于3D和4D的超声成像系统，使用2D CMUT阵列与在可重构硬件(FPGA)中实现的实时信号处理和控制算法接口。一个主要的应用目标是一种低成本、高性能的便携式超声系统，用于乳腺癌诊断和监测肿瘤的演变，并与新辅助化疗相结合。新兴的基于CMUT的成像技术是一个新的交叉学科领域，它将为在MHz范围内的超声成像领域实施先进的信息处理系统奠定基础。

Ultrasound imaging accounts for almost 25% of all clinical imaging methods, with two strategic directions insight: fabrication of low-cost, portable equipment, easy to deploy in remote areas and help in tele-diagnostic,and, on the high-end site, the design of high resolution 3D and 4D (i.e. real time 3D) acoustic imaging systems,which need 2D arrays with a large number of transducers for generating and receiving ultrasonic waves. Whilepresent piezoelectric transducers are commonly used as front-end for ultrasonic imaging systems, the lack ofchip-level integration with electronics and the relatively high cost are obstacles hindering both evolutiondirections. Taking advantage of the potential of newly existing CMOS-MEMS integrated technologies, thepresent proposal targets the development of a medical imaging system using as front-end an array of capacitivemicromachined ultrasonic transducers (CMUTs), integrated at chip level with CMOS electronics. MEMS(Microelectromechanical Systems) technology makes possible the fabrication of ultrasonic sensors that canoperate at higher frequencies than most piezoelectric devices, with a wide bandwidth and large dynamic range.On a short-term, within the duration of the project, the goal is to design and test a linear CMUT arrayintegrated with electronic circuitry and to interface it to existing ultrasound equipment; a second designiteration will target a 2D integrated CMUT array. A longer-term goal is to design an ultrasound imaging systemsuitable for 3D and 4D, using 2D CMUT arrays interfaced with real-time signal processing and controlalgorithms implemented in reconfigurable hardware (FPGA). A main aplication target is a low-cost, highperformance portable ultrasonic system for breast cancer diagnostic and monitoring the evolution of the tumorin conjunction with neo-adjuvant chemotherapy. The emerging CMUT-based imaging technology is a newcross-disciplinary field, that will set the stage for the implementation of advanced information processingsystems in the field of MHz-range ultrasound imaging.