Ultrasonic medical imaging system using capacitive micromachined transducer array

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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.