Demonstration of medical imaging using flexible polymer ultrasound technology

Abstract

We present a novel ultrasound transducer technology based on piezo polymers. Its fabrication process (PillarWaveTM), based on creating hexagonal micro-structured PVDF-TrFE pillars. This makes it fully flexible and allows scaling to large apertures (>15 × 15 cm2). Large area flexible transducers enable to select relevant field of view in automated post-processing. This can alleviate the need for a skilled sonographer and enable applications of echography outside clinics. To demonstrate its performance, a 128 element 8 MHz linear array is designed and manufactured. Its total thickness is 0.1 mm. Its acoustic characteristics are determined demonstrating 5.2 kPa/V transmit efficiency and 150 mV/Pa sensitivity. The receive bandwidth at -6dB is larger than 100%. A peak pressure in excess of 1 MPa at 4 cm from the array is measured in water. The transducer array is connected to a Verasonics Vantage research medical ultrasound system. The imaging performance of the array is demonstrated experimentally. Real-time imaging of an in vitro- medical phantom using plane wave compounding and delay-and-sum beamforming is demonstrated at 15 frames per second, with point spread functions at -20 dB of 1.3 and 0.92 mm in the lateral and depth directions, respectively. Finally, imaging of a human carotid in vivo is demonstrated.