A high-speed photoacoustic tomography system based on a commercial ultrasound and a custom transducer array

Abstract

Building photoacoustic imaging systems by using stand-alone ultrasound (US) units makes it convenient to take advantage of the state-of-the-art ultrasonic technologies. However, the sometimes limited receiving sensitivity and the comparatively narrow bandwidth of commercial US probes with elements driving long cables may not be sufficient for high quality photoacoustic imaging. In this work, a high-speed photoacoustic tomography (PAT) system has been developed using a commercial US unit and a custom built 128-element PVDF transducer array. Since the US unit supports simultaneous signal acquisition from 64 parallel receive channels, PAT data for synthetic image formation from a 64 or 128 element array aperture can be acquired after a single or dual laser firing, respectively. The PVDF array provides satisfactory receiving sensitivity and uniquely broad detection bandwidth, which enables good image quality for tomographic photoacoustic imaging. A specially designed 128-channel preamplifier board that connects the preamps directly to the PVDF elements not only enables impedance matching but also further elevates the signal-to-noise ratio in detecting weak photoacoustic signals. To examine the performance of this imaging system, experiments on phantoms were conducted and the results were compared with those acquired with commercial US probes.