Photoacoustic Imaging With a Commercial Ultrasound System and a Custom Probe

Abstract

Building photoacoustic imaging (PAI) 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 may not be sufficient to acquire high quality photoacoustic images. In this work, a high-speed PAI system has been developed using a commercial US unit and a custom built 128-element piezoelectric-polymer array (PPA) probe using a P(VDF-TrFE) film and flexible circuit to define the elements. Since the US unit supports simultaneous signal acquisition from 64 parallel receive channels, PAI data for synthetic image formation from a 64 or 128 element array aperture can be acquired after a single or dual laser firing, respectively. Therefore, 2D B-scan imaging can be achieved with a maximum frame rate up to 10 Hz, limited only by the laser repetition rate. The uniquely properties of P(VDF-TrFE) facilitated a wide -6 dB receiving bandwidth of over 120 % for the array. A specially designed 128-channel preamplifier board made the connection between the array and the system cable which not only enabled element electrical impedance matching but also further elevated the signal-to-noise ratio (SNR) to further enhance the detection of weak photoacoustic signals. Through the experiments on phantoms and rabbit ears, the good performance of this PAI system was demonstrated.

Photoacoustic and ultrasound dual-modality imaging of human peripheral joints

“…Moreover, by combining with a production medical US system, the development of PA imaging can be accelerated by taking advantage of the state-of-the-art US technologies such as large number of parallel channels each with commercial grade receiver sensitivity and noise characteristics. 15,16 In this study, a dual modal system facilitating both US and PA imaging for clinical study on human inflammatory arthritis is presented. Through preliminary experiments on human finger joints, the system, in noninvasive imaging of peripheral joints and presenting both ultrasonic and optical contrasts, has been validated.…”

Photoacoustic tomography to identify inflammatory arthritis

“…The detailed technical aspects of this imaging system on PAT mode have already been introduced in our previous publication. 22 Before PAT, gray-scale ultrasound of the target joint was conducted first to find the best view in visualizing articular tissues. Then, without moving the sample or the probe, photoacoustic signals were acquired from the same joint.…”

High speed photoacoustic tomography system with low cost portable pulsed diode laser

“…[1][2][3][4][5] It is one of the rapidly growing noninvasive, in vivo imaging technique owing to its deep penetration depth, good spatial resolution and high soft tissue contrast unlike other systems like confocal microscopy or two-photon microscopy, where the penetration depth is very low. 6,7 It is a combination including the best features of pure ultrasound imaging and pure optical imaging.…”