Broad bandwidth photoacoustic imaging using a PVDF receiver array

Photoacoustic (PA) signals are typically broadband, with a correlation between their frequency characteristics and source dimension. The transducers that are commonly used for PA acquisition are optimized for pulse-echo ultrasound imaging and are primarily based on inorganic piezoelectrics in ceramic, single-crystal, or composite form. These transducers are band-limited which limits their functionality as receivers for broadband PA signals. Custom broadband transducers are expensive and complex to manufacture. In this work, we propose to use a poly vinylidene difluoride (PVDF) based transducer for PA acquisition in combination with a commercial single-crystal linear array for pulse-echo acquisition. An 8-element PVDF array with 20dB onboard amplification was built in-house. The PVDF receiver is transparent to the pulse-echo ultrasound, and both transducers were positioned such that they image the same volume. The combined PA raw data from the PVDF and the linear array demonstrated the feasibility of achieving a broader overall reception bandwidth. This study establishes a foundation for a simpler acquisition system that enhances PA signal quality, co-registered with conventional ultrasound imaging, which may support the clinical adoption of PA imaging.