Bias-sensitive crossed-electrode relaxor 2D arrays for 3D photoacoustic imaging

We introduce novel bias-sensitive piezoelectric transducer (relaxor) arrays for 3D photoacoustic imaging. A 64×64 element relaxor array using a crossed electrode or Top-Orthogonal to Bottom-Electrode (TOBE) wiring configuration is used to receive photoacoustic data from two crossed wires with 17.8 um diameters in an intralipid medium. A 3D image was then reconstructed. By biasing a column and receiving along a row, individual elements can be isolated for readout of signals from all elements using bias-switching-based multiplexing. We demonstrate a reconstruction technique called Hadamard-bias encoding with dynamic receive beamforming in which, rather than using a single column to index an array element, multiple columns are biased simultaneously allowing for more receiving elements and substantially improved SNR. Ongoing work will investigate in vivo imaging. The proposed arrays represent a new paradigm for 3D photoacoustic imaging.