Volumetric Photoacoustic Imaging with a Rotational Row-Column-Addressed Array Based on Inverse Radon Transform

Existing row-column array (RCA) imaging methods mostly rely on sequential row/column and column/row transmissions. However, this imaging scheme is not compatible with photoacoustic imaging (PAI), in which signals originate from optical absorption and involve only one-way wave propagation. In this study, we propose a rotational RCA acquisition scheme that enables the synthesis of full matrix array (FMA) signals using the inverse Radon transform. By acquiring PA signals at multiple rotation angles with the RCA, the proposed method synthesizes the FMA-equivalent signals with the same aperture, thereby compensating for spatial sampling limitations. Simulation experiments using a 128+128 RCA array in k-Wave demonstrated successful FMA signal synthesis and high-quality volumetric reconstruction. Quantitative evaluation revealed a maximum structure similarity index measure (SSIM) of 0.650 for the PA volume obtained with rotational RCA acquisition, approaching the performance with FMA acquisition (SSIM: 0.706). Vascular structures were predominantly reconstructed even with a sparse angular pitch of 30° (only 9 views), albeit with an increased background noise level.