Circular-scanning variance delay and sum algorithm for photoacoustic imaging

Photoacoustic imaging (PAI) commonly uses the delay-and-sum (DAS) algorithm, which is fast but prone to artifacts. This work introduces variance delay-and-sum (VDAS), a novel algorithm for circular-array PAI that utilizes signal variance as a weighting factor. A high variance suggests a high probability of an optical absorber, significantly improving vasculature imaging. Numerical simulations and phantom/ex-vivo mouse ear experiments demonstrate that VDAS enhances image quality, reduces artifacts, and maintains computational efficiency compared to other DAS-based methods.