Volumetric photoacoustic imaging with symmetric spatial resolution in transverse plane from the asymmetric array using a virtual-transducer concept

Volumetric photoacoustic imaging based on the one-dimensional array has shown increasing applications for its low cost and convenient integration. However, due to the asymmetric angular detection aperture, the image obtained from such arrays faces challenges of asymmetric spatial resolution and artifacts. To address these issues, a virtual-transducer-based approach is proposed to achieve a volumetric image with symmetric resolution and low artifacts. By considering the asymmetric array as a symmetrical spherical-focused virtual transducer, the method ensures a symmetric angular detection aperture. The entire image reconstruction is then based on the equivalent symmetric data. Simulation and phantom experiment demonstrate excellent symmetric resolution and low artifact performance. The ratio of the average intensity between targets and artifacts is suppressed up to 25.09 dB. The in vivo experiment validates the biomedical practicability of the proposed method. This approach exhibits a general value and holds significant promise for low-cost, convenient, and high-quality volumetric photoacoustic imaging in biomedical applications.