High‐Speed Photoacoustic Volumetric Flow Tomography(PVFT)

Abstract Flow field analysis is critical in industrial and biomedical applications. Optical‐based methods suffer from limited penetration depth, while ultrasound‐based approaches are constrained by angular dependence in detection, making them unsuitable for 3D imaging in turbid media. Photoacoustic Volumetric Flow Tomography (PVFT) employs laser‐excited photoacoustic signals from nickel‐coated polystyrene particles, thereby combining the high contrast of optical imaging with the superior penetration depth of ultrasound detection. The system utilizes a 1024‐element hemispherical sensor array for volumetric signal acquisition, eliminating scanning‐induced latency while achieving measurable flow velocities spanning from 40 to 1200 mm s −1 . Experimental validation using vortex flow phantoms demonstrated high‐speed 3D imaging capabilities in turbid media at 50 frames per second (fps), with systematic confirmation of angular independence. Arterial phantom experiments successfully resolved fine flow structures, attaining velocity vector reconstruction with 480 µm spatial resolution. At a flow velocity of 125 mm s −1 , the relative measurement error is quantified at 8%. Stenotic regions exhibited accelerated flow dynamics accompanied by vortex formation. This technique establishes a groundbreaking solution for 3D flow field characterization in turbid media, overcoming conventional optical diffusion limitations and ultrasound Doppler dimensional constraints.