Dedicated photoacoustic imaging instrument for human periphery blood vessels: A new paradigm for understanding the vascular health.

A novel photoacoustic imaging system based on a semi-ring transducer array is proposed to imageperipheralbloodvessels. The system's penetration depth is deep (~15 mm) with high spatial (~200 m) and temporal resolution. In a clinical study, volumetric photoacoustic data of limbs were obtained within the 50s (for a FOV of 15 cm4 cm) with the volunteers in the standing and sitting posture. Compared to the previous studies, our system has many advantages, including (1) Larger field of view; (2) Finer elevational and in-plane resolutions; (3) Enhanced 3D visualization of peripheralvascular networks; (4) Compact size and better portability. The 3D visualization and cross-sectional images of five healthy volunteers clearly show the vascular network and the system's ability to image submillimeter blood vessels. This high-resolution PA system has great potential for imaging human periphery vasculatures noninvasively in clinical research.