Robot-assisted wide-amplitude oscillatory photoacoustic scanning for three-dimensional human peripheral vascular...

Photoacoustic tomography (PAT) is a promising tool for non-invasive vascular imaging, yet conventional linear scanning suffers from "limited-view" artifacts and structural discontinuities due to restricted transducer acceptance angles. To overcome these physical bottlenecks, we propose a robot-assisted wide-amplitude oscillatory (WAO) scanning strategy. By integrating controlled lateral harmonic oscillations into axial linear trajectories via a 6-DoF robotic arm, this method achieves kinematic modulation to physically synthesize a dynamic aperture. This approach effectively captures high-frequency acoustic information typically lost in single-path scans, compensating for hardware-based detection limits. Numerical simulations and a preliminary in vivo feasibility experiment in a healthy participant demonstrate that the WAO strategy expands acoustic spatial coverage by 32% and improves the contrast-to-noise ratio (CNR) by 2.4-fold. This enables high-fidelity 3D reconstruction of complex vascular networks with a high spatial resolution of $215\mu m$ . The current study is intended to evaluate the technical feasibility of robot-assisted WAO scanning for human peripheral vascular imaging; broader clinical validation, motion tracking, and motion correction remain necessary before claims related to vascular diagnosis or longitudinal monitoring can be made.