A Wide Field of Vision Photoacoustic Imaging Method Based on Axial-Lateral Multi-Angle Laser Excitation and Coherent Compounding Technique: A Simulation and Experiment Study

Background: Improving the field of vision (FOV) in photoacoustic images (PA) will provide effective information for the diagnosis of diseases. However, the wide FOV is usually limited by the laser spot size and energy. The laser beam diffusion method could expand spot size to increase the irradiation area, but it may cause a significant decrease in the overall PA signal amplitude. It is possible to increase the laser energy to enhance the PA amplitude, but it needs to be limited under the safety threshold. Objective: The objective of this study is to improve the PA imaging method to increase the FOV. Statement of Contribution/Methods: In this study, we present a PA image method named the Axial-Lateral Multi-Angle Laser Excitation and Coherent Compounding (MAC-PA) for increasing the FOV in PA imaging. The effectiveness of the method is verified both by the experiments and the simulation systems. Specifically, we designed a PA imaging system with a 64-element transducer combined Axial-Lateral direction multi-angle laser illumination technique and based on all angles' results and the coherent compounding algorithm to obtain a wide-FOV image. Results/Discussion: Both the experiment and simulation results in the figures show that the proposed laser excitation with the coherent compounding method can significantly expand the FOV and improve the signal-to-noise ratio in the PA image with no additional laser energy required. Conclusion: The MAC-PA method proposed in this study provides a new gate to significantly enhance FOV in the PA image without additional laser energy increase.