Dual-wavelength low-cost high-resolution photoacoustic microscopy system for blood oxygenation imaging

Abstract

Optical-resolution photoacoustic microscopy (OR-PAM) is a label-free and non-invasive technique for imaging blood vessel and hemoglobin oxygen saturation (sO₂) of living animals in vivo, providing functional information for disease diagnosis. However, most state-of-the-art OR-PAM systems require bulky and costly pulsed lasers, which hinders their wide applications in clinical settings. Here, a reflection-mode low-cost photoacoustic microscopy system using two laser diodes (LDs) was developed for in-vivo microvasculature and sO₂ imaging with a high resolution of ~6 μm. The sO2 measurement is validated in both blood phantom and in vivo animal experiments. The phantom study shows that our system has a strong linear relationship with the preset sO₂ (R ² = 0.96). The in-vivo experiment of mouse ear imaging demonstrated that our system can achieve high-resolution and high-quality imaging of microvasculature and sO₂. This technical advancement in cost reduction and superior imaging performance promotes the fast and wide applications of PAM in biomedical fields.