Optical-resolution photoacoustic microscopy (OR-PAM) has been widely used for imaging blood vessel and oxygen saturation of hemoglobin (sO2), providing high-resolution functional images of living animals in vivo. However, most of them require one or multiple bulky and costly pulsed lasers, hindering their applicability in preclinical and clinical settings. In this paper, we demonstrate a reflection-mode low-cost high-resolution OR-PAM system by using two cost-effective and compact laser diodes (LDs), achieving microvasculature and sO2 imaging with a high lateral resolution of ∼6 µm. The cost of the excitation sources has dramatically reduced by ∼20–40 times compared to that of the pulsed lasers used in state-of-the-art OR-PAM systems. A blood phantom study was performed to show a determination coefficient R2 of 0.96 in linear regression analysis. Experimental results of in vivo mouse ear imaging show that the proposed dual-wavelength LD-based PAM system can provide high-resolution functional images at a low cost.
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.
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