Large-field-of-view optical resolution photoacoustic microscopy.

The use of existing optical resolution photoacoustic microscopy (ORPAM) has been limited to small organs or part of large organs due to the millimeter-scale field of view (FOV) in both lateral and axial directions. Here, we report a large-field-of-view ORPAM (L-ORPAM) using a combination of a new scanning mechanism and an ultrafast pulsed laser. Phantom and in vivo experiments show that L-ORPAM has a spatial FOV of 40 mm in lateral and 12 mm in axial, which expends the effective imaging domain to one order that of existing ORPAMs. To show the advantages of L-ORPAM, we apply it to imaging vasculatures of both brain and ears simultaneously in mice, and to visualizing intestinal vasculatures in rats. The result suggests that L-ORPAM has sufficient contrast, resolution and spatial FOV to carry out studies of large rodents.