High-Speed Optical Resolution Photoacoustic Microscopy With a MEMS Scanner: Novel and Simple Distortion Correction Method

Abstract Optical resolution photoacoustic microscopy (OR-PAM) is a remarkable biomedical imaging tool that can selectively visualize microtissues with optical-dependent high resolution. However, traditional OR-PAM using mechanical stages provides slow imaging speed, making biological interpretation of in-vivo tissue difficult. Here, we developed a high-speed OR-PAM using a recently commercialized MEMS mirror. This system (MEMS-OR-PAM) consisted of a 1-axis MEMS mirror and a mechanical stage. Furthermore, this study proposed a novel calibration method that quickly removes the spatial distortion caused by fast MEMS scanning. The proposed calibration method needs to run imaging sequence only once using a ruler target and it can easily correct distortions caused by both the scan geometry of the MEMS mirror and its nonlinear motion. The combination of the MEMS-OR-PAM and the distortion correction method was verified by three experiments.; 1) Leaf skeleton phantom imaging to test the distortion correction efficacy.; 2) Spatial resolution and depth of focus (DOF) measurement for the system performance.; 3) In-Vivo finger capillaries imaging to verify their biomedical use. The results showed that the combination could achieve a high-speed (32 sec in 2 mm×4 mm) and high-lateral resolution (~6 µm) imaging capability and precisely visualize the circulating structure of the finger capillaries.