Retrieving small features in reflection-mode raster-scan optoacoustic mesoscopy (RSOM) using multi-frequency reconstruction

摘要

We developed a reflection-mode, raster-scan optoacoustic mesoscopy system, based on a custom-made ultrasonic detector, with an ultra wide bandwidth of 20-180 MHz. To optimally use this bandwidth, we implemented multi-frequency reconstruction. System characterization reveals a 4 μm axial, and 18 μm transverse resolution, at penetration depths reaching 5 mm. After characterization, the system was applied to image a zebrafish ex vivo, and an excised mouse ear. In the zebrafish, the lateral line, intestines, eyes, and melanocytes are seen, while in the mouse ear, multi-frequency reconstruction recovered the small vessels, otherwise not seen on the image.