Extended focus optical coherence microscope (xfOCM) circumvents the compromise between lateral resolution and
depth of field by us of a Bessel-like illumination beam. The high sensitivity and parallel depth profiling of Fourier
domain optical coherence tomography are preserved, and combined with high isotropic resolution of 1.5 - 2 μm. To
comply with the requirements for in vivo measurements, beam scanning had to be implemented. We then performed
measurements, first of excised pancreas, validated by standard immunohistochemistry, to investigate the structures that
can be observed. For a quantitative analysis, a semi-automatic islet detection algorithm evaluated the islet size, position,
contrast and homogeneity. The influence of streptozotocin on the signature of the islets was investigated in a next step.
Finally, xfOCM was applied to make measurements of the murine pancreas in situ and in vivo, visualizing pancreatic
lobules, ducts, blood vessels and individual islets of Langerhans.