Most cancers occur inside human body, so endoscopic high-resolution imaging modalities are required for early cancer
detection and surgical removal. This paper reports in vivo endoscopic 3D imaging based on optical coherence
tomography (OCT). Endoscopic imaging is enabled by integrating rapid-scanning MEMS mirror into a miniature
imaging probe. The MEMS mirror has an aperture size of 1 mm by 1 mm and a chip size of 2 mm by 2 mm. The optical
scan angle exceeds ±25 V at 6 Vdc, and thus large, constant-velocity, linear scan can be realized. The outer diameter of
the probe is only 5 mm. The axial resolution is about 10 μm and the imaging speed is 2.5 frames per second. Doppler
OCT imaging has also been demonstrated.
Imaging of immune system and tissue response to immunogenic agents can be important to the development of new
biomaterials. Additionally, quantitative functional imaging can be useful for testing and evaluation of methods to alter
or control the immune system response to implanted materials. In this preliminary study, we employ spectral imaging
and fluorescence imaging to measure immune system and tissue response to implanted immunogenic agents. Poly (D,L
lactide-co-glycolide) (PLGA) with a 50:50 composition was used to create immunogenic microparticles (MPs).
Lipopolysaccharide (LPS) encapsulated in the MPs was used to provoke a tissue immune response in mice and
encapsulated fluorescein isothiocyanate (FITC) was used to fluorescently label the MPs for imaging. Control MPs did
not contain LPS. The MPs were delivered at 50 particles/μL in a total volume of 20μL by subcutaneous injection in the
skin of a nude mouse in a dorsal skin-fold window chamber preparation. Cultured immune cells from a mouse
leukemic monocyte macrophage cell line were exogenously labeled with the fluorescent dye DiD in solution at a
concentration of 8000cells/μL. Immediately after window chamber surgery and implantation of the MPs, 100μL of the
fluorescent macrophage solution was administered via the tail vein. Fluorescence imaging was used to track MPs and
macrophages while spectral imaging was used for imaging and measurement of hemoglobin saturation in the tissue
microvasculature. Imaging was performed periodically over about three days. The spectral and fluorescence imaging
combination enabled detailed observations of the macrophage response and functional effects on the tissue.