Unglert, C. I., Namati, E., Warger, W. C., Liu, L., Yoo, H., Kang, D., Bouma, B. E., & Tearney, G. J. (2012). Evaluation of optical reflectance techniques for imaging of alveolar structure. Journal of biomedical optics, 17(7), 071303.
Three-dimensional (3-D) visualization of the fine structures within the lung parenchyma could advance our understanding of alveolar physiology and pathophysiology. Current knowledge has been primarily based on histology, but it is a destructive two-dimensional (2-D) technique that is limited by tissue processing artifacts. Micro-CT provides high-resolution three-dimensional (3-D) imaging within a limited sample size, but is not applicable to intact lungs from larger animals or humans. Optical reflectance techniques offer the promise to visualize alveolar regions of the large animal or human lung with sub-cellular resolution in three dimensions. Here, we present the capabilities of three optical reflectance techniques, namely optical frequency domain imaging, spectrally encoded confocal microscopy, and full field optical coherence microscopy, to visualize both gross architecture as well as cellular detail in fixed, phosphate buffered saline-immersed rat lung tissue. Images from all techniques were correlated to each other and then to corresponding histology. Spatial and temporal resolution, imaging depth, and suitability for in vivo probe development were compared to highlight the merits and limitations of each technology for studying respiratory physiology at the alveolar level.
Ikuta, M., Kang, D., Do, D., Zeidan, A., & Tearney, G. J. (2018). Spectrally encoded color imaging with a single light beam. Optics Letters.
Kang, D., & Gweon, D. (2003). Enhancement of lateral resolution in confocal self-interference microscopy. Optics letters, 28(24), 2470-2.
We describe confocal self-interference microscopy with enhanced lateral resolution. A uniaxial anisotropic crystal is used to cause interference between two linearly polarized beams that are reflected from the same pointlike object in the focal plane of the objective lens. Theory and the optimal design that maximizes the sensitivity of the interference signal are presented. A numerical experiment shows a 38% decrease in the lateral FWHM for simple confocal self-interference microscopy.
