Feature of The Week 03/26.2017: Segmentation of nucleus and cytoplasm of a single cell in 3D tomogram using OCT
uclear-to-cytoplasmic (N/C) ratio is an effective feature to distinguish cancer cells from their normal counterparts. In conventional cytopathology, cells printed or smeared on a glass slide were stained and then evaluated by two-dimensional (2D) images through light microscopy. A random rayburst sampling (RRBS) framework was developed to detect the nucleus and cell membrane boundaries in three-dimensional (3D) space. Raw images were acquired through a full-field optical coherence tomography (FF-OCT) system with submicron resolution—i.e. 0.8 µm in lateral and 0.9 µm in axial direction. The near isometric resolution enables 3D segmentation of nucleus and cell membrane for determining the volumetric N/C ratio of a single cell. The FF-OCT light source was generated from a laser-diode-pumped crystalline fiber. To achieve high brightness and broadband emissions from 400 nm to 1.6 μm, glass-clad crystal fibers were drawn by the laser-heated pedestal growth and cladded by various glass capillaries. These light sources are eminently suitable for FF-OCT because of their cw operation and near-Gaussian high-brightness spectra. The RRBS framework was insensitive to the selection of seeds and image pixel noise. The robustness of the RRBS framework was verified through the convergence of the N/C ratio searching algorithm. The relative standard deviation of the N/C ratio between different randomly selected seed sets was only 2%. This technique is useful for various in vitro assays on single cell analyses.
For more information see recent Articles. Courtesy Sheng-Lung Huang from National Taiwan University.