We have developed the novel video endoscope imaging techniques; Narrow band imaging (NBI), Auto-Fluorescence
Imaging (AFI), Infra-Red Imaging (IRI) and Endo-Cytoscopy System (ECS). The purpose of these imaging techniques is
to emphasize the important tissue features associated with early stage of lesions. We have already launched the new
medical endoscope system including NBI, AFI and IRI (EVIS LUCERA SPECTRUM, OLYMPUS MEDICAL
SYSTEMS Co., Ltd., Fig.1). Moreover ECS, which has enough magnification to observe cell nuclei on a superficial
mucosa under methylene blue dye staining, is the endoscopic instrument with ultra-high optical zoom. In this paper we
demonstrate the concepts and the medical efficacy of each technology.
Here, we propose a new method to enhance the sensitivity of the reflectance spectrum to the scattering feature of the superficial tissue layer. This method is based on multiple discriminant analysis (MDA) in the eigen subspace of the spectrum. Considering the application of scattering imaging, we evaluated this method by performing multispectral imaging of two-layered tissue phantoms. A color map converted from the spectral reflectance well corresponds to variations in the size of the scatter in the first layer. In order to confirm our proposed method works well under more realistic conditions, we performed the computational simulations of the light propagation in the tissue. We used the simulation model combined with the Monte Carlo and the Mie scattering. Its conditions like the slab geometry and the particle distribution of the cell nucleus were estimated by the image measuring of pathological slices. Results on simulations show the possibility of enhancing the sensitivity of the reflectance spectrum to the scattering feature of the superficial tissue layer.
We present the method which can calculate the spectral reflectance from physical parameters corresponding to the pathological features, e.g. average size of cell nuclei and standard deviation of cell nuclear size distribution, in consideration of multiple scattering in biological tissue. In this paper, the method combined the Monte Carlo method which simulates multiple scattering effects and the Mie theory which provides phase function (angular properties of light scattering) and scattering coefficient was employed. In order to investigate the validity of this method, the calculated spectra by the method and Monte Carlo method with Henyey-Greenstein phase functions were compared with measurement spectra derived from the tissue phantom whose size distribution has double peaks. From the results, it is shown that the method can better predict the spectral reflectance of tissue phantom rather than Monte Carlo method with Henyey-Greenstein phase function.