The Approximate Model Of Blood Cells And Its Light Scattering Characteristics

Various light scattering techniques has gained significant development and wide application in the field of cell biology because it is quick, accurate, convenient, non-invasive, and reproducible. The research on the morphology and composition of biological cells by light scattering method is a hot topic. However, existing methods describe elastic light scattering of a homogeneous spherical body with arbitrary size and refractive index based on Mie theory whereas nucleated cells are inhomogeneous and may be irregularly shape. Therefore, the sphere model and Mie theory does not fit the real non-spherical cells and diseased cells. This dissertation is supported by the Major Natural science fund for colleges and universities in Jiangsu Province (No. 09KJA140001) and the Natural science fund of Jiangsu Province (No. BK2008230) and study the problems of cell detection and classification. The blood cells are looked as the main object of study. The light scattering theory for near-real non-spherical cells and the relation between the cell morphology and the distribution of scattering intensity and phase have be studied that. And the questions have been preliminary discussed such as differential equations of scattering response, inversion, multiple scattering.A model is presented to calculate the light scatter properties of nucleated cells which are mimicked by two concentric ellipsoids based on the configuration of the real blood cell when it flows in the vas. The light scattering characteristics were derive by the application of field averaging of the internal field and modification of the propagation constant inside the different cellular compartments. The numerical analysis technique is applied to discuss the scattering intensity affection of the cell separately, such as in the variety of size, cytoplast, karyoplasms, body, refractive index, and an angel of incidence. A dynamic relationship and characters of responded scattering intensity distribution and related varying characteristic parameters of a nuclear cell are gotten after calculating and three dimensional fitting upon the modified model. Besides, scattering intensity distribution affected by its body and varying incidence angles is fitted and the error calculating of fitting effecting is estimated.According to the morphological structures of leukocyte, the double layer eccentric-sphere model is established for a kind of single-nuclear cell. Based on the geometrical-optics approximation which is originated from Mie scattering theory, the expressions of amplitude functions are revised and compared with the results from the VirtualLab imitation system. Results of numerical calculation and simulation show that the scattered light intensity is changed shocks with scattering angle and focused on the forward, and the polarization focus on the backward, the phase shocks attenuation rapidly with scattering angle and the intensity depends on the position of nucleus. Three kinds of intensity modulations with different frequencies can be found in the angular distribution. The physical mechanism about these three modulations has been analyzed. The relations between the modulation characteristics and the physical and optical parameters of the cell are as follow:Low-frequency modulation doesn't make any change in a scale as cell size; Sub-low frequency modulation is related to the relative refractive index and the nucleocytoplasmic ratio. The lack of high-frequency modulation is related to the relative refractive index and the incident orientation. The modulation distortion phenomenon will appear in the case of nuclei close to the cell.The phase information is looked as a supplement, the three sources of phase change about layer eccentric sphere model is analyzed and phase function is revised. The optical thickness of irregular muscle cell is extracted from microscopic image; the amplitude is calculated from the phase change. The scattering of cell populations is discussed simply. To the sparse media system, the probability distribution function and morphology factor function are used to derived scattering response differential equations for any morphology, it can solve the problem of particle size distribution. To the dense media, multiple scattering is considered; the angular distribution of intensity of spherical particle is derived base on the radiative transfer equation. the scattering problem of non-spherical particle swarm is solved using equivalent elliptical cross-section.Finally, two application examples are analyzed:The ellipsoid model is applied to red blood cells, the scattered intensity distribution and the numerical results are obtained by the body polarization of flat ellipsoid, The results show it can more easily identify the pathological state of red blood cells by forward, sideways and backward scattering intensity distribution. It also applied to study the deformation of red blood cells. Focusing on cell's light scattering technique and its application in cell identification, the analysis to the morphological structures of the WBC(white blood cells) is done, and the light scattering models of five types of WBC are built. Applying numerical simulation techniques to systematic study on the distribution of the back-scattering intensity distribution of the five types of the WBC, it is found that there are some important relations and characteristics of cell's back-scattering distribution response to their inside and outside morphological structures. Thus, the back-scattering theory and application have been expanded.This study is very useful to improve the cell's identification technique.