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Journal of Biomedical Optics • Open Access

Investigating the spectral characteristics of backscattering from heterogeneous spherical nuclei using broadband finite-difference time-domain simulations
Author(s): Guo-Shan Chao; Kung-Bin Sung

Paper Abstract

Reflectance spectra measured from epithelial tissue have been used to extract size distribution and refractive index of cell nuclei for noninvasive detection of precancerous changes. Despite many in vitro and in vivo experimental results, the underlying mechanism of sizing nuclei based on modeling nuclei as homogeneous spheres and fitting the measured data with Mie theory has not been fully explored. We describe the implementation of a three-dimensional finite-difference time-domain (FDTD) simulation tool using a Gaussian pulse as the light source to investigate the wavelength-dependent characteristics of backscattered light from a nuclear model consisting of a nucleolus and clumps of chromatin embedded in homogeneous nucleoplasm. The results show that small-sized heterogeneities within the nuclei generate about five times higher backscattering than homogeneous spheres. More interestingly, backscattering spectra from heterogeneous spherical nuclei show periodic oscillations similar to those from homogeneous spheres, leading to high accuracy of estimating the nuclear diameter by comparison with Mie theory. In addition to the application in light scattering spectroscopy, the reported FDTD method could be adapted to study the relations between measured spectral data and nuclear structures in other optical imaging and spectroscopic techniques for in vivo diagnosis.

Paper Details

Date Published: 1 January 2010
PDF: 6 pages
J. Biomed. Opt. 15(1) 015007 doi: 10.1117/1.3324838
Published in: Journal of Biomedical Optics Volume 15, Issue 1
Show Author Affiliations
Guo-Shan Chao, National Taiwan Univ. (Taiwan)
Kung-Bin Sung, National Taiwan Univ. (Taiwan)

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