Fast Imaging of 2-Dimensional High Resolution Reconstruction of Tissue Heterogeneity by a Spatially Resolved Algorithm

Diffusion optics has a great impact on recent development of biomedical applications. Scattering and absorption take place when light is propagating in biological tissue. Diffuse reflectance, which is the light intensity on the medium surface when a light beam enters a scattering medium, contains information on the absorbers and scatterers in the medium. This information can help us identify the concentration of chromophores in the tissue.;Monte Carlo simulation and diffusion theory, for given optical properties, can successfully simulate and calculate the spatial and temporal diffuse reflectance. In practice, we are more interested to find out the optical properties from the diffuse reflectance. At present, most methods that spatially resolve the optical properties are only applicable to homogenous medium. Biological tissue is non-homogeneous in nature. It is difficult to measure its optical properties, due to non-uniformity throughout the tissue being tested. To obtain the spatial distribution of optical parameters, conventional approaches use an array of light sources and detectors to reconstruct the image, thus spatial resolution is very limited. In contrast, solutions that provide high resolution have a high computational complexity.;In this thesis, we propose a fast, simple scheme to resolve the effective attenuation profile from the spatial diffuse reflectance. Rather than giving one single value for the absorption and reduced scattering coefficients, a novel algorithm is proposed for the reconstruction of an effective attenuation profile from a diffuse reflectance curve. This technique is applied to the reconstruction of a 2-D effective attenuation profile. By obtaining the diffuse reflectance image from a camera and using the algorithm developed here, fast imaging of the effective attenuation profile with relatively high spatial resolution can be achieved.