225 光 CT における有限要素逆解析

概要

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New inverse analysis method with the finite element method was developed for optical computed tomography (optical C.T.). In optical C.T., near-inferred light is sourced into human body and scattered light is measured to detect an oxygenated part. This inverse problem is reduced to estimate the location of a part with inhomogenous absorption coefficient from scattered light on a surface of human body. The fluence rate φ in human body was assumed to obey the photon diffusion eqation. The finite element method was used to discretize the equation. Non-steady problem was treated by applying Laplace transformation. Because the observation equation is a highly non-linear function of location of inhomogeneiry conventional iterative method requires huge amount of computational time. To overcome this difficulty, we introduced a vector which is easily obtained from the location of inhomogeneiry, and is also related to observed value. This vector enables us to solve the inverse problem without any iterative calculation. A simple 3D example problem was solves to demonstrate the usefulness of this method.
社団法人日本機械学会の論文
2000-10-03