Optimal Parameter Updating for Optical Diffusion Imaging

Because optical diffusion imaging is a highly nonlinear inverse problem, iterative inversion algorithms based on the Born approximation have usually been employed as reconstruction technique, but convergence is slow, especially for high contrast parameter distributions. We show here that the slow convergence of the conventional algorithms is due to the linear integral operator derived by the Born approximation not being the optimal Fre'chet derivative. W e derive the optimal Fre'chet derivative operator with respect to the spatially varying absorption and scattering coeficients in integral form, and then develop a new iterative inversion algorithm.