In this study, we measured the optical properties of optical tissue phantoms and human tissues by measuring the
photon density distribution on the boundary of the phantoms and tissues and by using the Frequency-Domain DOT
(Diffuse optical tomography) system. A trust region nonlinear optimization method is used for the image reconstruction
in DOT. This method is a more elaborated Newton method which takes advantage of the classical Newton method and
the gradient descent method. The validity of this method is verified by reconstructing the optical properties from
phantom experiment and simulated data using the Frequency-Domain DOT system.