Limits of high-order perturbation theory in time-domain optical mammography.

Higher order corrections to the Born approximation in perturbation theory are derived in order to improve its performance with the experiments in slablike geometry. A general expression of the nth order correction to absorption is developed. The cross talking between absorption and scattering is given. The convergence for higher orders of perturbation analysis for absorbing inclusions was studied. Second order absorption and scattering contributions to the transmitted flux are discussed by analyzing the data from forward simulations. The validity of the results is proven in the experiments with phantoms simulating breast tumors. The significant improvement for the fitted values of the absorption is observed. The alternative application of developed formalism as the first order theory to treat the multiple inclusions is suggested.