A combined fluorescence-optical tomography methodology of steady-state is developed to enhance the applicability of the breast-dedicated diffuse optical tomography (DOT). The system employed a 4-channel gated photon-counting technique working in a fiber-switch-based tandem series-to-parallel mode to achieve the tradeoff among the measuring time, probing sensitivity and cost effectiveness. Based on the graphics-processing-unit accelerated Monte Carlo modeling of photon migration, a fluorescence-guided hemoglobin DOT reconstruction algorithm was proposed, which can effectively alleviate the ill-posedness of the hemoglobin DOT using the localization prior provided by the high-contrast fluorescence DOT. The phantom experiments demonstrate that the reconstruction accuracy and quantitative performance can be improved efficiently comparing with the standalone-DOT.