Fluorescence Image Guided Surgery utilizes continuous wave epi-fluorescence measurements on the tissue surface to locate targets such as tumors or lymph nodes, but precise 3D localization of deep targets remains intractable due to the illposedness of the associated inverse problem. We propose a Fluorescence Diffuse Optical Tomography scheme which leverages the different contrast agent kinetics in malignant vs normal tissue and reconstructs the 3D tumor location from a time series of epi-fluorescence measurements. We conduct sequential synthetic experiments, which mimic the differential up-take and release profile of fluorescent dye ICG in tumors vs normal tissue and demonstrate for the first time that the proposed method can robustly recover targets up to 1cm deep and in the presence of realistic tumor-to-background ratios.