Fluorescence enhanced diffuse optical tomography is an emergent diagnosis tool for the localization and the quantification of fluorescent probes; this technique comes as a supplement or sometimes replaces the classical ionizing radiation imaging techniques, and in particular if a simple, inexpensive, non invasive and accurate instrumentation is sought. For 4 years now, the CEA-LETI has built a base of knowledge in markers and instrumentation within the framework of small animal imaging. More recently, an instrumentation has been developed, the purpose of which is a specific approach to the examination of underlying structures, deeply embedded within the tissues, and in fine for human being screening.