Light spectroscopic methods are critical to advances in molecular characterization of disease processes. However, these methods have been limited to in-vitro or cell culture studies. In fact, strong scattering in almost all tissue types causes dispersion of the photons paths which results in poor localization and resolution. Hence, quantitative analysis of spectral data obtained from structures below the tissue surface requires accounting for scattering which affects both the penetration of the photons and the path length over which the photons will be subject to molecularly speci£c absorption. The goal of much current research is to non-invasively obtain diagnostically useful molecular information from embedded sites. We have designed and built a six-band multi-spectral NIR imaging system which we have used on patients with highly vascularized tumors in the skin called Kaposi’s Sarcoma. The imaged lesions are undergoing treatment with experimental anti-angiogenesis drugs that are ...