Critical Review Upon the Role and Potential of Fluorescence and Near-Infrared Imaging and Absorption Spectroscopy in Cancer Related Cells, Serum, Saliva, Urine and Tissue Analysis

During the last years, non-invasive or minimally invasive diagnostic tools in cancer diagnostics have become more important. Many fluorescence spectroscopic methodologies have been established for nearly all different kinds of cancer. The reason therefore is its high sensitivity, low amount of sample required, short testing time, and the suitability for in situ testing. The potential influence factors for cancer diagnostics and the subsequent suitability of the method to different applications are well described. Near-Infrared spectroscopy (NIRS) is based on differences of endogenous chromophores between cancer and normal tissues using either oxyhaemoglobin or deoxy-haemoglobin, lipid or water bands, or a combination of two or more of these diagnostic markers. These marker bands are known to provide the fundamental for the diagnosis of several cancers and the spectroscopic setup can be applied for the analysis of cells, urine and tissue. For the preparation of this review the literature published during the last fifteen years has been taken into consideration. It will provide an overview on the importance of the fluorescence and NIRS tools in cancer analysis giving hints about how these techniques can play a crucial role in cancer diagnosis, treatment decisions and therapy. The two techniques, fluorescence and near-infrared spectroscopy (NIRS) are faced to each other and individual advantages and/or drawbacks are discussed. Finally, it will be taken into consideration; how the synergistic combination of different approaches can give additional information related to development and progression stages of cancer.