Detection and characterization of human tissue lesions with near-infrared Raman spectroscopy

Near infrared (NIR) Raman spectroscopy provides a powerful method for quantitative histochemistry of human tissue and disease diagnosis. The feasibility and potential of this technique for in situ histochemical analysis of human coronary artery has been demonstrated and presented in other reports from our laboratory. In this work, we review recent results obtained with the NIR Raman spectroscopy on a variety of tissue types studied at the MIT Laser Biomedical Research Center. We have collected NIR Raman spectra from colon, bladder, breast, and carotid artery. For colon, bladder and breast, consistent differences between carcinoma and normal tissue spectra were observed. For colon and bladder, the spectral differences appear to be due to an increased content of nucleic acid in carcinomas, while the spectral changes in malignant breast tissue are associated with an increase of protein content. Spectra from carotid artery have similar features as those from aorta and coronary arteries. We also show some preliminary results obtained with a NIR Raman microspectroscopy setup with 20 micron lateral resolution. The biochemical distributions for normal and diseased regions on the same tissue samples are observed. The potential of using this NIR Raman spectroscopy for detection and characterization of carcinoma and atherosclerosis, is discussed.