Confocal spectral imaging in tissue with contrast provided by Raman vibrational signatures.

Confocal Raman imaging of biological materials offers the opportunity to extract chemical information on histologically defined regions and on sub-cellular organelles. This article reviews the technology and some successful applications. The chemical contrast from vibrational Raman spectroscopy is derived from the specific atomic motion of every molecule as detected by the Raman phenomenon. Examples show the successful identification of foreign material in pathological specimens, identification of lipid-type and calcium mineral-type in a mouse model of atherosclerosis, and component mapping in a pharmaceutical tablet. It is suggested that these methods can even be useful in studying metabolic disorders.