Clinical Applications of Raman Spectroscopy

Recently, Raman microspectroscopic analysis has been the analytical tool of choice to determine human bone compositional and structural changes in health and disease, as a function of aging, and in response to various therapies, due to its superb spatial resolution and its combination with other techniques such as nanoindentation, quantitative backscattered electron imaging, FT-IR, and histol-ogy/histomorphometry [163,171,186,188, 201, 202, 262, 274, 277-281]. 

Outcomes of FT-IR and Raman spectroscopic analyses are complementary and each technique has its advantages. For example, FT-IR has superior signal-to-noise ratio while Raman has superior lateral spatial resolution and minimal sample 

Fratzl, P. et al. (2004) Structure and mechanical quality of the collagen-mineral nano-composite in bone./. Mater. Chem., 14, 2115-2123. Morris, M.D. and Mandair, G.S. (2011) Raman assessment of bone quality. 

Paschalis, E.P., Mendelsohn, R, and Boskey, A.L. (2011) Infrared assessment of bone quality a review, Clin. Orthop. Relat. Res., 469 (8), 2170-2178, Burstein, A.H. and Wright, T,W, (1994) in Fundamentals of Orthopaedic Biomechanics (ed. W.M,I, Passano), Williams Wilkins, Baltimore, MD, pp. 133-170. 

Burstein, A.H. et al. (1975) Contribution of collagen and mineral to the elastic-plastic properties of bone. 

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They employed principal components analysis (PCA) and linear discriminant analysis (LDA) to distinguish the two types of polyps. The spectra (Fig. 2.9) have bands at similar wave numbers and their features are similar, making it difficult for the untrained eye to distinguish between them. The application illustrates the importance of multivariate analysis in clinical applications of Raman spectroscopy. It is often the case that there are only small differences between normal and diseased tissues. 

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