Prospects for in vivo Raman spectroscopy

Raman spectroscopy is a potentially important clinical tool for real-time d iagnosis of disease and in situ evaluation of living tissue. The purpose of this article is to review the biological and physical basis of Raman spect roscopy of tissue, to assess the current status of the field and to explore future directions. The principles of Raman spectroscopy and the molecular level information it provides are explained. An overview of the evolution o f Raman spectroscopic techniques in biology and medicine, from early invest igations using visible laser excitation to present-day technology based on near-infrared laser excitation and charge-coupled device array detection, i s presented. State-of-the-art Raman spectrometer systems for research labor atory and clinical settings are described. Modem methods of multivariate sp ectral analysis for extracting diagnostic, chemical and morphological infor mation are reviewed. Several in-depth applications are presented to illustr ate the methods of collecting, processing and analysing data, as well as th e range of medical applications under study. Finally, the issues to be addr essed in implementing Raman spectroscopy in various clinical applications, as well as some long-term directions for future study, are discussed.