Integrated real-time Raman system for clinical in vivo skin analysis

Background: Raman spectroscopy is a non-invasive optical technique that can probe the molecular structure and conformation of biochemical constituents. The probability of Raman scattering is exceedingly low (similar to 10(-10)), and consequently up to now the practical application of Raman spectroscopy to clinical medicine has been limited by either the weak spectral signal or by the long data acquisition times. Recent advances in Raman hardware and probe design have reduced spectral acquisition times, paving the way for clinical applications. Methods: We present an integrated real-time Raman spectroscopy system for skin evaluation and characterization, which combines customized hardware features and software implementation. Real-time data acquisition and processing includes CCD dark-noise subtraction, wavelength calibration, spectral response calibration, intensity calibration, signal saturation detection, cosmic ray rejection, fluorescence background removal, and composition modeling. Real-time in vivo Raman measurement of volar forearm skin is presented to illustrate the methods and modeling. Results: The system design implemented full-chip vertical hardware binning to improve the signal-to-noise ratio by 16-fold. The total time for a single in vivo measurement with analysis can be reduced to 100 ms with this implementation. Human skin was well modeled using the base Raman spectra. Conclusion: In vivo real-time Raman can be a very promising research and practical technique for skin evaluation.