Identification of urinary calculi by Raman laser fiber optics spectroscopy

Human calculi of various compositions were automatically identified by using near-infrared excitation Fourier-transform Raman spectrometry. After having built a 150-compound Raman library as a first step, we used a commercial software for infrared spectra (program BIRSY, from Brüker) to determine the composition of different calculi. Good results were obtained for both classical Raman laser and Raman laser fiber optics spectroscopies. With the use of a natural biological medium, e.g., urine, to mimic as closely as possible clinical in vivo conditions, the automatic search correctly identified the calculus composition with relatively good test quality; in some mixtures, however, the results can only be considered semi-quantitative at present, even after smoothing of the spectra.