Study of Non-Altered Colorectal Tissue by FT-Raman Spectroscopy
  FT-Raman spectroscopy was employed to study (in-vitro) non-altered human colorectal tissues aiming evaluate their spectral differences. The samples were collected from 39 patients, adding 144 spectra. The results enable one estabilish 3 well defined spectroscopic groups of what was consistently checked by statistical (clustering) and biological (histopathology) analysis. The similarity within each group was better than 90%. Groups 1 and 2 had 80% of similarity while presenting both 70% of similarity to group 3. All groups presented connective and epithelial tissues as histopathological characteristic. Group 1 differs from others by the presence of soft muscle while group 3 by presence of fatty tissue. Tissues from group 2 are composed by samples with connective and epithelial tissues. This study is very relevant in order to establish the non-altered or normal spectroscopic standard for future studies and applications on optical biopsy and diagnosis of colorectal cancer. 
P. O. Andrade, R. A. Bitar, K. Yassoyama, H. Martinho, A. M. E. Santo,   P. M. Bruno, A. A. Martin