Affiliations: Institute of Research and Development, Universidade do Vale do Paraíba, São José dos Campos, SP, Brazil | Group of Biomedical Engineering, Universidade Camilo Castelo Branco, São José dos Campos, SP, Brazil | Department of Urology, University of São Paulo Medical School, São Paulo, SP, Brazil | Department of Pathology, University of São Paulo Medical School, São Paulo, SP, Brazil
Note: [] Corresponding author: Landulfo Silveira Jr., Group of Biomedical Engineering, Universidade Camilo Castelo Branco, Núcleo do Parque Tecnológico de São José dos Campos, Rod. Pres. Dutra, São José dos Campos, SP, Brazil 12247-004. Tel./Fax: +55 12 3905 4401; E-mails: landulfo.silveira@unicastelo.br, landulfo.silveira@gmail.com.
Abstract: This study evaluated the use of Raman spectroscopy to identify the spectral differences between normal (N), benign hyperplasia (BPH) and adenocarcinoma (CaP) in fragments of prostate biopsies in vitro with the aim of developing a spectral diagnostic model for tissue classification. A dispersive Raman spectrometer was used with 830 nm wavelength and 80 mW excitation. Following Raman data collection and tissue histopathology (48 fragments diagnosed as N, 43 as BPH and 14 as CaP), two diagnostic models were developed in order to extract diagnostic information: the first using PCA and Mahalanobis analysis techniques and the second one a simplified biochemical model based on spectral features of cholesterol, collagen, smooth muscle cell and adipocyte. Spectral differences between N, BPH and CaP tissues, were observed mainly in the Raman bands associated with proteins, lipids, nucleic and amino acids. The PCA diagnostic model showed a sensitivity and specificity of 100%, which indicates the ability of PCA and Mahalanobis distance techniques to classify tissue changes in vitro. Also, it was found that the relative amount of collagen decreased while the amount of cholesterol and adipocyte increased with severity of the disease. Smooth muscle cell increased in BPH tissue. These characteristics were used for diagnostic purposes.
Keywords: Raman spectroscopy, prostate cancer, benign prostatic hyperplasia, Principal Components Analysis (PCA), Mahalanobis distance, biochemical model
DOI: 10.3233/SPE-2011-0494
Journal: Spectroscopy, vol. 25, no. 2, pp. 89-102, 2011
