Multimodal Raman-fluorescence spectroscopy of formalin fixed samples is able to discriminate brain tumors from dysplastic tissue

Year: 2014

Authors: Anand S., Cicchi R., Giordano F., Buccoliero AM., Pavone FS.

Autors Affiliation: European Laboratory for Non-linear Spectroscopy (LENS), Via Nello Carrara 1, I-50019, Sesto Fiorentino, Italy;
National Institute of Optics, National Research Council, Largo E. Fermi 6, I-50125, Florence, Italy;
Division of Neurosurgery, Department of Neuroscience I, “Anna Meyer” Pediatric Hospital, Viale Gaetano Pieraccini 24 – 50141, Florence, Italy;
Division of Pathology, Department of Critical Care Medicine and Surgery, University of Florence, Viale Giovanni Battista Morgagni 85 – 50134, Florence, Italy

Abstract: In the recent years, there has been a considerable surge in the application of spectroscopy for disease diagnosis. Raman and fluorescence spectra provide characteristic spectral profile related to biochemical and morphological changes when tissues progress from normal state towards malignancy. Spectroscopic techniques offer the advantage of being minimally invasive compared to traditional histopathology, real time and quantitative. In biomedical optical diagnostics, freshly excised specimens are preferred for making ex-vivo spectroscopic measurements. With regard to fresh tissues, if the lab is located far away from the clinic it could pose a problem as spectral measurements have to be performed immediately after dissection. Tissue samples are usually placed in a fixative agent such as 4% formaldehyde to preserve the samples before processing them for routine histopathological studies. Fixation prevents the tissues from decomposition by arresting autolysis. In the present study, we intend to investigate the possibility of using formalin fixed samples for discrimination of brain tumours from dysplastic tissue using Raman and fluorescence spectroscopy. Formalin fixed samples were washed with phosphate buffered saline for about 5 minutes in order to remove the effects of formalin during spectroscopic measurements. In case of fluorescence spectroscopy, changes in spectral profile have been observed in the region between 550-670 nm between dysplastic and tumor samples. For Raman measurements, we found significant differences in the spectral profiles between dysplasia and tumor. In conclusion, formalin fixed samples can be potentially used for the spectroscopic discrimination of tumor against dysplastic tissue in brain samples.

Conference title: Photonics Europe 2014
Place: Bruxelles, Belgium

KeyWords: Antigen-antibody reactions; Brain; Diagnosis; Fluorescence; Fluorescence spectroscopy; Health care; Histology; Photonics; Raman spectroscopy; Tumors, Brain tumors; Dysplasia; Formalin fixation; Morphological changes; Phosphate-buffered salines; Spectral measurement; Spectroscopic measurements; Spectroscopic technique, Formaldehyde
DOI: 10.1117/12.2053715