Characterization of thyroid tissue using infrared spectroscopy

Abstract

Introduction: In recent years, the number of surgical procedures involving the thyroid gland has increased worldwide; however, no increase in mortality rate has been observed. The Fourier Transform Infrared (FTIR) spectroscopy technique presents evidence in the characterization of multiple tissues, such as the thyroid gland, with the advantage of being rapid and preserving the tissue analyzed. Objectives: Characterize both healthy and pathological thyroid tissues by FTIR spectroscopy. Methods: Patients were selected at the Head and Neck Surgery Service of the Hospital das Clínicas, Ribeirão Preto Medical School, University of Sao Paulo - USP, Ribeirão Preto-SP, Brazil, from 2014 to 2015. The sample consisted of 44 patients with reference for thyroidectomy. The analysis was performed by defining the areas of each band using the OriginPro 8.6.0 software. The band was then normalized to 1240 cm-1. The mean area was calculated using the Student’s t-test with p<0.05. After calculation of the means, the second-order derivative of the spectrum was evaluated to show the positions of each absorption band. Results: The infrared spectrum of each piece was obtained and expressed as a function of absorbance and wave numbers in the mean IR (4000-900 cm-1). The present study demonstrated that, in the analysis of thyroid tissue by FTIR spectroscopy, it is possible to differentiate benign nodules from healthy tissue with significant difference in the area of the B-band between healthy tissue and goiter, which corresponds to 1452.90 cm-1 in healthy tissue (proteins and lipids) and 1069.80 cm-1 in goiter (DNA), as well as significant difference in width between normal thyroid tissue and carcinoma of the C band. Conclusions: FTIR spectroscopy is able to differentiate pathologically altered thyroid tissues from the thyroid gland compared with findings in healthy thyroid tissues. In patients with benign nodular disease of the thyroid gland, it is possible to differentiate healthy goiter tissue with statistical significance, as well as malignant nodules from healthy tissue through FTIR spectroscopy.