Optical Characterization of Normal, Benign, and Malignant Thyroid Tissue: A Pilot Study

Abstract

Fine-needle aspiration cytology is the standard technique to diagnose thyroid pathologies. However, this method has a high percentage of inconclusive and false-negative results for benign and malignant lesions. Hence, it is important to search for a new method to assist medical evaluation during these surgical procedures. The use of time-resolved fluorescence techniques to detect biochemical composition and tissue structure alterations could help to develop a portable, minimally invasive, and non-destructive method to assist medical evaluation. In this study, we investigated 17 human thyroid samples by absorbance, fluorescence, excitation, and time-resolved fluorescence measurements. This initial investigation has demonstrated that thyroid fluorescence originates from many endogenous fluorophores and culminates in several bands. The fluorescence lifetimes of benign and malignant lesions were significantly different, as attested by analysis of variance using Tukey test with individual confidence level of 98.06%. Our results suggest that fluorescence lifetimes of benign and malignant lesions can potentially assist diagnosis. After further investigations, fluorescence methods could become a tool for the surgeon to identify differences between normal and pathological thyroid tissues.

Broadband (550–1350 nm) diffuse optical characterization of thyroid chromophores

“…In literature, various optical techniques have been explored to diagnose thyroid related pathologies, such as diffuse optical spectroscopy 5 , 6 , diffuse correlation spectroscopy 5 , static and time-resolved fluorescence spectroscopy 7 , 8 , optical biopsy using Raman spectroscopy 9 , 10 , Fourier transform infrared spectroscopy 11 , optical coherence tomography 12 , elastic light-scattering spectroscopy 13 and two-photon excited fluorescence spectroscopy 14 . Among these techniques, diffuse optical approaches are non-invasive in nature and have the capability to investigate both chemical and functional properties of the organ.…”

Optical Characterization of Parathyroid Tissues

“…The largest absorption band centered at 275 nm refers mostly to the presence of collagen, elastin, and tryptophan in the tissue. 7,9–13 The highest fluorescence intensity at around 340 nm, achieved by exciting the sample in the 285–300 nm region, also corresponds to the tryptophan fluorescence . 6,7 We believe the absorption bands around 410, 520, and 600 nm may indicate presence of hemoglobin on the samples.…”

Optical Diagnosis for Thyroid and Parathyroid Tissues—A Review

“…Brandao et al's (7,8) results indicate that time-resolved fluorescence can assist medical evaluation of thyroid pathologies during surgeries. This study used 59 human thyroid samples and was able to differentiate malign lesions from benign and healthy tissue by analysis of variance of the lifetime's values.…”

“…This article focuses primarily on the use of fluorescence spectroscopy (4-6), time-resolved fluorescence (7,8), near-infrared spectroscopy (9-11), Raman spectroscopy (12,13), infrared spectroscopy (14)(15)(16)(17), elastic scattering spectroscopy (18,19), second-harmonic generation (SHG) microscopy (20,21), and optical coherence tomography (22)(23)(24) to evaluate thyroid and parathyroid tissues.…”