title: Optical Characterization of Parathyroid Tissues.
abstract: The parathyroid glands are small and often similar to lymph nodes, fat, and thyroid tissue. These glands are difficult to identify during surgery and a biopsy of the parathyroid for identification can lead to damage of the gland. The use of static and time-resolved fluorescence techniques to detect biochemical composition and tissue structure alterations could help to develop a portable, minimally invasive, and nondestructive method to assist medical evaluation of parathyroid tissues. In this study, we investigated 10 human parathyroid samples by absorbance, fluorescence, excitation, and time-resolved fluorescence measurements. Moreover, we compared the results of time-resolved fluorescence measurements with 59 samples of thyroid tissues. The fluorescence lifetimes with emission at 340 nm were 1.09 ± 0.10 and 4.46 ± 0.06 ns for healthy tissue, 1.01 ± 0.25 and 4.39 ± 0.36 ns for benign lesions, and 0.67 ± 0.36 and 3.92 ± 0.72 ns for malignant lesions. The lifetimes for benign and malignant lesions were significantly different, as attested by the analysis of variance with confidence levels higher than 87%. For each class of samples (healthy, benign, and malignant) we perceived statistical differences between the thyroid and parathyroid tissue, independently. After further investigations, fluorescence methods could become a tool to identify normal and pathological parathyroid tissues and distinguish thyroid from parathyroid tissues.
authors.affiliation: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Departamento de Física, São Paulo, Brazil mpbrandao@gmail.com bachmann@ffclrp.usp.br.
authors.forename: M P
authors.initials: MP
authors.lastname: Brandao
authors.affiliation: Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Departamento de Oftalmo, Otorrino e Cirurgia de Cabeça e Pescoço, São Paulo, Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Iwakura
authors.affiliation: Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Departamento de Oftalmo, Otorrino e Cirurgia de Cabeça e Pescoço, São Paulo, Brazil.
authors.forename: A A
authors.initials: AA
authors.lastname: Honorato-Sobrinho
authors.affiliation: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Departamento de Física, São Paulo, Brazil.
authors.forename: K
authors.initials: K
authors.lastname: Haleplian
authors.affiliation: Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Departamento de Oftalmo, Otorrino e Cirurgia de Cabeça e Pescoço, São Paulo, Brazil.
authors.forename: A S
authors.initials: AS
authors.lastname: Ito
authors.affiliation: Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Departamento de Oftalmo, Otorrino e Cirurgia de Cabeça e Pescoço, São Paulo, Brazil.
authors.forename: L C Conti
authors.initials: LC
authors.lastname: de Freitas
authors.affiliation: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Departamento de Física, São Paulo, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Bachmann
keywords: Fluorescence spectroscopy; carcinoma; fluorescence lifetime; parathyroid tissue