Espectroscopia FT-Raman no diagnostico diferencial do melanoma cutâneo primário e metastático
Arquivos
Data
2007
Autores
Oliveira, Andrea Fernandes de 
Orientadores
Santos, Ivan Dunshee de Abranches Oliveira
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Introdução: O prognóstico do paciente com melanoma cutâneo está associado ao
diagnóstico precoce seguido de excisão correta da lesão, tornando essencial sua detecção em
estágio inicial. A espectroscopia Raman é uma técnica óptica que fornece informações sobre
as vibrações moleculares de uma amostra. Essa técnica utiliza a luz laser que pode ser
conduzida por fibras ópticas, como instrumento para investigação não destrutível de tecidos
biológicos possibilitando uma análise não invasiva da lesão, em tempo real. Objetivo: O
objetivo deste estudo foi qualificar os dados espectrais FT-Raman de melanoma cutâneo
primário e metastático, visando o diagnóstico diferencial. Métodos: Foram utilizadas
amostras de 10 fragmentos de pele sem alterações clínicas e histopatológicas, 10 de
melanomas cutâneos e 9 de metástases linfonodais. Após o procedimento cirúrgico, as
amostras foram identificadas e armazenadas individualmente em tubos e conservadas em
nitrogênio liquido. As amostras foram descongeladas em solução fisiológica a 0,9 %. Cada
amostra foi dividida em 2 ou 3 frações de 2 mm3
e colocada no porta-amostra e posicionados
para obtenção do espectro Raman, fazendo-se a luz monocromática do laser de Nd:YAG de
1064 nm incidir sobre a amostra. Eletronicamente, com auxílio do OPUS® foram variados
cinco pontos de coleta por amostra FT-Raman, em uma distância de 250 µ m. O registro total
de coleta foi realizado em um período de tempo menor que 10 minutos. A luz espalhada das
amostras chega ao detetor, que converte a intensidade da luz em sinais elétricos, que são
interpretados no computador na forma de espectro Raman. Resultados: A análise visual dos
espectros mostraram diferenças entre os grupos estudados, principalmente nas bandas e picos
do espectro Raman correspondentes a proteínas. Para diferenciar os três grupos formados de
acordo com as características extraídas dos espectros, realizou-se uma análise discriminante
dos dados. As variáveis Fenilalanina, DNA e Amido-I destacaram-se na diferenciação dos
três grupos. A porcentagem de indivíduos corretamente classificados com este critério foi de
93,1%; o que mostra a eficiência da análise realizada. Conclusão: A espectroscopia FTRaman
é capaz de diferenciar o melanoma de sua metástase, assim como da pele normal.
Introduction: The prognostic of a patient with cutaneous melanoma is linked to an early diagnosis followed by the excision of the lesion; thus, an early detection is essential. The Raman spectroscopy is an optical technique which supplies information about the molecular vibrations of a sample. This technique uses a laser light, which is conducted through optical fibers, as a tool to investigate in a non-destructive way the biological tissues and, thus; it makes it possible to carry out a non-invasive analysis of the lesion in real time. Objective: The objective of this study was to qualify the FT-Raman spectral data of primary and metastatic cutaneous melanoma in order to obtain a differential diagnosis. Methods: Samples of 10 skin fragments without clinical alterations or histopathology were used, as well as 10 cutaneous melanomas and 9 lymphonodal metastasis samples. After the surgical procedure, the samples were identified and individually stored in tubes and were conserved in liquid nitrogen. The samples were thawed in a physiological solution at 0,9%. Each sample was divided in 2 or 3 fractions of 2 mm3 each and placed and positioned at the sample carrier in order to obtain the Raman spectrum; a monochrome laser light Nd:YAG of 1064 nm was applied to the sample. With aid of the OPUS, five different collection points for sample FTRaman were electronically selected, at a distance of 250 m. The entire collection was accomplished in less than 10 minutes. The dispersed light of the samples arrives at the detector, which converts the light in electric signs, and then these signs are read by computer in the Raman spectrum form. Results: The visual analysis of the spectra showed differences among the studied groups, mainly in the bands and picks of the Raman spectrum which corresponded to the proteins. To differentiate the three groups formed according to the characteristics extracted from the spectra, we made a discriminative analysis of the data. The phenylalanine, DNA and Starch-I variables stood out in the differentiation of the three groups. The percentages of correctly classified items with this criterion was of 93,1%; what comes to show the efficiency of the analysis. Conclusion: The FT-Raman spectroscopy is capable of differentiating the melanoma from its metastasis, as well as from normal skin.
Introduction: The prognostic of a patient with cutaneous melanoma is linked to an early diagnosis followed by the excision of the lesion; thus, an early detection is essential. The Raman spectroscopy is an optical technique which supplies information about the molecular vibrations of a sample. This technique uses a laser light, which is conducted through optical fibers, as a tool to investigate in a non-destructive way the biological tissues and, thus; it makes it possible to carry out a non-invasive analysis of the lesion in real time. Objective: The objective of this study was to qualify the FT-Raman spectral data of primary and metastatic cutaneous melanoma in order to obtain a differential diagnosis. Methods: Samples of 10 skin fragments without clinical alterations or histopathology were used, as well as 10 cutaneous melanomas and 9 lymphonodal metastasis samples. After the surgical procedure, the samples were identified and individually stored in tubes and were conserved in liquid nitrogen. The samples were thawed in a physiological solution at 0,9%. Each sample was divided in 2 or 3 fractions of 2 mm3 each and placed and positioned at the sample carrier in order to obtain the Raman spectrum; a monochrome laser light Nd:YAG of 1064 nm was applied to the sample. With aid of the OPUS, five different collection points for sample FTRaman were electronically selected, at a distance of 250 m. The entire collection was accomplished in less than 10 minutes. The dispersed light of the samples arrives at the detector, which converts the light in electric signs, and then these signs are read by computer in the Raman spectrum form. Results: The visual analysis of the spectra showed differences among the studied groups, mainly in the bands and picks of the Raman spectrum which corresponded to the proteins. To differentiate the three groups formed according to the characteristics extracted from the spectra, we made a discriminative analysis of the data. The phenylalanine, DNA and Starch-I variables stood out in the differentiation of the three groups. The percentages of correctly classified items with this criterion was of 93,1%; what comes to show the efficiency of the analysis. Conclusion: The FT-Raman spectroscopy is capable of differentiating the melanoma from its metastasis, as well as from normal skin.
Descrição
Citação
OLIVEIRA, Andrea Fernandes de. Espectroscopia FT-Raman no diagnostico diferencial do melanoma cutâneo primário e metastático. 2007. 80 f. Dissertação (Mestrado em Ciências) - Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, 2007.