Métodos simplificados para obtenção de distribuição de luz em tecidos biológicos: aplicação para terapia fotodinâmica / Simplified methods for obtaining the light distribution in biological tissues

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

17/06/2011

RESUMO

The determination of light distribution within biological tissues is important for applications such as photodynamic therapy and photodiagnostics. Most applications use light that reaches the tissue surface and propagates along the depth. The combination of absorption and scattering leads to light intensity profiles which determines the therapeutic action. Considering photodynamic therapy, necrosis contour is determined by the threshold intensity. Therefore it is quite important to assure intensity above the threshold at the region where necrosis is desired. This determination involves the knowledge of light distribution. In this study, we have developed an empirical method to determine light distribution in optical phantom. This method is based on experimental measurements of light intensity as a function of position inside the medium. The data were collected for a collimated narrow laser beam and arranged in a tridimensional matrix. Using this matrix, simple mathematical operations were used to simulate different conditions of irradiation geometry. Comparison between experimental measurements and mathematical simulations show that our method can be used to recover light distribution in biological tissue for any condition of illumination, since we have previously performed simple measurements in a sample using a narrow beam. In vivo experiments showed that this method can be very useful to the determination of photodynamic therapy dosimetry.

ASSUNTO(S)

distribuição de luz dosimetria dosimetry light distribuition meios túrbidos photodynamic therapy terapia fotodinâmica turbid medium

ACESSO AO ARTIGO

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