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Instrumentação para avaliação da propagação da radiação em meios biológicos túrbidos utilizando radiação laser
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A radiação laser tem sido amplamente utilizada na área da medicina como ferramenta
para técnicas de diagnóstico não invasivas e até como instrumento cirúrgico na
biomedicina. As polivalências desta tecnologia e o sucesso da sua aplicação têm suscitado
a utilização da radiação laser direcionada para a terapia tumoral na fotoativação
de fármacos ou na ablação dos tumores. A principal dificuldade na aplicação da radiação
laser aos meios biológicos túrbidos prende-se com o desenvolvimento e implementação
de metodologias para avaliar a distribuição da radiação no interior de fantomas
simuladores desses meios específicos sob irradiação laser. Neste caso, a medição
deve ser o menos invasiva possível e insensível à própria radiação laser.
Até ao momento não existe nenhum estudo de técnicas que permitam avaliar a
interação da radiação laser com fantomas ópticos de diferentes coeficientes de difusão.
Tal estudo possibilitará inferir sobre o comportamento da radiação laser no interior de
diferentes meios biológicos túrbidos, permitindo terapias mais localizadas e eficientes.
Esta tese apresenta a performance de cinco instrumentos imagiológicos e metrológicos
na avaliação direta e indireta, respetivamente, da propagação da radiação laser
no interior de fantomas ópticos com diferentes coeficientes de difusão. Os instrumentos
estudados foram o Termómetro de Infravermelho, a câmara de telemóvel, a câmara
USB, o termómetro Termopar e o Sensor de fibra óptica. Na categoria de instrumentos
imagiológicos, a câmara de telemóvel apresenta os resultados mais conclusivos para
uma avaliação direta da propagação do feixe laser, enquanto que na categoria de instrumentos
metrológicos os resultados mais conclusivos para uma avaliação indireta
registam-se com a utilização do termómetro Termopar.
O estudo aqui desenvolvido possibilita ainda definir linhas mestras para moldar
a criação de novos instrumentos que permitam avaliar a fotoativação dos sistemas de
entrega de fármacos ou a hipertermia em meios biológicos túrbidos, com recurso à
radiação laser.
Laser radiation has been widely used in medicine as a tool of noninvasive diagnostic techniques and even as surgical in biomedicine. This multipurpose technology and its successful application have raised its use in tumoral therapy aiming the photoactivation of drugs or the tumor ablation. The biggest obstacle for the application of laser radiation in biological turbid means is related to the development and implementation of methodologies to evaluate the radiation distribution inside phantoms which mimic those specific means under laser irradiation. In this case, the measure must be the least invasive possible and insensitive to the own radiation itself. To date, there is no registered study in techniques that allow the evaluation of laser radiation interaction with different diffusion coefficient phantoms. Such study would enable the understanding of laser radiation behavior inside different biological turbid means, leading to more accurate and efficient therapies. This thesis presents the performance of five imaging and metrological instruments in the direct and indirect evaluation, respectively, of laser radiation propagation inside optical phantoms with different diffusion coefficients. The studied instruments were an Infrared Thermometer, a cellphone camera, a USB camera, a thermocouple and an optical fiber sensor. In imaging instrumentation category, the cellphone camera presents the most conclusive results for a direct evaluation of laser radiation propagation, while in metrological instrumentation category the most conclusive results for an indirect evaluation are registered using the thermocouple. The study conducted enables the definition of general outlines to mold the creation of new instrumentation which allows the evaluation of drugs delivery systems photoactivation in biological turbid means, using laser radiation.
Laser radiation has been widely used in medicine as a tool of noninvasive diagnostic techniques and even as surgical in biomedicine. This multipurpose technology and its successful application have raised its use in tumoral therapy aiming the photoactivation of drugs or the tumor ablation. The biggest obstacle for the application of laser radiation in biological turbid means is related to the development and implementation of methodologies to evaluate the radiation distribution inside phantoms which mimic those specific means under laser irradiation. In this case, the measure must be the least invasive possible and insensitive to the own radiation itself. To date, there is no registered study in techniques that allow the evaluation of laser radiation interaction with different diffusion coefficient phantoms. Such study would enable the understanding of laser radiation behavior inside different biological turbid means, leading to more accurate and efficient therapies. This thesis presents the performance of five imaging and metrological instruments in the direct and indirect evaluation, respectively, of laser radiation propagation inside optical phantoms with different diffusion coefficients. The studied instruments were an Infrared Thermometer, a cellphone camera, a USB camera, a thermocouple and an optical fiber sensor. In imaging instrumentation category, the cellphone camera presents the most conclusive results for a direct evaluation of laser radiation propagation, while in metrological instrumentation category the most conclusive results for an indirect evaluation are registered using the thermocouple. The study conducted enables the definition of general outlines to mold the creation of new instrumentation which allows the evaluation of drugs delivery systems photoactivation in biological turbid means, using laser radiation.
Descrição
Palavras-chave
Radiação laser fantoma óptico Termografia de Infravermelho Termopar sensor CMOS sensores de fibra óptica