Aplicações do problema inverso na Biosusceptometria AC para reconstrução e quantificação de distribuições de nanopartículas magnéticas
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Data
2021-02-26
Autores
Biasotti, Gabriel Gustavo de Albuquerque
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Universidade Estadual Paulista (Unesp)
Resumo
Aplicações biomédicas de nanopartículas magnéticas (MNPs – do inglês Magnetic Nanoparticles) têm se tornado cada vez mais comuns, onde as aplicações mais conhecidas são em diagnósticos de tumores, seu uso no tratamento por hipertermia e entrega de fármacos de maneira controlada. Para isso são essenciais técnicas capazes de detectar, localizar e quantificar as MNPs em meios biológicos. A biosusceptometria AC (BAC) é uma técnica biomagnética com histórico de estudos farmacológicos e fisiológicos utilizando marcadores magnéticos macroscópicos e, mais recentemente, na avaliação da circulação sanguínea, retenção hepática, perfusão renal e cerebral e a biodistribuição de MNPs. Diferente das outras técnicas, não há histórico da reconstrução de imagens quantitativas ou quantificação direta de materiais magnéticos via sistema BAC. Para outras técnicas biomagnéticas reconstruções quantitativas da distribuição espacial de MNPs já foram realizadas com sucesso por meio da resolução do problema inverso. A proposta desse trabalho foi criar e implementar modelos matemáticos e computacionais para a resolução do problema inverso dos sistemas BAC Mono Canal (B1C) e BAC Multi Canal 19 (B19C) para reconstruções quantitativas da distribuição 2D de MNPs. Para o B1C, foi possível reconstruir as distribuições de MNPs com boa resolução espacial (1 voxel/cm), tempo de escaneamento de 6 minutos e sensibilidade de 0.85 mg de MNPs nos objetos simuladores (fantomas cúbicos contendo MNPs de ferrita de manganês imobilizadas em gesso) distantes em 5 mm da superfície do sensor. Para o B19C, as imagens quantitativas foram reconstruídas em tempo real com resolução espacial moderada (0.33 voxels/cm) e sensibilidade de 0.71 mg de MNPs em objetos simuladores (MNP Perimag ® plain) distantes em 3 mm da superfície do sensor. A modelagem e simulação computacional do sistema BAC resultou em ganhos significativos na qualidade das imagens obtidas, além de permitir a recontrução quantitativa da distribuição espacial de MNPs pela primeira vez na literatura. Os resultados desse trabalho são de grande valia e permitirão novas aplicações e aprimoramento dos trabalhos do grupo que estão em andamento. Sendo assim, os resultados aqui obtidos podem e serão aplicados em diversos outros trabalhos envolvendo experimentação biológica in vitro e in vivo.
Biomedical applications of magnetic nanoparticles (MNPs) have become increasingly common. The most well-known applications are in tumor diagnostics, their treatment by hyperthermia, and drug delivery in a controlled manner. Thus, techniques capable of detecting, locating, and quantifying MNPs in biological media are essential. AC Biosusceptometry (BAC) is a biomagnetic technique with a history of pharmacological and physiological studies using macroscopic magnetic markers and, more recently, in the assessment liver retention, renal and cerebral perfusion and the biodistribution of MNPs. To the best of our knowledge, there is no history of reconstructing quantitative images or direct quantification of magnetic materials via the BAC system. For anothers biomagnetic technicals, the MNPs’ quantitative spatial distributionreconstruction has already been carried out successfully by solving the inverse problem. The purpose of this work was to create and implement mathematical and computational models to solve the inverse problem of the BAC Mono Channel (B1C) and BAC Multi Channels 19 (B19C) systems for reconstructing quantitative 2D images, and finally reconstructing spatial distributions of MNPs quantitatively. For B1C, it was possible to reconstruct quantitative images with a good spatial resolution (1 voxel/cm), scanning time of 6 minutes, and sensitivity of 1.8 mg of MNPs (cubic phantoms containing MNPs of manganese ferrite immobilized in gypsum) 5 mm from the sensor surface. For the B19C, the quantitative images were reconstructed in real-time with a moderate spatial resolution (0.33 voxels/cm), and a sensitivity of 0.71 mg of MNPs in simulator objects (MNPs Perimag ® plain) 3 mm away from the sensor surface. The BAC system's computational modeling resulted in significant gains in the quality of the reconstructed MNPs’ spatial distribution. This work results are of great value and will allow for countless new applications and improvement of the group's works that are in progress. Thus, the results obtained here can, and will, be applied in other works involving biological experimentation in vitro and in vivo.
Biomedical applications of magnetic nanoparticles (MNPs) have become increasingly common. The most well-known applications are in tumor diagnostics, their treatment by hyperthermia, and drug delivery in a controlled manner. Thus, techniques capable of detecting, locating, and quantifying MNPs in biological media are essential. AC Biosusceptometry (BAC) is a biomagnetic technique with a history of pharmacological and physiological studies using macroscopic magnetic markers and, more recently, in the assessment liver retention, renal and cerebral perfusion and the biodistribution of MNPs. To the best of our knowledge, there is no history of reconstructing quantitative images or direct quantification of magnetic materials via the BAC system. For anothers biomagnetic technicals, the MNPs’ quantitative spatial distributionreconstruction has already been carried out successfully by solving the inverse problem. The purpose of this work was to create and implement mathematical and computational models to solve the inverse problem of the BAC Mono Channel (B1C) and BAC Multi Channels 19 (B19C) systems for reconstructing quantitative 2D images, and finally reconstructing spatial distributions of MNPs quantitatively. For B1C, it was possible to reconstruct quantitative images with a good spatial resolution (1 voxel/cm), scanning time of 6 minutes, and sensitivity of 1.8 mg of MNPs (cubic phantoms containing MNPs of manganese ferrite immobilized in gypsum) 5 mm from the sensor surface. For the B19C, the quantitative images were reconstructed in real-time with a moderate spatial resolution (0.33 voxels/cm), and a sensitivity of 0.71 mg of MNPs in simulator objects (MNPs Perimag ® plain) 3 mm away from the sensor surface. The BAC system's computational modeling resulted in significant gains in the quality of the reconstructed MNPs’ spatial distribution. This work results are of great value and will allow for countless new applications and improvement of the group's works that are in progress. Thus, the results obtained here can, and will, be applied in other works involving biological experimentation in vitro and in vivo.
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Palavras-chave
Nanopartículas magnéticas, Biosusceptometria AC, Imagiamento quantitativo, Nanomedicina, Magnetic nanoparticles, AC Biosusceptometry, Quantitative imaging, Nanomedicine