Cette thèse présente des développements techniques et méthodologiques visant une alternative viable pour le traitement des cancers digestifs (rectum, œsophage). Par rapport aux méthodes standards de thérapie, les ultrasons de contact de haute intensité sous guidage IRM sont une approche moins invasive. L’IRM offre 2 avantages: bonne résolution spatiale et contrôle en temps réel de la température. Cette méthode de traitement demande efficacité et sécurité. Trois prototypes d’antenne RF intégrées à des transducteurs ultrasonores ont été réalisés afin d’améliorer la résolution spatiale et temporelle des images IRM et la précision de la mesure de température. Les antennes intégrées ont montré une meilleure sensibilité par rapport à une antenne extra corporelle standard. Des images IRM haute résolution, anatomiques (voxel0.4x0.4x5 mm3) et de thermométrie (voxel 0.75x0.75x8 mm3, 2s/image) ont été acquises in-vivo.La température a été mesurée, dans un rayon de 20 mm au-delà du ballon, avec un écart type<1°C. Les artéfacts de flux causés par l’eau circulante à l’intérieur du ballon de refroidissement ont pu être projetés hors de la région d’intérêt. L’évolution de la température a été contrôlée automatiquement, à des profondeurs variables, avec un point de contrôle par faisceau. Le contrôleur a montré une grande précision in-vivo (écart type <5%). Le transducteur ultrasonore matriciel permet d’activer successivement plusieurs faisceaux pendant la même dynamique de tir.Des simulations ont été conduites afin de proposer une planification du traitement optimale pour une tumeur désignée. Un nouveau concept de sonde ultrasonore à 256 éléments avec focalisation géométrique naturelle a été proposé. / This thesis presents technical and methodological developments aiming tooffer a viable alternative for the treatment of digestive cancers (rectum and esophagus). Compared to the standard methods of therapy, the high intensity contact ultrasound guided by MRI is a less invasive approach. MRI offers 2 advantages: good spatial resolution, and real-time temperature control. This treatment method requires efficacy and safety. Three prototypes of RF coil integrated with ultrasound transducers were built in order to increase the spatial and temporal resolution ofthe MR images, and the accuracy of the temperature measurement. The integrated coils showed a better sensitivity compared to a standard extracorporeal coil. Anatomical (voxel 0.4x0.4x5 mm3)and thermometry (voxel 0.75x0.75x8 mm3, 2s/image) high resolution MR images were acquired in-vivo. The temperature was measured, within a radius of 20 mm from the balloon, with a standard deviation <1°C. The flow artifacts caused by the water circulating inside the cooling balloon could be shifted out of the region of interest. The temperature evolution was controlled automatically, at different depths, with one control point per beam. The controller showed a good accuracy during in-vivo experiments (standard deviation less than 5%). The phased-arrayultra sound transducer permits the successive activation of multiple beams during the same dynamic of sonication. Simulations were conducted in order to offer an optimal treatment planning for a defined tumor. A new design of ultrasound transducer with 256 elements with revolution symmetry, based on a natural geometrical focalization, was proposed.

Foi realizado um estudo experimental da influência do ultra-som terapêutico na regeneração do nervo ciático submetido a esmagamento controlado, em ratos. Foram empregados no estudo 20 ratos da linhagem Wistar, de peso médio em torno de 250 g, divididos em dois grupos, conforme o tipo de procedimento realizado: 1) somente esmagamento, dez ratos; e 2) esmagamento e irradiação com ultra-som, 10 ratos. Sob anestesia, o nervo ciático era exposto na coxa direita do animal e esmagado com um dispositivo especialmente idealizado e confeccionado para essa finalidade, com uma carga fixa de 15 Kg, por 10 minutos, num segmento de 5 mm proximal à sua bifurcação. A irradiação com o ultra-som pulsado (1:5, freqüência de 1 MHz, intensidade de 0.4 W/'CM POT.2', duração de 2 minutos) era iniciada já no primeiro dia pós-operatório e realizada por dez dias consecutivos. Os resultados foram avaliados pela análise funcional da impressão plantar dos animais obtidas numa pista de marcha e determinação do índice funcional do ciático (De Medinaceli e Bain, Mackinnon e Hunter), e pela morfometria, através do cálculo da densidade de fibras nervosas, após sacrifício dos animais no vigésimo primeiro dia pós-operatório. Os resultados foram submetidos a análise estatística e mostraram que, nas condições do trabalho, o ultra-som acelerou a regeneração do nervo, demonstrável com significância no vigésimo primeiro dia pós-operatório / An experimental study of the influence of therapeutic ultrasound on the regeneration of the sciatic nerve submitted to controlled crush injury was carried out in rats. Twenty female Wistar rats weighing 250 g on average were used and distributed in two groups according to the procedure: 1) crush injury only, ten rats; 2) crush injury followed by ultrasound irradiation, ten rats. Under general anesthesia the sciatic nerve was exposed on the right thigh and crushed with a device especially devised and built for that purpose, with a 15 kg constant load for 10 minutes, affecting a 5 mm-long segment of the nerve proximal to its bifurcation. Pulsed ultrasound irradiation (1:5, 1 MHz frequency, 0.4 W/'CM POT.2' intensity, 2 minutes duration) was started the day after the operation and repeated for ten consecutive days. The results were evaluated by functional footprint analysis and determination of the sciatic functional index (DeMedinaceli's and Bain, Mackinnon and Hunter's methods) at weekly intervals, and by morphometry (nerve fiber density) of the resected sciatic nerve after killing the animals on the 21st postoperative day. Results were submitted to statistical evaluation and showed that, in the conditions of the study, ultrasound accelerated nerve regeneration, as demonstrated with significance on the 21st postoperative day

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-12T13:26:08Z No. of bitstreams: 1 thaisabranchesbuenosabinobertges.pdf: 1644405 bytes, checksum: 3b8373f3de0b6d396b5af331c1897b4a (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T17:14:55Z (GMT) No. of bitstreams: 1 thaisabranchesbuenosabinobertges.pdf: 1644405 bytes, checksum: 3b8373f3de0b6d396b5af331c1897b4a (MD5) / Made available in DSpace on 2016-01-25T17:14:55Z (GMT). No. of bitstreams: 1 thaisabranchesbuenosabinobertges.pdf: 1644405 bytes, checksum: 3b8373f3de0b6d396b5af331c1897b4a (MD5) Previous issue date: 2015-09-14 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / A cicatrização é um evento complexo que tem por objetivo restaurar a integridade anatômica, histológica e funcional de um tecido que sofreu lesão por diferentes etiologias. O potencial de modulação do sistema imunológico e das reações inflamatórias locais, por técnicas não invasivas, é alvo de diversos trabalhos e apesar de tal efeito modulador já ser comprovado clinicamente e corroborado por estudos histomorfológicos, os mecanismos celular e molecular de ação local e sistêmica das principais terapias adjuvantes disponíveis, a laserterapia de baixa intensidade e o ultrassom terapêutico, ainda não estão totalmente esclarecidas. O objetivo do presente estudo foi comparar os efeitos da terapia a laser de baixa intensidade e do ultrassom terapêutico, isolados e associados no processo de reparo tecidual, de feridas cutâneas cirúrgicas em ratos Wistar, com pesquisa da produção in situ de TGF-β1, TGF-β2 e IL-17 por imuno-histoquímica, além de avaliar, por histomorfometria, a deposição de matriz colagenosa na área em cicatrização por estudo retrospectivo em material emblocado em parafina (n = 24), cujas amostras foram divididas em: um grupo controle (GI), um submetido apenas à laserterapia (GII), um submetido apenas ao ultrassom (GIII) e um submetido às duas terapias associadas (GIV). Os dados foram expressos em média e desvio padrão, sendo considerado p < 0,05 para indicar resultados estatisticamente significantes. A expressão de TGF-β1 foi significativa quando as amostras de GIV foram comparadas com GII e GIII. Em relação a IL-17, as amostras de GI e de GII apresentaram maior porcentagem de células coradas, e a diferença foi significativa entre GII e GIII, e entre GII e GIV. / Wound healing is a complex event that aims to restore anatomical, histological and functional integrity of a tissue injury suffered by different etiologies. The potential modulation of the immune system and local inflammatory reactions by noninvasive techniques is the subject of several studies and although such modulating effect already being clinically proven and confirmed by histopathologic studies, the cellular and molecular mechanisms of local and systemic actions of main adjuvant therapies available, the low level laser therapy and ultrasonic energy, are still unclear. The aim of this study was to compare the effects of laser therapy of low intensity and the therapeutic ultrasound, isolated and associates in the tissue repair process in surgical wounds in Wistar rats, with research in situ production of TGF-β1, TGF-β2 and IL-17 by immunohistochemistry, and to evaluate by histomorphometry, the deposition of collagenous matrix in the area in healing by retrospective study in emblocado material paraffin (n = 24), the samples were divided into: a control group (GI) one subject only to laser therapy (GII), a submitted only to the ultrasound (GIII) and submitted to the two associated therapies (GIV). Data were expressed as mean and standard deviation, being considered p < 0.05 to indicate a statistically significant results. The TGF-β1 expression was significant when samples of GIV were compared with GII and GIII. With regard to IL-17, samples of GI and GII had a higher percentage of stained cells, and the difference was significant between GII and GIII, and between GII and GIV.

Foi realizado um estudo experimental da influência do ultra-som terapêutico na regeneração do nervo ciático submetido a esmagamento controlado, em ratos. Foram empregados no estudo 20 ratos da linhagem Wistar, de peso médio em torno de 250 g, divididos em dois grupos, conforme o tipo de procedimento realizado: 1) somente esmagamento, dez ratos; e 2) esmagamento e irradiação com ultra-som, 10 ratos. Sob anestesia, o nervo ciático era exposto na coxa direita do animal e esmagado com um dispositivo especialmente idealizado e confeccionado para essa finalidade, com uma carga fixa de 15 Kg, por 10 minutos, num segmento de 5 mm proximal à sua bifurcação. A irradiação com o ultra-som pulsado (1:5, freqüência de 1 MHz, intensidade de 0.4 W/'CM POT.2', duração de 2 minutos) era iniciada já no primeiro dia pós-operatório e realizada por dez dias consecutivos. Os resultados foram avaliados pela análise funcional da impressão plantar dos animais obtidas numa pista de marcha e determinação do índice funcional do ciático (De Medinaceli e Bain, Mackinnon e Hunter), e pela morfometria, através do cálculo da densidade de fibras nervosas, após sacrifício dos animais no vigésimo primeiro dia pós-operatório. Os resultados foram submetidos a análise estatística e mostraram que, nas condições do trabalho, o ultra-som acelerou a regeneração do nervo, demonstrável com significância no vigésimo primeiro dia pós-operatório / An experimental study of the influence of therapeutic ultrasound on the regeneration of the sciatic nerve submitted to controlled crush injury was carried out in rats. Twenty female Wistar rats weighing 250 g on average were used and distributed in two groups according to the procedure: 1) crush injury only, ten rats; 2) crush injury followed by ultrasound irradiation, ten rats. Under general anesthesia the sciatic nerve was exposed on the right thigh and crushed with a device especially devised and built for that purpose, with a 15 kg constant load for 10 minutes, affecting a 5 mm-long segment of the nerve proximal to its bifurcation. Pulsed ultrasound irradiation (1:5, 1 MHz frequency, 0.4 W/'CM POT.2' intensity, 2 minutes duration) was started the day after the operation and repeated for ten consecutive days. The results were evaluated by functional footprint analysis and determination of the sciatic functional index (DeMedinaceli's and Bain, Mackinnon and Hunter's methods) at weekly intervals, and by morphometry (nerve fiber density) of the resected sciatic nerve after killing the animals on the 21st postoperative day. Results were submitted to statistical evaluation and showed that, in the conditions of the study, ultrasound accelerated nerve regeneration, as demonstrated with significance on the 21st postoperative day