Considerando que o petróleo quando extraído dos poços em águas profundas chega a ter teor de água superior a 50% e que antes de ser enviado à refinaria deve ter uma quantidade de água inferior a 1%, torna-se necessário o uso de técnicas de redução da quantidade de água. Durante a extração do petróleo formam-se emulsões de água em óleo que são muito estáveis devido a um filme interfacial contendo asfaltenos e/ou resinas ao redor das gotas de água. Nesse trabalho é apresentada a utilização de ondas estacionárias de ultrassom para realizar a quebra dessas emulsões. Quando gotículas de água com dimensões da ordem de 10m, muito menores que o comprimento de onda, são submetidas a um campo acústico estacionário em óleo, a força de radiação acústica empurra as gotículas para os nós de pressão da onda. Uma célula de coalescência com frequência central ao redor de 1 MHz, constituída por quatro camadas sendo uma piezelétrica, uma de acoplamento sólido, uma com o líquido e outra refletora, foi modelada empregando o método da matriz de transferência, que permite calcular a impedância elétrica em função da frequência. Para minimizar o efeito do gradiente de temperatura entre a entrada e a saída da cavidade da célula, quando está em operação, foram utilizados dois transdutores piezelétricos posicionados transversalmente ao fluxo que são excitados e controlados independentemente. Foi implementado um controlador digital para ajustar a frequência e a potência de cada transdutor. O controlador tem como entrada o módulo e a fase da corrente elétrica no transdutor e como saída a amplitude da tensão elétrica e a frequência. Para as células desenvolvidas, o algoritmo de controle segue um determinado pico de ressonância no interior da cavidade da célula no intervalo de frequência de 1,09 a 1,15 MHz. A separação acústica de emulsões de água em óleo foi realizada em uma planta de laboratório de processamento de petróleo no CENPES/PETROBRAS. Foram testados a variação da quantidade de desemulsificante, o teor inicial de água na emulsão e a influência da vazão do sistema, com uma potência de 80 W. O teor final de água na emulsão mostrou que a aplicação de ultrassom aumentou a coalescência de água da emulsão, em todas as condições testadas, quando comparada a um teste sem aplicação de ultrassom. Identificou-se o tempo de residência no interior da célula de separação como um fator importante no processo de coalescência de emulsões de água e óleo. O uso de desemulsificante químico é necessário para realizar a separação, porém, em quantidades elevadas implicaria no uso de processos adicionais antes do repasse final do petróleo à refinaria. Os teores iniciais de água na emulsão de 30 e 50% indicam que o uso da onda estacionária na coalescência de emulsões não tem limitação quanto a esse parâmetro. De acordo com os resultados obtidos em laboratório, essa técnica seria indicada como uma alternativa para integrar um sistema de processamento primário em conjunto com um separador eletrostático. / Considering that oil when extracted from the wells in deep water have water content greater than 50%, and that before to be sent to the refinery must have a quantity of water less than 1%, it becomes necessary to use water amount reduction techniques. During the oil extraction are formed water-in-oil emulsions that are highly stable due to an interfacial film containing asphaltenes and / or resins around the water droplets. This work presents the use of ultrasonic standing waves to perform that emulsion break. When water droplets with dimensions about 10m, much smaller than the wavelength, are placed in a standing acoustic field in oil, the acoustic radiation force pushes the water droplets to the pressure wave nodes. A coalescing chamber with frequency about 1 MHz, with four layers comprising a piezoelectric, a solid coupling, one with the liquid, and another reflector, was modeled using the matrix transfer method, that allows calculating the electrical impedance as a function of frequency. To minimize the effect of the temperature gradient between the inlet and the outlet of the chamber cavity, when it is operating, were used two groups of piezoelectric transducers positioned transverse to the flow which are excited and controlled independently. A digital controller has been implemented to adjust the frequency and the power of each transducer. The controller has as input the modulus and phase of electrical current of the transducer and as output the amplitude of voltage and the frequency. For developed cells, the control algorithm follows an specific resonance peak within the chambers cavity in the frequency range 1.09 to 1.15 MHz. Acoustic separation of water in oil emulsions was carried out on a laboratory oil processing plant. Tests were performed by varying the amount of the chemical demulsifier, the initial water content in the emulsion. The system flow rate was kept constant at 80 W using the control system. Residence time within the separation chamber was identified as an important factor in the water in oil emulsions coalescence process. The use of chemical demulsifier is required to perform the separation, however in large quantities, it implies the use of additional processes before the oil final transfer to the refinery. Initial water contents in the emulsion about 30 and 50% indicate that the use of the acoustic standing wave in the emulsion coalescence has not limitation on this parameter. According to the results obtained in laboratory, this technique would be indicated as an alternative to integrate a primary processing system together with an electrostatic separator.

INTRODUÇÃO: O tratamento estrogênico isolado e contínuo por seis meses é uma opção no tratamento de sintomas climatéricos. A monitorização endometrial deve ser realizada rotineiramente; nela, a ultra-sonografia (US) e a biópsia uterina têm papel importante. A US e a Dopplervelocimetria também avaliam as mudanças circulatórias uterinas. OBJETIVO: Estudar o comportamento da vascularização uterina e do endométrio em mulheres na pós-menopausa tratadas com estrógeno contínuo por seis meses, seguido de progestógeno isolado por 14 dias, e estabelecer suas relações com a proliferação endometrial. MÉTODO: Estudo clínico, prospectivo e controlado, onde quarenta mulheres na pós-menopausa, sem contraindicações para tratamento hormonal (TH). Foram divididas em dois grupos: Estrógeno e Controle. As do Grupo Estrógeno (GE), n= 24, receberam 50 mcg de estradiol-17 beta (E2) transdérmico, duas vezes por semana, durante seis meses. As mulheres do Grupo Controle (GC), n=16, não receberam TH. Todas realizaram FSH, E2 e glicemia de jejum; US transvaginal; Dopplervelocimetria das artérias uterinas, miometriais e endometriais e biópsia aspirativa de endométrio. O GE repetiu os mesmos exames, com exceção de FSH, E2 e glicemia, no terceiro e no sexto mês de tratamento. No GC, a biópsia do endométrio foi repetida apenas no sexto mês de tratamento. As mulheres do GE utilizaram, ao fim de seis meses, 10 mg de acetato de medroxiprogesterona por dia, durante 14 dias. RESULTADOS: No GE, a resistência vascular das artérias uterinas diminuiu no terceiro e no sexto mês de tratamento. O fluxo miometrial das artérias arqueadas aumentou significantemente no sexto mês de tratamento. O aumento da espessura do endométrio ocorreu de forma significante no terceiro mês. No GE houve hiperplasia endometrial simples e sem atipias em 20,8 % das mulheres. No GE, comparando as mulheres que tiveram proliferação com aquelas que mantiveram a atrofia endometrial, observou-se que, no sexto mês de tratamento, o grupo que apresentou proliferação teve diminuição significante da resistência vascular da artéria uterina esquerda, enquanto no grupo que manteve a atrofia, a resistência vascular aumentou na artéria uterina direita. No GC não ocorreu variação da resistência vascular das artérias uterinas bilaterais; o fluxo miometrial das artérias arqueadas não se modificou e não houve proliferação endometrial. CONCLUSÃO: A terapia estrogênica isolada por seis meses diminuiu a resistência vascular das artérias uterinas bilateralmente. A proliferação endometrial precedeu o aumento de vascularização miometrial. Houve associação entre a proliferação endometrial e a diminuição da resistência vascular na artéria uterina esquerda, no final do sexto mês de tratamento estrogênico / INTRODUCTION: Isolated continuous estrogen therapy for 6 months is an option to manage climacteric symptoms. Endometrial monitoring should be performed as a routine, in which ultrasound and uterine biopsy have an important role. Ultrasound with Dopplervelocimetry also assesses uterine circulatory changes. OBJECTIVE: To study the uterine circulatory changes of women in continuous estrogen therapy for 6 months using Doppler velocimetry and to define correlations with endometrial proliferation. METHOD: Clinical prospective controlled study. Forty menopause women were studied, without contraindications to hormone therapy (HT). They were divided into 2 groups: Estrogen and Control. In the Estrogen Group (EG) n = 24, they were treated with transdermal 50mcg estradiol-17 beta (E2), changed twice a week for 6 months. Women in the Control Group (CG) n=16, were not treated with hormones. They all underwent FSH, E2, fast glucose, transvaginal ultrasound , uterine, myometrial and endometrial artery Dopplervelocimetry and aspiration biopsy of endometrium. The EG repeated the same procedures in months 3 and 6 of treatment. In CG, endometrial biopsy was repeated only in the 6th month of treatment. At the end of treatment, EG women received 10 mg of medroxyprogesterone acetate per day for 14 days. RESULTS: In EG, vascular resistance of uterine arteries reduced in the 3rd and 6th months of treatment. Myometrial flow of arcuate arteries was significantly increased in the 6th month of treatment. Increased endometrial thickness was significant in the 3rd month. In EG, the authors detected simple endometrial hyperplasia without atypias in 20.8% of the subjects. In EG, in the 6th month of treatment, upon comparing women who had proliferation and those who maintained the endometrial atrophy, we observed that the group that presented proliferation had significant reduction of vascular resistance of left uterine artery, whereas the group that maintained atrophy had increase in vascular resistance of right uterine artery. In CG, there was no vascular resistance modification, no myometrial flow diference and no endometrial proliferation. CONCLUSION: Isolated estrogen therapy for 6 months reduced vascular resistance of bilateral uterine arteries. Morphological affections to the endometrium preceded myometrial vascular abnormalities. There was association of endometrial proliferation and reduction of vascular resistance of the left uterine artery in the 6th month of estrogen treatment

Les lithiases urinaires peuvent affecter le rein, l'uretère ou la vessie, et affectent en moyenne, au moins une fois durant leur vie, 1 personne sur 11 aux Etats-Unis. La lithotritie extracorporelle est une technique largement répandue dans le monde qui consiste à focaliser des ondes de choc acoustiques de haute intensité sur les lithiases afin de les briser. Le travail présenté dans cette thèse porte sur l'optimisation de la lithotritie piézoélectrique, à la fois dans sa conception mais aussi dans son efficacité, tout en réduisant son coût de fabrication. Premièrement, une étude de l'état de l'art de la lithotritie a été réalisée, suivie par des expériences sur des lithotriteurs commerciaux et expérimentaux afin de déterminer les différents axes de recherche de la thèse. Ensuite, une optimisation des éléments piézoélectriques d'un lithotriteur a été réalisée afin d'obtenir un traitement plus performant. Finalement, des lithotriteurs composés de transducteurs piézoélectriques focalisés grâce à des lentilles optimisées ont été conçus et fabriqués. Leurs champs acoustiques, leurs effets sur la cavitation et leur efficacité à fragmenter des lithiases artificielles ont été évalués. Les lithotriteurs résultant ont montré des performances équivalentes à des lithotriteurs commerciaux existant, tout en permettant un traitement plus flexible que ces derniers / Kidney Stones can be found in the kidney, ureter, or in the bladder, and affect about 1 in 11 people at least once in a lifetime in the US. Extracorporeal shock wave lithotripsy is a widely used technique where high intensity acoustic pulses are focused toward kidney stones in order to break them. The work presented in this thesis focus on optimizing piezoelectric lithotripter, both in design and efficiency, in order to have more efficient treatment while also being less costly. First, a study of the current state of lithotripsy was made, followed by experiments on commercial and experimental lithotripters in order to define properly the different parameters to be worked on. From this, it was decided to optimize the current piezoelectric elements in the lithotripter to obtain a more efficient treatment. Then, a lithotripter using optimized lens focused piezoelectric transducers set in confocal setups was designed and manufactured. Its acoustic characterization, effect on cavitation and model stone fragmentation efficiency were evaluated. The resulting lithotripter showed performances equivalent to existing commercial lithotripter, while allowing more flexible treatment than traditional lithotripter

Polyfluorinated compounds (PFCs) are a class of anthropogenic chemicals that have been found in groundwater and wastewater around the world. Perfluoroctane sulfonate (PFOS) and perfluoroctanoic acid (PFOA) are primarily used for industrial surfactants, and aqueous film forming foams (AFFFs). These PFCs and many of their constituents have been found to be carcinogenic to humans and other animals. A simple method for defluorination of these compounds is needed. Advanced oxidation of PFOS, PFHxS, and PFBS-k was carried out using activated sodium persulfate through ultrasonic irradiation with the following condition; [PFC] = 20 millimolar (mM), [Na2S2O8] = 25 mM, pH = 7, and 25°C. Fluoride concentrations were quantified by ion chromatography (IC). In laboratory experiments, batch reactions of PFBS solutions were conducted in purified water at different pH conditions and N2S¬2O8: PFBS molar ratios of 1:1, 2:1, 10:1, and 100:1 respectively. Solution pH was maintained at 7 using HNO3. Of the three compounds, PFHxS had the greatest defluorination (11%) after 120 minutes reaction time. However, PFBS-K had the greatest increase in defluorination (115%) between the control ultrasound (US) experiment and the combination experiment. When Na2S2O8 was increased, the defluorination ratio of PFBS decreased. This decrease was partly attributed to scavenging reactions between SO4¯• and S2O8²¯. These results show a synergism between ultrasonic irradiation and activated sodium persulfate as a form of advanced oxidation. Recommendations for further research into defluorination of PFOS and its constituents by ultrasonic degradation include: the use of high performance liquid chromatograph with accompanying mass spectrometry (HPLC/MS), the use of an ultrasonic probe with alternate frequencies, and the effects of surface tension on defluorination.

Foi realizado um estudo experimental dos efeitos do ultra-som terapêutico sobre a resistência à tração de tendões flexores em cicatrização, usando o tendão flexor dos dedos de coelho como modelo. Foram utilizados 25 coelhos fêmea, da raça Nova Zelândia, adultos jovens de 3 Kg de peso corporal médio. Todos os animais foram operados sob anestesia geral para terem o tendão flexor profundo do terceiro dedo da pata dianteira direita seccionado e imediatamente reparado com a técnica de Kessler. As patas operadas eram imobilizadas com uma órtese de material termoplástico durante todo o período do experimento (4 semanas) e os animais foram distribuídos em dois grupos ( A e B) de acordo com o tratamento pós-operatório. No grupo A (13 animais) todos os animais receberam uma aplicação diária de 6 minutos de duração de ultra-som pulsado (1:5), regulado para uma freqüência de 3 MHz e intensidade de 0,8 W/cm², por sete dias consecutivos começando do primeiro dia. O grupo B (12 animais) era apenas de controle. Quatro semanas mais tarde, os animais eram mortas e todo o tendão operado era ressecado, incluindo a junção miotendínea e o segmento distal, e submetidos aos testes de resistência à tração na máquina universal de ensaios. Gráficos das cargas versus a deformação foram obtidos, permitindo a análise dos parâmetros carga e deformação máximas, carga e deformação no limite de proporcionalidade e rigidez. Os resultados mostraram que não houve diferenças significantes entre os grupos A e B, levando à conclusão de que o ultra-som terapêutico não tem influência no curso do processo de cicatrização dos tendões, particularmente no que se refere à resistência mecânica. / An experimental study of the effects of the therapeutic ultrasound on the resistance to traction of healing flexor tendons carried out using the rabbit flexor tendon as model. Twenty five young adult female New Zeland rabbits of average 3 Kg body weight were used. All the animals were operated under general anesthetics to have the profundus flexor tendon of the third finger of the right forepaw divided and immediately repaired with Kessler technique. The operated on paw was immobilized with an orthesis made of thermoplastic material for the entire length of the experiment (four weeks) and the animals were divided in two groups (A and B), according to the postoperative treatment. In group A (13 animals) all animals received one 6 minutes daily application of pulsed ultrasound (1:5), set for 3 MHz frequence and 0,8 W/cm² intensity, for seven consecutive days beginning on the first postoperative day. Group B (12 animals) was for control only. Four weeks later, the animals were killed, the entire operated tendons were resected including the myotendinous junction and the distal segment and submitted to the test of resistance to traction in a universal testing machine. Load versus deformation graphs were obtained allowing for the analysis of the parameters maximum load and deformation, load and deformation in the limit of proportionality, and stiffness. The results showed that there was no significant difference between groups A and B, leading to the conclusion that therapeutic ultrasound does not influence the course of the tendon healing process, as refers to mechanical resistance.

O estudo da força de radiação acústica é de extrema importância para compreender o fenômeno da levitação acústica, tendo em vista que ela é que permite a levitação de objetos no interior de uma cavidade acústica. A cavidade acústica é uma região do espaço delimitada pelas faces de um transdutor e de um refletor, onde é produzida uma onda estacionária de alta intensidade. Nesta técnica, conhecida como levitação por ondas estacionárias, pequenos objetos são aprisionados nos nós de pressão da onda estacionária. Além desta, também existe uma outra técnica de levitação onde não há a necessidade de se utilizar um refletor, técnica conhecida como levitação de campo próximo, na qual se tem apenas um transdutor e o objeto de face plana que se deseja levitar. Nesta técnica há uma pequena região com ar entre o transdutor e o objeto, sendo que a espessura da camada de ar é muito menor que o comprimento de onda. Neste trabalho foi feito um estudo numérico e experimental da força de radiação acústica em levitadores acústicos de onda estacionária e em levitadores de campo próximo. As simulações foram realizadas no software de elementos finitos COMSOL Mutiphysics. No estudo experimental foi utilizada uma balança eletrônica para medir a força de radiação acústica e uma câmera de alta velocidade para observar o comportamento oscilatório de objetos esféricos no interior da cavidade acústica. O estudo da força de radiação acústica resultou em três principais contribuições. A primeira contribuição está relacionada com a caracterização de efeitos não lineares em um levitador acústico, como o fenômeno de salto (jump phenomenon) e o fenômeno de histerese. A segunda contribuição está relacionada com o estudo numérico e experimental da força de radiação acústica que atua no refletor de um levitador acústico. Por último também foi feito um estudo da força de radiação acústica que atua no refletor para a região do campo próximo. Neste último estudo foi verificado que quando o diâmetro da face do transdutor é pequeno em comparação com o comprimento de onda, surge uma força atrativa sobre o refletor, e esta força pode ser utilizada para levitar um objeto plano em baixo da face do transdutor, sem haver necessidade de utilizar refletores. / The study of the acoustic radiation force is of high relevance to understand the acoustic levitation, since it is responsible for the levitation of small objects in the interior of an acoustic cavity. The acoustic cavity is the region delimited by the surfaces of the transducer and the reflector, where it is generated an acoustic standing wave field of high intensity. In this technique, called standing wave acoustic levitation, small objects are entrapped at the pressure nodes of the standing wave. In addition, there is also another levitation technique where there is no need to use a reflector. This technique is known as near-field levitation, in which there is only one transducer and the flat-faced object to be levitated. In this technique there is a small region with air between the transducer and the object, with the thickness of the air layer being much smaller than the wavelength. In this work, a numerical and experimental study of the acoustic radiation force in acoustic wave levitators and near-field levitators was done. The simulations were performed in the finite element software COMSOL Mutiphysics. In the experimental results, an electronic scale was used to measure the acoustic radiation force and a high speed camera was applied to observe the oscillatory behavior of spherical objects inside the acoustic cavity. The study of acoustic radiation strength resulted in three main contributions. The first contribution is related to the characterization of nonlinear effects in an acoustic levitator, such as the jump phenomenon and the hysteresis phenomenon. The second contribution is related to the numerical and experimental study of the acoustic radiation force that acts on the reflector of an acoustic levitator. Finally, a study of the acoustic radiation force that acts on the reflector for the near field region was also made. In this last study, it was verified that when the transducer is small in comparison with the wavelength, an attractive force appears on the reflector. This force can be used to levitate a flat object below the transducer face, without requiring a reflector.

O efeito do ultra-som de baixa intensidade no reparo ósseo tem sido investigado em experimentos animais e clínicos no Brasil e exterior. Essas investigações resultaram em uma tecnologia não invasiva para o tratamento de fraturas aprovada pela Agência Nacional de Vigilância Sanitária (Brasil) e pelo Food and Drug Administration (FDA - EUA). Os resultados obtidos no tratamento de fraturas motivaram investigações sobre os efeitos do mesmo ultra-som na osseointegração de implantes metálicos (EUA). Neste estudo foram utilizados 18 coelhos da raça Nova Zelândia, com peso entre 2,5 e 3,0 kg. Em cada tíbia foram inseridos 2 implantes de titânio de uso comercial em odontologia com superfície tratada por subtração ácida e com dimensões de 3,75mm X 8,5 mm. Os implantes da tíbia esquerda foram tratados por ultra-som de baixa intensidade por 20 minutos diários, durante 3, 5 e 7 semanas. Os da tíbia direita foram usados como controle. A osseointegração nos implantes foi avaliada por testes mecânicos e histomorfométricos. Os implantes tratados por ultra-som apresentaram em regiões ao redor das espiras superiores, após 3 e 5 semanas, maior quantidade de osso calcificado que nos implantes não tratados. Não houve significância estatística na quantidade de osso calcificado nas espiras de ambos os grupos após 7 semanas. As espiras de ambos os grupos, tratados e não-tratados, em contato com o osso cortical da tíbia, foram totalmente preenchidas por tecido ósseo após 3, 5 e 7 semanas da sua colocação. Os ensaios mecânicos de torque por desroqueamento e força de arrancamento não detectaram diferença na resistência mecânica entre implantes tratados e não-tratados por ultra-som após 3, 5 e 7 semanas. A resistência mecânica apresentada pelos testes mecânicos nesta investigação parece ser dependente do preenchimento total ou parcial das espiras dos implantes e não da quantidade de tecido ósseo calcificado presente. / The low intensity ultrasound effect in bone repair has been investigated in animal and clinical experiments in Brazil and other countries. The result of these investigations was the development of a non-invasive technology for treating fractures which has been approved by FDA (USA) and by an agency (ANVISA) of the Brazilian Ministry of Health. The success in treating fractures motivated studies on the effects of the same ultrasound on bone ingrowth into metallic implants. In this study two commercial titanium dental implants (STE) with 3,75mm X 8,5mm were inserted bilaterally in the tibia of New Zealand rabbits (n=18) weighing between 2.5 - 3.0 kg. The implants in the left tibia were subjected to 20 minutes daily ultrasound treatment for 3, 5 and 7 weeks. The implants in the right tibia served as a control. The osseointegration in the implants was analysed by mechanical tests (torsion and pull-out) and histomorfometry. The implants treated by ultrasound showed more calcified bone in its threads and surrounding areas after 3 and 5 weeks than nontreated implants. The difference in the amount of calcified bone was not statiscally significant in the treated and non treated implants after 7 weeks. The area of treated and non-treated implants in contact with cortical bone was full filled with bone after 3, 5 and 7 weeks. Mechanical tests (torsion and pull-out) did not show differences statistically significant between treated and non-treated implants after 3, 5 and 7 weeks. The mechanical resistance of the implants seems to be more dependent on the amount of bone in the implants threads than the amount of calcified bone existing in the threads and surrounding areas.

O ultra-som é um recurso imaginológico relativamente recente, que foi desenvolvido primeiramente para utilização submarina, e só depois fundamentada na área da Saúde. Esse sistema utiliza ondas ultra-sônicas, que são produzidas em um dispositivo denominado transdutor, responsável também por enviá-las ao tecido a ser avaliado; é também o responsável por receber os ecos sonoros que são refletidos pelas estruturas que possuem diferentes impedâncias acústicas, obtendo-se assim os resultados. As primeiras gerações de US (modo-A) utilizavam um sistema numérico pouco atrativo para a interpretação dos resultados. Somente com o advento do modo-B, que apresenta imagens tomográficas, o ultra-som começou a se tornar um método imaginológico mais utilizado. Com a evolução dos aparelhos, a técnica permitia que as imagens fossem processadas a uma velocidade suficientemente rápida para deixar passar a percepção de movimento. É possível por meio do Doppler colorido, caracterizado pela associação das imagens em movimento em tempo real, mapear o fluxo vascular. Pela revisão da literatura, concluímos que: o ultra-som é um exame imaginológico recente; é um método auxiliar na elaboração do diagnóstico, não invasivo, indolor e sem nenhum efeito deletério conhecido até os dias atuais; é um exame imaginológico com alta especificidade para tecidos moles; é um recurso capaz de detectar, delimitar 9 (inclusive em profundidade) e avaliar o conteúdo interno, tanto na normalidade quanto nas alterações do complexo dento-maxilo-cervico-facial; a interpretação pode ser feita em tempo real, sendo passível de repetição, sempre que necessário; é operador-dependente e tem ampla aplicação nas diferentes Especialidades Odontológicas. / The Ultrasound (US) is a relatively recent imaginologic resource that was first developed for submarine use, and then applied in the Health area. This system makes use of ultrasonic waves, produced in a device called transducer, which is also responsible for sending them to the tissue to be evaluated. The transducer is responsible for receiving the eco sounds that are reflected by structures that possess different acoustic impedances, thus obtaining results. The first generations of US (A-mode) used a numerical system that was not very attractive for results interpretation. Only with the discovery of the B-mode, which presents tomographic images, the ultrasound started to become a more utilized method. As devices evolved, the technique allowed images to be processed in such a high velocity that would let the perception of movement pass. It is possible to map the vascular flux in real time by using Coloured Doppler, characterized by the association of moving images. By literature review, we concluded that: the ultrasound is a recent imaginologic exam; it is a non-invasive, painless, auxiliary diagnostic method and has shown no known side effects until the present date; it is a high-specificity imaginologic exam for soft tissues; it is a resource capable to detect, delimitate (including in depth), and evaluate the internal content in normality as much as in dento-maxilo-cervico-facial alterations; the interpretation can be made in real time, and repetition is always 11 possible when necessary; it is operator-dependent and has a wide application in different odontological specialities.

" A novel Markov Random Field (MRF) based method for the mosaicing of 3D ultrasound volumes is presented in this dissertation. The motivation for this work is the production of training volumes for an affordable ultrasound simulator, which offers a low-cost/portable training solution for new users of diagnostic ultrasound, by providing the scanning experience essential for developing the necessary psycho-motor skills. It also has the potential for introducing ultrasound instruction into medical education curriculums. The interest in ultrasound training stems in part from the widespread adoption of point-of-care scanners, i.e. low cost portable ultrasound scanning systems in the medical community. This work develops a novel approach for producing 3D composite image volumes and validates the approach using clinically acquired fetal images from the obstetrics department at the University of Massachusetts Medical School (UMMS). Results using the Visible Human Female dataset as well as an abdominal trauma phantom are also presented. The process is broken down into five distinct steps, which include individual 3D volume acquisition, rigid registration, calculation of a mosaicing function, group-wise non-rigid registration, and finally blending. Each of these steps, common in medical image processing, has been investigated in the context of ultrasound mosaicing and has resulted in improved algorithms. Rigid and non-rigid registration methods are analyzed in a probabilistic framework and their sensitivity to ultrasound shadowing artifacts is studied. The group-wise non-rigid registration problem is initially formulated as a maximum likelihood estimation, where the joint probability density function is comprised of the partially overlapping ultrasound image volumes. This expression is simplified using a block-matching methodology and the resulting discrete registration energy is shown to be equivalent to a Markov Random Field. Graph based methods common in computer vision are then used for optimization, resulting in a set of transformations that bring the overlapping volumes into alignment. This optimization is parallelized using a fusion approach, where the registration problem is divided into 8 independent sub-problems whose solutions are fused together at the end of each iteration. This method provided a speedup factor of 3.91 over the single threaded approach with no noticeable reduction in accuracy during our simulations. Furthermore, the registration problem is simplified by introducing a mosaicing function, which partitions the composite volume into regions filled with data from unique partially overlapping source volumes. This mosaicing functions attempts to minimize intensity and gradient differences between adjacent sources in the composite volume. Experimental results to demonstrate the performance of the group-wise registration algorithm are also presented. This algorithm is initially tested on deformed abdominal image volumes generated using a finite element model of the Visible Human Female to show the accuracy of its calculated displacement fields. In addition, the algorithm is evaluated using real ultrasound data from an abdominal phantom. Finally, composite obstetrics image volumes are constructed using clinical scans of pregnant subjects, where fetal movement makes registration/mosaicing especially difficult. Our solution to blending, which is the final step of the mosaicing process, is also discussed. The trainee will have a better experience if the volume boundaries are visually seamless, and this usually requires some blending prior to stitching. Also, regions of the volume where no data was collected during scanning should have an ultrasound-like appearance before being displayed in the simulator. This ensures the trainee's visual experience isn't degraded by unrealistic images. A discrete Poisson approach has been adapted to accomplish these tasks. Following this, we will describe how a 4D fetal heart image volume can be constructed from swept 2D ultrasound. A 4D probe, such as the Philips X6-1 xMATRIX Array, would make this task simpler as it can acquire 3D ultrasound volumes of the fetal heart in real-time; However, probes such as these aren't widespread yet. Once the theory has been introduced, we will describe the clinical component of this dissertation. For the purpose of acquiring actual clinical ultrasound data, from which training datasets were produced, 11 pregnant subjects were scanned by experienced sonographers at the UMMS following an approved IRB protocol. First, we will discuss the software/hardware configuration that was used to conduct these scans, which included some custom mechanical design. With the data collected using this arrangement we generated seamless 3D fetal mosaics, that is, the training datasets, loaded them into our ultrasound training simulator, and then subsequently had them evaluated by the sonographers at the UMMS for accuracy. These mosaics were constructed from the raw scan data using the techniques previously introduced. Specific training objectives were established based on the input from our collaborators in the obstetrics sonography group. Important fetal measurements are reviewed, which form the basis for training in obstetrics ultrasound. Finally clinical images demonstrating the sonographer making fetal measurements in practice, which were acquired directly by the Philips iU22 ultrasound machine from one of our 11 subjects, are compared with screenshots of corresponding images produced by our simulator. "

"Ultrasound has become a widely used form of medical imaging because it is low-cost, safe, and portable. However, it is heavily dependent on the skill of the operator to capture quality images and properly detect abnormalities. Training is a key component of ultrasound, but the limited availability of training courses and programs presents a significant obstacle to the wider use of ultrasound systems. The goal of this work was to design and implement an interactive training system to help train and evaluate sonographers. This Virtual Training System for Diagnostic Ultrasound is an inexpensive, software-based training system in which the trainee scans a generic scan surface with a sham transducer containing position and orientation sensors. The observed ultrasound image is generated from a pre-stored 3D image volume and is controlled interactively by the user€™s movements of the sham transducer. The patient in the virtual environment represented by the 3D image data may depict normal anatomy, exhibit a specific trauma, or present a given physical condition. The training system provides a realistic scanning experience by providing an interactive real-time display with adjustable image parameters similar to those of an actual diagnostic ultrasound system. This system has been designed to limit the amount of hardware needed to allow for low-cost and portability for the user. The system is able to utilize a PC to run the software. To represent the patient to be scanned, a specific scan surface has been produced that allows for an optical sensor to track the position of the sham transducer. The orientation of the sham transducer is tracked by using an inexpensive inertial measurement unit that relies on the use of quaternions to be integrated into the system. The lack of a physical manikin is overcome by using a visual implementation of a virtual patient in the software along with a virtual transducer that reflects the movements of the user on the scan surface. Pre-processing is performed on the selected 3D image volume to provide coordinate transformation parameters that yield a least-mean square fit from the scan surface to the scanning region of the virtual patient. This thesis presents a prototype training system accomplishing the main goals of being low-cost, portable, and accurate. The ultrasound training system can provide cost-effective and convenient training of physicians and sonographers. This system has the potential to become a powerful tool for training sonographers in recognizing a wide variety of medical conditions."