O aumento na longevidade humana fez surgir uma série de doenças com a idade; em contrapartida o avanço da medicina possibilitou o diagnóstico precoce e o tratamento de várias doenças antes incuráveis. Esse cenário atual estendese também aos animais domésticos (cães e gatos - PETs) que dobraram sua expectativa de vida nas últimas décadas, fato que os humanos demoraram séculos para alcançar. Do mesmo modo que os humanos, esse aumento na longevidade dos animais veio acompanhado de doenças relacionadas com a idade, entre elas o câncer. Uma das terapias utilizadas atualmente no tratamento do câncer é a radioterapia, técnica que utiliza a radiação ionizante para destruir as células tumorais (volume-alvo) com mínimo prejuízo aos tecidos circunvizinhos sadios (órgãos de risco). Essa técnica exige a realização periódica de testes de controle de qualidade, incluindo a dosimetria com a utilização de objetos simuladores equivalentes ao tecido, de modo a verificar a dose de radiação recebida pelo paciente em tratamento e compará-la posteriormente com a dose de radiação calculada pelo sistema de planejamento. A rápida expansão do mercado de impressoras 3D abriu caminho para uma revolução na área da saúde. Atualmente os objetos simuladores por impressão 3D estão sendo usados em planejamentos de Radioterapia para a localização espacial e mapeamento das curvas de isodose, realizando, assim, um planejamento mais personalizado para cada campo de radiação, além da confecção de implantes dentais, customização de próteses e confecção de bólus. Diante do exposto esse trabalho projetou e desenvolveu um objeto simulador chamado de \"Canis Morphic\" utilizando uma impressora 3D e materiais tecido-equivalentes para a realização dos testes de controle de qualidade e otimização das doses na área de Radioterapia em animais (cães). Os resultados obtidos demonstraram-se promissores na área de criação de simuladores por impressão 3D, com materiais de baixo custo, para aplicação no controle de qualidade em Radioterapia veterinária. / The increase in human longevity caused a number of diseases with age; in contrast the advancement of medicine made possible the early diagnosis and treatment of several previously incurable diseases. This scenario is also important for domestic animals (dogs and cats - PETs) that have doubled their life expectancy in recent decades, a fact that humans took centuries to reach. Like humans, this increase in animal longevity was accompanied by age-related diseases, including cancer. One of the therapies currently used in the treatment of cancer is radiation therapy, a technique that uses ionizing radiation to destroy tumor cells (target volume) with minimal impairment to healthy surrounding tissues (organs at risk). This technique requires periodic quality control testing, including dosimetry with the use of tissue-equivalent phantoms, in order to verify the dose of radiation received by the patient being treated and to compare it subsequently with the calculated radiation dose by the treatment planning system. The rapid expansion of the 3D printer opened the way for a health revolution. Currently the 3D impression of phantoms are being used in Radiation therapy\'s planning for the spatial location and mapping of the isodose curves, thus realizing a more personalized planning for each radiation field, besides the preparation of dental implants, customization of prostheses and build of bolus. This work aimed has designed and developed a simulator object called \"Canis Morphic\" using a 3D printer and tissue-equivalent materials to perform quality control and dose optimization tests in the area of Radiation therapy in animals (dogs). The results obtained demonstrated be promising in the area of development of phantoms by 3D printing, with materials of low cost, for application in quality control in Veterinary Radiation therapy.

Este trabalho tem por objetivo avaliar o desempenho dos equipamentos de radilogia digital, especificamente, mamógrafo de campo total e mamógrafos convencionais no que se refere à detecção de sinais e em termos da geometria da exposição. O trabalho se desenvolve a partir da formação de um conjunto de imagens mamográficas do simulador ACR modelo 156; este conjunto é composto por imagens mamográficas de equipamentos convencionais e digitais de campo total e imagens obtidas por um simulador radiográfico incorporado a um pacote computacional que fornece informações características de equipamentos radiológicos quanto ao desempenho do sistema em termos da geometria de exposição como ponto focal, limites de resolução e ruído aleatório produzido. A partir dos resultados das interpretações das imagens do simulador ACR pelos observadores, determina-se o índice de acertos; paralelamente analisam-se os dados relativos à geometria da exposição. / This work is aimed at evaluating the performance of digital radiology especially full digital mammograph and conventional mammograph in order to detect signals send in terms of geometry of the exposition. The work is developed from the formation of a pool of mammographic images of the ACR Phantom 156; this bank is formed by mammograph images of both conventional and full field digital equipments and images got by a radiographic test gadget linked to a software package that provides typical information of radiologic equipments concerning the system\'s performance regarding geometric of exposition like focal spot, margins of resolution and aleatory noise. From the results of the interpretation of the ACR simulator\'s images by the observers, then, we are able to determine what is right, at the same time to analyze the data related to the geometry of exposition.

Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2012-12-21T18:30:14Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_TransmissaoDSLModo.pdf: 1763755 bytes, checksum: 3acefaab13451aad5141d583fb5b5561 (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-01-14T18:28:08Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_TransmissaoDSLModo.pdf: 1763755 bytes, checksum: 3acefaab13451aad5141d583fb5b5561 (MD5) / Made available in DSpace on 2013-01-14T18:28:08Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_TransmissaoDSLModo.pdf: 1763755 bytes, checksum: 3acefaab13451aad5141d583fb5b5561 (MD5) Previous issue date: 2012 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / ERICSSON Telecomunicações S.A. / A demanda por taxa de bits vem aumentando a cada ano, devido principalmente pela incorporação de aplicativos online ao cotidiano das pessoas. Assim, as companhias prestadoras deste tipo de serviço estão sempre investindo em pesquisa por tecnologias que possibilitem o aumento da taxa de bits com um bom custo-benefício. Seguindo esta perspectiva, este trabalho apresenta o modo de transmissão fantasma (Phantom mode), que visa aumentar a taxa total de transmissão de bits em sistemas DSL, quando múltiplos pares de cobre estão disponíveis. Aqui também são mostrados resultados e discussões importantes sobre desempenho do modo de transmissão fantasma. Também são discutidos procedimentos para a execução de medições de modo fantasma em frequências de 100 kHz a 300 MHz, em uma maneira que permite a medição de modo fantasma e modo diferencial com o mesmo setup. Novos resultados são apresentados sobre canal direto, far-end crosstalk (FEXT) e conversão de modo, para um cabo Cat-5e de 50 metros. Dentre outros fatos, foram verificadas grandes diferenças no canal direto de modo fantasma quando foram comparadas medições com cabo enrolado e desenrolado, e que a forma como o modo fantasma _e construção da influência bastante no comportamento das curvas de canal direto, FEXT e conversão de modo. Também são apresentados resultados de estimação da taxa de bits quando são usados modo fantasma e modo diferencial simultaneamente, e observou-se que ha um ganho de ate 60% quando foram usados este dois modos e vectoring. / Demand for bit rate is increasing every year, mainly due to the incorporation of online applications into people's life. So the companies which provide this type of service are always investing in research for technologies that enable increased bit rate with a good value for money. Following this perspective, this paper presents transmission phantom mode, which aims to increase the overall rate of transmission of bits in DSL systems when multiple copper pairs available. Here we also show results and discussions on performance of phantom mode. We discuss procedures for performing measurements in phantom mode at frequencies from 100 kHz to 300 MHz, in a way that allows the measurement of phantom mode and deferential mode with the same setup. New results are presented on the direct channel, far-end crosstalk (FEXT) and mode conversion for a Cat-5e cable of 50 meters. Among other facts, we verify large deference’s in the direct channel phantom mode when comparing rolled and unrolled cable measurements, and that manner how we build the phantom mode greatly inuences the behavior of the curves of direct channel, FEXT and mode conversion. We also present results of estimating bit rate when using phantom mode and deferential mode simultaneously, and observed that there is a gain of up to 60 when we use this two modes and vectoring.

O aumento na longevidade humana fez surgir uma série de doenças com a idade; em contrapartida o avanço da medicina possibilitou o diagnóstico precoce e o tratamento de várias doenças antes incuráveis. Esse cenário atual estendese também aos animais domésticos (cães e gatos - PETs) que dobraram sua expectativa de vida nas últimas décadas, fato que os humanos demoraram séculos para alcançar. Do mesmo modo que os humanos, esse aumento na longevidade dos animais veio acompanhado de doenças relacionadas com a idade, entre elas o câncer. Uma das terapias utilizadas atualmente no tratamento do câncer é a radioterapia, técnica que utiliza a radiação ionizante para destruir as células tumorais (volume-alvo) com mínimo prejuízo aos tecidos circunvizinhos sadios (órgãos de risco). Essa técnica exige a realização periódica de testes de controle de qualidade, incluindo a dosimetria com a utilização de objetos simuladores equivalentes ao tecido, de modo a verificar a dose de radiação recebida pelo paciente em tratamento e compará-la posteriormente com a dose de radiação calculada pelo sistema de planejamento. A rápida expansão do mercado de impressoras 3D abriu caminho para uma revolução na área da saúde. Atualmente os objetos simuladores por impressão 3D estão sendo usados em planejamentos de Radioterapia para a localização espacial e mapeamento das curvas de isodose, realizando, assim, um planejamento mais personalizado para cada campo de radiação, além da confecção de implantes dentais, customização de próteses e confecção de bólus. Diante do exposto esse trabalho projetou e desenvolveu um objeto simulador chamado de \"Canis Morphic\" utilizando uma impressora 3D e materiais tecido-equivalentes para a realização dos testes de controle de qualidade e otimização das doses na área de Radioterapia em animais (cães). Os resultados obtidos demonstraram-se promissores na área de criação de simuladores por impressão 3D, com materiais de baixo custo, para aplicação no controle de qualidade em Radioterapia veterinária. / The increase in human longevity caused a number of diseases with age; in contrast the advancement of medicine made possible the early diagnosis and treatment of several previously incurable diseases. This scenario is also important for domestic animals (dogs and cats - PETs) that have doubled their life expectancy in recent decades, a fact that humans took centuries to reach. Like humans, this increase in animal longevity was accompanied by age-related diseases, including cancer. One of the therapies currently used in the treatment of cancer is radiation therapy, a technique that uses ionizing radiation to destroy tumor cells (target volume) with minimal impairment to healthy surrounding tissues (organs at risk). This technique requires periodic quality control testing, including dosimetry with the use of tissue-equivalent phantoms, in order to verify the dose of radiation received by the patient being treated and to compare it subsequently with the calculated radiation dose by the treatment planning system. The rapid expansion of the 3D printer opened the way for a health revolution. Currently the 3D impression of phantoms are being used in Radiation therapy\'s planning for the spatial location and mapping of the isodose curves, thus realizing a more personalized planning for each radiation field, besides the preparation of dental implants, customization of prostheses and build of bolus. This work aimed has designed and developed a simulator object called \"Canis Morphic\" using a 3D printer and tissue-equivalent materials to perform quality control and dose optimization tests in the area of Radiation therapy in animals (dogs). The results obtained demonstrated be promising in the area of development of phantoms by 3D printing, with materials of low cost, for application in quality control in Veterinary Radiation therapy.

The incidence of disease of the cardiovascular system is very high and increasing worldwide, especially in the developing world. The radial and ulnar arteries are implicated in some important ailments where blood flow related parameters such as flow rate (FR), wall shear rate (WSR), arterial wall motion (AWM) and pressure, all of which can be measured using ultrasound techniques, are useful in diagnosis and patient management. However these measurements are prone to error due to the manner of image formation and the complex flow conditions within the vessels. In this thesis, the errors in ultrasound-measured parameters in the radial and ulnar arteries are investigated using experimental phantoms, computer simulation and on volunteers. Using the Womersley theory, FR and WSR were estimated using a clinical ultrasound scanner with the pulsed wave (PW) mode and B mode. Experimental flow phantoms were designed to evaluate those measurements under different circumstances. A simulation technique which combined image-based computational fluid dynamics and ultrasound simulation was also used to evaluate ultrasound estimation of these parameters. A case study was then conducted on healthy volunteers to evaluate the method of measuring FR and WSR in-vivo. For the AWM in the radial artery, an auto-correlation method was used based on the radio-frequency (RF) data and validations were done by a flow phantom, simulation, and in-vivo trial. The blood pressure waveform in a volunteer’s radial artery was derived from the ultrasound measured AWM and compared with the waveform from a tonometry. FR and WSR were both found to be overestimated by up to 50%, mainly due to the beam-vessel angle in the PW Doppler ultrasound. Measurement of the vessel diameter and assumption of the blood flow direction can also influence the estimations. Other factors, such as flow amplitude, vessel size, imaging depth and flow waveforms, do not seem to affect the estimation of these two parameters. Results taken from the flow phantoms agree with those from simulation and the estimations from the in-vivo case study also agree with the published data. The auto-correlation method for the AWM was validated from the phantom and simulation. It is able to detect motion amplitude of about tens of micrometres. The trial on volunteers proved the feasibility of this motion detection method. Blood pressure waveforms at the radial artery of a volunteer, derived from this ultrasound-measured wall motion and from the tonometry, were very similar. The Womersley-based method is able to estimate the FR and WSR in the radial and ulnar arteries with high accuracy. Sources of the error and their magnitudes in estimation of the two parameters by ultrasound pointed out in this thesis are beam-vessel angle, vessel diameter measurement and flow direction assumption. Researchers and clinicians using these measurements in practice and research should be aware. The capability of ultrasound imaging to measure arterial AWM in the radial artery is demonstrated and it is found that the blood pressure waveform can also be derived from the arterial AWM.

Colonoscopy is the current standard for colorectal cancer screening. This procedure requires improvement since it causes patient pain and can even result in injury. Novel colonoscopy devices have to be evaluated to gain information about their performance. At the preclinical stage of the device development the evaluation is typically performed in laboratory experiments. For these experiments an artificial environment is required which can recreate the anatomical and biomechanical features of the colon. A colonoscopy simulator for the evaluation of colonoscopy devices was developed within the ERC funded CoDIR project (Colonic Disease Investigation by Robotic Hydrocolonoscopy). The here developed simulator had to provide a colon phantom with realistic biomechanical properties as well as a sensor setup to measure signals which can be used to quantify the performance of devices which are tested within the simulator. Related literature was reviewed and possible tissue mimicking materials were selected. The suitability of the selected materials was evaluated by testing the frictional and elastic properties of the materials and subsequently comparing the results to those of colon tissue. PVA cryogel was selected as the most suitable material as it exhibits comparable elasticity and coefficients of friction. The tissue mimicking materials were mould casted into phantoms which were designed to represent the anatomical features of the colon. A simulator environment was developed which integrates the phantom as well as force and pressure sensors into a functional system. The sensors measure mesenteric forces and intraluminal pressures which can be related to the performance of tested devices. The simulator allows the arrangement of the sensors and the phantoms in an adjustable, modular approach. The simulator environment was successfully applied in the evaluation of a novel colonoscopy device. The results indicate that PVA cryogels exhibit unique mechanical properties which can be compared to those of colon tissue. The developed colonoscopy simulator provides a promising tool which can aid the development of novel colonoscopy devices.

Mesoporous silica particles are of significant interest for biomedical applications due to their good general biocompatibility compared to other nanoparticle matrices such as quantum dots, high specific surface areas up to 1000 m2/g, and extreme synthetic tunability in terms of particle size, pore size and topology, core material, and surface functionalization. For one application, drug delivery, mesoporous silica nanoparticles (MSNs) of two pore structures, MCM-41 – parallel, hexagonally ordered pores approximately 3 nm in diameter – and wormhole (WO) – interconnected, disordered pores also approximately 3 nm in diameter – were synthesized with particle diameters under 100 nm. Additionally, a magnetic Fe3O4 nanoparticle core was incorporated into Fe3O4-core WO-MS-shell particles. The particles were loaded with doxorubicin, a chemotherapeutic, and the drug release into phosphate buffered saline (PBS, 10 mM, pH 7.4) at 37 °C was monitored by fluorescence spectroscopy. The data were fit to three models: Korsmeyer-Peppas, first order exponential release, and Weibull. The Korsmeyer-Peppas model provided useful information concerning the kinetics and mechanism of drug release from each MSN type. A small but statistically significant difference in the release kinetics was found due to the different pore topologies. A much larger kinetic effect was observed due to the inclusion of an iron oxide core. Applying a static magnetic field to the Fe3O4-core WO-MS shell particles did not have a significant impact on the doxorubicin release. This is the first time that the effects of pore topology and iron oxide core have been isolated from pore diameter and particle size for these materials. In vitro cell studies were conducted to determine the cytotoxicity of the bare and doxorubicin-loaded materials against three cancerous cell lines – A549 human lung carcinoma cells, HEC50CO human endometrial cancer cells, and CT26 mouse colon cancer cells. The MCM-41 and WO MSNs generally displayed similar toxicities within each cell line, and the Fe3O4-core WO-MS shell particles were less toxic. Doxorubicin-loaded particles generally displayed greater toxicity than bare MSNs, but the A549 cells were very resistant to all concentrations of MSNs tested. For another biomedical application, tissue phantom development, mesoporous silica particles with approximately 10 μm diameters and C18 surface functionalization were evaluated for their use as a substrate for optical tissue phantoms. Tissue phantoms are synthetic imitations of biological material, and C18-modified silica provides a substrate that is simple to load with optically active biological molecules. The molecules are then hydrophobically trapped to maintain a clear optical boundary between the biological loading within the particle and an aqueous suspension gel. Several preparation techniques were evaluated for the dispersal of hydrophobic particles in aqueous media, and qualitative analysis indicated that surfactant coating of the outer surface could fully disperse the hydrophobic particle while maintaining the clear optical boundary. A novel analysis was developed to provide a single numerical indicator of clustering for a quantitative assessment of particle dispersal in tissue phantoms.

Health-care associated infections (HAIs) on medical implant surfaces present a unique challenge to physicians due to their existence in the biofilm phenotype which defends the pathogen from antibiotics and the host’s own immune system. A 2004 study in the U.S. showed that 2 to 4% of implanted devices become infected and must be treated via surgical explantation—a process that is both expensive and dangerous for the patient. A potential, alternative strategy to antibiotics and surgery is to use heat delivered wirelessly by a magnetic coating. This thermal treatment strategy has the potential to kill these HAIs directly on the implanted surface and without the patient requiring surgery. This thesis introduces an iron oxide nanoparticle composite coating that is wirelessly heated using energy converted from an alternating magnetic field. Iron oxide nanoparticle composites are demonstrated to be remotely heated in both hydrophilic and hydrophobic polymer composites. In designing the composite coating, multiple parameters were investigated for how they impact the normalized heating rate of the material. Specifically, the amount of iron in the coating, the coating thickness, the polymer type, and the orientation of the coating relative to the applied magnetic field were investigated. Power output was shown to increase proportionally with iron loading whereas nearly two times the amount of power output was observed for the same coatings positioned parallel to magnetic field lines versus those positioned perpendicular—a result believed to be due to magnetic shielding from neighboring particles. Microscope slides coated with 226 µm of composite delivered up to 10.9 W cm⁻² of power when loaded with 30.0% Fe and positioned parallel in a 2.3 kA m⁻¹AMF. Pseudomonas aeruginosa biofilms were grown directly on these coatings and heated for times ranging from 1 to 30 min and temperatures from 50 to 80 °C. Less than one order of magnitude of cell death was observed for temperatures less than 60 °C and heat shock times less than 5 min. Up to six orders of magnitude reduction in viable bacteria were observed for the most extreme heat shock (80 °C for 30 min). Introducing this wirelessly heated composite into the body has the potential to kill harmful bacteria but at the risk of thermally damaging the surrounding tissue and organs if the treatment is not designed and predicted intelligently. Thermal energy will propagate differently depending on the surrounding heat sink, with convective heat sinks (i.e. those due to blood flow) requiring much more power to reach the same surface temperature than a conduction-only heat sink. To study how heat is transferred in biological tissues, a robust, poly(vinyl alcohol) tissue phantom was developed that can be poured to accommodate any geometry, is volume stable in water and under thermal stress, and can be modified with inert particle fillers to adjust its thermal conductivity from 0.475 to 0.795 W m⁻¹°C⁻¹. In vitro heat transfer was measured through this hydrogel tissue phantom with at least 10 °C of temperature rise, penetrating 5 mm of tissue in less than 120 sec for an 80 °C boundary condition. A computational model was used to solve three-dimensional energy transfer through a combined fluid mimic/tissue mimic heat sink spanning the same surface boundary condition. The model was validated with experimental models using a custom designed heat transfer station. This scenario is applicable in the instance where the same coating is subject to starkly different heat sinks: half subject to convective heat loss, half to conductive heat loss. Based on these conditions, a magnetic coating would need to be designed that has a power gradient up to 15 times larger on the fluid half versus the other.

Computer designed missing tissue and dose compensators have been produced and dosimetrically tested under a linear accelerator 6MV X-ray beam. Missing tissues compensators were developed to correct for patient external contour change only. Target dose compensators were developed to achieve a uniform dose throughout the target volume. With compensators present in the beam, data acquisition was repeated in a water phantom and an Anthropomorphic phantom. Clinically acceptable dose uniformity was achieved within these phantoms. For external contour compensation flat isodose curves were obtained giving an even dose in the region of interest. The dose difference found was within plus/minus 3% only. For the phantoms containing inhomogeneities dose uniformity to target volume was achieved within plus/minus 7%. Prediction of radiation dose was made using a GE Target Series 2 Treatment Planning Computer for each of the phantoms. Validation of the computer predicted dose was carried out using diode and TLD measurements. The measured data in the water tank was consistent with the computer data within plus/minus 2% for external contour changes and for inhomogeneities. The TLD measured results in the anthropomorphic phantom agreed with the planning computer results within 6%. Up to 4% of the difference is explainable due to supra-linearity and scatter effects / Master of Science (Hons) (Physics)

The radiation dose in radiation therapy is mainly measured by ion chamber. The ion chamber measurement will not be accurate if there is not enough phantom material surrounding the ion chamber to provide the electron equilibrium condition. The lack of electron equilibrium will cause a reduction of dose. This may introduce problems in treatment planning. Because some planning algorithms cannot predict the reduction, they over estimate the dose in the region. Electron disequilibrium will happen when the radiation field size is too small or the density of irradiated material is too low to provide sufficient electrons going into the dose volume. The amount of tissue required to provide electron equilibrium in a 6MV photon beam by three methods: direct calculation from Klein-Nisina equation, measurement in low density material phantom and a Monte Carlo simulation is done to compare with the measurement, an indirect method from a planning algorithm which does not provide an accurate result under lateral electron disequilibrium. When the error starts to happen in such planning algorithm, we know that the electron equilibrium conditions does not exist. Only the 6MV photon beam is investigated. This is because in most cases, a 6MV small fields are used for head and neck (larynx cavity) and 6MV fields are commonly used for lung to minimise uncertainity due to lateral electron at higher energies. / Master of Science (Hons)