958 resultados para Tomografia computadorizada de feixe cônico
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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As Eriocaulaceae brasileiras encontram-se distribuídas principalmente nos campos rupestres que se estendem de Minas Gerais à Bahia, na Cadeia do Espinhaço. Paepalanthus Mart. é o maior gênero da família e apresenta cerca de 450 espécies, sendo que Paepalanthus sect. Diphyomene Ruhl. possui cerca de 20 espécies que já pertenceram a diversas categorias taxonômicas. Com o objetivo de correlacionar a anatomia e a taxonomia desta seção, além de levantar caracteres diagnósticos para suas espécies, foi estudada a anatomia de folhas, brácteas e escapos. Folhas e brácteas de Paepalanthus sect. Diphyomene apresentam diferenças na forma e no espessamento das células epidérmicas; no espessamento do mesofilo; na disposição dos feixes vasculares; presença ou ausência de hipoderme; diferente forma e composição de parede das células da extensão de bainha do feixe vascular; forma e constituição da margem e presença ou ausência de parênquima aqüífero na face adaxial. No escapo, foram observadas diferenças quanto ao número e contorno de costelas e extensão da medula. Assim, a proposta de divisão de P. sect. Diphyomene em duas categorias é corroborada. São caracteres diagnósticos para as espécies: presença de parênquima aquífero na face adaxial e ausência de extensão de bainha do feixe vascular em folhas de Paepalanthus urbanianus; presença de feixes vasculares distribuídos em ordem decrescente de tamanho em direção à margem em folhas e brácteas e contorno triangular do escapo em P. flaccidus, presença de nove costelas em escapos de P. acanthophyllus e dez em P. macer. Foi elaborada uma chave de identificação das espécies de Paepalanthus sect. Diphyomene com base nas características anatômicas levantadas
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Nowadays the mammography is the most effective way of revealing early breast cancer. The image in this kind of exam is gotten trough a x-ray sheaf of low energy, however, the suitable visualization of the interesting structures by the radiologist is not always possible due several factors that appears since the mamma composition until the equipments limitation. The regulation 453/98 sets quality control tests and limits of acceptation that guarantee a good development of the mammographys. The purpose of this study is the 3D principle ( Diagnostic, Dose and Dollar), that means, an improved diagnosis, a dose reduction in the patient and a cost decrease for the Institution. In this study was made the quality control tests set by the Regulation in two mammography equipments from Hospital das Clínicas da Faculdade de Medicina de Botucatu (HCFMB - UNESP). The results reached in this research were used in the renovation process of quality stamp in mammography granted by Colégio Brasileiro de Radiologia (CBR) to the diagnosis by image from the HCFMB – UNESP
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Radiotherapy is a field of medical physics, which has been going through a scientific and technological advancement, it is extreme important the professionals that work in this area continuous their study to improve the quality of service provided. For it, they should know the physical principles related as well their employment in radiotherapy. The electrons have been using in therapy of superficial tumors, because they show rapid decrease of dose in depth, they don’t expose the deeper tissues to radiation. The electron therapy has replaced the surface therapy with x-ray and mold brachytherapy, and nowadays, it represents 10 to 15% of radiotherapy treatments. This study brings the definition of physical parameters used in the dosimetry of electron beam, describes the tests for quality control of linear accelerator with a electrons beam, as well the activities realized in the Radiotherapy Division, of Hospital de Clinicas, in the Universidade Estadual of Campinas, in the Clinac 2100C machine
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The treatment of a tumor with ionizing radiation is an ongoing process with well differentiated stages. These ones include the tumor diagnosis and location, the decision on the treatment strategy, the absorbed dose planning and calculation, the treatment administration, the absorbed dose verification and the evaluation of results in short and long terms. The quality of a radiotherapy procedure is closely linked to factors that may be classified as clinical, such as the diagnosis, the tumor location, the treatment strategy chosen and the continuous treatment reassessment; dosimetric or physical, such as the uncertainty in the dose calculation, its optimization and verification, the suitability of the equipment to provide a radiation beam consistent with the treatment planning; finally, others which are related to the practical application of radiotherapy treatment and the handling of the patient. In order to analyze the radiotherapy quality, one should realize that the three aspects (medical, physical or dosimetric and practical application) should be considered in a combined way. This means that numerous actions of the radiotherapists, medical physicists and technicians in radiotherapy should be held jointly and their knowledge level will significantly affect the treatment quality. In this study, the main physical parameters used in dosimetry are defined as well as determined experimentally for a linear accelerator Mevatron - MXT. With this, it is intended to provide recommendations for the physical aspects of Quality Assurance (QA) in the radiotherapy treatments, and these will usually be applied by professionals in Medical Physics. In addition to these instructions, it is recommended that additional texts are prepared to address in detail the clinical aspects of the treatments QA
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The Medical Physics has been developing very fast due to the progress of the technologies and to the increase of the concerns with cure of diseases. One of the Medical Physics main performances at the present time is the use of ionizing radiations for cancer treatment, especially, services as Radiotherapy. The radiotherapy technique uses ionizing radiation with therapeutic end of cancer controls, avoiding your proliferation and it worsens of the patient. For the treatment a radiation bunch is used, with rectangular form, that it passes through the different types of tissues of the patient's body, and depending on the attenuation and of the depth of the fabrics, a great amount of energy is deposited inside in different points of the body. Like this, to plan this treatment type it should be obtained the dimension of the distribution and dose absorption along the volume. For this, it is necessary in the planning of the treatment of the cancer for radiotherapy to build isodose curves, which are lines that represent points of same amount of dose to be deposited in the area to be treated. To aid the construction of the curves of form isodose to reach the best result in the planning of the treatment, in other words, a great planning, providing the maximum of dose in the tumor and saving the healthy and critical organs, it has been using mathematical tools and computational. A plan of cancer treatment for radiotherapy is considered great when all the parameters that involve the treatment, be them physical or biological, they were investigated and adapted individually for the patient. For that, is considered the type and the location of the tumor, worrying about the elimination of the cancer without damaging the healthy tissue of the treated area, mainly the risk organs, which are in general very sensitive to the radiations. This way, the optimization techniques... (Complete abstract click electronic access below)
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Qualidade na coleta de dados do feixe de radiação, modelagem por meio do sistema de planejamento de tratamento (SPT) e controle da qualidade do processo envolvido são cruciais à fidedignidade do serviço de radioterapia de forma a contribuir à eficácia do tratamento e segurança do principal ente envolvido no final de toda essa sistemática, o paciente. Para isso foi proposto nesse presente trabalho a coleta de dados do feixe de raios-x de 6MV seguido da introdução desses dados ao SPT para processo de modelagem computacional que teve agregado, a todo esses processos, o controle da qualidade segundo critérios de aceitação
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Several hormonal and physiological changes that occur during pregnancy directly affect gastrointestinal motility (GI), however, very little is known about the relationship between the electrical and mechanical activities of the stomach and its implications. The aim of this study was to compare the female sex hormones, with profiles of gastrointestinal motility using AC biosusceptometry (BAC) in pregnant rats. Seven female Wistar rats (weighing 250-350 g) were used and all procedures were approved by the local Ethics Committee of animal. Laparotomy was performed on anesthetized rats and a magnetic marker (3.5 mm in diameter and 3.0 mm height) was implanted in the distal stomach. After 10 days of recuperation, the mice were put to mate until confirmation of pregnancy. Fed animals were anesthetized (mg pentobarbital 30 / kg) and kept supine for recording the signal with a sensor 30 min BAC placed on the abdominal surface on days 0, 7, 14 and 20 of gestation. Statistical analysis was performed by Student's t test statistical Newman-Keuls and a P value of .05 was considered statistically significant. The frequency of contraction of the stomach was 74 mHz ± 3, 67 ± 7 mHz, 59 mHz ± 6 (p <0.05 vs day -1) and 71 ± 5 mHz on days -0, -7, -14, and -20, respectively. The values of 44 ± 15 pg / mL and 31 ± 9 pg / ml 25 ± 6 pg / ml, 22 ± 9 pg / ml on days -0, -7, -14 and -20, respectively, obtained by 17ß- estradiol were not statistically significant. The values of progesterone were 13 ± 6 pg / ml at 54 ± 15 pg / ml, 127 ± 42 pg / ml (p <0.05 vs day-1), 22 ± 13 pg / mL on day -0, - 7, -14 and -20, respectively. A linear correlation (Pearson's test) between the lower frequency gastric and increased levels of progesterone was 80% (p <0.0000001). Until then, the relationship between changes in motility and hormone were not described in detail, but with the work that we were able to demonstrate the high correlation between progesterone concentration ...
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Radiography is currently an important method of diagnosis, both medical, dental and veterinary. The image in this type of survey is obtained using an X-ray beam, where the radiologist can possibly view structures of interest. It isn't always possible to get the desired images due to various factors, such as equipment limitations. The Administrative Law 453/98, the State Resolution SS 625/94, and other standards require testing and quality control acceptance limits that guarantee a good performance of the equipment for the security and quality of care, giving service users greater effectiveness in exams. This study were performed in the accompaniment of testing procedures for quality control established by Administrative Law 453/98 in several X-ray equipment to make a comparison and optimization in the descriptions of the procedures used by the Institute for Electrical Energy and the University of São Paulo (IEE / USP / SP).The optimization of the procedures were performed with the aid of a current literature, the Resolution 453/98, State Resolution SS 625/94 and other international standards. On this basis it was possible to observe the importance of regular monitoring of tests for an update, following the technological development of instruments used in the service
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This project aims the verification of doses in canines and felines to chest and coxal exams due to the transition from screen-film to computed radiography system. It also seeks a possible optimization of the new techniques employed in this new system. The study was carried out in Diagnostic Imaging service in Hospital Veterinário da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo using a conventional x-ray equipment. Initially, data about the physical characteristics of animals and the technique currently used in computed radiography was collected for each of 80 chest and 16 coxal X-ray examinations. The animals were divided into different groups according to the body weight. For each group, were calculated the averages of each item: thickness of the region to be imaged, voltage, current, exposure time, current-time product, size of film used, presence or absence of bucky and focus (small or large). The techniques have been reproduced in phantoms (representative of the thickness of the animal) in order to collect the air kerma entrance. Based on the average of intermediate size M group (weights less than 5 kg for cats and from 10.1 kg and 20 kg for dogs) analysis of image quality using three devices test patterns were made consisting of the evaluation of spatial resolution, low-contrast resolution and contrast-detail. In general, the results showed the dose animals decreased with the use of computed radiography and was possible to preliminary optimization of some techniques used currently in CR
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Thin films of Ga1-xMnxN have great interest in its potential for control of electron spin (spintronics), in most cases this material is synthesized by techniques that have a high degree of control the deposition parameters, such as molecular beam epitaxy (MBE) and deposition of metalorganic chemical vapor deposition (MOCVD). The sputtering technique is an alternative route to produce such materials. Here we study the film deposition Ga1-xMnxN by reactive sputtering technique and apply enhancements such as a glove box, a residual gas analyzer and temperature control system, in order to growth films epitaxially using an analysis of the preconditions of films analyzed by spectroscopic techniques and microscopic. These procedures helped to improve the technique of deposition by cleaning substrates in an inert environment, and by the analysis of trace gases and heating the substrate holder as explained in the literature. Through the applications and comparisons it can be pointed out that the technique has the advantage of its simplicity and relatively low cost compared to MBE and MOCVD, but produces polycrystalline material
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This paper presents a study about the operation of the major system’s components of a linear particle acclerator (Linac). It addresses the components mainly responsible for the formation of the beam, through the inclusion of several block diagrams showing the details of the structure. Among the systems discussed may be mentioned the system modulator, automatic frequency control, dosimetry and auxiliary systems. The main objective is the dissemination of basic technology applied in linear accelerators and create literature about this subject in national language. Despite the high complexity and large number of devices that comprise a linear accelerator, it has been developed an easy to understand text that adresses the most relevant issues to the operation of the linear accelerator from the point of view of electrical engineering
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The main objective of this project step is the evolution of scenery matter on the occidental theater media, related to space and technical possibilities of the theatrical building and space on history of contemporary arts. The main point is that scenery must communicate with a specific matter. Something in touch with the plot speeches. Something that makes all the plot elements to communicate. Acting has an specific message to deliver, and that message is what really matter to the viewer of the show. “It’s never late to state that scenery is not a decoration, or just an interior composition. Scenery is not a painting or a sculpture: it’s an integrated art form. It’s never too repetitive to say that scenery is a result from the composition with lights, shadows, shapes, lines and volumes, in balance and on harmony as a whole, that create movement and contrast” (Dias, 2001) On the second step of the project, the objective is to analyze the building process and the scenery aspects of the “Be-a-bá Brasil” show, using illustrations, pictures and analysis data of the context the show was inserted on
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Radiotherapy is a branch of medical physics related to the treatment of malignant neoplasm, being an important instrument in the fight against cancer, when combined with the effort of a multidisciplinary team, composed of, physicians, physicists, nurses and technicians. Every year more than 3.5 million new cases of cancer are recorded in the world, being the prostate cancer responsible for approximately 25% of this amount (INCA and IARC, 2008). In this type of cancer, radiotherapy is a method indicated for treatement. The technological advance in this area over years has allowed a greater accuracy in the tumor location, more conformation of the radiation beam around the tumor, reducing the dose in healthy tissues and a consequent dose increase on treatment (Bedford et al., 1999). A radiotherapy planning, in which the physicist develops an important role, is composed of several steps, including choosing the best configuration of treatment beams. This choice has a close relationship with success of therapy and is critical to achieve the best distribution of dose inside the tumor and expose the least as possible the healthy tissue to radiation. In this work, two options for setting up camps in the first phase in a treatment of prostate cancer were simulated in computer planning: 4 fields orthogonal or “Box” with gantry angles in 00, 1800, 2700 e 90° and 4 fields angled or “X” (1350, 450, 3150 e 2250). The percentage of the rectal volume exposed to 40, 50, 60, 72 and 76 Gy should be limited to 60, 50, 25, 15 and 5% respectively (Greco et al., 2003). The femoral toxicity have limited dose by 70% of the total dose prescribed in a prostate treatment (Bedford et al., 1999). The planning of 27 patients with prostate adenocarcinoma submitted to 3D conformal radiotherapy were accompanied. As a result, it was assessed that the best TCP (tumor control probability)... (Complete abstract click electronic access below)
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O trabalho propõe rotinas computacionais usando o Método de Monte Carlo com o Código MCNP-5, para analisar os perfis de dose de radiação liberada nos tratamentos de tumores de pele e otimizar os cálculos radiométricos dos feixes de radiação estudados. Foram realizadas medidas dosimétricas do feixe de radiação, comparando os resultados obtidos com os respectivos valores fornecidos pelo serviço de física médica das instituições, com resultados informados pelo fabricante do equipamento e com as simulações computacionais efetuadas com o Código MCNP-5. A quantificação dos erros relativos percentual entre os resultados simulados e os fornecidos pelo Serviço de Radioterapia (E1), os informados pelo fabricante (E2) e os medidos experimentalmente (E3) são inferiores a 4,0% e validam a metodologia computacional proposta para avaliação do comportamento do feixe de raios-X superficial e do feixe de raios γ da unidade de Cobaltoterapia. A metodologia de análise do espectro energético e da curva de porcentagem de dose profunda (PDP) desenvolvida neste trabalho pode ser estendida para estudos de outros feixes clínicos e subsidiar os dados radiométricos utilizados nos planejamentos e cálculos de dose realizados pelo profissional da física médica na sua rotina nos Serviços de Radioterapia