Search Results - José Wilson Vieira

Radiotherapy uses various techniques and equipment for local treatment of cancer. The equipment most often used in radiotherapy to the patient irradiation is linear accelerator (Linac). Among the many algorithms developed for evaluation of dose distributions in radiotherapy planning, the algorithms...

Full description

Terapia por prótons é uma técnica de tratamento para neoplasias são de difícil acesso, minimizando os danos ao tecido vizinho do volume de destino e / ou nos órgãos de tamanhos muito pequenos, tais como crianças, os órgãos em que as células são bombardeados por iões pesados e uma definida colimada e...

Full description

Terapia por prótons é uma técnica para o tratamento de neoplasias através partículas pesadas que têm uma característica única no processo de transferência de energia em meios materiais; o feixe tem uma forma muito bem definida, com faixa bem definida para cada massa de repouso e energia cinética. No...

Full description

Modelos Computacionais de Exposição (MCEs) utilizam técnicas Monte Carlo (MC) para simular a interação da radiação com a matéria. Um MCE é constituído, basicamente por um fantoma (geometria a ser irradiada), algoritmos simuladores de fontes radioativas e um código MC para simular o transporte, inter...

Full description

This work describes the development and validation of a simulation platform, called Quimera, based on the Monte Carlo (MC) code Geant4 for dose evaluation in radiotherapy. Quimera consists of two MC applications (qMATphantoms and qNCTphantoms) for dose evaluation from a phase-space and a graphical u...

Full description

Among the many algorithms developed for evaluation of dose distributions in radiotherapy, the Monte Carlo methods provide more realistic results. In intensity modulated radiation therapy, significant differences in dose distributions within the fields defined by the multileaf collimator (MLC) could...

Full description

Due to the embryo/fetus radiosensitivity the accurate estimation of the absorbed dose distribution in the abdominal area is an additional problem caused by the exposure of pregnant women to ionizing radiation in medical applications. This paper reports the construction and insertion of a fetal repre...

Full description

Algumas das irradiações a que o homem é submetido podem ser modeladas por um fantoma de voxels acoplado a um código Monte Carlo (MC) que simule o transporte da radiação pelos órgãos e tecidos do fantoma, a interação desta com os átomos constituintes do meio e a avaliação da energia depositada em reg...

Full description

Modelos Computacionais de Exposicão (MCEs) utilizam fantomas acoplados a codigos Monte Carlo (MC) e simuladores de fontes emissoras de eletrons, positrons e fotons para estimar a dose absorvida por órgãos radiossensveis de indivduos expostos as radiações. Recentemente o Grupo de Dosimetria Numerica...

Full description

Introdução : O câncer de próstata é tido como um problema de saúde pública. No Brasil, de acordo com o Instituto Nacional do Câncer, ele é o segundo mais frequente em homens [1]. Um dos tratamentos que pode ser utilizado para esse câncer é a braquiterapia de próstata com baixa taxa de dose. Esta, co...

Full description

Discrepancies between ICRP phantoms and real patients lead to disparities on patient-dose estimations. This paper aims to compare distribution of dose in organs of male/female individualized-phantoms and ICRP reference phantoms. The absorbed dose estimation was performed using the EGSnrc Monte Carlo...

Full description

This work is demonstrated the step by step how to segment color images on the thoracic region of an adult in order to separate the tumor volume at present same conditions without significantly changing the values of R components (Red), G (Green) and B (Blue) color of the pixels . For information all...

Full description

The aim of this work is to show that a computer program, called digital image processing (DIP), can be used as an alternative method for breast diagnosis in hospitals and clinics that have not yet computerized mammography service. The image of mammogram obtained in reference is used to demonstrate t...

Full description

Due to its vast number of occurrences, cancer has caused an economic impact on the public and supplementary health care sectors. It is estimated that more than 50% of patients diagnosed with malignant neoplasms need radiotherapy at some stage of their treatment, most of them treated with photon and/...

Full description

The use of unsealed radiation sources in nuclear medicine can lead to important incorporation of radionuclides, especially for occupationally exposed individuals (OEIs) during production and handling of radiopharmaceuticals. In this study, computer simulation was proposed as an alternative methodolo...

Full description

The level of natural radiation in some regions of Brazil, and the world, have become high. One of the places that have these high levels are underground mines. At these locations, the radiation may come from the ground, the walls, and the environment in the form of gases. The Group of Numerical Dosi...

Full description

Modelos computacionais de exposição (MCEs) são usados em dosimetria numérica para estimar a dose absorvida (energia depositada/ massa) nos órgãos e tecidos radiossensíveis do corpo humano. Um MCE é composto, fundamentalmente, por um fantoma computacional, um algoritmo simulador de uma fonte radioati...

Full description

Nuclear medicine is a medical specialty used for diagnosis and therapy of some diseases. For the treatment of differentiated thyroid carcinoma (papillary and follicular) Radioiodine therapy is employed, in order to eliminate the rest of thyroid tissue after removal of the thyroid (thyroidectomy). In...

Full description

To evaluate the amount of energy deposited in radiosensitive organs and tissues of the human body, when an anthropomorphic phantom is irradiated, researchers in numerical dosimetry use the so-called exposure computational models (ECMs). One can imagine an ECM as a virtual scene composed of a phantom...

Full description

In computational dosimetry of ionizing radiation, the energy deposited in radiosensitive organs and tissues is evaluated when an anthropomorphic simulator (phantom) is irradiated using Exposure Computational Models (ECMs). An ECM is a virtual scene with a phantom positioned mathematically relative t...

Full description