Estudo teórico das funções de anisotropia e radial de dose para braquiterapia com semente de Ir192 em diferentes materiais de interesse em radiologia

The brachytherapy braquiterapia is an x-ray modality radiotherapy in which stamped or halfstamped radioactive sources in format of seeds are used, wires or to one short distance, in contact or implanted to the fabric to be treated. All the treatment modalities require a previous planning.The formalism recommended for calculation of dose was considered by the AAPM for the first TG-43 Report. In it distributions of dose of isolated seeds measured and calculated by Monte Carlo method in water instead of with models half-empiricists.In this work we in accordance with present some preliminary results of the calculation of functions of radial anisotropy and of dose in the distance for seed of 192Ir, wide used in brachytherapy treatments of high tax of dose (HDR), with the aid of the program based on the Monte Carlo method MCNPX v2.50 (Mount Carlo N ParticleeXtended).The materials chosen in the simulation beyond water, had been MS20 and estriado muscle

Aplicação dos princípios de radioproteção em medicina nuclear

The Nuclear Medicine is a medical specialty which uses different radioisotopes for diagnostic and therapeutic purposes. The isotopes are radioactive elements which are administered in vivo and present distribution to specific organs or cell types. The knowledge of radioactivity and notions related to ionizing radiation allow to contextualize the radiological protection measures to be taken in Nuclear Medicine. So it is possible to minimize unnecessary exposure to patients, the public, and individuals occupationally exposed and the environmental. For this it is necessary to relate the physical and technological bases apply to this mode with the standards established by regulatory agencies, including the CNEN (National Nuclear Energy Commission) and ANVISA (National Agency for Sanitary Vigilance). In this scenario, it is important that the theoretical endorse the activities which are periodically audited for verification of compliance with the standards that aim to radioprotection. One role of the Medical Physicist in these services is, therefore, act as Radiation Protection Supervisor exerting numerous activities and ensuring compliance with these standards. In this context the stage in the area of Nuclear Medicine was developed in many customers of the enterprise Rad Dimenstein & Associados LTDA, among them the hospitals Israelita Albert Einstein (HIAE), Nossa Senhora de Lourdes (HNSL), Santa Paula (HSP), Cruz Azul (CRAZ), Grupo Fleury, among other clinics. Following the routine and then carrying out various activities pertaining to the Medical Physicist in the area, it was noted that the measures and actions are extremely effective and fundamental in terms of radiological protection

SPECT (Single photon emission tomography): Gama câmara, reconstrução tomográfica e características funcional

The SPECT (Single Photon Emission Computed Tomography) systems are part of a medical image acquisition technology which has been outstanding, because the resultant images are functional images complementary to those that give anatomic information, such as X-Ray CT, presenting a high diagnostic value. These equipments acquire, in a non-invasive way, images from the interior of the human body through tomographic mapping of radioactive material administered to the patient. The SPECT systems are based on the Gamma Camera detection system, and one of them being set on a rotational gantry is enough to obtain the necessary data for a tomographic image. The images obtained from the SPECT system consist in a group of flat images that describe the radioactive distribution on the patient. The trans-axial cuts are obtained from the tomographic reconstruction techniques. There are analytic and iterative methods to obtain the tomographic reconstruction. The analytic methods are based on the Fourier Cut Theorem (FCT), while the iterative methods search for numeric solutions to solve the equations from the projections. Within the analytic methods, the filtered backprojection (FBP) method maybe is the simplest of all the tomographic reconstruction techniques. This paper's goal is to present the operation of the SPECT system, the Gamma Camera detection system, some tomographic reconstruction techniques and the requisites for the implementation of this system in a Nuclear Medicine service

Dosimetria ambiental do gás 222Rn: um exemplo de estudo das águas da região de Presidente Prudente – SP e considerações sobre abordagem do tema através do Banco Internacional de Objetos Educacionais – BIOE

Over the years, the concern with the detection of the levels of radionuclides in the environment has increased, given that they are carcinogenic to the human respiratory system. Present in the air, waters, soil and building materials, among other substances, radionuclides are unknown by most of the population. In this paper, we present the radioactive gas 222Rn, predominant element among all others and one way of detecting it in an example study of the waters of the Presidente Prudente - SP, through the plastic detector called CR-39. Likewise, we realized the need to approach this issue more broadly in schools and even in higher education, since this field of modern physics and environmental physics usually appears only in master's and doctorate. Thus, we attempted to perform the didactic transposition schooluniversity, through the construction of an object Educational, OE, to be placed on the Bank for International Educational Objects - bioethanol and by developing this contribute to the knowledge and understanding of the importance of monitoring of radioactivity in a way accessible to the population as a whole

Contaminação radioativa: aspectos fundamentais associados à poluição nuclear

Since its discovery, radioactivity has brought numerous benefits to human societies. It has many applications in medicine, serving as a tool for non-invasive methods for diagnosis and therapies against diseases such as cancer. It also applies to technologies for energy in nuclear power plants with relatively low impacts on terms of perfect security. All applications, however, have risks, requiring maximum caution to drive processes and operations involving radioactive elements because, once released into the environment, they have extremely harmful effects on organisms affected. This paper presents fundamental concepts and principles of nuclear physics in order to understand the effects of radioactive elements released into the environment, culminating on the issue of radioactive contamination. Literature review allowed us to understand the radioactive contamination problem on living beings. Three major nuclear accidents have happened in the last thirty years, two of them in consecutive years. The nuclear accident at Chernobyl, Ukraine, in 1986, polluted large areas, condemning hundreds of thousands of people to live with consequences of the accident and effects of radiation, killing thousands of people throughout the years. In 1987, a major radiological accident occurred in Goiania (GO) when a source of radioactive cesium was violated, leading to the death of those who had direct or indirect contact with cesium. The most recent accident, in March, 2011, was located at the nuclear power plant in Fukushima Prefecture, Japan, after an earthquake and tsunami hit the region. There is no extensive and accurate knowledge about the consequences of the contamination entailed in that accident, although it is possible to verify signals on a global scale. An analysis of reports of contamination of large areas generated by nuclear plants with release of hazardous wastes suggests it is necessary to rethink the energy matrix of the various countries...

Braquiterapia com sementes de iodo-125: manufatura e tratamento

According to the National Institute of Cancer – INCA, 466.730 new cancer cases will occur in Brazil in 2009. Prostate and Lung cancer in man are the most incident types (in exception of the non-melanoma cancer). The brachytherapy with 125-iodine sources is an important method of prostate cancer treatment. The implant with iodine-125 seeds uses aproximately 100 seeds that are imported impossibilitating the treatment in large scale. For this reason, a multidisciplinary group was created at the Energetic and Nuclear Research Institute – Radiation Technology Center (IPEN –CTR / SP) to develop a national 125-iodine source and established a facility for local production. The seeds manufacture in Brazil will diminish the cost of treatment and prostate brachytherapy will be offered to more patients. This work aim is to observe and discuss the methods used in seeds manufacture there are being developed in Brazil and to present an prostate cancer case folloied in A.C. Camargo Hospital. The 125-iodine is adsorbed in an silver wire, then deposited at titanium coat. The weld is made by an process of plasm sealing. The seeds goes through several test to guarantee that there is no leakage. The result is an high quality and cheaper product. The implant tecnique is an fast and save procedure. The medical physicst preplan the case to stipulate the quantity of seeds there will be used. At the dat of the implant the medical physicst replan the procedure due to changes of volume in the organ. That assure the correct dose distribution in the target. Besides, the 125-iodine low energy is absorbed at the volume of interrest saving sourronding healthy tissues such as the rectum and the urethra

Análise dosimétrica de aplicadores de Betaterapia

Betatherapy is a special medical technique using a radioactive source of strontium-90 for the treatment of superficial lesions, especially in dermatology and ophthalmology. Strontium-90 sources emit β radiation, which possesses high ionization power, but a very short distance propagation into matter. This work presents a method of dosimetric analysis of betatherapy using strontium- 90-based instrumentation, commonly used against superficial diseases, such as keloid and pterygium, aiming the description of the dosimetry analysis procedures, which can be easily implemented on tradiotherapy services that offers the betatherapy treatment. IBF-MEDIX radiographic films (conventional films) were exposed to betatherapy applicators during different time intervals according to the activity of the source, and afterwards the optical densities (O. D.) of the radiographic images were measured using an optical densitometer MACBETH. Therefore, the parameters used to make the dosimetric analysis in betatherapy were standardized, as the exposure time depended on the geometry and size of the source, providing an efficient and fast method of dosimetric analysis of the betatherapy equipment of the services, the majority of which do not have the scientific structure to perform this study

Métodos de Calibração e Dosimetria de Aplicadores de Betaterapia

The sources of betatherapy for clinical use in Brazil are, the vast majority of strontium-90, radioactive element that is not produced in the country, and therefore requires importation of international laboratories accredited by the International Atomic Energy Agency (IAEA).The use of these resources is always limited the crediting of characteristic values supplied by the manufacturer tables that provide the nominal value of activity and dose distribution to determine the irradiation time of the injury. The Institute of Nuclear Energy Research (IPEN / CNEN-SP) has recently researching the emission profile of these types of radiation sources, and some jobs are being developed with ionization chambers extrapolation for the purpose of standardizing a systematic calibration sources betatherapy. Other studies using parallel measures dosimeters (TLD's) and simulations with the Monte Carlo method. Radiological films have also been used in studies of applicators dosimetric analysis of strontium-90. This paper seeks to analyze the different methods for calibration of applicators betatherapy, already consolidated in studies by examining the advantages and disadvantages of each procedure

Gama Câmara CZT: alteração de paradigmas em aquisição de imagens de medicina nuclear

Nuclear medicine is a medical specialty related to imagery that deals with imaging techniques, diagnosis and therapy, allowing observing the physiological state of tissues noninvasively by marking the molecules participating of these physiological processes with radioactive isotopes, thus creating the called radionuclides. The image of a radionuclide is one of the most important applications of radioactivity in nuclear medicine. The equipment’s of nuclear medicine imaging use the principle of radiation detection, turning it into an electrical signal which, through specific algorithms, allows forming tomographic images that provide information about the functional status of organs. New detection systems have been developed for tomographic acquisitions using solid state detectors. These devices use crystals of cadmium zinc telluride (CdZnTe). Some of the advantages of this detector are a significant improvement of signal to noise ratio, the increased spectral and spatial resolution, which in sum, result in greater clarity of the images obtained, opening new perspectives for imaging protocols previously unattainable. In contrast, all other gamma-cameras equipped with vacuum tubes have remained relatively unchanged for nearly fifty years. In these gamma-cameras, the images are obtained using two steps significantly less efficient: the gamma rays are converted to light through a first device, and then the light is converted into an electrical signal through a second device. One of functions the Medical Physicist is related to the quality control of equipment. This control ensures that the information and images provided are true and thus credible to be used in medical reports. To perform this type of analysis the physicist must understand the performance characteristics and operation of all equipment of the department concerned; besides, in the absence of specific legislation, proposing...(Complete abstract click electronic access below)

Processamento do alho negro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Inorganic elemental analysis and identification of residual monomers released from different glass ionomer cements in cell culture medium

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeitos da congelação lenta e da vitrificação na viabilidade, ultraestrutura e expressão gênica de embriões caninos produzidos in vivo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mapeamento do nível radiométrico e construção de mapa espacial em serviço de medicina nuclear

Nuclear Medicine is a medical modality of therapy and diagnostic imaging using unsealed radioactive sources for its purposes. This routine activity promotes the transit of radioactive sources for the area of installation, beyond the transit of patients injected with radioisotope, which also contribute to raising the radiometric level of environment. As a consequence, it has exposured workers and public individuals to the ionizing radiation. There are protective mechanisms of radiation exposure, personal protective equipments, and measurement planes established in standard measurement at certain points of the environment in order to identify any increase in radiometric levels and \ or contamination, but do not cover the entire space occupied by workers and patients. To accomplish with the individual dose limits established by the National Commission of Nuclear Energy, it is interesting if there is an individualized classification for each Nuclear Medicine service. This work aimed to promote an analysis of the radiometric level distribution across the extent of the Technical Nuclear Medicine Sector of Hospital of the Botucatu Medical School, and produce a spatial map to identify locations with higher exposure rate to the ionizing radiation, can be used as a risk map to assist the Occupationally Exposed Individuals (IOE). To perform the radiometric levels checking it was used a digital Geiger-Muller detector available in the sector, due to its practicality compared to other detectors. Measurements were carried out at four different times for all days of the week, at points strategically established to cover all the installation

Síntese de tetra-hidropiridinas por meio de reações multicomponentes

Multicomponent Reactions are defined as reactions between three or more reagents in a single reaction step in the same reaction vial, forming a product that includes the majority of atoms and structural characteristics of the reagents. Thus these reactions save time and energy. One of the ways to improve the yield and reaction time of a multicomponent reaction is to use different catalysts, an example of catalyst that shows great potential and has been studied in recent years is the molecular iodine is known to be a Lewis acid with high catalytic power. The functionalized piperidines, also known as tetrahydropyridines, are alkaloids that have pharmacological potential, this is due to the piperidine ring present in many natural product structures with muscarinic activity, nicotine, analgesic, antipsychotic, anti-proliferative, among others. In this paper we describe studies about on the application of molecular iodine (I2) in the multicomponent reaction between aniline derivatives, benzaldehyde and β-ketoester (methyl acetoacetate) for the synthesis of functionalized piperidines and the synthesis of a corresponding piperidone by acid hydrolysis. Data analysis allowed us to demonstrate the efficacy of molecular iodine in the synthesis of functionalized piperidines, obtaining results with yields 44-87% and short reaction time of 8 to 24 hours, and the efficacy of acid hydrolysis of enamine in the structure of the tetrahydropyridine derivative in a yield of 81%

Adição de desinfetantes na água de bebida durante o jejum pré-abate de frangos de corte: microbiologia e morfologia do trato gastrintestinal

Pós-graduação em Medicina Veterinária - FCAV