Hasil untuk "Radioactivity and radioactive substances"

Feifei Li, Qiang Liu, Wei Liu et al.

Hefan Liu, Guiying You, Chengwei Lu et al.

K. V. Varfolomeeva, S. A. Zelentsova, V. S. Repin

The  article  presents  results  of  the  analysis  of  questionnaire  survey  data  on  preferences  in  the  choice  of  cooking methods of different types of forest mushrooms by residents of the most contaminated south-western  districts  of  the  Bryansk  region  in  the  remote  period  after  the  Chernobyl  accident.  In  the  period  from  2019  to 2022, the employees of Federal Budgetary Institution of Science «Saint-Petersburg Research Institute of  Radiation Hygiene after Professor P.V. Ramzaev» conducted a face-to-face questionnaire survey of the adult  population.  In  addition  to  general  questions  about  the  respondent,  the  questionnaires  included  questions  about the species composition of the mushroom basket, the volume and proportion of consumption of each type  of mushroom by the respondent and his family members (both in the current and last year), as well as methods  of culinary processing of the mushrooms consumed. Based on the analysis of individual survey data, a group  of 1 311 respondents, whose diet included various types of mushrooms, was selected. Analysis of the survey  results showes that respondents prefer to process a large proportion of freshly picked forest mushrooms (59%)  for  long-term  storage  (pickling,  freezing,  drying,  salting,  etc.);  41%  of  mushrooms  are  consumed  immediately. The most popular pretreatments of freshly picked mushrooms are washing and boiling (34 and 26%,  respectively). When freezing, pickling and pickling up to 97% of respondents carry out pre-treatment (rinsing,  soaking and / or boiling) of freshly picked mushrooms. Less popular methods of the mushroom preparation  (from 2 to 4%) are pickling, drying and frying of fresh mushrooms with their subsequent preservation. Thus,  the majority of respondents actively use various types of culinary processing with the use of preliminary stages  of technological processing in the form of rinsing, soaking and (or) boiling. The use of the above methods of  pre-cooking of freshly harvested mushrooms leads to a decrease in the  137Cs content in the consumed product.

Noé Gabriel Pinheiro Machado, Frederico Antonio Genezini, Marcus Paulo Raele

Radioactive thin films have a direct application in the development of beta-voltaic batteries. The main advantage of that kind of nuclear battery is its durability, which can range from a hundred years, depending on the half-life of the radioisotope used. In this context, Pulsed Laser Deposition (PLD) is an important tool. A relevant aspect of a system using this technique is that the main equipment is outside the chamber where the material is processed. Consequently, this feature allows the growth of radioactive thin films, as it enables the development of an arrangement where the contaminated area is controlled. In this way, the present work proposed the development of a PLD system for the growth of radioactive thin films. The PLD system was then implemented and radioactive copper targets were processed for 60 min and 120 min, resulting in radioactive thin films with an average thickness of (167.8 ± 3.7) nm and (313.5 ± 9.2) nm, respectively. Then, a study was performed about the radioactive contamination spread in the PLD system in order to prove if the filtering implemented was effective in retaining the contamination inside the vacuum chamber. Thus, it is demonstrated for the first time the feasibility of using the PLD technique in the growth of radioactive thin films, making its use possible in future studies on the development of beta-voltaic nuclear batteries.

A. C. C. S. Ribeiro, W. O. Sousa, F. C. A. Silva

In the oil field, Naturally Occurring Radioactive Material - NORM is present in petroleum-forming rocks and this is related to the presence of radioactive decay series of 238U and 232Th, mainly the daughter radionuclides 226Ra and 228Ra. These radionuclides are detected during the process of production and extraction of oil and gas. They migrate from the reservoir rock and flow through the production lines until the operating areas, forming sludge and scale. The presence of 226Ra and 228Ra can be found in many pieces of equipment on the platforms, and NORM concentrations may increase due to different extraction processes. When this accumulation of NORM occurs inside the equipment, it is necessary to decontaminate them. Depending on the decontamination technique, workers can be exposed to radioactive materials contained in sludge and scale, which are released in the form of aerosols. The existing radiological risk during decontamination is based on external irradiation and internal contamination of workers, this is why an individual monitoring program covering both external and internal dosimetry is necessary. External monitoring is widely used during the routine work of decontamination of equipment, but for internal monitoring, the real importance has not been given, despite the probability of being the greatest contribution to radiological risk for workers. This article presents the need for internal individual monitoring for a comprehensive assessment of radiological risk and a general description of how it is being done in several countries to assist in the implementation of a complete individual monitoring program, mainly in Brazil.

Alexander I. Wiechert, Austin P. Ladshaw, Yong-ha Kim et al.

Indranil Hazra, Mahesh D. Pandey, Mokhles Rahman

Z. A. Lantukh, M. P. Shatenok, Yu. V. Druzhinina et al.

There is a well-established opinion that the radiation safety of the patient and staff lies within the scope of the activities and responsibilities of the radiation diagnostics departments. However, repeated referrals and unjustified X-ray examinations from clinicians can make a significant contribution to the radiation load of the patient and the workload of the staff. The radiation safety requirements formulated in the article are designed for an effective monitoring tool for unjustified studies – the Clinical Decision Support System. The modern park of domestic software in this area was also analyzed. It was found, that the existing domestic Clinical Decision Support Systems do not fully meet the formulated current radiation safety requirements. The majority of clinical decision support system do not offer a choice of the most sparing methods of X-ray examinations (only 31% offer), and do not contain information about the accumulated patient dose for making a decision on the appointment of studies (only 23% contain). The developed methodology for assessing the Clinical Decision Support Systems will allow choosing and implementing the most optimal system in terms of radiation safety into clinical practice.

A. M. Biblin, E. V. Khramtsov, V. S. Repin et al.

The aim of this study was to evaluate radiation situation at the “Pirit” peaceful underground nuclear explosion site. The peaceful underground nuclear explosion “Pirit” with the capacity of 37.6 kt оf TNT equivalent was carried out on May 25, 1981 on the territory of the Kumzhinskoye gas condensate field at a depth of 1.5 km. The field is located near the northern coast of the European part of Russia in the delta of the Pechora River (Nenets Autonomous District). The peaceful underground nuclear explosion “Pirit” was carried out with the aim to stop the uncontrolled gas gushing. Radiation situation is assessed according to the main indicators: dose rate values and content of technogenic radionuclides in soil and water. The radiation survey included determining geographic coordinates of specific landscape elements, measurement and sampling points using satellite navigators, measurement of ambient dose equivalent rate, identification of gamma-emitting radionuclides in situ by field gamma spectrometry, sampling of water, photo and video shooting. On the site of the underground nuclear explosion “Pirit” the values of the ambient dose equivalent rate were in the range of 0.050–0.089 μSv/h, which corresponds to the levels of the natural radiation background. No sites of local radioactive contamination of soil by 137Cs were detected. The tritium content (less than 5 Bq/kg) in water bodies does not exceed the levels of fluctuations of this indicator in other regions of the European territory of Russia. The estimated value of the effective dose due to ingestion of tritium in drinking water in local settlements was 0.044 μSv/year. The radiation situation on the territory of the peaceful nuclear explosion “Pirit” meets the requirements of the Russian Sanitary Regulations and Standards 2.6.1.2819-10 “Ensuring the radiation safety of the population living in the regions of nuclear explosions for peaceful purposes (1965–1988)” and currently does not pose a threat to public health. Due to the potential danger of technogenic radionuclides coming from the epicenter of the explosion to the surface for long-term radiation safety, it is necessary to organize radiation monitoring of the territory adjacent to the explosion site, determine the boundaries of the protected zone and set appropriate information signs warning of radiation danger.

Sheng Liu, Yiyang Zeng, Ai Zhang et al.

Alexandre Pinho dos Santos Souza, Luiz Paulo de Oliveira, Frederico Antonio Genezini et al.

The Brazilian Multipurpose Reactor (RMB) is a fundamental project that aims to turn Brazil into a self-sufficient country in the production of radioisotopes and radiopharmaceuticals to supply the Unified Health System (SUS) as much as the private institutions. In addition, the RMB project describes other applications as irradiation and testing of nuclear fuels and structural material analysis, for instance. There are many techniques in the project to study structural aspects of materials, where neutron diffraction represents one of the priorities for implementation. This technique will take place mainly on two diffractometers on Thermal Neutron Guide 1 (TG1), namely Araponga, a high-resolution diffractometer, and Flautim, a high-intensity diffractometer. In this work, we study the performance of the Araponga diffractometer through McStas simulations with input produced by the MCNP code of the RMB core. We investigate the neutron flux values considering a state-of-art high-resolution diffractometer, and the results are promising since some simulated scenarios present values compatible with high-intensity devices.

Thalita Tieko Silva, Sueli Ivone Borrely

Cyanobacteria are an ancient and diverse group of microorganisms, considered as important contributors to the formation of Earth's atmosphere and nitrogen fixation. However, the input of nutrients in water by anthropogenic activities frequently provides cyanobacteria blooms associated with toxic compounds. Secondary metabolites, also called cyanotoxins, are often harmful to wild and domestic life, including humans. The first part of this review focuses on cyanobacteria and their ability to produce a variety of toxins as well as describe the Brazilian guidelines on the evaluation and management of these toxins in water quality. Then, we present a review of recent literature on the use of ionizing radiation in terms of cyanobacteria cell removal, degree of degradation of cyanotoxins in water, and reaction kinetics. In view of the exposed results, the paper concludes that ionizing radiation is an efficient and economically viable alternative for the remediation of areas contaminated by cyanobacterial blooms and cyanotoxins, especially in reservoirs intended for water treatment and supply. In addition, some suggestions are provided for further studies on the use of this technology in the treatment of drinking water.

N. K. Ryzhakova, K. O. Stavitskaya, A. A. Udalov

Radon and its daughter products create more than half dose from all natural radiation sources. The radon entering the buildings is emitted mainly from soils lying at the base of the foundation. Therefore, before carrying out construction work, the radon hazard of the construction area are determined. In the Russian Federation, the radon hazard of an area can be determined using radon flux density measured on the soil surface. To date, radon researchers came to the conclusion that the geology of the territory affects the amount of radon released from the soil surface. However, there are almost no studies devoted to the release of radon from the surface of various soil types. The paper presents the measuring results of the radon flux density on the surface of loess loams, porcelain clay, argillaceous slate, sand-and-gravel sediment, rocky limestone, clayey limestone, andesite-basalt porphyrite and quartzrock. The measurements were carried out by the accumulation chamber method using the Alfarad Plus measuring complex. Also, measuring radium activity concentration and soil moisture were carried out. The research demonstrates that, depending on the type of soil, the amount of radon emanating from its surface differs by more than an order of magnitude. The largest values of radon flux density of ~ 800 mBq∙m-2s-1 were recorded for andesite-basalt porphyrite and quartzrock. The smallest ones of ~ 40 mBq∙m-2s-1 were registered for loess loams and argillaceous slates. For soils consisting of small sand and clay grains, a rather strong dependence of the radon flux density on soil moisture was found. When measuring soils with low moisture (2-6%), a proportional dependence of the radium activity concentration on the amount of radon emanating from the soil surface is not observed. The types of soils that lie at the foundations of the buildings, and their physical properties can be used as the basis for classifying building sites according to the degree of radon hazard. Relevant information may be provided by organizations engaged in design and survey work at building plots. The approach proposed in the work for assessing radon hazard will allow avoiding labor-intensive measurements of radon and thereby reduce the financial, material and labor costs of building construction.

Alexandre França Velo, Alexandre Gimenes Alvarez, Margarida Mizue Hamada et al.

The greatest impact of the computed tomography (CT) applications currently occurs in medicine. In industry there is much interest of using CT in order to know the interior of: (i) industrial objects; (ii) machines and their means of production. The purpose of this tomography is to: (a) control the quality of the final product and (b) optimize production and analyze the quality of the means of production. An instant non-scanning tomography system is being developed at the IPEN. This tomography comprised different collimators was simulated with Monte Carlo using the MCNP4C. The image quality was evaluated with Matlab® 2013b analyzing the contrast to noise (CNR), root mean square ratio (RMSE), signal to noise ratio (SNR) and the spatial resolution by the Modulation Transfer Function (MTF(f)), to identify which collimator fits better to the tomography in development. It was simulated three situations; (i) with no collimator; (ii) ø 25x 50 mm2 cylindrical collimator with a septum of ø5.0 x 50 mm2; (iii) ø25 x 50 mm2 cylindrical collimator with a slit septum of 24 x 5.0 x 50 mm3. RMSE values for no collimator presented better results. CNR showed that no collimator and slit collimator reaches the same CNR values, but no collimator decreases more than the slit collimator as the number of iteration rises. The hole collimator reaches a higher CNR value, however decreases more than the others. The spatial resolution with no collimator and slit collimator were around 31.9 mm, and for the hole collimator was around 20 mm

I. G. Shatskiy

The purpose of the study is to evaluate the effective doses of patients for the most common radiographic dental studies, comparing the obtained data with the literature and reference values given in the guidelines “Filling in the forms of the federal state statistical observation No. 3-DOZ” and are still often used for form filling instead of measured values. In the framework of this work in 2016-2018, 44 X-ray units were examined at 37 dental medical facilities in St. Petersburg and the Leningrad Region. Seven radiographic studies were included: radiographs of three groups of teeth (incisors, premolars, and molars) for the upper and lower jaw and bite radiography. Physical-technical and geometrical parameters were collected for selected types of the standard patient studies: X-ray tube voltages, total filtration, radiation output, combination of the time and the current of exposure or the exposure, area of the study, size of the irradiation field; the focal length. Further, the input (surface) dose was calculated from the radiation output of the device. Then, based on the initial information about the parameters of the procedures and the input dose, the absorbed doses and the effective dose were calculated using the PCXMC program. For most devices, the dose values are in the range of 0.5 to 10.7 µSv, which is significantly lower than the values used to fill in the 3-DOS form. The results of evaluating the effective dose for these devices are fairly homogeneous, but on one device, there were doses exceeding not only the values of doses on other devices, but also the values from the recommendations for 3-DOS for devices with digital receivers, as well as those approaching similar values for film devices. An almost linear dependence of the effective dose on the exposure time was established, while a similar dependence on the voltage on the X-ray tube was not found. The median value of the effective dose for the units with films detectors was 3.2 µSv for the maxillary incisors, 3.8 µSv for the maxillary premolars, 6.8 µSv for the maxillary molars, and for the mandibular incisors, premolars and molars – 3.2, 3.4 and 5.8 µSv, and for bitewing – 6.7 µSv. For the unit with digital detectors, effective doses were 1 µSv, 1,2 µSv, 2,2 µSv for maxilla, 1 µSv, 1,3 µSv, 2 µSv for mandibula and 2,8 µSv for bitewing. Attention is drawn to the substantial width of the ranges without emissions for the examination of premolars of the upper jaw, molars of both jaws and occlusion, which is the reason for the possible enhancement of optimization measures in these studies. When comparing with published data, it was found that the effective doses in St. Petersburg and the regional institutions are lower than the values obtained using standard round collimator and medium and high sensitivity films (class D and F, respectively), as well as lower dose levels in the European Commission Guidelines. In addition, the dose values deduced in this study are significantly lower than the values given in the guidelines “Filling in the forms of federal state statistical observation No. 3-DOZ” and which are still often used to fill in the form instead of the measured values. This indicates an overestimation of estimates of patient doses when using reference values from the 3-DOZ manual and the need to use individual patient doses, obtained on the basis of measurements. However, the effective doses in St. Petersburg and the Leningrad Region are higher than those obtained using a square collimator and high-sensitivity films. The above results suggest that it is necessary and possible to carry out optimization in X-ray dental studies in St. Petersburg and the Leningrad Region. Analysis of similar studies on other X-ray diagnostic techniques allows to extrapolate this statement to other regions of Russia.

LEONARDO CASTRO PACIFICO, José Guilherme Peixoto, Luis Alexandre Gonçalves

The objective of the present work was to study the feasibility of the use of an ionization chamber dedicated to mammography in the characterization of radioprotection qualities referring to the series of narrow spectrum beams provided by ISO 4037-1. The results were satisfactory, and we conclude that it is feasible to use the ionization chamber dedicated to mammography to characterize the radiation protection qualities ISO-N15 to ISO-N120.

Evelyn Pereira Martins Neri, Francisco Cesar Augusto Da Silva

O Brasil possui, aproximadamente, 2000 instalações radiativas que usam fontes de radiação nos seus processos e são controladas pela CNEN através de normas, autorizações e inspeções. Esses materiais radioativos, usados tanto na área médica, indústria, pesquisa, comércio, entre outras, são algumas vezes descartados e encontrados em locais inadequados, tais como, lixões, lixo industrial, ruas, praças, podendo, assim, serem encontrados por profissionais de limpeza urbana sem o devido conhecimento dos mesmos. Este trabalho apresenta as ações de proteção radiológica necessárias para a identificação e recolhimento de material radioativo visando prevenir a exposição desnecessária dos profissionais de limpeza. As ações estão baseadas nos princípios, guias e normas de proteção radiológica. De acordo com o tipo de material radioativo as principais ações de proteção radiológica são, entre outras: reconhecimento de um material radioativo; uso correto de equipamento de proteção individual para conter possível contaminação radiológica; uso de um monitor de radiação; implementação de um controle de área; etc. Para que as ações de proteção radiológica, na identificação e recolhimento de material radioativo descartado sejam eficazes, há necessidade de implementar um programa de treinamento em proteção radiológica para os profissionais de limpeza urbana de maneira que não se exponham desnecessariamente, até a chegada de um perito em proteção radiológica da CNEN que providencie o recolhimento seguro deste material.

Yu. I. Stepkin, M. K. Kuzmichev, O. V. Klepikov et al.

The purpose of the study was to estimate the doses to the Voronezh region population from natural sources of ionizing radiation and the technologically altered background in the territory of Voronezh Region. The data of forms of state statistical observation No. 4-DOZ “Information on the doses of population exposure due to natural and technologically altered background” for 20102017 and the radiation and hygienic passport of the territory of the Voronezh Region were used. The average annual per caput effective dose due to all types of ionizing radiation remains stable with a slight upward trend and lies in the range from 2.925 (2010) to 3.656 mSv (2017). Natural sources are the main dose-forming factors for the population. Their annual contribution to the annual effective dose ranges from 74.96 to 83.65%. The leading contribution to the total dose from natural sources is the exposure due to the inhalation of radon isotopes: it ranges from 37.6 to 51.1%. In second place,there is the share of external exposure from sources of terrigenous origin, which ranges from 21.2 to 28.9% of the total dose. The average annual effective dose of natural exposure to humans varies from 2,355 to 2,980 mSv / year, the exposure from radon – from 0,83 to 1,65 mSv / year. The dose from technogenic-altered radiation background, including global radioactive fallout due to atmospheric nuclear tests and due to past radiation accidents are insignificant (0,062 mSv / year). Its annual contribution to the total dose is less than 2%. Based on the results of the assessment of the indicators characterizing the level of exposure of sources of ionizing radiation to natural and technogenic-altered radiation background, no excess of radiation safety standards has been recorded. The situation associated with exposure to ionizing radiation sources in the Voronezh region has been described as safe for the last 8 years.

Juliana Silva de Oliveira, Karine Ramos Rocha Silva, Alexandre dos Santos Gomes

As radiações ionizantes são empregadas em áreas como saúde, indústria e segurança, não apenas no setor privado, mas também no público. Assim urge a necessidade da proteção radiológica, conjunto de estudos e práticas que aumenta a segurança nessas aplicações, onde um profissional fortemente envolvido é o tecnólogo em radiologia. O objetivo desse trabalho foi analisar os conteúdos efetivamente exigidos pelos órgãos públicos brasileiros em seus concursos para tecnólogo em radiologia, no que tange a área de proteção radiológica, identificando seu perfil de exigência. Consistiu em três etapas: na primeira, realizou-se um levantamento de todos os concursos públicos já realizados no país até o término de 2016, rastreáveis pela internet, que solicitassem diploma de graduação em Tecnologia em Radiologia; na segunda, todas as questões específicas destes certames foram coletadas e agrupadas em um arquivo eletrônico de texto; na terceira, foram segregadas as questões que envolviam proteção radiológica, usando como referência a edição 2017 do manual da prova geral de supervisão de radioproteção da Comissão Nacional de Energia Nuclear. Os resultados mostraram que quase 40% das questões dos concursos foram sobre proteção radiológica. Dessa amostragem, as unidades mais abordadas foram segurança radiológica (36%), fundamentos de física atômica e nuclear (24%) e efeitos biológicos das radiações (16%). Conclui-se que os concursos para tecnólogo em radiologia têm o perfil de concentração de exigência em segurança radiológica, fundamentos de física atômica e nuclear e efeitos biológicos das radiações.

Sarah Soriano, Thiago Barboza, Sérgio Augusto Lopes Souza et al.

The objective of this study was to evaluate spatial resolution and the influence of different reconstruction methods in a FLEX Triumph ™ Pre-Clinical Imaging System images applied to mice C57BL6 dosimetry in a new radiopharmaceuticals development for humans use. CT and SPECT images were obtained from a homemade phantom containing four spheres with diameters (d) simulating iodine-accumulating injuries at University Hospital (HU / UFRJ). The SPECT images were reconstructed with filtered back projection method (FBP) and the influence in resolution and partial volume effect was evaluated for different filters: Hamming, Hann and Ramp. The resolution found was 9.3 to 9.4 mm, significantly lower than the value provided by the manufacturer, 1.6 mm. Thus, the protocol for mice can be optimized by FBP reconstruction method and Hamming filter, 0.5 cut-off, yielding a resolution from 9.3 to 9.4 mm. This value indicates that iodine-accumulating regions diameter below 9.3 mm is not quantifiable.