Hasil untuk "Radioactivity and radioactive substances"

João Guilherme Rivera Santiago, Laura Furnari, Marcus Vinicius Saad de Paula Rodrigues et al.

The increasing complexity of techniques used in radiotherapy demands a quality assurance program that evolves to ensure efficient quality control of equipment and associated devices. Many periodic tests rely on analyzing acquired images, typically compared to predefined standards to verify consistancy—checks that can often be automated. Automated analyses enable greater standardization, reduced subjectivity, improved accuracy, and shorter quality control times. To implement such tools, it is essential to assess factors such as accuracy, error detection sensitivity, adaptability to institution needs, and ease of access and use for those involved in quality control processes. This study evaluated two automation tool interfaces: the commercial SunCHECK Machine by Sun Nuclear® and a web application implementing modules from the open-source Pylinac library. Both interfaces were suitable to the quality assurance program, using coherent methodologies to calculate key metrics outlined in reference documents. Each tool has unique features and specific considerations, highlighted throughout the study based on evaluating Picket Fence, Star Shot, Winston-Lutz tests, field analysis, and Cone Beam Computed Tomography image quality. The findings highlight the importance of conducting studies during the implementation phase of such tools to understand the algorithms used and establish appropriate usage and control measures for routine practice. Both interfaces proved capable of quantifying the relevant quantities based on the reference documents, providing more efficient and effective quality control.    

A. V. Vodovatov, L. A. Chipiga, S. A. Ryzhov et al.

Identification, prevention and response to events in medical exposure are an integral part of the radiation safety system in medicine. The existing approaches in the Russian Federation, presented in the current regulatory and methodological documents, need to be updated and harmonised with international practice. At the same time, it is advisable to focus on events related with patients, because of potential overexposure of workers and public is presented comprehensively. The study presents suggestions for amendments to terminology in medical exposure events of patients and development of classification of the events criteria as well. Schemes to identify and respond to events in medical exposure that related to overexposure of patients are defined. It is advisable to implement the results of the study into the section on radiation safety in medical exposure in the updated version of OSPORB-99/2010.

Katia Elisa Prus Pinho, Rita Zanlorensi Visneck Costa, Roberta Aumann et al.

This article discusses the problems faced in daily hospital and clinical practice in Brazil, where there are no examination protocols or bibliographies that professionals can use as a basis for performing radiological examinations on patients with movement limitations and clinical conditions, such as paraplegia and tetraplegia. The objective of this study was to develop a booklet of adaptations of radiological positions for patients with reduced mobility. This material can improve and optimize the services provided in the area, offering greater radiological safety to both the professional and the patient during the examinations. The methodology used involved national bibliographic reviews, technical visits and hospital monitoring, as well as discussions with professionals specialized in the area of ​​radiology, in order to consolidate a more concrete and specific basis for the studied content. Based on these data, it was possible to formalize a simplified booklet, in Portuguese and English versions, accessed through specific QR Codes. The booklet includes some adaptations of radiological examination positions for patients with physical limitations or reduced mobility. The booklet contains a didactic structure for quick consultation to better guide the professional regarding the performance of the examinations. It contains a cover, a presentation, a summary, an introduction, a summary of conventional exams, the adaptation of exams, the conclusion and finally the references. The conclusion of the study emphasizes the importance of expanding research aimed at adapting radiological exams for patients with physical limitations or reduced mobility. These adaptations aim not only at the well-being of the patient, but also at the health, radiological protection and ergonomic safety of professionals, avoiding injuries during the conduct of the exam or its repetition. It is hoped that this material can provide a more humanized  environment for both patients and professionals.

Pedro Emanuel Moraes Santos, Mariana Cecilia Betancourt, Leorlen Yunier Rojas Mazaira et al.

This paper presents a computational study on the thermohydraulic performance of subchannels within Small Modular Reactor (SMR) configurations using Mixed Oxide (MOX) fuels comprising (U, Th)O2 alongside subchannels containing conventional UO2. The research aims to evaluate these fuel types operational efficiency and safety within the context of small-scale reactors. Utilizing a Computational Fluid Dynamics (CFD) model implemented in OpenFOAM, this study considers the variability of the thermophysical properties of the materials as influenced by temperature changes. The findings reveal that MOX fuels exhibit lower maximum temperatures than UO2, suggesting a more uniform radial temperature distribution. Moreover, both the cladding and coolant temperatures remain within safe operational limits across all scenarios examined, highlighting the potential of MOX fuels to enhance the safety and efficiency of SMRs. This analysis advances our understanding of the thermal behavior of advanced fuel compositions in nuclear reactors. It underscores the importance of comprehensive thermohydraulic studies in the design and operation of next-generation nuclear power systems.

N. M. Daineko, S. F. Timofeev

The purpose of the study is to identify differences in the content of 137Cs in the phytomass of coastal aquatic vegetation of the Vetka and Chechersk districts of the Gomel region for the period 2012–2022. The description and identification of ecological groups of coastal aquatic vegetation and the sampling of soil and plants to determine the content of radiocesium in the growing seasons of 2012 and 2022 were carried out according to generally accepted methods. It was found that the content of 137Cs in water samples from the objects of Vetka district did not exceed the normative value for drinking water (10 Bq/kg). The average specific activity of radiocesium in the soil for the studied objects was 807±125 and 586±84 Bq/kg in 2012 and 2022, respectively; and for soil was 549±85 and 395±46 Bq/kg respectively. Over time, there was a decrease in the amount of radiocesium in soil and in ground by 1.3–1.4 times. The average content of the isotope in the plants in 2012 and 2022 was 93–917 and 59–578 Bq/kg, respectively. The amplitude of variation in the average values of accumulation coefficient in the soil-plant system was 1.03 and 0.11 Bq/kg:Bq/kg in 2012 and 2022, respectively. In the ground-plant system it was 3.08 and 0.01 Bq/kg:Bq/kg, respectively. The specific activity of 137Cs in the water of objects in the Chechersk region did not exceed 3 Bq/l. The average content of 137Cs in the ground was 316 and 231 Bq/kg in 2012 and 2022, respectively. The same parameters for the soil were within the limits of 471 and 340 Bq/kg, respectively. The average content of 137Cs in phytomass varied from 149 to 483 Bq/kg in 2012. After 10 years, the amount of radionuclide was 115–288 Bq/kg. The average values of accumulation coefficient in the soil-plant system in 2012 and 2022 were 1.44 and 1.01 Bq/kg:Bq/kg, and in the soil-plant system were 1.70 and 1.10 Bq/kg:Bq/kg, respectively. As a result of the study, similar dominant groups of coastal aquatic plants were not identified in terms of the accumulation of radiocesium in the objects of the Vetka and Chechersk regions.

Fernando Codelo Nascimento, Pedro Márcio Munhoz, Luiz Fernando Núbile Nascimento et al.

Paint is a prevalent type of surface of coating well known to most peoPaint is a prevalent type of surface of coating well known to most people. It is an easy-to-apply product, with excellent physical and chemical resistance and a wide range of applications. The function of a paint is to protect and beautify amongst other properties. Paints are formed using five components: resin, pigments, fillers, solvents and additives. This work deals with a specific type of paint, composed of a water-based acrylic emulsion, whose film formation is by coalescence and used to coat walls and other surfaces. The aim of this innovative  research was to evaluate the effect of  the addition of cellulosic dispersion of waste paper tissues treated by electron beam irradiation to an acrylic emulsion-based paint. The methodology used was a case study carried out at the Nuclear and Energy Research Institute that consisted of adding aqueous dispersions of cellulosic wipes with mass concentrations varying  from 0.1% to 10% in deionized water, and treated by electron beam processing with absorbed doses from 5 kGy to 50 kGy. The results obtained followed the parameters of the Abrafati Sectorial Quality Program. The main sample parameters analyzed  were specific density, which reached an average of 1.35 g/cm3; and covering power, whose value  of 93.55% was above the specified limit (minimum of 90%). Among other results obtained, improvements in appearance, applicability and functionality were significant.  It was concluded that this research constitutes an incremental improvement to the acrylic emulsion paints segment, and environmental sustainability, through the reuse of cellulosic tissue residues

Peter Bossew, Nils Suhr

Radon is a hazardous air pollutant which can cause detriment to individuals and to the society. Thus, the natural consequence is avoiding it or in practice, limiting exposure. This has led to regulation on national and international level whose objective is reduction of radon exposure. In Europe, the Basic Safety Standards (BSS) issued in 2013, whose implementation is mandatory for EU Member States, caused a boost to efforts towards radon regulation as well as to radon research since a number of components of radon abatement policy appeared not resolved sufficiently reliable in the sense of quality assurance. In this contribution, we present the state of implementation of EURATOM Basic Safety Standards in Europe and in Germany, as a particular example. We also address a number of topics currently discussed.

Edson Luiz Pontes Perger, Rodrigo Sanchez Giarola, Izabella Santos Silva Lemes et al.

All living things are constantly exposed to background radiation. The presence of radioactive materials in the earth's crust and cosmic radiation are largely responsible for this exposure. The present study aimed to develop a new methodology of easy applicability and low cost to carry out measurements of environmental background radiation and to be able to establish a map of environmental radiation for primary monitoring of these exposures. For that, ionizing radiation measurements, Meteorological and Radiometric measurements were performed. Geiger Mueller Counter (GM) was used, as it is widely used in services that use radioactive sources and research centers. Measurements obtained showed that there were no statistically significant changes in the 24 hours of measurements with the GM, in relation to the variations presented in the Meteorological and Radiometric measurements that changed according to the time of day. The average value of the background radiation readings was 0.0194 mR/h, with an average variance of 1.8E-06 and an average standard deviation of 1.35E-03. GM proved to be useful for primary measurement of background radiation. The map was developed using open source libraries for the Python programming language. The map may be hosted on an open access website, so that professionals, students and researchers may contribute, sending new data from different locations. It is essential that the levels of radiation exposure are demonstrated and understood. Easy access to this information may contribute to health organizations, agriculture and research centers to establish a baseline for future research.

Torsten Schmiermund

Diogo Teixeira Moreira, Maria Ângela de Barros Correia Menezes, Adriana de Souza Medeiros Batista

Steel slag is considered a by-product of the steel industry and its reuse is a strategy for environmental protection, since it consists of potential polluting materials. Its main applications involve the use of large quantities of the raw material, but the extraction of ores in smaller proportions can be attractive. For example, magnetite (Fe3O4) may be of great interest for its magnetic properties in the production of composites with different applications. On the other hand, rare earth elements (REE) production is vital for new technologies and since traces of the different REE are found in most iron ores, their extraction can be conducted together. However, previous characterization of the slag is necessary; since they vary in mineralogical composition conform to steelmaking operations. Classical characterization techniques of ores such as X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) may be limited to characterize small fractions of materials. Therefore, in this study, neutron activation analysis was used as the characterization technique to confirm the presence of iron and REE in the slag. The steel slag composite sample of the Linz-Donawitz (LD) process was collected in a steelwork localized in the Iron Quadrangle, Minas Gerais, Brazil. The steel slag sample was characterized by instrumental neutron activation analysis (INAA), using the nuclear research reactor TRIGA MARK I IPR-R1. The results are compared with the characterizations made with XRD and SEM-EDS. Although XRD and EDS results indicated the presence of magnetite in a small proportion, INAA was decisive confirming the presence of REE in the mineralogical composition of the composite sample collected.

Bianca Franchesqueti Vivaldini, Elaine Bortoleti de Araújo

Gaining prominence in clinical practice, the 68Ga, positron emitter radionuclide easily obtained by 68Ge/68Ga generator elution, has shown potential and excellent quality on radiolabeling of peptide for use in positron emission tomography (PET), in particular urea-based inhibitor peptides, directed to the prostate-specific membrane receptor (PSMA). Previous studies with the PSMA linked to the chelator HBED-CC (PSMA-11) radiolabeled with 68Ga showed high contrast PET/CT images to evaluate recurrence and metastasis of prostate cancer, becoming an important imaging agent in the clinical routine. This work intended to evaluate the influence of the quality of the 68Ge/68Ga generator eluate in direct labelling of PSMA-11 with 68Ga, assisting in the development of kit for prompt radiolabeling. It was evaluated the 68GaCl3 eluate from 68Ge/68Ga non-GMP generator (manufacturer A) and 68Ge/68Ga GMP generator (manufacturer B), both commercially available. To evaluate the influence of  the 68Ga eluate on radiochemical yield of the preparations,  the radiochemical purity was determined by thin layer chromatography and HPLC. The radiolabeling with non-GMP generator eluate was made with and without preliminary purification of the 68 gallium chloride eluate, employing cationic purification columns. The results showed higher radiochemical yield with the 68GaCl3 eluate from the 68Ge/68Ga GMP generator, obtaining the radiolabeled product more easily and speed to clinical practice, without preliminary purification, as opposed to the use of non-GMP 68Ge/68Ga generator which required preliminary purification of the 68GaCl3 eluate to promote satisfactory radiochemical purity results.

L. Yu. Krestinina, S. S. Silkin, L. D. Mikryukova et al.

To date, the study of the effects of chronic exposure of the South Ural population has been carried out in two separate cohorts – in the Techa River Cohort and in the East Urals Radioactive Trace Cohort. In 2019, the Ural cohort of accidentally exposed population was formed. It included the population exposed in two radiation situations in the Southern Urals in the 1950s. The number of the combined cohort for the cancer incidence analysis was about 60 thousand people, the follow-up period was extended to 2017, the number of solid cancers was 4537, and the number of person-years was 1283267, which is 3 times more than when analyzing the effects of exposure in each of the two radiation situations separately. In the incidence analysis of all solid cancer types, we used the dose accumulated in the walls of the stomach, which corresponds to the dose accumulated in most organs and tissues with the exception of bone tissue and red bone marrow. The mean dose to the stomach accumulated over the entire follow-up period for cohort members was 38 mGy, the maximum -1.13 Gy. The paper presents the first results of solid cancer incidence risk analysis in the combined cohort, which show a statistically significant dose dependence of the incidence in case of chronic exposure in the range of low and medium doses. The sex and age-averaged excess relative risk value of 0.075/100 mGy (the 95% confidence interval is 0.039–0.113) is comparable to that obtained in the studies of the Japanese cohort of atomic bomb survivors. The statistically significant excess relative risk value of 0.047/100 mGy, obtained separately for men, is in good agreement with that in professional cohorts where men prevail – in the cohort of the Chernobyl NPP accident clean-up workers and in the cohort of professional workers in the three countries (UK, France, USA). The established cohort with a long follow-up period has a great potential for furthermore detailed studies of the effects of radiation and non-radiation factors on public health.

Nodira U. Khakimova, Elena Yu. Malysheva, Shoira G. Shosafarova et al.

The work provides a comparative analysis of average annual individual radiation doses based on the obtained values of individual dose equivalent Hp (10), which had been obtained during 5 years of investigations (2014-2018) by using the thermo-luminescent dosimetry method of 70 employees working computed tomography, radioscopy, fluorography and radiography from 15 medical institutions in Dushanbe city. The ratio of medical personnel of the different professional groups showed that 63% of them were engaged in radiography, 19% x-ray, 10% computed tomography and 8% radioscopy. Analysis of the average annual radiation doses of every occupational group showed that the specialists in charge of fluorography have a high dose (max 1.74 mSv) and the personal of computed tomography have the lowest dose (max 1.34 mSv), and over time there is a tendency to equalize the values of average annual doses for all professional groups in the area close to the value of 1.5 mSv. The obtained data of the effective annual dose for all occupational categories had not exceeded the permissible dose limits values required by the «Radiation Safety Standards» (NRB-06 SP 2.6.1.001-06). Calculations are given without subtracting background values. The analysis data allows to identify the most exposed professional groups and to address the issues of ensuring radiation safety in a targeted manner.

S. Fesenko, G. Kozmin, N. Sanzharova et al.

Márcia Maia Sathler, Paula Maria Borges de Salles, Hellen Simões Oliveira et al.

O Laboratório de Análise por Ativação Neutrônica do Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte tem desenvolvido atividades analíticas desde o início de operação do reator nuclear de pesquisa TRIGA MARK I IPR-R1 em 1960. Além do método relativo de análise por ativação neutrônica, tem sido aplicado o método k0-padronizado, em que os cálculos de concentração dos elementos químicos não se baseiam em padrões dos elementos de interesse e sim no uso de monitores de fluxo de nêutrons, espectrômetro gama absolutamente calibrado, conhecimento de parâmetros espectrais na posição de irradiação do reator nuclear e constantes nucleares compostas que caracterizam os nuclídeos, os chamados fatores k0. Ao longo do tempo, vários melhoramentos têm sido efetivados nos procedimentos de análise no laboratório, entre eles, o estabelecimento da metodologia para analisar amostras consideradas grandes, de 1 a 5 g, quando o usual em ativação neutrônica é analisar amostra pequena ou puntual com cerca de 200 mg. A metodologia consiste em analisar amostras com geometria cilíndrica, aplicando o método k0, sem alterar as instalações locais. Neste trabalho são mostrados os resultados de análise de concentrações elementares de diversas amostras de materiais de referência e de amostras de alimentos analisadas como amostras puntuais e cilíndricas. Os resultados indicam que a metodologia de análise de amostra grande ou cilíndrica pode ser aplicada na análise de amostras de alimentos.

Mevlan Qafleshi, Misin Misini, Driton Kryeziu et al.

Kosovo thermal power plants (TPP) produce annually more than 1 million tons of fly ash as a byproduct of lignite combustion. The focus of this study was to characterize the activity concentration of natural radionuclides of hardened concrete specimens with Hyper Pure Germanium gamma-ray spectrometry (HPGe). Concrete mixtures with different content of fly ash as cement replacement were prepared.    Four concrete mixes with 15, 20, 25 and 30% fly ash replacing the respective content of cement were tested for activity concentration of 40K, 226Ra and 232Th, activity concentration index, indoor and outdoor specific and annual absorption dose rates. Two other reference mixes were normal concrete with cement. The obtained results were compared to reference concrete mixtures without fly ash.  The results of measurements in six concrete mixtures showed that the activity concentrations of 40K, 226Ra and 232Th were very low in all concrete specimens. 

Hiroshi Fujiwara, Hidetoshi Kuramochi, Kazutaka Nomura et al.

Thammiris El Hajj, Paulo Sergio Cardoso Silva, Mauro Pietro Angelo Gandolla et al.

The objective of this paper was to evaluate the radiological risk index of ornamental rocks sold both in Brazil and Europe and to correlate its radioactive content with their chemical composition. The 238U, 232Th and 40K mean values were 62 ± 65, 122 ± 111, 1126 ± 516 Bq kg-1 for Brazilian and 93 ± 59, 70 ± 67 and 1005 ± 780 Bq kg-1 for Swiss samples, respectively. The radiological index: radium equivalent, external hazard index, absorbed dose rate in air, annual gonadal equivalent dose, annual effective dose equivalent and excess lifetime cancer risk for Brazilian and Swiss samples were calculated. The main contribution for the radiological indices observed was the radionuclide 232Th, which is associated with REE, Br, Hf, Na, Rb, Sb and Zr in the rock matrix.

V. K. Ivanov, A. F. Tsyb

Summarized radiation-epidemiological data on health effects of the accident at the Chernobyl NPP registered in the follow-up period 1986-2006 on the Russian population are reported. Two groups of population: Chernobyl Emergency accident workers and residents of the most contaminated with radionuclides territories are examined. Impact of radiation-associated risk of solid cancers and leukaemia in these groups is assessed. Prognostic estimates of health effects of the Chernobyl accident on the Russian population are offered in the article.

M. Yu Soloviev, M. V. Kalinina, I. P. Stamat

The article presents issues of radon accumulation in the air of dwellings and public buildings in the Rostov region. It is shown that radon concentration in the air of commissioned buildings does not depend on the season when the investigation was carried out, while equivalent equilibrium volumetric activity of radon in the operating buildings is approximately twice higher during the cold period, then during the hot period of a year.