Hasil untuk "Radioactivity and radioactive substances"

M.A. Edomskaya, S.N. Lukashenko, A.A. Shupik et al.

Alexandre Vilaça Silva, Rodrigo Modesto Gadelha Gontijo, Andrea Vidal Ferreira

The Centro de Desenvolvimento da Tecnologia Nuclear has a small animals positron emission tomograph in its Laboratório de Imagem Molecular. This equipment, the GE HealthCare LabPET SOLO 4 model, is widely used in preclinical studies related to the development of new radiopharmaceuticals or novel applications of conventional radiopharmaceuticals. The “PET Image Quality” subproject, integrated into the Centro de Desenvolvimento da Tecnologia Nuclear multi-year planning for 2018-2022, proposed actions involving quality assurance and human resources development for the laboratory. This work aims to consolidate the historical trajectory of Quality Assurance at Laboratório de Imagem Molecular of the Centro de Desenvolvimento da Tecnologia Nuclear. A search for documents related to the laboratory was conducted in the institutional quality system, called d-Qualidade, while a search for the curricula vitae of laboratory researchers was performed on the Plataforma Lattes, with the purpose of identifying the main products generated related to the Quality theme in the laboratory. The scientific production of the laboratory team demonstrates its pioneering role in Brazil in developing studies about the Quality Management applied to the small animals positron emission tomogragh. The laboratory history in the field of Quality Management emphasizes its national prominence and reveals the group's commitment over the past decade to significant technical/scientific production.

Marcus Vinicius Araujo Vieira, Giulianna Santos Pereira, Fabiane Garbim Modenese et al.

The paper thoroughly covers the nuclear fuel cycle, a complex and vital process in energy generation through uranium fission. The cycle comprises various stages, from uranium extraction and processing to its use as fuel material in nuclear reactors. This work primarily aims to highlight the peculiarities and innovations of the nuclear fuel cycle in the Brazilian context, seeking to promote academic and commercial interest and drive research and investments in this strategic area. The research conducted to underpin this work was comprehensive, involving literature reviews, technical visits, and discussions with specialized professionals. The conclusion emphasizes the relevance of the nuclear fuel cycle and how this work intends to highlight its specificities, underscoring the importance of this cycle for Brazil as a source of clean and safe energy generation.

Jin-jie Yuan, Yicong Bian, Sheng Ma et al.

Danny Giancarlo Apaza-Veliz, Vinicus Fernando dos Santos, Daniel Luis Franze et al.

A planar nuclear medicine image can be used to estimate dosimetry during iodine therapy. To this end, radionuclide activity distribution should be quantified in the patient’s body in terms of a calibration coefficient. This coefficient allows the net counts to correlate with the image’s activity. This study aims propose a simple and easy calibration protocol to quantify 131I activity in thyroid phantom by molecular planar images. Were acquired 13 planar images of different phantoms: thyroid phantom of symmetrical lobes; thyroid phantom of asymmetrical lobes; the Jacszack cylinder phantom with a syringe surrounded by air and water, and finally a plastic bottle containing a syringe with radionuclide. We applied the 131I radionuclide in a General Electric gamma camera, model Discovery NM/CT 670 with a high energy general purpose parallel hole collimator above the phantoms positioned at camera bed. The calibration coefficient of the gamma camera and the standard deviation were determined for each phantom; the average calibration coefficient obtained was 0.062±0.006 MBq/cps. The results suggested that the phantoms applied as too the calibration coefficient obtained by them can provides reasonable value for the gamma camera calibration factor for iodine 131, therefore an accurate evaluation of the scattering media as the source detector distance could impose higher variability and uncertainties on results.

Ziyu Wang, Jianbin Pan, Qian Li et al.

The development of highly sensitive and selective uranyl ion (UO22+) probes has attracted significant attention owing to the threat to human health caused by high toxicity, radioactivity, and long half‐life. Herein, the development of aggregation‐induced emission (AIE) active polymer dots (Pdots) is described for an accurate UO22+ monitoring using a portable electrochemiluminescence (ECL) system. An AIE‐active polymer containing tetraphenylethene and boron ketoiminate moieties is prepared into Pdots and modified with ssDNA to capture UO22+, which can amplify the ECL signal of the Pdots through a resonance energy transfer mechanism. This probe provides an ultralow detection limit of 10.6 pm/2.5 ppt, which is at least two orders of magnitude lower than the known UO22+ luminescent probes. Only UO22+ can provide an obvious ECL enhancement among the various metal ions, indicating the excellent selectivity of this probe. Furthermore, a portable ECL analyzer is designed to realize UO22+ measurements in the wild. The anodic ECL mechanism of UO22+ is discovered and ECL technology is first applied in monitoring radioactive substances. This study provides a novel strategy for the development of accurate UO22+ probes and a practical UO22+ monitoring method, indicating its potential application in the environmental and energy fields.

Elena Yushkova

Baoyan Zuo, Mingxue Cao, Xiumei Tao et al.

In vivo metabolism of polyethylene glycol (PEG) hydrogels has rarely been studied. In this study, we prepared a chemically crosslinked hydrogel formulation using 14C-labeled tetra-armed poly (ethylene glycol) succinimidyl succinate (Tetra-PEG-SS) and 3H-labeled crosslinking agent for implantation into the pelvis of Sprague-Dawley (SD) rats. This radioactive labeling technique was used to investigate the radioactivity excretion rates in of feces and urine, the blood exposure time curve, and the radioactivity recovery rate in each tissue over time. We showed that the primary excretion route of the hydrogel was via urine (3H: about 86.4%, 14C: about 90.0%), with fewer portion through feces (3H: about 6.922%, 14C: about 8.16%). The hydrogel metabolites exhibited the highest distribution in the kidney, followed by the jejunal contents; The 3H and 14C radioactivity exposures in the remaining tissues were low. We also showed that the 3H and 14C radioactivity recovery rates in the blood were usually low (<0.10% g−1 at 12 h after implantation), even though, in theory, the hydrogel could be absorbed into the blood through the adjacent tissues. By using a combination of HPLC-MS/MS and offline radioactivity counting method, we established that the tetra-PEG-based hydrogel was mainly metabolized to lower-order PEG polymers and other low-molecular-weight substances in vivo.

V. Yu. Golikov

The aim of the study was to develop a methodology that allows taking into account the age and sex dependencies of the risk of radiogenic cancer and the age and sex distribution of the patients to evaluate the collective risk due to separate X-ray examinations and medical exposure in the Russian Federation as a whole. Methodology is based on the use of lifetime risk coefficients estimated for the Russian and Composite population and the results of the study of typical doses of patients for various X-ray examinations in the Russian Federation. It is shown that the assessment of the radiation risk of separate X-ray examinations calculated using lifetime age and sex risk coefficients, organ doses and age distributions of patients may differ up to order of magnitude from the risk assessment based on effective dose and nominal risk coefficients. The difference in estimating of the collective risk of total medical exposure in the Russian Federation by these two methods reached 2.5 times in 2018.

Rodrigo Modesto Gadelha Gontijo, Andréa Vidal Ferreira, Juliana Batista da Silva et al.

This study aimed to evaluate the general performance of the preclinical PET scanner (LabPET Solo 4, GE) at CDTN/CNEN using the NEMA NU 4-2008 protocol. The performance parameters include: (i) spatial resolution; (ii) scatter fraction and counts rate performance; (iii) sensitivity and (iv) image quality. For the evaluation specific simulators and a sealed radioactive source of Sodium-22 were used. The results revealed that the NEMA-based radial spatial resolution ranged from 1.79 mm at the center of the FOV to 2.49 mm at a radial offset of 25mm. Tangential resolution ranged from 1.95mm at the center of the FOV to 3.50mm at a radial offset of 25mm. Axial resolution ranged from 1.78mm at the center of the FOV to 5.42mm at a radial offset of 25mm. Iterative image reconstruction improved the radial spatial resolution to 0.93mm at the center of the FOV. For the mouse-sized phantom, the peak noise equivalent count rate (NECR) was 37.8kcps at 85MBq whereas the peak true count rate was 169.9kcps at 125MBq with a count loss of 7.8% for the maximum rate reached at 103.3MBq. The peak of sensitivity (S) and absolute sensitivity (SA) at the center of axial field-of-view (FOV) is 5.7cps.Bq-1 and 0.63%, respectively. The overall imaging capabilities of the scanner were assessed using the NEMA image-quality phantom. The image roughness was 9.5%. Spillover rates (SORs) in air and in water were 0.26 and 0.17 respectively. The recovery coefficients (RCs) were 0.12 for the 1-mm-diameter rod and 0.91 for the 5-mm-diameter rod. The results demonstrate that CDTN/CNENsmall animal PET scanner has adequate reliability and acquired images are compatible with international quality standards for the molecular imaging research.

Marcelo Bessa Nisti, Andressa Nery, Cátia H. R. Saueia et al.

The approach taken in the WHO Guidelines for controlling radiological hazards in public water supplies has two stages. The first is an initial screening for gross alpha and beta activity to determine whether the activity concentrations are below levels at which no further action is required; and if these screening levels are exceeded, investigation of the concentration of individual radionuclides and comparison with specific guidance levels. Mineral water is obtained directly from natural sources or by extracting groundwater, it is characterized by the quantity of mineral salts, trace elements and other constituents. The bottled water industry is present in the major regions of the world, and the population consumption has increased every year in Brazil and world, also increasing new mineral water mining sites, so it is necessary to constantly check the amount of radioactivity in mineral water. The aim of this study is to quantify the concentration of the natural radionuclides in the bottled mineral water consumed in São Paulo city. The bottled mineral water samples were purchased in a supermarket in São Paulo, with 23 different brands. The determination of gross alpha and beta activity concentration in bottled mineral water by Liquid Scintillation Counting measurement was performed using a 1220 Quantulus™ Ultra Low-Level Liquid Scintillation Spectrometer. The natural radionuclides (226Ra, 228Ra, 210Pb and 40K) were measured by gamma spectrometry, using an HPGe detector. The results obtained in this study can be used for a database on bottled mineral water radioactivity from Brazil.

Ricardo Bastos Smith, Tereza Cristina Salvetti, Ana Paula Gimenes Tessaro et al.

In the second half of the twentieth century in Brazil, several nuclear facilities were built for the most varied objectives. The largest number of such facilities is at the Nuclear and Energy Research Institute in São Paulo (IPEN-CNEN/SP). For different reasons, some of these facilities had their projects finalized and were deactivated. Some of the equipment was then dismantled, but the respective nuclear and radioactive material remained isolated in the original sites awaiting the proper decommissioning procedures. The Celeste Project is an example of a facility where the nuclear material has been kept, and is subject to Argentine-Brazilian Agency for Accounting and Control of Nuclear Materials (ABACC) periodic inspections. Because of a number of interests, including financial and/or budgeting situations at the institutions, decades have passed without any further action, and the people who withold information and knowledge about these facilities have already moved away from the area or are in the process of. Therefore, because of the absence of knowledge management techniques in force at the time of establishing and operating these installations, this work proposes an analysis about the possible consequences in case of loss of perhaps the only one remaining knowledge, the one from the people who designed those departments and worked there.

Sarah Andresa Bonfim, Zildete Rocha, Raoni Adão Salviano Jonusan et al.

Non-Aqueous Phase Liquids (NAPLs) compounds are complex mixtures of organic liquids derived from petroleum and/or industrial activity. Contamination of soils and groundwater by NAPLs can generate health and economics problems by compromising water resources; restrict soils use; and cause damage to the public and private patrimony, and the environment. Today there is an increase in areas contaminated by different types of NAPLs, cause of great concern worldwide, due to the difficulty of locating and quantifying contamination, which is a major obstacle that prevents the cleaning of soils and groundwater in affected locations. This work aims to use the concentrations of the Radon gas in the soil as a way to determine areas contaminated by NAPL, using/prove the high affinity of the Radon for NAPLs, which causes the concentration of Radon in the soil to have a deficit in relation to that naturally observed in the studied region. After understanding the affinity of the Radon by the NAPLs, a gas station was located (with the contribution of the city hall of Belo Horizonte – Minas Gerais – Brazil), which went through a diesel oil leak from the storage tank making the area contaminated. Measurements of the Radon concentration were carried out with the AlphaGUARD® Radon monitor. These measurements confirmed the presence of a deficiency in the Radon concentration, which demonstrated its ability to be used as a marker for the presence of NAPL, contributing to future plans remediation and control of pollution, as well as studies of oil wells on-shore.

Angélica Bueno Barbezan, Luma Ramirez Carvalho, Daniel Perez Vieira et al.

Food irradiation has been approved in more than 60 countries for many applications in a wide variety of foods. 2-Alkylcyclobutanones (2-ACBs) are the only known radiolytic products formed when food containing fatty acids are irradiated. Despite the importance of food irradiation, the toxicological potential of 2-ACBs in irradiated food is still no fully understood. In this study we investigated the cytotoxic effects of irradiated palmitic and stearic fatty acids byproducts, 2-dDCB and 2-tDCB, in the hepatic cells (HepG2, BRL3A and HTC). The cytotoxic effects of 2-dDCB and 2-tDCB were evaluated at 100, 300 and 500 μM for 24 and 48 hours and the cell viability was measured using the MTS assay. While no toxicity was observed for 2-tDCB in all cells for all tested conditions, 2-dDCB was found to be toxic in BRL3A cells (at 100 µM after 48 hours) and HTC cells (at 24 hours in all tested concentrations). HepG2 cells on the other hand, were found to be resistant to 2-dDCB-induced toxicity.  Overall our data shows that the byproduct 2-tDCB is not toxic for hepatic cells while 2-dDCB can be used has a potential marker for food irradiation-induced toxicity.

Regina Bitelli Medeiros, Adriano Henrique Pereira Barbosa, Marcelo José Carvalho Cantarelli et al.

Our goal was evaluate if cardiologists and their team are compromising with radiation protection. This survey intends to support a study about  eyes lens opacity, also realized at SOLACI/2016-RJ-Brazil. An questionary about work conditions in cathlab, individual and colletive radioprotection, was applied for 127 professionals, being 95 cardiologists from several regions of Brazil, by means of personal interview. Among the responses, 38% said performed 50 procedures mensally while 43.7% between 50 and 100. Among them, 33.9% perform catheterims (CAT) and percutaneous coronary intervention (PCI), and 37% CAT, Ventriculography and  Coronary Artery Bypass Graft. Around 70% of professionals reported that they have been working for more than 10 years and most have answered that they routinely use protective tools such as lead apron and thyroid shield. Cardiologists answered that they did not routinely wear lead glasses (46%) and a suspended ceiling shield (33%). In general, they justified that the glasses do not fit perfectly on face. Around 27.6% answered that the radiologic equipment don’t have protective side shields. We verify that 39.4% have never received a formal training in radioprotection. We estimated that 63.8% wear dosimeters over the apron at chest level for personal doses control. The professionals reported that they work in public and private institutions and 28.6% reported working in more than two services. About 52.8% associate the use of lead aprons with acquired ergonomic diseases. We conclude that strategies should be established to reinforce  radiological protection practice and to guarantee better protection conditions for Cathlab professionals.

A. T. Gubin

Research and Technical Center of Radiation-Chemical Safety and Hygiene (RTC RCSH), Moscow, Russia Generalized radiogenic risk models presented in ICRP Publication 103 have a number of attractive features. The models themselves and the corresponding models of background risks are generalized by a single function containing only three parameters specific to the localization of cancer, sex and risk indicator (absolute or relative; mortality or morbidity). However, there are several discrepancies in the values of model parameters for the individual cancer sites and in some predictions based on these models. The aim of this study was to clarify the possibility of refining the parameters of the ICRP models using the LSS cohort data. The method of calculation of the parameters of these models has been developed and verified based on the data on baseline mortality in the cohort and among entire Japanese population. The method consists in the averaging of the local estimates of the parameters calculated based on the values of the rate of the mortality in the ends of different segments of age at exposure and attained age within the entire examined area of change of these variables. The latest published mortality data in the cohort and mortality tables for Japan from the WHO database were used to calculate the mortality rate matrices. Data on the baseline mortality from solid cancers in LSS were in good agreement with statistically more reliable data for the entire Japanese population. Hence, the latter were used for verification of the method.According to the criteria of absolute and relative standard deviation, the ICRP models at whole better approximate baseline and radiogenic mortality from solid cancers in the cohort based on the values of parameters calculated using the proposed method compared to the values from the ICRP. The sets of parameter values for men and women, calculated from LSS data and for the Japanese population differ significantly, while in ICRP models they are almost the same.

Durga Parajuli, Akiko Kitajima, Akira Takahashi et al.

I. P. Stamat, D. I. Stamat

The article addresses issues of the population radiation protection regulatory framework development for the natural sources of radiation. Calculations for justification of standard for natural radionuclide concentration in the wide range of contemporary building materials - facing products - are formulated. The basic consideration of calculations is that implementation of these products could lead to the additional population exposure from natural sources less than 0,1 mSv/year. On the base of this assumption it is shown that effective specific activity of natural radionuclides in these products must not exceed 740 Bq/kg.

N. A. Koroljova, I. P. Stamat, M. V. Terentjev et al.

The article contains the analysis of the results of radiation survey at more than 100 non-uranium mining enterprises fulfilled by the Institute over the last 20 years. The article considers radiation situation formation appropriateness, demonstrates the evaluation of effective exposure doses of mining enterprises personnel from natural irradiation sources in working conditions, the dose structure is given.

Nobuo Niimura, Kenji Kikuchi, Ninh Duc Tuyen et al.