Search

When a cost-benefit analysis is applied to the optimization of practices involving radiation protection, the alpha value is used to determine the amount of money required to be invested in a practice to minimize radiation doses to acceptable levels. The alpha value is often linked to the gross domestic product (GDP) per capita, so the monetary reference value of person-Sievert can often be different in each country. Evaluation of the alpha value in Brazil was performed in 1993 and 2000 making use of the procedure advised by ICRP to produce projections up to 2015 and subsequently in 2004 by using the procedure recommended by the IAEA. This paper, in response to the social and economic situation in Brazil, calculates the alpha value and compares it with the projections of the 1993 and 2000 papers and includes a dollar correction to take account of the differences in the purchasing power from that time. This procedure illustrates the significant gap of value in use and that the actual value should be two to three times higher. By GDP per capita, the authors could calculate the alpha value updated to various countries including the European Union and compare them with the official value currently in use. In conclusion, it is believed that all countries that adopt an alpha value should upgrade it to the present day. [ABSTRACT FROM AUTHOR]

18FDG, an analogue of glucose labelled with the radionuclide 18F, is the most widely used radiopharmaceutical in positron emission tomography/computed tomography technique. In Brazil, there are currently eight 18FDG plants in operation and other facilities are expected to start their production in the near future. The growth in the production and clinical use of 18FDG represents an increasing risk of worker exposures. According to national regulations and international recommendations, internal exposures should be effectively controlled in order to keep doses as low as possible. The implementation of a routine monitoring programme towards the estimation of internal doses related to the incorporation of 18F is difficult, mainly due to its short physical half-life, the cost of a bioassay laboratory and the need of a monitoring service promptly available near the production plant. This paper describes the implementation and evaluation of a methodology for in vivo brain monitoring of 18F to be applied in cases of suspected incorporation of 18FDG. The technique presented a minimum detectable effective dose in the order of nanoSieverts, which allows its application for occupational monitoring purposes. [ABSTRACT FROM AUTHOR]

Brazil, a large country, with more than 120 000 workers under individual monitoring for ionising radiation, developed, more than 20 y ago, a centralised data bank for external occupational dose. This old database, however, presented some problems and does not satisfy any more Brazilian present needs, not allowing dose analysis reports, for example. Therefore, a new system that reduces manual tasks, provides system communication support, manages reports and improves data storage management is being developed. This paper describes this new web-based information system, named Brazilian External Occupational Dose Management database system—GDOSE. [ABSTRACT FROM PUBLISHER]

Brazil has about 300 nuclear medicine services (NMS), 44 of them located in the state of Rio de Janeiro (RJ). Most nuclear medicine staff are routinely monitored for external dose. This paper makes a statistical analysis of all the RJ NMS annual external occupational doses in year 2005. Around 100 professionals of RJ NMS received annual doses >4.0 mSv, considering only external doses, but no one receives doses higher than the mean annual dose limit of 20 mSv. Extremities dosemeters are used by about 10 % of the staff. In some cases, these doses are more than 10 times higher than the dose in thorax. The maximum ratio of extremity dose/thorax dose, in 2005, was 72. This study shows the importance to improve radiation protection procedures in nuclear medicine, mainly because the number of occupational individuals in nuclear medicine and their external doses are increasing. [ABSTRACT FROM PUBLISHER]

Instituto de Radioproteção e Dosimetria, a Brazilian government research institute, provides individual monitoring services since 1972. Its dosemeters are: film-based thorax for whole body photons, thermoluminescence dosimetry (TLD) albedo for whole body neutrons and TLD ring for extremity photons. About 6000 radiation workers are currently being monitored with film dosemeters in 256 different facilities in Brazil, most of them working in health-related activities. Around 400 Brazilian radiation workers are monitored with TLD albedo neutron monitor and about 500 workers use TLD rings. This paper describes the monitoring systems used, presents the results obtained in internal quality programs and in intercomparison exercises and analyses the measured dose values from 1985 to 2009. [ABSTRACT FROM PUBLISHER]

The exploitation of natural resources containing naturally occurring radionuclides may lead to enhanced levels of radioactive isotope and enhanced potential for exposure to naturally occurring radionudides in products, by-products, residues or wastes. Such resources include, for instance, monazite, the processing of which, in Brazil, generated a great amount of radioactive residues, being stored in buried concrete tanks, in temporary storage buildings and in sealed trenches. In addition, during the 1980s there were no radiological protection rules concerning the storage and transportation of these kinds of residues. Mineral radioactive residues were used as landfills and the residues of chemical processes contaminated floors and buildings. The decommissioning process and cleaning of old plants have generated tons of wastes that has been added to previously produced wastes. This paper reports and discusses the cycle of monazite in Brazil and its consequences in terms of site remediation and amount of wastes and residues generated and stored. [ABSTRACT FROM AUTHOR]

This study assessed occupational radiation doses in Santa Catarina, Brazil, from 2014 to 2017. Data were collected from Sistema de Informação Estadual de Radiações Ionizantes (SIERI), a compulsory occupational dose registration system established in Santa Catarina in 2014. Most doses were registered as lower than the dosemeter recording level (RL; 99.12%). Diagnostic radiology workers registered doses higher than the RL (61.13%) more frequently than nuclear medicine workers; however, the former received lower doses. Nuclear medicine workers represented 38.87% of dosemeter values higher than the RL, but their mean doses were higher. The professionals who registered the highest doses across both categories were radiology technologists/technicians and nursing workers. Establishment of a compulsory information system is important for monitoring the safety of workers. This study compiled data from the first few years of the SIERI program. Here, we report the current status of exposure in Santa Catarina. [ABSTRACT FROM AUTHOR]

Recently, the idea of generating radon map of Brazil has emerged. First attempts of coordinating radon surveys—carried out by different groups across the country—and initial discussions on how to proceed on a larger scale were made at the First Brazilian Radon Seminary, Natal, September 2012. Conventionally, it is believed that indoor radon is no major problem in Brazil, because the overall benign climate usually allows high ventilation rates. Nevertheless, scattered measurements have shown that moderately high indoor radon concentrations (up to a few hundred Bq m−³) do occur regionally. Brazilian geology is very diverse and there are regions where an elevated geogenic radon potential exists or is expected to exist. Therefore, a Brazilian Radon Survey is expected to be a challenge, although it appears an important issue, given the rising concern of the public about the quality of its environment. [ABSTRACT FROM AUTHOR]

Termas de Araxá spa is located in Araxá, State of Minas Gerais. In this region, several minerals rich in uranium and thorium are found. The mineral waters and mud from Termas de Araxá spa have been used for therapeutic and recreation purposes. In this study, the committed effective dose was evaluated for workers and patients at Araxá spa due to 222Rn and 212Pb inhalation. Radon measurements were carried out through the passive method with solid state nuclear track detectors (Makrofol E) over a period of 21 months, with results varying from 258±20 to 1634±111 Bq m-3. The 212Pb air concentration was assessed through the modified Kusnetz's method, the results varying from 0.3±0.1 to 2.1±0.2 Bq m-3. Doses received by the spa workers are below 20 mSv⋅y-1, suggested by ICRP 60 as an annual effective dose limit for occupational exposure. The radiation doses for the patients are below the mean annual effective dose due to natural sources estimated to be 2.4 mSv⋅y-1. [ABSTRACT FROM AUTHOR]

The Brazilian national regulatory authority, National Commission of Nuclear Energy, requires that dose rates in the vicinity of teletherapy treatment rooms do not exceed the permissible limits for workers as well as members of the public, depending on the place considered. At the end of 2005, the Brazilian national regulatory authority reduced the permissible dose limit for controlled areas from 1000 to 400 µSv week−1. Therefore, the aim of this work is to verify the adequacy of structural shielding to this new limit for telecobalt units that had their sources changed and clinic linear accelerators (ALs) installed before the end of 2005. Considering the ALs, measurements of dose rates in controlled areas did not exceed the new permissible limit, excepting for a single case. In the case of 60Co units, a similar situation is observed for controlled areas, although several non-conformities to the limit of uncontrolled area could be observed. [ABSTRACT FROM PUBLISHER]

Two indigenous ceramics fragments, one from Lagoa Queimada (LQ) and another from Barra dos Negros (BN), both sites located on Bahia state (Brazil), were dated by termoluminescence (TL) method. Each fragment was physically prepared and divided into two fractions, one was used for TL measurement and the other for annual dose determination. The TL fraction was chemically treated, divided in sub samples and irradiated with several doses. The plot extrapolation from TL intensities as function of radiation dose enabled the determination of the accumulated dose (Dac), 3.99 Gy and 1.88 Gy for LQ and BN, respectively. The annual dose was obtained through the uranium, thorium and potassium determination by ICP-MS. The annual doses (Dan) obtained were 2.86 and 2.26 mGy/year. The estimated ages were ~1375 and 709 y for BN and LQ ceramics, respectively. The ages agreed with the archaeologists' estimation for the Aratu and Tupi tradition periods, respectively. [ABSTRACT FROM AUTHOR]

The introduction of routine patient dosimetry to Brazilian radiological institutions is very necessary in order to meet national and international standard requirements for radiation protection. This work presents a survey of the air kerma-area product (PKA), the entrance surface air kerma (Ke) and the effective dose (E) in common radiographic examinations during the routine of a large public hospital in the city of Belo Horizonte, Brazil. Results draw attention to the use of field sizes larger than the cassette dimension, the lack of both the collimation X-ray beam and the standardisation of the exposure parameters by radiology technicians. [ABSTRACT FROM AUTHOR]

The introduction of routine patient dosimetry to Brazilian radiological institutions is very necessary in order to meet national and international standard requirements for radiation protection. This work presents a survey of the air kerma-area product (PKA), the entrance surface air kerma (Ke) and the effective dose (E) in common radiographic examinations during the routine of a large public hospital in the city of Belo Horizonte, Brazil. Results draw attention to the use of field sizes larger than the cassette dimension, the lack of both the collimation X-ray beam and the standardisation of the exposure parameters by radiology technicians. [ABSTRACT FROM AUTHOR]

Phosphogypsum, a waste by-product derived from the wet process production of phosphoric acid, represents a serious problem facing the phosphate industry in Brazil. This by-product (mainly calcium sulphate dihydrate) precipitates during the reaction of sulphuric acid with phosphate rock and is stored at a rate of about 4 × 106 kg per day on several piles in Cubatâo, Brazil. Contents of natural radionuclides from thorium and uranium series were measured in Brazilian phosphogypsum samples from disposal piles, using high-resolution gamma ray spectrometry and instrumental neutron activation analysis (NAA). These phosphogypsum piles present a potential threat to the surrounding environment and to the individual occupationally exposed. The results obtained in this study show that radionuclides, although present in relatively high concentrations in phosphogypsum, do not imply in significant doses for individuals occupationally exposed. The results obtained for the water activity in the monitor wells showed that the run-off of the piles is influenced by the activity present in the piles, giving indication of a possible groundwater contamination. Sediments from rivers in the area of influence of the pile presented higher concentrations of 238U and 232Th when compared with reference values. [ABSTRACT FROM AUTHOR]

In the present work, systematic dating by luminescence methods has been done on 50 Quaternary geological samples within the study area of São Paulo State, Brazil. Bleaching experiments showed that residual TL intensity of 375°C peak, of the quartz, was obtained after 10 h of sunlight exposition. Intensities decays of the 325 and 375°C TL peaks can be fitted using second order exponential equation. Paleodose values were evaluated using regeneration methods with multiple aliquots. Samples dated indicate preliminary ages varying from 9 ± 1 to 935 ± 130 ka for colluvio-elluvial deposits, and from 17 ± 2 to 215 ± 30 ka for alluvial deposits of the study area. They cover four peneplained surfaces shaped during the Quaternary: I (1000-400 ka), II (400-120 ka), III (120-10 ka) and IV (10 ka until today), in decreasing order. [ABSTRACT FROM AUTHOR]

In Brazil there are many regions where the extraction mining and processing of ores containing elements of great economical importance as tin, niobium and tantalum. Some of these ores have uranium and thorium natural decay series associated. This study was carried out in a niobium mine, where is obtained concentrates of niobates-tantalates, cassiterite and zirconite. The aim of this study is the evaluation of the occupational exposure to uranium, thorium, niobium and tin through urine bioassay data. In order to have it, 105 urine samples were analysed: 17 samples of exposed workers collected after a working day, 49 samples of exposed workers collected before a working day and 39 samples of local non-exposed people, assigned as a control group. The samples were analysed by mass spectrometry. The obtained results showed that the average concentration of Nb, Sn and U in the exposed group is statistically higher than those found in the control group indicating an occupational exposure. For Th there were no statistically difference between the exposed and the control group. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the incident air kerma (INAK) and the mean glandular dose (MGD) during mammography in Recife, North-east Brazil. The study was performed in three institutions: a private clinic (A), a public hospital (B) and a private hospital (C). The incident air kerma to mammography procedures were estimated using a standard breast phantom and the patient MCD, evaluated in the units B and C, was performed using the calibration of output method. This method involves the recording of the patient exposure parameters (kVp, mAs, filter) and the measurement of these parameters of the incident air kerma using a calibrated ionisation chamber. The results obtained showed that INAK for the standard breast phantom, in the institutions A, B and C, were 18.2, 9.4 and 8.5 mGy, respectively. The results of patient MGD values ranged from 0.23 to 7.46 mGy per film, and the MCD values per woman were between 8.23 and 40.6 mGy for the C institution and between 1.50 and 18.78 mGy for the B institution. [ABSTRACT FROM AUTHOR]