RESUMO
Cumulative exposure to radon can be evaluated by measuring 210Pb in bone. The skull and knee are two convenient parts of the skeleton for in vivo measuring 210Pb because these regions of the body present a high concentration of bone, the detectors are easily positioned and the likelihood of cross contribution from other organs or tissues is low. A radiological survey of non-uranium mines in Brazil indicated that an underground coal mine in Paraná, located in the south of Brazil, exhibited a high radon concentration. In vivo measurements of 32 underground coal miners were performed in the IRD-CNEN Whole Body Counter shielded room using an array of four high-resolution germanium detectors. Estimations of 210Pb in the total skeleton were determined from direct in vivo measurements of 210Pb in the head and knees. In vivo measurements of 210Pb in 6 out of 32 underground coal miners ranged from 80 to 164 Bq, suggesting that these workers were significantly exposed to 222Rn.
Assuntos
Articulação do Joelho/metabolismo , Radioisótopos de Chumbo/metabolismo , Mineração , Modelos Biológicos , Exposição Ocupacional/análise , Radônio/metabolismo , Crânio/metabolismo , Contagem Corporal Total/métodos , Algoritmos , Bioensaio/métodos , Brasil , Carvão Mineral , Simulação por Computador , Humanos , Internacionalidade , Radioisótopos de Chumbo/análise , Doses de Radiação , Proteção Radiológica/métodos , Radônio/análise , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Potassium is an essential element for human metabolism. It is present in all living cells, predominantly in the skeletal muscle tissue. The energy of the 40K photon and its uniform distribution within the human body allow its in vivo measurement. Subjects of both sexes were monitored at the whole-body counter of the IRD facility for the evaluation of 40K body burden, being divided into two groups: (1) subjects who do not exercise routinely, and (2) subjects who do exercise routinely. The average values found for potassium mass and potassium concentration in group 1 were 99 +/- 17 g of K and 1.3 +/- 0.2 g of K kg(-1) of body mass, respectively, and in group 2 the average values found for potassium mass and potassium concentration were 118 +/- 33 g of K and 1.6 +/- 0.2 g of K kg(-1) of body mass, respectively. The comparison between average values for potassium mass and concentration shows a significant statistical difference.
Assuntos
Exercício Físico/fisiologia , Marcação por Isótopo/métodos , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/metabolismo , Radioisótopos de Potássio/farmacocinética , Contagem Corporal Total/métodos , Adulto , Fatores Etários , Feminino , Humanos , Masculino , Imagens de Fantasmas , Radioisótopos de Potássio/análise , Cintilografia , Compostos Radiofarmacêuticos/farmacocinética , Fatores Sexuais , Estatística como Assunto , Contagem Corporal Total/instrumentaçãoRESUMO
A dose reconstruction study was performed for personnel occupationally exposed to 131I in radiopharmaceutical production, during the years 1981 to 1994, with the objective of estimating committed effective doses and critically reviewing the main causes of their exposures. The workers were selected from a group responsible for the production, labelling and distribution of all radiopharmaceutical material in Brazil. Best estimates of intakes and doses were derived from the examination of the individual monitoring records and the reports from the radiation protection supervisor, complemented by interviews with the workers and with radiation protection officers. Over this time period workers had chronic as well as acute intakes of 131I. Committed effective doses were found to be dependent on the task performed by the worker and the site of operation and inversely correlated with the amounts of iodine handled. Intakes in general were a consequence of inadequate radiation protection control.
Assuntos
Indústrias , Radioisótopos do Iodo/urina , Exposição Ocupacional , Doses de Radiação , Monitoramento de Radiação/métodos , Compostos Radiofarmacêuticos , Humanos , Estudos RetrospectivosRESUMO
The mining, milling and processing of uranium and thorium bearing minerals may result in radiation doses to workers. A preliminary survey pilot program, that included six mines in Brazil (two coal mines, one niobium mine, one nickel mine, one gold mine and one phosphate mine), was launched in order to determine the need to control the radioactive exposure of the mine-workers. Our survey consisted of the collection and analysis of urine samples, complemented by feces and air samples. The concentrations of uranium, thorium and polonium were measured in these samples and compared to background data from family members of the workers living in the same dwelling and from residents from the general population of Rio de Janeiro. The results from the coal mines indicated that the inhalation of radon progeny may be a source of occupational exposure. The workers from the nickel, gold and phosphate mines that were visited do not require a program to control internal radiological doses. The niobium mine results showed that in some areas of the industry exposure to thorium and uranium might occur.
Assuntos
Indústria Química , Mineração , Exposição Ocupacional , Brasil , Humanos , Doses de Radiação , Tório , UrânioRESUMO
An improved biokinetic model for 137Cs in humans was developed based on an analysis of data obtained from individuals internally contaminated during an accident in Goiania, Brazil, and other data. Seventeen children (ten girls and seven boys 1-10 y old), ten adolescents (four females and six males), and thirty adults, (fifteen females and fifteen males contaminated in the accident in Goiânia contributed to this study. 137Cs retention was determined through periodic measurements in a whole-body counter. In addition to the data on 137Cs retention from these individuals, data from a study on the metabolism of 137Cs in immature, adult, and aged Beagle dogs and data from the literature were used in the formulation of the 137Cs biokinetic model presented. Mathematically, the retention of cesium is described by three exponential terms, and the retention model is based on a step function of body weight. When the ICRP Publication 56 model for cesium was compared to the model suggested in this paper, it was determined that the ICRP model predicts lower effective doses in 5-y-old children and higher effective doses in infants, adolescents, and adults.
Assuntos
Radioisótopos de Césio/farmacocinética , Adolescente , Adulto , Idoso , Animais , Criança , Pré-Escolar , Cães , Feminino , Meia-Vida , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Doses de RadiaçãoRESUMO
In an accident involving the stealing and breaching of a radiotherapy source in Goiânia, Brazil, 39 individuals had a high level of 137Cs internal contamination. Prussian Blue was used, in doses that varied from 3-10 g d-1 for adults, to enhance the elimination of 137Cs from the body. The total internal committed doses and the effect of Prussian Blue treatment for 15 contaminated adults involved in this accident have been evaluated in this paper. Prussian Blue caused dose reductions in the range of 51-84%, with an average of 71%. This reduction was shown to be independent of the dosage of Prussian Blue. Total internal committed doses were in the range of 4.6 x 10(-3) Gy to 9.7 x 10(-1) Gy for the most-contaminated adults. Data on 137Cs biological half-lives for seven children contaminated in the accident are also presented.
Assuntos
Acidentes , Antídotos , Radioisótopos de Césio , Descontaminação/métodos , Ferrocianetos/uso terapêutico , Lesões por Radiação/prevenção & controle , Adolescente , Adulto , Carga Corporal (Radioterapia) , Brasil , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Lesões por Radiação/etiologiaRESUMO
In the Goiânia accident, many individuals suffered external and internal contamination. The screening of internal contamination was done through 137Cs urinary excretion. During the first month after the accident, only in-vitro bioassay procedures were done. Incorporation into the body and committed doses were estimated using age-specific mathematical models correlating these quantities to the 137Cs excreted in urine. The ratio of feces to urine of 137Cs excretion was used to evaluate the effectiveness of the administration of Prussian Blue on removal of 137Cs from the body.
Assuntos
Acidentes , Radioisótopos de Césio/análise , Exposição Ambiental , Adulto , Bioensaio , Carga Corporal (Radioterapia) , Brasil , Radioisótopos de Césio/urina , Criança , Descontaminação/métodos , Fezes/química , Ferrocianetos/uso terapêutico , Humanos , Técnicas In Vitro , Teleterapia por Radioisótopo/instrumentação , Manejo de EspécimesRESUMO
Using the in-vivo monitoring data from the individuals that suffered internal contamination in the Goiânia accident, a preliminary study on the elimination of Cs from their body was conducted. It was concluded that elimination follows a first-order linear kinetic pattern, both with and without Prussian Blue treatment. Cesium half-lives for both sexes were shown to be influenced mainly by the weight of each individual. In general, Prussian Blue seems to reduce the half-life by 32%. At the time our study was conducted, patients who were under treatment with the drug were receiving 3 g d-1, 6 g d-1, or 10 g d-1 of the medication. Our results suggest that there is an optimum dosage for a certain weight range to achieve this reduction in half-life, but one would need more data to statistically prove this assumption.