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This paper describes dose reconstruction for a joint Ukrainian-American case-control study of leukemia that was conducted in a cohort of 110,645 male Ukrainian cleanup workers of the Chornobyl (Chernobyl) accident who were exposed to various radiation doses over the 1986-1990 time period. Individual bone-marrow doses due to external irradiation along with respective uncertainty distributions were calculated for 1,000 study subjects using the RADRUE method, which employed personal cleanup history data collected in the course of an interview with the subject himself if he was alive or with two proxies if he was deceased. The central estimates of the bone-marrow dose distributions range from 3.7 × 10(-5) to 3,260 mGy, with an arithmetic mean of 92 mGy. The uncertainties in the individual stochastic dose estimates can be approximated by lognormal distributions; the average geometric standard deviation is 2.0.

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We report on the surface UV index (UVI) variations in Santiago (Chile) a city with high air pollution and complex surrounding topography. Ground-based UV measurements were continuously carried out between January 1995 and December 2011, by using a multi-channel filter radiometer (PUV-510). Ground-based measurements and satellite-derived data retrieved from the Total Ozone Mapping Spectrometer (TOMS), the Ozone Monitoring Instrument (OMI), and the Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY), were compared. We found that satellite-derived UVI products largely overestimate surface UVI. Our ground-based UVI measurements were significantly lower than TOMS-derived UVI data: (46.1±6.3)% (in the period 1997-2003), and OMI-derived UVI data: (47.0±6.3)% (in the period 2005-2007). Clear-sky SCIAMACHY-derived UVI were found to be also nearly systematically greater than ground-based UVI measurements in the period 2002-2011. An exceptionally long period of clear skies between December 2010 and January 2011 was used to test further satellite-derived UVI data; in the whole period, OMI and SCIAMACHY data were 53.1% and 38.3% greater than our ground-based measurements, respectively. These differences are presumably due to aerosol load associated with the local pollution and the complex topography surrounding Santiago. In addition, linear regression allowed us to estimate trends that we use for forecasting. Methodological details are provided below.

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This paper presents the results of the Environmental Monitoring Program for the Radioactive waste repository of Abadia de Goiás, which was originated from the accident of Goiania, conducted by the Regional Center of Nuclear Sciences (CRCN-CO) of the National Commission on Nuclear Energy (CNEN), from 1998 to 2008. The results are related to the determination of (137)Cs activity per unit of mass or volume of samples from surface water, ground water, depth sediments of the river, soil and vegetation, and also the air-kerma rate estimation for gamma exposure in the monitored site. In the phase of operational Environmental Monitoring Program, the values of the geometric mean and standard deviation obtained for (137)Cs activity per unit of mass or volume in the analyzed samples were (0.08 ± 1.16) Bq.L(-1) for surface and underground water, (0.22 ± 2.79) Bq.kg(-1) for soil, and (0.19 ± 2.72) Bq.kg(-1) for sediment, and (0.19 ± 2.30) Bq.kg(-1) for vegetation. These results were similar to the values of the pre-operational Environmental Monitoring Program. With these data, estimations for effective dose were evaluated for public individuals in the neighborhood of the waste repository, considering the main possible way of exposure of this population group. The annual effective dose obtained from the analysis of these results were lower than 0.3 mSv.y(-1), which is the limit established by CNEN for environmental impact in the public individuals indicating that the facility is operating safely, without any radiological impact to the surrounding environment.

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OBJECTIVE: To estimate the prevalence of exposure to magnetic fields generated by transmission lines (TL) and characterize the exposed population. METHODS: Information about TL in the metropolitan region of São Paulo, Southeastern Brazil, was provided by the electricity companies and mapped out using geographic information system (GIS). Demographic and socioeconomic data were obtained from the 2000 Census and added to the GIS in another layer. Households and their inhabitants that were located at a distance from the TL that was sufficient to generate a magnetic field 0.3 microT (microteslas) were deemed to be exposed. The prevalence was estimated according to the area of the corridors of exposure along the TL. Two approaches were used to delimit the corridor width: one consisted of widths that were predefined by the TL voltage, and the other consisted of calculation of the magnetic field. The socioeconomic information on the exposed and non-exposed populations were compared by applying the two-proportion test (alpha= 5%). RESULTS: In the corridors with predefined widths, the prevalence of exposure was 2.4%, and in the calculated corridors, the prevalence was 1.4%. Both methods indicated higher prevalence of exposure among the younger population, and among individuals with lower education and income levels (p < 0.001). CONCLUSIONS: The prevalence of exposure to magnetic fields generated by TL in the metropolitan region of São Paulo was lower than what has been observed in other countries. The results indicate inequality in the exposure to magnetic fields in this urban area, with greater risk to vulnerable populations such as children and socioeconomically less favored individuals.

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OBJETIVO: Estimar a prevalência de exposição aos campos magnéticos gerados por linhas de transmissão (LT) e caracterizar a população exposta. MÉTODOS: Informações sobre LT da Região Metropolitana de São Paulo foram fornecidas pelas concessionárias de energia e mapeadas usando sistema de informação geográfica (SIG). Dados demográficos e socioeconômicos foram obtidos por meio do Censo 2000 e incluídos no SIG em outra camada. Foram considerados expostos os domicílios e seus habitantes localizados a uma distância da LT suficiente para gerar um campo magnético 0,3 µT (microteslas). A prevalência foi estimada por meio da área de corredores de exposição ao longo das LT. A largura dos corredores de exposição se baseou em duas abordagens: uma consistiu em larguras pré-definidas pela tensão da LT e a outra por meio de cálculo do campo magnético. As informações socioeconômicas entre expostos e não expostos foram comparadas pela aplicação do teste de duas proporções (α= 5 por cento)...

OBJECTIVE: To estimate the prevalence of exposure to magnetic fields generated by transmission lines (TL) and characterize the exposed population. METHODS: Information about TL in the metropolitan region of São Paulo, Southeastern Brazil, was provided by the electricity companies and mapped out using geographic information system (GIS). Demographic and socioeconomic data were obtained from the 2000 Census and added to the GIS in another layer. Households and their inhabitants that were located at a distance from the TL that was sufficient to generate a magnetic field 0.3 µT (microteslas) were deemed to be exposed. The prevalence was estimated according to the area of the corridors of exposure along the TL. Two approaches were used to delimit the corridor width: one consisted of widths that were predefined by the TL voltage, and the other consisted of calculation of the magnetic field. The socioeconomic information on the exposed and non-exposed populations were compared by applying the two-proportion test (α= 5 percent)...

OBJETIVO: Estimar la prevalencia de exposición a los campos magnéticos generados por líneas de transmisión (LT) y caracterizar la población expuesta. MÉTODOS: Informaciones sobre LT de la Región Metropolitana de São Paulo (Sureste de Brasil) fueron providenciadas por las concesionarias de energía y mapeadas usando el sistema de información geográfica (SIG). Datos demográficos y socioeconómicos fueron obtenidos por medio del Censo 2000 e incluidos en el SIG en otra camada. Fueron considerados expuestos los domicilios y sus habitantes localizados a una distancia de la LT suficiente para generar un campo magnético 0,3 μT (microteslas). La prevalencia fue estimada por medio del área de corredores de exposición a lo largo de las LT. El ancho de los corredores de exposición se basó en dos abordajes: uno consistió en anchos pre-definidos por la tensión de la LT y la otra por medio del cálculo del campo magnético. Las informaciones socioeconómicas entre expuestos y no expuestos fueron comparadas por la aplicación de la prueba de dos proporciones (α=5 por ciento)...

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A crescente inserção de tecnologia eletroeletrônica em estabelecimentos assistenciais de saúde (EAS), seja como equipamentos terapêuticos, de diagnóstico ou até mesmo suporte vital, tem sido vista pela comunidade científica como a grande responsável pelo aumento dos níveis de energia eletromagnética emitidos ao ambiente hospitalar. Dessa forma, quando a energia eletromagnética presente no ambiente atinge um determinado nível crítico, fica estabelecida uma situação que é propícia ao aparecimento de dois fenômenos indesejados: a interferência eletromagnética (EMI) em equipamentos médicos, e os riscos biológicos (RBL) em seres vivos. Um importante recurso para gerenciar a compatibilidade eletromagnética e evitar o aparecimento destes fenômenos é o conhecimento das características eletromagnéticas presentes nestes ambientes. O objetivo deste trabalho é diagnosticar o comportamento eletromagnético estabelecido em ambientes de grande concentração de fontes emissoras como, por exemplo, o encontrado em centros cirúrgicos, através de uma série de medições in situ das grandezas eletromagnéticas envolvidas nestes meios (campos elétricos, campos magnéticos, ruídos conduzidos). Com base nestas medidas é realizada uma avaliação crítica de modo a comparar a situação estabelecida nos EAS e os limites de segurança preconizados por organismos competentes, tanto para EMI quanto para RBL. Como resultado desta análise, começa a existir maior discernimento quanto à real situação do ambiente eletromagnético encontrado em EAS nacionais, subsidiando informações para a definição de diretrizes mais eficientes para implementação de programas de gestão tecnológica que são direcionados às necessidades específicas destes hospitais.

Advances in technology and the increased use of electro-medical equipment (EME) to support medical procedures such as monitoring, diagnosis, therapeutic or even life support are considered as greatly responsible for the increase of electromagnetic energy within health care facilities (HCF) environments. In such circumstances, when electromagnetic energy reaches a certain critical level, a dangerous situation is established and two undesirable phenomena can take place, both electromagnetic interference (EMI) in medical equipment, and biological risks (BLR) in living beings. The knowledge of electromagneticcharacteristics shown by these environments can represent an important tool in order to promote electromagnetic compatibility and avoid the appearance of undesirable phenomena. Therefore, this work aims to diagnose the electromagnetic profile established in critical areas, such as operating rooms, through a number of “in situ” measurements concerning electromagnetic quantities present in this environment (electric field, magnetic field, conducted noise). Moreover, a critical evaluation follows in order to compare the establishedsituation within HCF and the safety levels prescribed by regulatory organizations regarding EMI and BLR. As a result of this assessment, a better understanding on the actual situation concerning the electromagnetic environment in HCF can be achieved, allowing clinical engineers to define better directives in order to implement an adequate management programs in these hospitals.

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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 (P(KA)), the entrance surface air kerma (K(e)) 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.

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To show the influence of measurement uncertainties in performance evaluation of laboratories, data from 42 comparison runs were evaluated using two statistical criteria. The normalized standard deviation, D, used by US EPA, that mainly takes into account the accuracy, and the normalized deviation, E, that includes the individual laboratory uncertainty used for performance evaluation in the key-comparisons by BIPM. The results show that data evaluated by the different criteria give a significant deviation of laboratory performance in each radionuclide assay when we analyse a large quantity of data.

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This paper reports (222)Rn concentrations in ground and drinking water of nine cities of Chihuahua State, Mexico. Fifty percent of the 114 sampled wells exhibited (222)Rn concentrations exceeding 11Bq/L, the maximum contaminant level (MCL) recommended by the USEPA. Furthermore, around 48% (123 samples) of the tap-water samples taken from 255 dwellings showed radon concentrations over the MCL. There is an apparent correlation between total dissolved solids and radon concentration in ground-water. The high levels of (222)Rn found may be entirely attributed to the nature of aquifer rocks.

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A novel system to determine thermal neutron flux in real time during NCT treatments was developed in the National Atomic Energy Commission of Argentina. The system is based on a special self-powered detector that can be implanted in patients owing to its small size and biocompatibility. High voltage is not required to operate this kind of detectors, which is a considerable advantage in terms of medical uses. By choosing the appropriate materials, it was possible to obtain a prototype with thermal neutron sensitivity providing for an adequate signal level in typical NCT thermal fluxes. It was also possible to minimize gamma response in order to neglect its contribution.

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River and reservoir sediments have been collected annually by Los Alamos National Laboratory since 1974 and 1979, respectively. These background samples are collected from five river stations and four reservoirs located throughout northern New Mexico and southern Colorado. Analyses include 3H, 90Sr, 137Cs, total U, 238Pu, 239,240Pu, 241Am, gross alpha, gross beta, and gross gamma radioactivity. Surprisingly, there are no federal or state regulatory standards in the USA that specify how to compute background radioactivity values on sediments. Hence, the sample median (or 0.50 quantile) is proposed for this background because it reflects central data tendency and is distribution-free. Estimates for the upper limit of background radioactivity on river and reservoir sediments are made for sampled analytes using the 0.95 quantile (two-tail). These analyses also show that seven of ten analytes from reservoir sediments are normally distributed, or are normally distributed after a logarithmic or square root transformation. However, only three of ten analytes from river sediments are similarly distributed. In addition, isotope ratios for 137Cs/238Pu, 137Cs/239,240Pu, and 239,240Pu/238Pu from reservoir sediments are independent of clay content, total organic carbon/specific surface area (TOC/SSA) and cation exchange capacity/specific surface area (CEC/SSA) ratios. These TOC/SSA and CEC/SSA ratios reflect sediment organic carbon and surface charge densities that are associated with radionuclide absorption, adsorption, and ion exchange reactions on clay mineral structures. These latter ratio values greatly exceed the availability of background radionuclides in the environment, and insure that measured background levels are a maximum. Since finer-grained reservoir sediments contain larger clay-sized fractions compared to coarser river sediments, they show higher background levels for most analytes. Furthermore, radioactivity values on reservoir sediments have remained relatively constant since the early 1980s. These results suggest that clay contents in terrestrial sediments are often more important at concentrating background radionuclides than many other environmental factors, including geology, climate and vegetation. Hence, reservoirs and floodplains represent ideal radionuclide sampling locations because fine-grained materials are more easily trapped here. Ultimately, most of these differences still reflect spatial and temporal variability originating from global atmospheric nuclear weapons testing and disintegration of nuclear-powered satellites upon atmospheric reentry.

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Mexico City, also called Federal District, covers an area of 1504 km(2), and has more than 8 million inhabitants. It is located more than 2200 m above sea level in a zone of high seismic activity, and founded on an ancient lake. At present it is one of the most crowded and contaminated cities in the world, with thermal inversions. Chemical contaminants and aerosol particles in the environmental air are high most of the year. Due to these geological, environmental and socioeconomic conditions, Federal District presents very peculiar characteristics, which are important for understanding the distribution and measurements of indoor radon concentration. In this work the results of 3 year (1998-2000) measurements of indoor radon levels in the Federal District are presented. For the detector distribution and measurements, the actual political administrative divisions of the Federal District, consisting of 16 very well defined zones, was used. Nuclear track detection methodology was selected for the measurement, with a passive device close-end-cup system with CR-39 (Lantrack) polycarbonate as the detection material, with one step chemical etching, following a very well established protocol developed at the Instituto de Física, UNAM. Calibration was carried out at the Oak Ridge National Laboratory, and verification at the Instituto de Física chamber. The results show that the arithmetical mean values of the indoor radon concentration for each region of the Federal District follow a non-homogenous distribution.

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Accessing the NASA trapped radiation models AP-8 and AE-8 with (B,L) values obtained with modern geomagnetic field models causes an unrealistic secular increase of the predicted flux over low altitude orbits. We show the secular variation of the orbit-averaged particle flux along the LDEF orbit and the mission dose, obtained using the AP-8 trapped radiation models with an epoch-dependent magnetic field. The artificially increased epoch-dependent fluxes and doses are compared to the flux and dose obtained with a consistent and more correct procedure for predicting fluxes with the NASA models. This procedure has been implemented in the radiation analysis software package UNIRAD developed and distributed by BIRA-IASB.

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Este trabalho analisa os resultados da monitoração individual externa de trabalhadores da área médica enfocando os níveis de dose em diferentes departamentos de diferentes hospitais.

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El Servicio de Radiodiagnóstico del Hospital Universitario de la Universidad Federal de Río de Janeiro, juntamente con el Instituto de Radioprotección y Densitometría de la Comisión Nacional de Energía Nuclear, se encuentra desarrolllando programas en el área de garantía de calidad en radiodiagnóstico. Estas actividades contemplan como objetivo importante la optimización de las dosis. Uno de los programas en marcha comprende exámenes de fluoroscopia gastrointestinal. A fin de investigar los niveles de exposición a la radiación fueron realizadas medidas de dosis de entrada en la piel recibidas por pacientes y médicos en exámenes de esofagografía, seriografía y colon, utilizando dosímetros colocados en varias posiciones del cuerpo. En este trabajo se describe la metodología seguida y se muestran los resultados obtenidos hasta el presente. Se hace un análisis del espectro de dosis observadas en pacientes y profesionales, de acuerdo con diversos parámetros tales como ubicación de dosímetros, tiempo de exposición, técnicas empleadas, número de radiografías, etc. También se describen los pasos a seguir con el objeto de concretar la implantación de un programa de control de calidad en los exámenes mencionados

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El Servicio de Radiodiagnóstico del Hospital Universitario de la Universidad Federal de Río de Janeiro, juntamente con el Instituto de Radioprotección y Densitometría de la Comisión Nacional de Energía Nuclear, se encuentra desarrolllando programas en el área de garantía de calidad en radiodiagnóstico. Estas actividades contemplan como objetivo importante la optimización de las dosis. Uno de los programas en marcha comprende exámenes de fluoroscopia gastrointestinal. A fin de investigar los niveles de exposición a la radiación fueron realizadas medidas de dosis de entrada en la piel recibidas por pacientes y médicos en exámenes de esofagografía, seriografía y colon, utilizando dosímetros colocados en varias posiciones del cuerpo. En este trabajo se describe la metodología seguida y se muestran los resultados obtenidos hasta el presente. Se hace un análisis del espectro de dosis observadas en pacientes y profesionales, de acuerdo con diversos parámetros tales como ubicación de dosímetros, tiempo de exposición, técnicas empleadas, número de radiografías, etc. También se describen los pasos a seguir con el objeto de concretar la implantación de un programa de control de calidad en los exámenes mencionados (AU)

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We have flown two new charged particle detectors in five recent Shuttle flights. In this paper we report on the dose rate, equivalent dose rate, and radiation quality factor for trapped protons and cosmic radiation separately. A comparison of the integral linear energy transfer (LET) spectra with recent transport code calculations show significant disagreement. Using the calculated dose rate from the omni-directional AP8MAX model with IGRF reference magnetic field epoch 1970, and observed dose rate as a function of (averaged over all geographic latitude) and longitude, we have determined the westward drift of the South Atlantic anomaly. We have also studied the east-west effect, and observed a 'second' radiation belt. A comparison of the galactic cosmic radiation lineal energy transfer spectra with model calculations shows disagreement comparable to those of the trapped protons.

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Two new charged particle detectors have been flown in five recent Shuttle flights. The tissue-equivalent proportional counter measures the lineal energy spectrum of space radiation in the 0.26-300 keV micrometer-1 range. The charged particle spectrometer is a double dE/dx x E and dE/dx x Chrenekov detector system which provides a measurement of the differential energy spectrum of protons from 13 to 350 MeV and dose rate in silicon. In this paper the dose rate, equivalent dose rate, and radiation, quality factor for trapped protons and cosmic radiation are reported on separately. A comparison of the integral LET spectra with recent transport code calculations shows significant disagreement. Using the calculated dose rate from the omnidirectional AP8MAX model with IGRF reference magnetic field epoch 1970, and observed dose rate as a function of geographic latitude and longitude, the westward drift of the south Atlantic anomaly has been determined. The east-west effect has also been studied and a 'second' radiation belt observed. A comparison of the galactic cosmic radiation (GCR) lineal energy transfer spectra with model calculations shows disagreement comparable with those of the trapped protons.

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