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1.
J Nutr Health Aging ; 26(2): 161-168, 2022.
Article in English | MEDLINE | ID: mdl-35166309

ABSTRACT

OBJECTIVES: Defining an adequate protein intake in older adults remains unresolved. We examined the association between calibrated protein intake and comprehensive frailty by sex in the Kyoto-Kameoka study. DESIGN: Cross-sectional study of baseline data. SETTING AND PARTICIPANTS: The study included 5679 Japanese participants aged 65 years or older. METHODS: Calibration coefficients were estimated from food frequency questionnaires and 7-day dietary records as a reference. Comprehensive frailty was evaluated using the 25-item Kihon Checklist (KCL) and defined as a total KCL score of ≥7points. Sex-specific calibrated protein intakes were presented as % of energy, per kg of actual body weight (BW), and per kg of ideal BW. RESULTS: Multiple logistic regression analysis showed that calibrated protein intake is inversely associated with comprehensive frailty. The association between protein intake and comprehensive frailty was also evaluated using curve fitting with non-linear regression, a weak U-shaped association was found in males and an L-shaped association in females. Men had a low prevalence of frailty at a calibrated protein intake of 15-17% energy from protein, 1.2 g/kg actual BW/day, or 1.4 g/kg ideal BW/day, and women had a low prevalence of frailty at 17-21% energy from protein or 1.6 g/kg ideal BW/day, with the prevalence of frailty remaining unchanged at higher protein intakes. Meanwhile, the inverse relationship between protein intake per ABW and frailty showed a gradual decrease at 1.4 g/kg ABW/day for protein in women. CONCLUSIONS AND IMPLICATIONS: A non-linear relationship was found between calibrated protein intake and frailty, with a U-shaped association in men and an L-shaped association in women. Adequate protein intake in healthy Japanese older adults was higher than the current recommended daily allowance.


Subject(s)
Frailty , Aged , Checklist , Cross-Sectional Studies , Diet Records , Female , Frailty/epidemiology , Humans , Japan/epidemiology , Male , Prevalence
2.
J Nutr Health Aging ; 24(9): 1023-1030, 2020.
Article in English | MEDLINE | ID: mdl-33155632

ABSTRACT

OBJECTIVES: The purpose of this study was to examine if there is a relationship between lower-extremity muscle performance (LEMP) and physical activity, especially the physical activity level (PAL) value, in community-dwelling middle-aged and older adults. DESIGN: Cross-sectional study. SETTING: Community-based. PARTICIPANTS: Participants were 54 community-dwelling and independent middle-aged and older individuals (aged 54-89 years). MEASUREMENTS: Physical activity level was calculated from the total energy expenditure of each participant obtained using the doubly labeled water method (PALDLW) and estimated basal metabolic rate. Daily step count and intensity of physical activity was monitored with a triaxial accelerometer, and LEMP was assessed using the five-repetition sit-to-stand test (STS-5) and vertical jumping (VJ). RESULTS: The results of STS-5 nearly negatively correlated with those of PALDLW when analysing the middle-aged and older man and woman, separately. VJ positively correlated with PALDLW when analysing the middle-aged and older men and woman, separately. The relationship between LEMP (e.g. STS-5 and VJ) and PAL were maintained, regardless of sex and body composition. PALDLW was significantly positively correlated with LPA, MVPA, and steps, and significantly negatively correlated with sedentary time. The relationship PALDLW and steps was described as following equation: PALDLW = 0.0000392 × steps +1.531. CONCLUSIONS: These findings suggest that PALDLW is a key contributor to increasing LEMP among middle-aged and older adults. Maintaining high PALDLW may be beneficial to independent living, and participation in recreational and social activities in middle-aged and older adults.


Subject(s)
Accelerometry/methods , Exercise/physiology , Lower Extremity/physiopathology , Muscles/physiopathology , Water/metabolism , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Humans , Male , Middle Aged
3.
Appl Radiat Isot ; 166: 109402, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32911438

ABSTRACT

Luminescent properties of alexandrite crystals (BeAl2O4:Cr3+) are studied. Partial readouts of thermoluminescence (TL) and optically stimulated luminescence (OSL) signals were obtained to infer the relations of OSL and TL trapping centers. Four TL peaks were studied; their intensities decrease at different rates by illumination with blue OSL light. The OSL curve shows two-time components (exponential decay constants 3.15 and 28.4 s). The short time component is preferentially diminished when the sample is heated to temperatures from 363 to 513 K. About 50% of the whole TL intensity remains after a complete 300s OSL readout.

4.
Radiat Prot Dosimetry ; 182(2): 258-265, 2018 Dec 01.
Article in English | MEDLINE | ID: mdl-29684169

ABSTRACT

We propose a personal dosemeter based on the combination of thermoluminescence (TL) and optically stimulated luminescence (OSL) detectors employing the advantages of both techniques. The new OSL/TL dosemeter using a badge manufactured in a 3D printer was tested for assessment of photon doses in simulated and actual situations of exposure. Additionally, Brazilian national performance tests adapted to the new dosemeter were run as well as the performance tests of international standards on the passive dosimetry systems. The results showed the advantages of combined OSL and TL techniques when using the three different configurations of detector combination, Al2O3/BeO, BeO/CaSO4 and Al2O3/LiF. The dosemeter allowed corrections for radiation energy without the necessity of attenuation filters, the evaluation of single and accumulated doses and the triple check of the dose values. Further, the performance tests were consistent with national and international requirements, showing the viability of application of the new dosemeter to the assessment of equivalent doses.


Subject(s)
Optically Stimulated Luminescence Dosimetry/instrumentation , Thermoluminescent Dosimetry/instrumentation , Brazil , Equipment Design , Humans , Materials Testing , Photons , Printing, Three-Dimensional
5.
Radiat Prot Dosimetry ; 177(3): 285-288, 2017 Dec 01.
Article in English | MEDLINE | ID: mdl-28402564

ABSTRACT

As the ionizing radiation to which workers are exposed is related to possible harmful biological effect, its dose evaluation gains relevance. Although the effects of low doses are still controversial, the radiation protection authorities assume that any dose of ionizing radiation is potentially harmful to the human health and adopt the linear non-threshold model for the dose-effect relation. The Dosimetry Laboratory of the Institute of Physics of the University of São Paulo performs the external individual monitoring of workers exposed to X- and gamma-rays since 1981, with the technique of thermoluminescence. Currently, ~500 badges are provided to the university professionals mostly working in research laboratories and hospitals. Data of individual annual dose equivalent collected from 1995 to 2015 and the performance of the monitoring service are presented in this paper.


Subject(s)
Occupational Exposure/analysis , Thermoluminescent Dosimetry/methods , Brazil , Equipment Design , Gamma Rays , Humans , Occupational Diseases/prevention & control , Radiation Dosage , Radiation Injuries/prevention & control , Radiation, Ionizing , Risk Assessment , Thermoluminescent Dosimetry/instrumentation , Universities , X-Rays
6.
Transplant Proc ; 46(10): 3515-22, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25498083

ABSTRACT

BACKGROUND: Following improvements in patient and graft survival after liver transplantation (LT), the recipients' quality of life has become an important focus of patient care. Sleep is closely related to physical and mental health; however, sleep disturbances in LT patients have not yet been evaluated. METHODS: We assessed 59 LT patients (aged ≥18 years) between September 2011 and September 2012. The patients completed the restless legs syndrome (RLS), 36-item short-form health survey (SF-36), Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale (ESS) questionnaires. In addition, laboratory data were obtained and neuropsychological tests (NPT) were performed during study entry. RESULTS: Thirty-eight patients (64%) were included in the poor sleep group (PSQI ≥6 or ESS ≥10). The SF-36 scores were lower in the poor sleep group than in the good sleep group. Eleven patients (18%) had RLS. An NPT score ≥3 indicated minimal hepatic encephalopathy (MHE3). The MHE3 group consisted of 22 patients (43%). The time after LT was shorter; serum albumin, branched chain amino acid/tyrosine molar ratio (BTR), and role limitations due to poor physical health were lower; and serum ammonia levels were higher in the MHE3 group than in the MHE0-2 group. When the poor sleep group was divided into subgroups (control, MHE, RLS, and unknown), MHE patients had high model for end-stage liver disease scores, high ammonia levels, and low BTR, whereas RLS patients showed a short time after LT. CONCLUSION: Sixty-four percent of recipients were classified as poor sleepers. SF-36 scores were lower for poor sleepers than good sleepers. RLS and MHE are major diseases that cause sleep disturbances in patients after LT.


Subject(s)
Liver Transplantation/adverse effects , Living Donors/psychology , Quality of Life , Sleep Wake Disorders/epidemiology , Sleep/physiology , Female , Humans , Incidence , Japan/epidemiology , Male , Middle Aged , Neuropsychological Tests , Severity of Illness Index , Sleep Wake Disorders/etiology , Sleep Wake Disorders/psychology
7.
Radiat Prot Dosimetry ; 160(1-3): 226-30, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24743768

ABSTRACT

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.


Subject(s)
Air Pollution, Indoor/analysis , Radiation Monitoring , Radioactive Pollutants/analysis , Radon/analysis , Brazil , Data Collection , Environment , Geological Phenomena , Housing , Humans
8.
Sci Total Environ ; 468-469: 12-8, 2014 Jan 15.
Article in English | MEDLINE | ID: mdl-24012891

ABSTRACT

Radon levels in two old mines in San Luis, Argentina, were measured and analyzed, with the aim to assess the potential use of this radioactive noble gas as a tracer of geological processes in underground environments. La Carolina gold mine and Los Cóndores tungsten mine are today used as tourism mines. CR-39 nuclear track detectors were used for this purpose. Measurements were performed during both winter and summer seasons. The findings show that in these environments, significant radon concentrations are subject to large seasonal fluctuations, due to the strong dependence on natural ventilation with the outside temperature variations. For both mines, higher concentration values of (222)Rn were observed in summer than in winter; with an extreme ratio of 2.5 times between summer and winter seasons for Los Cóndores mine. The pattern of radon transport inside La Carolina mine revealed, contrary to what was believed, that this mine behaves as a system with two entrances located at different levels. However, this feature can only be observed in the winter season, when there is a marked difference between the inside and outside temperatures of the mine. In the case of Los Cóndores mine, the radon concentration pattern distribution is principally established by air current due to chimney-effect in summer and winter seasons. In both cases, the analyses of radon pattern distribution appear as a good method to trace air currents, and then localize unknown ducts, fissures or secondary tunnels in subterranean environments.


Subject(s)
Environmental Monitoring/methods , Mining , Radioactive Tracers , Radon/analysis , Air Movements , Argentina , Polyethylene Glycols , Seasons , Temperature
9.
Appl Radiat Isot ; 69(2): 350-7, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21074445

ABSTRACT

Primary beam spectra were obtained for an X-ray industrial equipment (40-150 kV), and for a clinical mammography apparatus (25-35 kV) from beams scattered at angles close to 90°, measured with a CdTe Compton spectrometer. Actual scattering angles were determined from the Compton energy shift of characteristic X-rays or spectra end-point energy. Evaluated contribution of coherent scattering amounts to more than 15% of fluence in mammographic beams. This technique can be used in clinical environments.


Subject(s)
Spectrometry, X-Ray Emission/instrumentation , Mammography/methods , Scattering, Radiation , Spectrometry, X-Ray Emission/methods
10.
J Environ Radioact ; 101(2): 153-8, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19945773

ABSTRACT

Radon and gamma radiation level measurements were carried out inside the La Carolina mine, one of the oldest gold mining camps of southern South America, which is open for touristic visits nowadays. CR-39 track-etch detectors and thermoluminescent dosimeters of natural CaF(2) and LiF TLD-100 were exposed at 14 points along the mine tunnels in order to estimate the mean (222)Rn concentration and the ambient dose equivalent during the summer season (November 2008 to February 2009). The values for the (222)Rn concentration at each monitoring site ranged from 1.8+/-0.1 kBqm(-3) to 6.0+/-0.5 kBqm(-3), with a mean value of 4.8 kBqm(-3), indicating that these measurements exceed in about three times the upper action level recommended by ICRP for workplaces. The correlations between radon and gamma radiation levels inside the mine were also investigated. Effective doses due to (222)Rn and gamma rays inside the mine were determined, resulting in negligible values to tourists. Considering the effective dose to the mine tourist guides, values exceeding 20mSv of internal contribution to the effective doses can be reached, depending on the number of working hours inside the mine.


Subject(s)
Gamma Rays , Gold , Mining , Occupational Exposure/analysis , Radioactive Pollutants/analysis , Radon/analysis , Argentina , Geography , Humans , International Agencies , Polyethylene Glycols , Radiation Dosage , Radiation Protection/standards , Risk Assessment , Seasons , Thermoluminescent Dosimetry , Time Factors , Travel , Workplace
11.
Biofouling ; 25(4): 313-20, 2009.
Article in English | MEDLINE | ID: mdl-19191084

ABSTRACT

Barnacle (Balanus amphitrite) settlement on synthetic hydrogels with various chemical structures was tested in laboratory assays. The results demonstrated that cyprids settle less or not at all on hydrogels and PDMS elastomer compared with the polystyrene control. The low settlement on gels is most likely due to the 'easy release' of initially attached cyprids from the gel surfaces. This low adhesion of cyprids is independent of surface hydrophilicity or hydrophobicity, and of surface charge. The results also revealed that hydrogels can be categorized into two groups. One group showed an extremely strong antifouling (AF) performance that was independent of the elasticity (E) or swelling degree (q) of the gels. The second group showed relatively less strong AF performance that was E- or q-dependent. In the latter case, E, rather than the q, may be the more important factor for cyprid settlement.


Subject(s)
Ecosystem , Polymers/chemistry , Polymers/pharmacology , Thoracica/anatomy & histology , Thoracica/drug effects , Animals , Gels/chemical synthesis , Gels/chemistry , Molecular Structure , Polymers/chemical synthesis
12.
Phys Med Biol ; 50(23): 5619-28, 2005 Dec 07.
Article in English | MEDLINE | ID: mdl-16306656

ABSTRACT

The potential of using the optically stimulated luminescence (OSL) technique with aluminium oxide (Al(2)O(3):C) dosimeters for a precise and accurate estimation of absorbed doses delivered by high-energy photon beams was investigated. This study demonstrates the high reproducibility of the OSL measurements and presents a preliminary determination of the depth-dose curve in water for a 6 MV photon beam from a linear accelerator. The uncertainty of a single OSL measurement, estimated from the variance of a large sample of dosimeters irradiated with the same dose, was 0.7%. In the depth-dose curve obtained using the OSL technique, the difference between the measured and expected doses was < or =0.7% for depths between 1.5 and 10 cm, and 1.1% for a depth of 15 cm. The readout procedure includes a normalization of the response of the dosimeter with respect to a reference dose in order to eliminate variations in the dosimeter mass, dosimeter sensitivity, and the reader's sensitivity. This may be relevant for quality assurance programmes, since it simplifies the requirements in terms of personnel training to achieve the precision and accuracy necessary for radiotherapy applications. We concluded that the OSL technique has the potential to be reliably incorporated in quality assurance programmes and dose verification.


Subject(s)
Aluminum Oxide/chemistry , Radiometry/instrumentation , Radiometry/methods , Radiotherapy/methods , Light , Luminescence , Particle Accelerators , Photons , Radiation Dosage , Reproducibility of Results , Strontium Radioisotopes , Thermoluminescent Dosimetry , Time Factors , Yttrium Radioisotopes
13.
Health Phys ; 88(1): 65-70, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15596991

ABSTRACT

This work analyzes the influence of the most abundant natural gamma emitters in soil (226Ra, 232Th, and 40K) on the total outdoor gamma dose rate in the city of São Paulo, Brazil. A new method is introduced to determine gamma dose rates due to soil 1 m above the ground through measurements performed deep in the soil. This allows evaluation of the soil component even in places where the measurement at 1 m height is influenced by other sources (mainly the presence of buildings). The methodology was tested in non-urbanized areas by comparing direct dose rate measurements in air with those deep in soil. In addition, high-resolution gamma ray spectrometry of soil samples collected throughout the city was used to determine the natural radionuclide concentrations, allowing the comparison with the in-situ dose rate results. Measurements deep in soil followed a log-normal distribution. The fitted geometric mean (median) and geometric standard deviation of the soil contribution to the ambient dose equivalent rate at 1 m height were, respectively, 80.9(6) and 0.642(4) nSv h(-1). Compared to previous data, these values show that buildings enhance about 35% the outdoor gamma dose rate expected only from soil. The specific activities of 226Ra, 232Th, and 40K in dry soil, given by their medians, were, respectively, 41, 75, and 176 Bq k(-1). These results reveal that the terrestrial gamma dose rates in São Paulo are higher than the world average, a fact that can be attributed to high thorium concentration. Direct measurements of dose rates were compared to the corresponding values determined from radionuclide concentrations in soil. Good agreement between methods was found.


Subject(s)
Gamma Rays , Radiation Dosage , Soil Pollutants, Radioactive/analysis , Spectrometry, Gamma
14.
Radiat Prot Dosimetry ; 111(1): 73-6, 2004.
Article in English | MEDLINE | ID: mdl-15367772

ABSTRACT

This survey was carried out in the state of São Paulo, Brazil. The health services located in the state perform approximately 321 radiological examinations per 1000 inhabitants. A representative sample of 200 health services was selected using sampling techniques, and a postal dosimetric kit was sent to each one who agreed to participate. The kit evaluates entrance surface dose (ESD), making use of thermoluminescence dosemeters attached to the skin of patients. The radiographic technique employed and some physical data of patients were also gathered. In this stage of the survey, only chest examinations, projections AP, PA and LAT, were evaluated. A total of 917 ESD values were measured, which correspond to 588 patients and 74 examination rooms. The ESD to patients were analysed according to weight and age. Groups of standard patients (children and adults) were selected, and reference doses were determined. Large variations of ESD were observed, indicating that much can be done in order to reduce the patient doses by changing the technical parameters. Moreover, the results of ESD in paediatric radiology point to the necessity of special attention in the practice of radiological examinations in this age group.


Subject(s)
Radiography, Thoracic/statistics & numerical data , Adolescent , Adult , Age Factors , Body Height , Body Size , Body Weight , Brazil , Child , Child, Preschool , Female , Health Services/statistics & numerical data , Humans , Infant , Male , Radiation Dosage , Radiography, Thoracic/methods , Sampling Studies , Thermoluminescent Dosimetry
15.
Radiat Prot Dosimetry ; 103(4): 367-70, 2003.
Article in English | MEDLINE | ID: mdl-12797561

ABSTRACT

The dose received by people exposed to indoor radon is mainly due to radon progeny. This fact points to the establishment of techniques that access either radon and progeny together, or only radon progeny concentration. In this work a low cost and easy to use methodology is presented to determine the total indoor alpha emission concentration. It is based on passive detection using LR-115 and CR-39 detectors, taking into account the plateout effect. A calibration of LR-115 track density response was done by indoor exposure in controlled environments and dwellings, places where 222Rn and progeny concentration were measured with CR-39. The calibration factor obtained showed great dependence on the ambient condition: (0.69 +/- 0.04) cm for controlled environments and (0.43 +/- 0.03) cm for dwellings.


Subject(s)
Housing , Radon/analysis , Air Pollutants, Radioactive , Air Pollution, Indoor , Alpha Particles , Calibration , Humans , Radiometry/instrumentation
16.
Radiat Prot Dosimetry ; 103(2): 141-8, 2003.
Article in English | MEDLINE | ID: mdl-12593433

ABSTRACT

Recently the Brazilian health organisation published information conceming the number of hospitals, details of radiological equipment and frequency of medical examinations in the country. The information concerning the city of São Paulo is compiled here, complemented by a survey of absorbed doses to patients undergoing the most frequent examination: chest radiographs (postero-anterior (PA) and lateral (LAT) projections), as well as the physical parameters employed (tube voltage, current-time product, focus-film distance, field size). To collect the data, a sample of 12 hospitals (a representative sample of the 199 located in the city) was chosen, totalling 27 X ray machines. An anthropomorphic phantom was irradiated to simulate the patient. Absorbed doses were determined with thermoluminescence dosemeters placed in the phantom, externally and internally. Mean values of entrance surface dose (ESD) for PA and LAT projections were 0.22 mGy (from 0.07 to 0.61 mGy) and 0.98 mGy (from (1.30 to 4.01 mGy), respectively. The average organ doses per complete examination (PA and LAT) were 0.15 and 0.24 mGy to thyroid and lung, respectively. The thyroid was thus in the primary beam in many cases. The large variation in the ESD and organ doses indicates that much can be done in order to reduce the patient doses by adequate changes of physical parameters, without loss of image quality.


Subject(s)
Radiography, Thoracic/statistics & numerical data , Radiometry , Brazil , Female , Health Surveys , Humans , Lung/radiation effects , Male , Organ Specificity , Phantoms, Imaging , Radiation Dosage , Radiography/statistics & numerical data , Radiography, Thoracic/instrumentation , Radiometry/instrumentation , Retrospective Studies , Thermoluminescent Dosimetry , Thyroid Gland/radiation effects , Urban Population
17.
Radiat Prot Dosimetry ; 101(1-4): 201-4, 2002.
Article in English | MEDLINE | ID: mdl-12382735

ABSTRACT

In 1987, in the city of Goiânia, Brazil, occurred one of the worst radiological accidents ever reported. The remains of 137Cs contamination in a terrain where part of a radiotherapy unit had been manipulated in 1987 were measured in 1999-2000, and some of the results are presented here. Using the technique of gamma ray spectrometry in situ and in the laboratory, the ambient dose equivalent rate at 1 m above the ground and 137Cs concentration in soil were determined. Values higher than the ones established by the Brazilian National Nuclear Energy Commission (CNEN) as action levels in 1987, namely 0.8 microGy x h and 22.5 kBq x kg(-1), were obtained in that terrain. The 137Cs distribution profile in the soil shows high values of the specific activity in a layer located at a depth of 10-40 cm from the surface, where the soil is mixed with rubble, reaching values as high as 175 kBq x kg(-1).


Subject(s)
Cesium Radioisotopes/analysis , Nuclear Medicine , Radioactive Hazard Release , Soil Pollutants, Radioactive/analysis , Brazil , Gamma Rays , Geography
18.
Radiat Prot Dosimetry ; 100(1-4): 361-4, 2002.
Article in English | MEDLINE | ID: mdl-12382898

ABSTRACT

Thermally stimulated conductivity (TSC) and thermoluminescence (TL) measurements were conducted to investigate the mechanisms of charge transfer and luminescence emission in natural samples of Brazilian topaz irradiated with beta particles from a 90Sr/90Y source or with a 1.75 MeV Van de Graaff electron beam. The luminescence and conductivity were simultaneously monitored during the heating of the samples, allowing direct comparison of the TL and TSC peaks. The results show that the three main TL peaks are accompanied by corresponding TSC peaks, usually shifted to higher temperatures. Comparison of the relative TL/TSC intensities of peaks 2 and 3 indicates that the process of thermal quenching of the luminescence is probably active, which is also supported by TL/TSC measurements at different heating rates. Results on the dose response of TL/TSC peaks also reveal an interesting feature: the TL intensity shows a monotonic increase with dose in the range of study (50 Gy-3 kGy) comprising a linear-supralinear-saturation characteristic, while the TSC peaks exhibit an increase from 50 Gy to 1 kGy, followed by a small decrease for doses greater than 1 kGy. This result is interpreted in terms of a model involving multiple traps and one recombination centre.


Subject(s)
Aluminum Silicates/radiation effects , Thermoluminescent Dosimetry/methods , Aluminum Silicates/chemistry , Beta Particles , Crystallization , Luminescent Measurements , Radiochemistry , Thermal Conductivity , Thermoluminescent Dosimetry/statistics & numerical data
19.
Radiat Prot Dosimetry ; 98(4): 433-6, 2002.
Article in English | MEDLINE | ID: mdl-12120671

ABSTRACT

Brazil's worst radiological accident took place in 1987, in the city of Goiânia. In 1999 and 2000, detailed measurements of 137Cs contamination were performed in junkyard II, one of the places involved in the accident. High values of 137Cs activity per unit mass were found in soil layers at depths between 10 and 40 cm from the surface, reaching values as high as 175 kBq x kg(-1). High values of 137Cs concentration in fruits and plants were also observed. Moreover, values of ambient dose equivalent rate at 1 m above the ground were found to be higher than the limit of 1.0 microSv x h(-1) set by the Brazilian National Nuclear Energy Commission (CNEN) in 1987. In February 2000, the CNEN was informed about the results of our measurements. As consequence, in August 2001, the CNEN performed a new intervention action in the area, covering all its extension with a concrete layer and removing some plants and trees. The new remedial action reduced the dose rate to approximately 13% of the value prior to covering the site in concrete, reaching values below the CNEN limit, as demonstrated by the measurements presented here.


Subject(s)
Radiation Injuries/diagnosis , Radioactive Hazard Release , Radiometry/methods , Brazil , Cesium Radioisotopes , Humans , Radiometry/instrumentation , Time Factors
20.
Radiat Prot Dosimetry ; 95(2): 165-71, 2001.
Article in English | MEDLINE | ID: mdl-11572645

ABSTRACT

The results of measurements, performed in 1999, of the remaining 137Cs contamination in some of the sites where fragments of a radioactive source of a teletherapy unit had been manipulated in 1987 are presented. This episode occurred in the city of Goiânia, during Brazil's worst radiological accident ever reported. Using the technique of gamma ray spectrometry, analyses of both surface and profile soil and vegetable samples were made. High values of 137Cs activity per unit mass were found in soil layers at depths between 10 and 40cm from the surface. Some values exceeded by up to eight times the action level of 22.5 kBq x kg(-1) proposed by the Brazilian National Nuclear Energy Commission (CNEN) during the decontamination process at the time of the accident, for the first year after the accident. Absorbed dose rates at 1 m above the ground were calculated from the data of 137Cs concentration in the soil and compared with those obtained from in situ gamma ray spectrometry and from thermoluminescence dosimetry.


Subject(s)
Cesium Radioisotopes/analysis , Radioisotope Teletherapy , Soil Pollutants, Radioactive/analysis , Brazil , Decontamination , Hazardous Substances , Radiation Dosage , Radiation Monitoring , Radioactive Hazard Release , Radioisotope Teletherapy/instrumentation , Radiometry , Spectrometry, Gamma/methods , Time Factors
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