ESTIMATION OF RADIONUCLIDES IN SOILS -A COMPARISON OF METHODS FOR ANNUAL DOSE IN LUMINESCENCE DATING

Abstract. A study was made in order to compare and test the performance of several methods for the annual radiation dose determination in luminescence dating. The following techniques were used: instrumental neutron activation, high resolution gamma ray spectrometry and alpha spectrometry. Detailed analysis was carried out through gamma spectrometry, the activities of different nuclides ( Tl) in the uranium and thorium series being measured, as well as 40 K. The potential of this method in checking the occurrence of radioactive disequilibrium in the series was investigated. The assumption that radium disequilibrium caused by the percolation of groundwater in soils can be encountered was supported by our finds. The consistency of the results obtained through the three different methods indicate the reliability of using high resolution gamma ray spectrometry as a fast and accurate method for measuring natural radionuclides concentrations in luminescence dating and as well for purposes of environmental monitoring

Estimating radiation effective doses from whole body computed tomography scans based on U.S. soldier patient height and weight

<p>Abstract</p> <p>Background</p> <p>The purpose of this study is to explore how a patient's height and weight can be used to predict the effective dose to a reference phantom with similar height and weight from a chest abdomen pelvis computed tomography scan when machine-based parameters are unknown. Since machine-based scanning parameters can be misplaced or lost, a predictive model will enable the medical professional to quantify a patient's cumulative radiation dose.</p> <p>Methods</p> <p>One hundred mathematical phantoms of varying heights and weights were defined within an x-ray Monte Carlo based software code in order to calculate organ absorbed doses and effective doses from a chest abdomen pelvis scan. Regression analysis was used to develop an effective dose predictive model. The regression model was experimentally verified using anthropomorphic phantoms and validated against a real patient population.</p> <p>Results</p> <p>Estimates of the effective doses as calculated by the predictive model were within 10% of the estimates of the effective doses using experimentally measured absorbed doses within the anthropomorphic phantoms. Comparisons of the patient population effective doses show that the predictive model is within 33% of current methods of estimating effective dose using machine-based parameters.</p> <p>Conclusions</p> <p>A patient's height and weight can be used to estimate the effective dose from a chest abdomen pelvis computed tomography scan. The presented predictive model can be used interchangeably with current effective dose estimating techniques that rely on computed tomography machine-based techniques.</p

Radon Measurements and Radon Remediationin Băiţa-Ştei Pronearea

Băiţa-Ştei was the largest uranium reserve in Romania with estimated reserves of 450,000 tons of high grade metal. It was a large open pit mine in the northwest of Romania (West Carpathian Mountains), situated at 123 km south-east of Oradea, the capital of Bihor County. The transport during the time of sediment by Crişul Băiţa water course increased the uranium and radium content in the river meadow. The building material from Crişul Băiţariver bed (stone, gravel, sand) was used as construction material for the houses. In addition, some people living on this valley and surroundings after the opening exploitation used as building material the uranium waste from this mine. Preliminary indoor radon measurement (grab samples) in the villages situated on the route of ore transport (BăiţaPlai -Ştei) shown high radon concentrations, until 5000 Bq m−3. The new result obtained in this work in springer season 252 Bq m−3 is comparable with the annual means of 241 Bq m−3 and 229 Bq m−3 respectively, previously obtained, but more than twice times higher than the average value of 126 Bq m−3, computed for Romania. About 3000 of etched CR-39 track detectors were used followed by a selection of 20 houses proposed for remediation where a systematic investigation regarding radon sources was performed. The measured indoor radon concentration in the surveyed buildings ranged from 40 to 4000 Bq m−3. For experimental research, a representative pilot house was chosen. This house represents an example of a typical building from this area, with complex and various radon entry pathways which are correlated with the geology of soil. This building was chosen as pilot house due to the fact that it requires different ventilation systems or other remedial measures to be installe