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Sample records for additional dose assessment

  1. "The Dose Makes the Poison": Informing Consumers About the Scientific Risk Assessment of Food Additives.

    Bearth, Angela; Cousin, Marie-Eve; Siegrist, Michael

    2016-01-01

    Intensive risk assessment is required before the approval of food additives. During this process, based on the toxicological principle of "the dose makes the poison,ˮ maximum usage doses are assessed. However, most consumers are not aware of these efforts to ensure the safety of food additives and are therefore sceptical, even though food additives bring certain benefits to consumers. This study investigated the effect of a short video, which explains the scientific risk assessment and regulation of food additives, on consumers' perceptions and acceptance of food additives. The primary goal of this study was to inform consumers and enable them to construct their own risk-benefit assessment and make informed decisions about food additives. The secondary goal was to investigate whether people have different perceptions of food additives of artificial (i.e., aspartame) or natural origin (i.e., steviolglycoside). To attain these research goals, an online experiment was conducted on 185 Swiss consumers. Participants were randomly assigned to either the experimental group, which was shown a video about the scientific risk assessment of food additives, or the control group, which was shown a video about a topic irrelevant to the study. After watching the video, the respondents knew significantly more, expressed more positive thoughts and feelings, had less risk perception, and more acceptance than prior to watching the video. Thus, it appears that informing consumers about complex food safety topics, such as the scientific risk assessment of food additives, is possible, and using a carefully developed information video is a successful strategy for informing consumers. PMID:25951078

  2. Assessment of the Annual Additional Effective Doses amongst Minamisoma Children during the Second Year after the Fukushima Daiichi Nuclear Power Plant Disaster.

    Masaharu Tsubokura

    Full Text Available An assessment of the external and internal radiation exposure levels, which includes calculation of effective doses from chronic radiation exposure and assessment of long-term radiation-related health risks, has become mandatory for residents living near the nuclear power plant in Fukushima, Japan. Data for all primary and secondary children in Minamisoma who participated in both external and internal screening programs were employed to assess the annual additional effective dose acquired due to the Fukushima Daiichi nuclear power plant disaster. In total, 881 children took part in both internal and external radiation exposure screening programs between 1st April 2012 to 31st March 2013. The level of additional effective doses ranged from 0.025 to 3.49 mSv/year with the median of 0.70 mSv/year. While 99.7% of the children (n = 878 were not detected with internal contamination, 90.3% of the additional effective doses was the result of external radiation exposure. This finding is relatively consistent with the doses estimated by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR. The present study showed that the level of annual additional effective doses among children in Minamisoma has been low, even after the inter-individual differences were taken into account. The dose from internal radiation exposure was negligible presumably due to the success of contaminated food control.

  3. Utirik Atoll Dose Assessment

    Robison, W.L.; Conrado, C.L.; Bogen, K.T

    1999-10-06

    On March 1, 1954, radioactive fallout from the nuclear test at Bikini Atoll code-named BRAVO was deposited on Utirik Atoll which lies about 187 km (300 miles) east of Bikini Atoll. The residents of Utirik were evacuated three days after the fallout started and returned to their atoll in May 1954. In this report we provide a final dose assessment for current conditions at the atoll based on extensive data generated from samples collected in 1993 and 1994. The estimated population average maximum annual effective dose using a diet including imported foods is 0.037 mSv y{sup -1} (3.7 mrem y{sup -1}). The 95% confidence limits are within a factor of three of their population average value. The population average integrated effective dose over 30-, 50-, and 70-y is 0.84 mSv (84, mrem), 1.2 mSv (120 mrem), and 1.4 mSv (140 mrem), respectively. The 95% confidence limits on the population-average value post 1998, i.e., the 30-, 50-, and 70-y integral doses, are within a factor of two of the mean value and are independent of time, t, for t > 5 y. Cesium-137 ({sup 137}Cs) is the radionuclide that contributes most of this dose, mostly through the terrestrial food chain and secondarily from external gamma exposure. The dose from weapons-related radionuclides is very low and of no consequence to the health of the population. The annual background doses in the U. S. and Europe are 3.0 mSv (300 mrem), and 2.4 mSv (240 mrem), respectively. The annual background dose in the Marshall Islands is estimated to be 1.4 mSv (140 mrem). The total estimated combined Marshall Islands background dose plus the weapons-related dose is about 1.5 mSv y{sup -1} (150 mrem y{sup -1}) which can be directly compared to the annual background effective dose of 3.0 mSv y{sup -1} (300 mrem y{sup -1}) for the U. S. and 2.4 mSv y{sup -1} (240 mrem y{sup -1}) for Europe. Moreover, the doses listed in this report are based only on the radiological decay of {sup 137}Cs (30.1 y half-life) and other

  4. Enjebi Island dose assessment

    We have updeated the radiological dose assessment for Enjebi Island at Enewetak Atoll using data derived from analysis of food crops grown on Enjebi. This is a much more precise assessment of potential doses to people resettling Enjebi Island than the 1980 assessment in which there were no data available from food crops on Enjebi. Details of the methods and data used to evaluate each exposure pathway are presented. The terrestrial food chain is the most significant potential exposure pathway and 137Cs is the radionuclide responsible for most of the estimated dose over the next 50 y. The doses are calculated assuming a resettlement date of 1990. The average wholebody maximum annual estimated dose equivalent derived using our diet model is 166 mremy;the effective dose equivalent is 169 mremy. The estimated 30-, 50-, and 70-y integral whole-body dose equivalents are 3.5 rem, 5.1 rem, and 6.2 rem, respectively. Bone-marrow dose equivalents are only slightly higher than the whole-body estimates in each case. The bone-surface cells (endosteal cells) receive the highest dose, but they are a less sensitive cell population and are less sensitive to fatal cancer induction than whole body and bone marrow. The effective dose equivalents for 30, 50, and 70 y are 3.6 rem, 5.3 rem, and 6.6 rem, respectively. 79 refs., 17 figs., 24 tabs

  5. Assessment of internal doses

    Rahola, T; Falk, R; Isaksson, M; Skuterud, L

    2002-01-01

    There is a definite need for training in dose calculation. Our first course was successful and was followed by a second, both courses were fully booked. An example of new tools for software products for bioassay analysis and internal dose assessment is the Integrated Modules for Bioassay Analysis (IMBA) were demonstrated at the second course. This suite of quality assured code modules have been adopted in the UK as the standard for regulatory assessment purposes. The intercomparison measurements are an important part of the Quality Assurance work. In what is known as the sup O utside workers ' directive it is stated that the internal dose measurements shall be included in the European Unions supervision system for radiation protection. The emergency preparedness regarding internal contamination was much improved by the training with and calibration of handheld instruments from participants' laboratories. More improvement will be gained with the handbook giving practical instructions on what to do in case of e...

  6. Role of sulfite additives in wine induced asthma: single dose and cumulative dose studies

    Vally, H; Thompson, Van P.

    2001-01-01

    BACKGROUND—Wine appears to be a significant trigger for asthma. Although sulfite additives have been implicated as a major cause of wine induced asthma, direct evidence is limited. Two studies were undertaken to assess sulfite reactivity in wine sensitive asthmatics. The first study assessed sensitivity to sulfites in wine using a single dose sulfited wine challenge protocol followed by a double blind, placebo controlled challenge. In the second study a cumulative dose su...

  7. Dose assessments for SFR 1

    Bergstroem, Ulla (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Avila, Rodolfo; Ekstroem, Per-Anders; Cruz, Idalmis de la (Facilia AB, Bromma (Sweden))

    2008-06-15

    Following a review by the Swedish regulatory authorities of the safety analysis of the SFR 1 disposal facility for low and intermediate level waste, SKB has prepared an updated safety analysis, SAR-08. This report presents estimations of annual doses to the most exposed groups from potential radionuclide releases from the SFR 1 repository for a number of calculation cases, selected using a systematic approach for identifying relevant scenarios for the safety analysis. The dose estimates can be used for demonstrating that the long term safety of the repository is in compliance with the regulatory requirements. In particular, the mean values of the annual doses can be used to estimate the expected risks to the most exposed individuals, which can then be compared with the regulatory risk criteria for human health. The conversion from doses to risks is performed in the main report. For one scenario however, where the effects of an earthquake taking place close to the repository are analysed, risk calculations are presented in this report. In addition, prediction of concentrations of radionuclides in environmental media, such as water and soil, are compared with concentration limits suggested by the Erica-project as a base for estimating potential effects on the environment. The assessment of the impact on non-human biota showed that the potential impact is negligible. Committed collective dose for an integration period of 10,000 years for releases occurring during the first thousand years after closure are also calculated. The collective dose commitment was estimated to be 8 manSv. The dose calculations were carried out for a period of 100,000 years, which was sufficient to observe peak doses in all scenarios considered. Releases to the landscape and to a well were considered. The peaks of the mean annual doses from releases to the landscape are associated with C-14 releases to a future lake around year 5,000 AD. In the case of releases to a well, the peak annual doses

  8. Dose assessments for SFR 1

    Following a review by the Swedish regulatory authorities of the safety analysis of the SFR 1 disposal facility for low and intermediate level waste, SKB has prepared an updated safety analysis, SAR-08. This report presents estimations of annual doses to the most exposed groups from potential radionuclide releases from the SFR 1 repository for a number of calculation cases, selected using a systematic approach for identifying relevant scenarios for the safety analysis. The dose estimates can be used for demonstrating that the long term safety of the repository is in compliance with the regulatory requirements. In particular, the mean values of the annual doses can be used to estimate the expected risks to the most exposed individuals, which can then be compared with the regulatory risk criteria for human health. The conversion from doses to risks is performed in the main report. For one scenario however, where the effects of an earthquake taking place close to the repository are analysed, risk calculations are presented in this report. In addition, prediction of concentrations of radionuclides in environmental media, such as water and soil, are compared with concentration limits suggested by the Erica-project as a base for estimating potential effects on the environment. The assessment of the impact on non-human biota showed that the potential impact is negligible. Committed collective dose for an integration period of 10,000 years for releases occurring during the first thousand years after closure are also calculated. The collective dose commitment was estimated to be 8 manSv. The dose calculations were carried out for a period of 100,000 years, which was sufficient to observe peak doses in all scenarios considered. Releases to the landscape and to a well were considered. The peaks of the mean annual doses from releases to the landscape are associated with C-14 releases to a future lake around year 5,000 AD. In the case of releases to a well, the peak annual doses

  9. Formative Assessment: Simply, No Additives

    Roskos, Kathleen; Neuman, Susan B.

    2012-01-01

    Among the types of assessment the closest to daily reading instruction is formative assessment. In contrast to summative assessment, which occurs after instruction, formative assessment involves forming judgments frequently in the flow of instruction. Key features of formative assessment include identifying gaps between where students are and…

  10. Irrigation in dose assessments models

    SKB has carried out several safety analyses for repositories for radioactive waste, one of which was SR 97, a multi-site study concerned with a future deep bedrock repository for high-level waste. In case of future releases due to unforeseen failure of the protective multiple barrier system, radionuclides may be transported with groundwater and may reach the biosphere. Assessments of doses have to be carried out with a long-term perspective. Specific models are therefore employed to estimate consequences to man. It has been determined that the main pathway for nuclides from groundwater or surface water to soil is via irrigation. Irrigation may cause contamination of crops directly by e.g. interception or rain-splash, and indirectly via root-uptake from contaminated soil. The exposed people are in many safety assessments assumed to be self-sufficient, i.e. their food is produced locally where the concentration of radionuclides may be the highest. Irrigation therefore plays an important role when estimating consequences. The present study is therefore concerned with a more extensive analysis of the role of irrigation for possible future doses to people living in the area surrounding a repository. Current irrigation practices in Sweden are summarised, showing that vegetables and potatoes are the most common crops for irrigation. In general, however, irrigation is not so common in Sweden. The irrigation model used in the latest assessments is described. A sensitivity analysis is performed showing that, as expected, interception of irrigation water and retention on vegetation surfaces are important parameters. The parameters used to describe this are discussed. A summary is also given how irrigation is proposed to be handled in the international BIOMASS (BIOsphere Modelling and ASSessment) project and in models like TAME and BIOTRAC. Similarities and differences are pointed out. Some numerical results are presented showing that surface contamination in general gives the

  11. Irrigation in dose assessments models

    Bergstroem, Ulla; Barkefors, Catarina [Studsvik RadWaste AB, Nykoeping (Sweden)

    2004-05-01

    SKB has carried out several safety analyses for repositories for radioactive waste, one of which was SR 97, a multi-site study concerned with a future deep bedrock repository for high-level waste. In case of future releases due to unforeseen failure of the protective multiple barrier system, radionuclides may be transported with groundwater and may reach the biosphere. Assessments of doses have to be carried out with a long-term perspective. Specific models are therefore employed to estimate consequences to man. It has been determined that the main pathway for nuclides from groundwater or surface water to soil is via irrigation. Irrigation may cause contamination of crops directly by e.g. interception or rain-splash, and indirectly via root-uptake from contaminated soil. The exposed people are in many safety assessments assumed to be self-sufficient, i.e. their food is produced locally where the concentration of radionuclides may be the highest. Irrigation therefore plays an important role when estimating consequences. The present study is therefore concerned with a more extensive analysis of the role of irrigation for possible future doses to people living in the area surrounding a repository. Current irrigation practices in Sweden are summarised, showing that vegetables and potatoes are the most common crops for irrigation. In general, however, irrigation is not so common in Sweden. The irrigation model used in the latest assessments is described. A sensitivity analysis is performed showing that, as expected, interception of irrigation water and retention on vegetation surfaces are important parameters. The parameters used to describe this are discussed. A summary is also given how irrigation is proposed to be handled in the international BIOMASS (BIOsphere Modelling and ASSessment) project and in models like TAME and BIOTRAC. Similarities and differences are pointed out. Some numerical results are presented showing that surface contamination in general gives the

  12. Radiological dose assessment for vault storage concepts

    Richard, R.F.

    1997-02-25

    This radiological dose assessment presents neutron and photon dose rates in support of project W-460. Dose rates are provided for a single 3013 container, the ``infloor`` storage vault concept, and the ``cubicle`` storage vault concept.

  13. UAE national occupational and environmental dose assessment

    Radiation safety guidelines and federal regulations require that radiation workers should be monitored in order to maintain the exposure as low as reasonably achievable. Due to the peaceful applications of ionizing radiation in different fields in UAE, there are certain risks which can be restricted and controlled through successful implementation such as occupational and environmental dose assessment. External and internal dose assessment for radiation workers needs to establish monitoring programmes with appropriate dosimetry to be used for individual, workplace and environmental monitoring. Radiation protection department implement the TLD system for external dose assessment and gamma spectrometer for internal dose assessment. Results of applications of both external and internal dose assessment are present. (author)

  14. Howard Hughes Medical Institute dose assessment survey

    Biomedical science researchers often express frustration that health physics practices vary widely between individual institutions. A survey examining both internal and external dose assessment practices was devised and mailed to fifty institutions supporting biomedical science research. The results indicate that health physics dose assessment practices and policies are highly variable. Factors which may contribute to the degree of variation are discussed. 2 tabs

  15. Dose reconstruction starting from the pre-dose effect of quartz: combined procedure of additive dose and multiple activation

    The pre-dose effect of the 110 C thermoluminescence (Tl) peak of quartz gives rise to the use of a sensitive technique to estimate of low-level doses under retrospective conditions. However, one can appreciate how aliquots of quartz, from the same mineral fraction, display different sensitivities. In this sense, we herein report on a new measurement protocol based on the aforementioned pre-dose effect. Such procedure includes additive dose and multiple activation steps allows to determine simultaneously the sensitivity changes induced by the thermal activation and the Tl dose dependence. This behaviour let calculate the field accrued dose by interpolation thus permitting an increase of both precision and accuracy. (Author)

  16. Interactive Rapid Dose Assessment Model (IRDAM): scenarios for comparing dose-assessment models. Vol.3

    The Interactive Rapid Dose Assessment Model (IRDAM) is a micro-computer based program designed to provide rapid assessments of the radiological impact of accidents at nuclear power plants. The main body of this document consists of 28 examples of IRDAM input and output, representing various types of accidents and releases. These examples are intended to provide a basis for comparison with other models or for testing IRDAM itself. Figures are included which show dose rates calculated by IRDAM for each scenario. Figures are also included which show calculations made using the computer codes WRAITH (Scherpelz, Borst and Hoenes, 1980) and RADPUR (Dabbert, et. al., 1982). Two other companion volumes to this one provide additional information on IRDAM. The User's Guide (NUREG/CR-3012, Volume 1) describes the setup and operation of equipment necessary to run IRDAM. Reactor Accident Assessment Methods (NUREG/CR-3012, Volume 2) describes the technical bases for IRDAM including methods, models and assumptions used in calculations

  17. Personal monitoring and assessment of doses received by radiation workers

    The Personal Radiation Monitoring Service operated by the Australian Radiation Laboratory is outlined and the types of monitors used for assessment of doses received by radiation workers are described. The distribution of doses received by radiation workers in different occupational categories is determined. From these distributions, the average doses received have been assessed and the maximum likely additional increase in cancer deaths in Australia as a result of occupational exposure estimated. This increase is shown to be very small. There is, however, a considerable spread of doses received by individuals within occupational groups

  18. Application of biota dose assessment tools for Japan environment

    We examined applicability of two biota assessment tools RESRAD-BIOTA and ERICA assessment tool, to Japanese environment. We considered paddy field as the typical Japan environment and used maximum of global fallout nuclide concentrations. The case studies showed that graded approaches used in RESRAD-BIOTA and ERICA assessment tool are effective to apply Japanese environment. In addition, we concluded that it is important to clarify the suitability of some parameter values used in biota dose assessment. Further study is necessary on the recommendation of environmental parameter values for biota dose assessment for Japan environment. (author)

  19. Calculational Tool for Skin Contamination Dose Assessment

    Hill, R L

    2002-01-01

    Spreadsheet calculational tool was developed to automate the calculations preformed for dose assessment of skin contamination. This document reports on the design and testing of the spreadsheet calculational tool.

  20. Environmental Impact Assessment Studies in Additive Manufacturing

    Kerbrat, Olivier; Le Bourhis, Florent; MOGNOL, Pascal; Hascoët, Jean-Yves

    2016-01-01

    International audience This chapter focuses on the environmental studies in additive manufacturing. For a cleaner production, environmental impacts that occur during the manufacturing phase should be assessed with accuracy. First, the literature on all the studies led to the characterization of the environmental impact of additive manufacturing processes. The studies on electric energy consumption of these processes are analyzed here, and then some studies taking into account raw material ...

  1. Thermoluminescent dosimetry and assessment of personal dose

    Thermoluminescence is discussed in terms of the energy band structure of a crystalline solid and the trapping of charge carriers by point defects. Some general properties of thermoluminescent materials used for dosimetry are outlined, with thermoluminescence of CaSO4:Dy being described in detail. The energy response function and the modification of the energy response of a dosimeter by shielding are discussed. The final section covers the connection between exposure, as recorded by a TLD badge, and the absorbed dose to various organs from gamma radiation in a uranium mine; the conversion from absorbed dose to dose equivalent; and uncertainties in assessment of dose equivalent

  2. An updated dose assessment for Rongelap Island

    Robison, W.L.; Conrado, C.L.; Bogen, K.T.

    1994-07-01

    We have updated the radiological dose assessment for Rongelap Island at Rongelap Atoll using data generated from field trips to the atoll during 1986 through 1993. The data base used for this dose assessment is ten fold greater than that available for the 1982 assessment. Details of each data base are presented along with details about the methods used to calculate the dose from each exposure pathway. The doses are calculated for a resettlement date of January 1, 1995. The maximum annual effective dose is 0.26 mSv y{sup {minus}1} (26 mrem y{sup {minus}1}). The estimated 30-, 50-, and 70-y integral effective doses are 0.0059 Sv (0.59 rem), 0.0082 Sv (0.82 rem), and 0.0097 Sv (0.97 rem), respectively. More than 95% of these estimated doses are due to 137-Cesium ({sup 137}Cs). About 1.5% of the estimated dose is contributed by 90-Strontium ({sup 90}Sr), and about the same amount each by 239+240-Plutonium ({sup 239+240}PU), and 241-Americium ({sup 241}Am).

  3. Dose assessment from radon in tourist caves

    Indoor radon measurements in tourist caves have traditionally being used in the studies of conservation of existent prehistoric artistic manifestations inside cavities. This kind of measurements can provide the grade, and partly the dynamics, of ventilation and renovation of the air of the caves. On the other hand, since 2001, Spanish law incorporated EURATOM basic standards for radiological protection, which include a request at the EC Member States to determine the working places on which exposure to natural radiation is significant. On Title VII (BOE 178/2001) radiation coming from natural sources has analogous role than radiation emitted from artificial ones used to. Because of the low ventilation rates existing at tourist caves, indoor radon concentration can be significantly high. In developed caves in which guides provide tours for the general public great care is needed for taking remedial actions concerning radon, because in some circumstances forced ventilation may alter the humidity inside the cave affecting some of the formations or paintings that attract tourists. Tourist guides can work about 1900 hours per year, so the only option to protect them and other cave workers from radon exposure is to apply an appropriate system of radiation protection mainly based on limitation of exposure by restricting the amount of time spent in the cave. From a previous radon measurement campaign carried out in caves at the region of Cantabria (Spain), those with higher concentration values were selected for a new survey. In this study more detailed radon measurements were performed in order to get more detailed information about monthly concentration variations, as well to determine the dose received by people working there. In dose assessment, specific characteristics of the cave concerning the behaviour of radon and its decay products are of main importance. Factors like unattached progeny fraction (fp), equilibrium factor (F) and particle concentration (Z) are

  4. Assessing dose rate distributions in VMAT plans

    Mackeprang, P.-H.; Volken, W.; Terribilini, D.; Frauchiger, D.; Zaugg, K.; Aebersold, D. M.; Fix, M. K.; Manser, P.

    2016-04-01

    Dose rate is an essential factor in radiobiology. As modern radiotherapy delivery techniques such as volumetric modulated arc therapy (VMAT) introduce dynamic modulation of the dose rate, it is important to assess the changes in dose rate. Both the rate of monitor units per minute (MU rate) and collimation are varied over the course of a fraction, leading to different dose rates in every voxel of the calculation volume at any point in time during dose delivery. Given the radiotherapy plan and machine specific limitations, a VMAT treatment plan can be split into arc sectors between Digital Imaging and Communications in Medicine control points (CPs) of constant and known MU rate. By calculating dose distributions in each of these arc sectors independently and multiplying them with the MU rate, the dose rate in every single voxel at every time point during the fraction can be calculated. Independently calculated and then summed dose distributions per arc sector were compared to the whole arc dose calculation for validation. Dose measurements and video analysis were performed to validate the calculated datasets. A clinical head and neck, cranial and liver case were analyzed using the tool developed. Measurement validation of synthetic test cases showed linac agreement to precalculated arc sector times within  ±0.4 s and doses  ±0.1 MU (one standard deviation). Two methods for the visualization of dose rate datasets were developed: the first method plots a two-dimensional (2D) histogram of the number of voxels receiving a given dose rate over the course of the arc treatment delivery. In similarity to treatment planning system display of dose, the second method displays the dose rate as color wash on top of the corresponding computed tomography image, allowing the user to scroll through the variation over time. Examining clinical cases showed dose rates spread over a continuous spectrum, with mean dose rates hardly exceeding 100 cGy min-1 for conventional

  5. Reduction of Radiation Dose Requirements of Foods by Additives

    Utilizing a recording photometer, a rapid turbidimetric method was worked out for the determination of nisin and tylosin activity. Those antibiotics affected by irradiation with X-rays in the range of 0 to 800 krad were also investigated. In a solution of pH 5.7 containing pea extract, the activity of the antibiotics decreased at a high rate when irradiated up to 200 krad, however, this rate slowed down with further radiation treatment. Tylosin lactate proved more radiation resistant than nisin. When treated with dosages between 400 and 800 krad the activity of nisin decreased by 73 to 87% and that of tylosin lactate by only 52 to 57%. During one-month storage at room temperature the residual activity of both the irradiated and untreated antibiotic solutions remained practically unchanged. The addition of antibiotics increased the preserving effect of X-rays. A 1:1 mixture of peas and a solution containing 4% sugar and 1.5% salt was heat treated for 15 minutes at 70°C. Samples taken from the liquid phase of this mixture were treated with various radiation-antibiotic combinations. When 100 ppm Nisaplin or 1 ppm tylosin lactate was added the radiation dose requirement was a quarter of that needed in the control samples to ensure microbiological stability. (author)

  6. Metrics, Dose, and Dose Concept: The Need for a Proper Dose Concept in the Risk Assessment of Nanoparticles

    Myrtill Simkó

    2014-04-01

    Full Text Available In order to calculate the dose for nanoparticles (NP, (i relevant information about the dose metrics and (ii a proper dose concept are crucial. Since the appropriate metrics for NP toxicity are yet to be elaborated, a general dose calculation model for nanomaterials is not available. Here we propose how to develop a dose assessment model for NP in analogy to the radiation protection dose calculation, introducing the so-called “deposited and the equivalent dose”. As a dose metric we propose the total deposited NP surface area (SA, which has been shown frequently to determine toxicological responses e.g. of lung tissue. The deposited NP dose is proportional to the total surface area of deposited NP per tissue mass, and takes into account primary and agglomerated NP. By using several weighting factors the equivalent dose additionally takes into account various physico-chemical properties of the NP which are influencing the biological responses. These weighting factors consider the specific surface area, the surface textures, the zeta-potential as a measure for surface charge, the particle morphology such as the shape and the length-to-diameter ratio (aspect ratio, the band gap energy levels of metal and metal oxide NP, and the particle dissolution rate. Furthermore, we discuss how these weighting factors influence the equivalent dose of the deposited NP.

  7. Inhalation dose assessment for Maralinga and Emu

    Dose assessments for the inhalation of artificial radionuclides are presented for all types of contaminated areas at Maralinga and Emu. These enable Committed Effective Dose Equivalent (CEDE), to be estimated by scaling at any area of interest where activity concentrations are known. In the case of Aborigines, these dose are estimated assuming respirable dust loadings of 1 mg/m3 for adults and 1.5 mg/m3 for children and infants. Details of the calculations are presented in the appendix. The model of the respiratory system used in this assessment is that described in Interantional Commission on Radiological Protection (ICRP) Publication 30 (ICRP, 1979a). With the exception of Kuli, which is contaminated with uranium, at all other sites it is only the inhalation of plutonium and americium that contributes significantly to the dose, and of these 239Pu is the largest contributor. Therefore, considering the long half lives of the radionuclides concerned, it appears that the inhalation problems highlighted by this dose assessment will not diminish significantly within any reasonable period of time and hence management strategies must be developed to deal with such problems. 32 refs., 5 tabs., 1 fig

  8. The embryogenesis of dose assessment at Hanford

    Several significant events occurred between 1955 and 1960 that resulted in major changes in environmental monitoring at Hanford and in the initiation of comprehensive dose assessments. These included: (1) specification of dose limits for nonoccupational exposure (including internal emitters); (2) a national and international awakening to the need for managing the disposal of radioactive wastes; (3) identification of the most important radionuclides and their sources of exposure; (4) data that quantified the transfer coefficients of nuclides along environmental pathways; and (5) development of greatly improved radiation detection instrumentation. In response to a growing need, the Hanford Laboratories formed the Environmental Studies and Evaluation component. This group revamped the monitoring and sampling programs so that analytical results contributed directly to dose estimation. Special studies were conducted to ascertain local dietary and recreational habits that affected dose calculations and to calibrate the models. These studies involved extensive contact with the public and governmental agencies, which elicited a positive reaction

  9. Internal dose assessment in radiation accidents

    Although numerous models have been developed for occupational and medical internal dosimetry, they may not be applicable to an accident situation. Published dose coefficients relate effective dose to intake, but if acute deterministic effects are possible, effective dose is not a useful parameter. Consequently, dose rates to the organs of interest need to be computed from first principles. Standard bioassay methods may be used to assess body contents, but, again, the standard models for bioassay interpretation may not be applicable because of the circumstances of the accident and the prompt initiation of decorporation therapy. Examples of modifications to the standard methodologies include adjustment of biological half-times under therapy, such as in the Goiania accident, and the same effect, complicated by continued input from contaminated wounds, in the Hanford 241Am accident. (author)

  10. Assessment of external dose indoors in Lithuania

    The aim of this paper was an assessment of external exposure indoors and its dependence on construction materials and indoor radon concentrations in Lithuanian living houses. Relationship of absorbed dose rate in air indoors and activity indexes of the most commonly used construction materials (wood, concrete and bricks) have been studied using results received in measurements done in >4700 rooms in 1995-2005. Possible connections of dose rate indoors with indoor radon concentrations are also discussed. Findings of this study helped to make an assessment of the mean value of effective dose of Lithuanian population due to external exposure indoors which is equal to 0.58 mSv y-1. The received data might also be used in improvement of quality of personal dosimetric measurements done in premises constructed of different construction materials. (authors)

  11. Human data and internal dose assessment

    Recent data on physical and anatomical and physiological or metabolic data regarding Japanese Reference Man is briefly reviewed. This includes reference values for masses of all organs and tissues proposed for a Japanese Reference male adult. Part of the data is used to assess alpha doses to bone tissues from naturally occurring 226Ra in bone of Japanese adult. (author)

  12. Dose assessment in the Marshall Islands

    Bikini Atoll and Enewetak Atoll in the Marshall Islands were the sites of major U.S. weapons testing from 1948 through 1958. Both the Bikini and Knewetak people have expressed a desire to return to their native Atolls. In 1968 clean-up and resettlement of Bikini was begun. In 1972-73 the initial survey of Enewetak Atoll was conducted and clean-up began in 1977. Surveys have been conducted at both Atolls to establish the concentrations of radionuclides in the biota and to determine the external exposure rates. Subsequent to the surveys dose assessments have been made to determine the potential dose to returning (100) populations at both Atolls. This talk will include discussions of the relative importance of the critical exposure pathways (i.e., external exposure, inhalation, marine, terrestrial and drinking water), the predominant radionuclides contributing to the predicted doses for each pathway, the doses predicted for alternate living patterns, comparison to Federal Guidelines, the comparison between Atolls, some of the social problems created by adherence to Federal Guidelines and the follow-up research identified and initiated to help refine the dose assessments and better predict the long term use of the Atolls (86). (author)

  13. Radiation dose assessment for building material

    A mathematical model for radiation dose assessment for building materials based on attenuation and build up for gamma rays of the natural emitters was studied in this work. This was done by calculate the air absorbed dose from elemental volume and integrate over the total wall volume, which uniformed density and activity concentration. The used form of the build-up is a mixing of exponential and linear form for Berger model [1]. To convert absorbed dose to effective dose for all natural emitter (include 137Cs in case of fallout), the dose rate conversion factors which were reported in UNSCEAR (1993) Report [2] and U. S. NCRP (1987) [3] was used. These factors are 0.7 Sv/Gy for adult and 0.8 Sv/Gy for children. A computer program for calculating the absorbed and the annual effective dose was prepared in MATLAB language. The program is applicable for wall or room building materials when walls consist of one or two layers. The obtained results were compared with published studies. (author)

  14. Exposure pathways and environmental dose assessment

    Radionuclides released into the environment from various nuclear facilities during normal operating conditions and under accident conditions eventually reach man through various pathways of exposure. It is required to assess the dose received by members of the public at various stages of nuclear facility. At the design stage of the nuclear facility such assessment is necessary for determining the adequacy of design provisions. During the operational phase, the assessment is needed to establish compliance with the standards and limits laid down for the facility and site

  15. A new approach to radiopharmaceutical dose assessment

    Dosimetry for bone-seeking radiopharmaceuticals relies on an accurate measurement of the activity administered, a model for uptake of the pharmaceutical, and calculations of the dose to the target organ. The authors report here a new approach to experimental assessment of the radiation dose to bone using electron paramagnetic resonance (EPR) spectrometry. Ionizing radiations interact with mineralized bone tissue (hydroxyapatite) to produce dose-dependent concentrations of long-lived paramagnetic centers. They have successfully applied the EPR technique to bone tissues of an animal treated with a radiopharmaceutical to demonstrate its sensitivity towards radiation-induced centers in the mineralized tissue. Although the EPR bone dosimetry method is invasive, it does offer the first experimental technique for measuring and mapping the tissue response to the administered radioactivity

  16. Bio-indicators for radiation dose assessment

    In nuclear facilities, such as Chalk River Laboratories, dose to the atomic radiation workers (ARWs) is assessed routinely by using physical dosimeters and bioassay procedures in accordance with regulatory recommendations. However, these procedures may be insufficient in some circumstances, e.g., in cases where the reading of the physical dosimeters is questioned, in cases of radiation accidents where the person(s) in question was not wearing a dosimeter, or in the event of a radiation emergency when an exposure above the dose limits is possible. The desirability of being able to assess radiation dose on the basis of radio-biological effects has prompted the Dosimetric Research Branch to investigate the suitability of biological devices and techniques that could be used for this purpose. Current biological dosimetry concepts suggest that there does not appear to be any bio-indicator that could reliably measure the very low doses that are routinely measured by the physical devices presently in use. Nonetheless, bio-indicators may be useful in providing valuable supplementary information in cases of unusual radiation exposures, such as when the estimated body doses are doubtful because of lack of proper physical measurements, or in cases where available results need to be confirmed for medical treatment plannings. This report evaluates the present state of biological dosimetry and, in particular, assesses the efficiency and limits of individual indicators. This has led to the recommendation of a few promising research areas that may result in the development of appropriate biological dosimeters for operational and emergency needs at Chalk River

  17. A Real Time Dose Assessment System

    The construction of the second Egyptian Research Reactor ETRR-2 at Anshas area in the same site as the first Egyptian Research Reactor ETRR-1 together with all the other nuclear Laboratories and installations necessitates the presence of a real time dose assessment system (RTDAS). The RTDAS as a part of an overall decision making aid, will help the emergency response manager to consolidate decisions regarding the required management of an off-site emergency. The present work describes a proposed dose assessment system based on a Geographical Information System (GIS). The system consists of Hardware and Software parts. The Hardware includes radiation-monitoring equipment connected to a central computer. The real time model is designed for operational use so it can provide decisions makers with information about the probable future consequences of an accidental release of radioactivity almost immediately of few minutes of receipt of the appropriate information. The output information from the model can be presented in terms of dose estimates for population at risk and can be displayed either as tabulated data or as dose contours superimposed upon a map of the area

  18. Dose. Detriment. Limit assessment; Dosis. Schadensmass. Grenzwertsetzung

    Breckow, J. [Technische Hochschule Mittelhessen, Giessen (Germany). Inst. fuer Medizinische Physik und Strahlenschutz (IMPS)

    2015-07-01

    One goal of radiation protection is the limitation of stochastic effects due to radiation exposure. The probability of occurrence of a radiation induced stochastic effect, however, is only one of several other parameters which determine the radiation detriment. Though the ICRP-concept of detriment is a quantitative definition, the kind of detriment weighting includes somewhat subjective elements. In this sense, the detriment-concept of ICRP represents already at the stage of effective dose a kind of assessment. Thus, by comparing radiation protection standards and concepts interconvertible or with those of environment or occupational protection one should be aware of the possibly different principles of detriment assessment.

  19. Assessment of the expected harm from prenatal irradiation with low doses and low dose rates

    The validity of the coefficients, suggested by ICRP (Publication 45) for assessment of the risk from prenatal irradiation with low doses and low dose rates is discussed. This includes: development of lethal and curable cancer, severe genetic defects, death before implantation and retarded mental development. Summarizing the individual assessment, the total harm from prenatal irradiation with 1 mvSv have been estimated at 4,9.104 lost years. The expected harm from the additional irradiation of the Bulgarian population during the first year after the Chernobyl accident is evaluated on that basis, taking into account the number of expected pregnancies among Bulgarian women in reproductive age and the individual effective equivalent doses. 15 refs

  20. Automated size-specific CT dose monitoring program: Assessing variability in CT dose

    Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan [Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States) and Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States)

    2012-11-15

    Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED{sub adj}). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED{sub adj} between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED{sub adj} that differed by up to 44% from effective dose

  1. A Novel Approach for Evaluating Carbamate Mixtures for Dose Additivity

    Two mathematical approaches were used to test the hypothesis ofdose-addition for a binary and a seven-chemical mixture ofN-methyl carbamates, toxicologically similar chemicals that inhibit cholinesterase (ChE). In the more novel approach, mixture data were not included in the ana...

  2. A mathematical approach to optimal selection of dose values in the additive dose method of ERP dosimetry

    Additive dose methods commonly used in electron paramagnetic resonance (EPR) dosimetry are time consuming and labor intensive. We have developed a mathematical approach for determining optimal spacing of applied doses and the number of spectra which should be taken at each dose level. Expected uncertainitites in the data points are assumed to be normally distributed with a fixed standard deviation and linearity of dose response is also assumed. The optimum spacing and number of points necessary for the minimal error can be estimated, as can the likely error in the resulting estimate. When low doses are being estimated for tooth enamel samples the optimal spacing is shown to be a concentration of points near the zero dose value with fewer spectra taken at a single high dose value within the range of known linearity. Optimization of the analytical process results in increased accuracy and sample throughput

  3. A mathematical approach to optimal selection of dose values in the additive dose method of ERP dosimetry

    Hayes, R.B.; Haskell, E.H.; Kenner, G.H. [Utah Univ., Salt Lake City, UT (United States)

    1996-01-01

    Additive dose methods commonly used in electron paramagnetic resonance (EPR) dosimetry are time consuming and labor intensive. We have developed a mathematical approach for determining optimal spacing of applied doses and the number of spectra which should be taken at each dose level. Expected uncertainitites in the data points are assumed to be normally distributed with a fixed standard deviation and linearity of dose response is also assumed. The optimum spacing and number of points necessary for the minimal error can be estimated, as can the likely error in the resulting estimate. When low doses are being estimated for tooth enamel samples the optimal spacing is shown to be a concentration of points near the zero dose value with fewer spectra taken at a single high dose value within the range of known linearity. Optimization of the analytical process results in increased accuracy and sample throughput.

  4. Dose estimates for the solid waste performance assessment

    The Solid Waste Performance Assessment calculations by PNL in 1990 were redone to incorporate changes in methods and parameters since then. The ten scenarios found in their report were reduced to three, the Post-Drilling Resident, the Post-Excavation Resident, and an All Pathways Irrigator. In addition, estimates of population dose to people along the Columbia River are also included. The attached report describes the methods and parameters used in the calculations, and derives dose factors for each scenario. In addition, waste concentrations, ground water concentrations, and river water concentrations needed to reach the performance objectives of 100 mrem/yr and 500 person-rem/yr are computed. Internal dose factors from DOE-0071 were applied when computing internal dose. External dose rate factors came from the GENII Version 1.485 software package. Dose calculations were carried out on a spreadsheet. The calculations are described in detail in the report for 63 nuclides, including 5 not presently in the GENII libraries. The spreadsheet calculations were checked by comparison with GENII, as described in Appendix D

  5. Dose estimates for the solid waste performance assessment

    Rittman, P.D.

    1994-08-30

    The Solid Waste Performance Assessment calculations by PNL in 1990 were redone to incorporate changes in methods and parameters since then. The ten scenarios found in their report were reduced to three, the Post-Drilling Resident, the Post-Excavation Resident, and an All Pathways Irrigator. In addition, estimates of population dose to people along the Columbia River are also included. The attached report describes the methods and parameters used in the calculations, and derives dose factors for each scenario. In addition, waste concentrations, ground water concentrations, and river water concentrations needed to reach the performance objectives of 100 mrem/yr and 500 person-rem/yr are computed. Internal dose factors from DOE-0071 were applied when computing internal dose. External dose rate factors came from the GENII Version 1.485 software package. Dose calculations were carried out on a spreadsheet. The calculations are described in detail in the report for 63 nuclides, including 5 not presently in the GENII libraries. The spreadsheet calculations were checked by comparison with GENII, as described in Appendix D.

  6. Peak Dose Assessment for Proposed DOE-PPPO Authorized Limits

    The Oak Ridge Institute for Science and Education (ORISE), a U.S. Department of Energy (DOE) prime contractor, was contracted by the DOE Portsmouth/Paducah Project Office (DOE-PPPO) to conduct a peak dose assessment in support of the Authorized Limits Request for Solid Waste Disposal at Landfill C-746-U at the Paducah Gaseous Diffusion Plant (DOE-PPPO 2011a). The peak doses were calculated based on the DOE-PPPO Proposed Single Radionuclides Soil Guidelines and the DOE-PPPO Proposed Authorized Limits (AL) Volumetric Concentrations available in DOE-PPPO 2011a. This work is provided as an appendix to the Dose Modeling Evaluations and Technical Support Document for the Authorized Limits Request for the C-746-U Landfill at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky (ORISE 2012). The receptors evaluated in ORISE 2012 were selected by the DOE-PPPO for the additional peak dose evaluations. These receptors included a Landfill Worker, Trespasser, Resident Farmer (onsite), Resident Gardener, Recreational User, Outdoor Worker and an Offsite Resident Farmer. The RESRAD (Version 6.5) and RESRAD-OFFSITE (Version 2.5) computer codes were used for the peak dose assessments. Deterministic peak dose assessments were performed for all the receptors and a probabilistic dose assessment was performed only for the Offsite Resident Farmer at the request of the DOE-PPPO. In a deterministic analysis, a single input value results in a single output value. In other words, a deterministic analysis uses single parameter values for every variable in the code. By contrast, a probabilistic approach assigns parameter ranges to certain variables, and the code randomly selects the values for each variable from the parameter range each time it calculates the dose (NRC 2006). The receptor scenarios, computer codes and parameter input files were previously used in ORISE 2012. A few modifications were made to the parameter input files as appropriate for this effort. Some of these changes

  7. Peak Dose Assessment for Proposed DOE-PPPO Authorized Limits

    Maldonado, Delis [Oak Ridge Institute for Science and Education, Oak Ridge, TN (United States). Independent Environmental Assessment and Verification Program

    2012-06-01

    The Oak Ridge Institute for Science and Education (ORISE), a U.S. Department of Energy (DOE) prime contractor, was contracted by the DOE Portsmouth/Paducah Project Office (DOE-PPPO) to conduct a peak dose assessment in support of the Authorized Limits Request for Solid Waste Disposal at Landfill C-746-U at the Paducah Gaseous Diffusion Plant (DOE-PPPO 2011a). The peak doses were calculated based on the DOE-PPPO Proposed Single Radionuclides Soil Guidelines and the DOE-PPPO Proposed Authorized Limits (AL) Volumetric Concentrations available in DOE-PPPO 2011a. This work is provided as an appendix to the Dose Modeling Evaluations and Technical Support Document for the Authorized Limits Request for the C-746-U Landfill at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky (ORISE 2012). The receptors evaluated in ORISE 2012 were selected by the DOE-PPPO for the additional peak dose evaluations. These receptors included a Landfill Worker, Trespasser, Resident Farmer (onsite), Resident Gardener, Recreational User, Outdoor Worker and an Offsite Resident Farmer. The RESRAD (Version 6.5) and RESRAD-OFFSITE (Version 2.5) computer codes were used for the peak dose assessments. Deterministic peak dose assessments were performed for all the receptors and a probabilistic dose assessment was performed only for the Offsite Resident Farmer at the request of the DOE-PPPO. In a deterministic analysis, a single input value results in a single output value. In other words, a deterministic analysis uses single parameter values for every variable in the code. By contrast, a probabilistic approach assigns parameter ranges to certain variables, and the code randomly selects the values for each variable from the parameter range each time it calculates the dose (NRC 2006). The receptor scenarios, computer codes and parameter input files were previously used in ORISE 2012. A few modifications were made to the parameter input files as appropriate for this effort. Some of these changes

  8. Biological indicators for radiation dose assessment

    After an introductory report on the present level of practical experience in using biological indicator systems to identify and assess doses from radiation exposures, the state of the art in the field of biochemical, cytological and immunological indicators was presented as a basis for discussions in working groups. With reference to the type of radiation - gamma radiation, electrons, neutrons - the question was examined how and to which extent body doses could be evaluated on the basis of results from biological indicator systems. The indicator systems were examined and evaluated in working groups under the aspects of practical use, validity of results and demand of research according to uniform criteria. These were, among others, dose effect relationship, detection limit, reproducibility and specificity, interference factors, stress and reasonable inconvenience of the examined person, earliest possible availability of results and the maximum time needed to identify a biological effect after radiation exposure, as well as the possible maximum number of persons examined from a population group of radiation exposed individuals. The results of the working groups discussions were compiled and summarized in recommendations. (orig./MG)

  9. Assessment of dose during an SGTR

    The Nuclear Regulatory Commission requires utilities to determine the response of a pressurized water reactor to a steam generator tube rupture (SGTR) as part of the safety analysis for the plant. The SGTR analysis includes assumptions regarding the iodine concentration in the reactor coolant system (RCS) due to iodine spikes, primary flashing and bypass fractions, and iodine partitioning in the secondary coolant system (SCS). Experimental and analytical investigations have recently been completed wherein these assumptions were tested to determine whether and to what degree they were conservative (that is, whether they result in a calculated iodine source term/dose that is at least as large or larger than that expected during an actual event). The current study has the objective to assess the overall effects of the results of these investigations on the calculated iodine dose to the environment during an SGTR. To assist in this study, a computer program, DOSE, was written. This program uses a simple, non-mechanistic model to calculate the iodine source term to the environment during an SGTR as a function of water mass inventories and flow rates and iodine concentrations in the RCS and SCS. The principal conclusion of this study is that the iodine concentration in the RCS is the dominant parameter, due to the dominance of primary flashing on the iodine source term

  10. Changes of radiation dose and image quality due to additional filtration material in computed radiography

    Filter absorbs low-energy X-ray to increase the average energy and reduces patient exposure dose. This study investigates if the materials of Mo and W could be used for the digital imaging device CR by conducting image assessment and dose measurement of SNR, FOM and histogram. In addition, measurement of beam quality was conducted depending on the material of the filter, and at the same time, a proper combination of filters was examined depending on the change in tube voltage (kVp). In regard to entrance skin dose, Mo filter showed the dose reduction by 42∼56%, compared to Cu filter. Moreover, Mo filter showed higher transmission dose by around 1.5 times than that of Cu filter. In image assessment, it was found that W was unsuitable to be used as a filter, whereas Mo could be used as a filter to reduce dose without decline in image quality at the tube voltage of 80 kVp or higher. As tube voltage increased, 2.0 mm Al+0.1 mm Mo almost had a similar histogram width to that of 2.0 mm Al+0.2 mm Cu. Therefore, Mo filter can be used at relatively high tube voltage of 80 kVp, 100 kVp and 120 kVp. The SNR of 2.0 mm Al+0.1 mm Mo did not show any significant difference from those of 2.0 mm Al+0.2 mm Cu and 2.0 mm Al+0.1 mm Cu. As a result, if Mo filter is used to replace Cu filter in general radiography, where 80 kVp or higher is used for digital radiation image, patient exposure dose can be reduced significantly without decline in image quality, compared to Cu filter. Therefore, it is believed that Mo filter can be applied to chest X-ray and high tube voltage X-ray in actual clinical practice

  11. Dose assessment considering evolution of the biosphere

    Swedish Nuclear Fuel and Waste Management AB (SKB) is presently updating the safety assessment for SFR (Final repository for radioactive operational waste) in Sweden. The bio-spheric part of the analysis is performed by Studsvik Eco and Safety AB. According to the regulations the safety of the repository has to be accounted for different possible courses of the development of the biosphere. A number of studies have been carried out during the past years to investigate and document the biosphere in the area surrounding the repository. Modelling of shore-level displacement by land uplift, coastal water exchange and sedimentation have provided data for prediction of the evolution of the area. The prediction is done without considering a future change in climatic conditions. The results from this study show that accumulation of radionuclides in sediments is an important process to simulate when performing dose assessments covering biosphere evolution. The dose calculated for the first years of the period with agricultural use of the contaminated sediments may be severely underestimated in a scenario with large accumulation in coastal and lake stages. (LN)

  12. Wound trauma alters ionizing radiation dose assessment

    Kiang Juliann G

    2012-06-01

    Full Text Available Abstract Background Wounding following whole-body γ-irradiation (radiation combined injury, RCI increases mortality. Wounding-induced increases in radiation mortality are triggered by sustained activation of inducible nitric oxide synthase pathways, persistent alteration of cytokine homeostasis, and increased susceptibility to bacterial infection. Among these factors, cytokines along with other biomarkers have been adopted for biodosimetric evaluation and assessment of radiation dose and injury. Therefore, wounding could complicate biodosimetric assessments. Results In this report, such confounding effects were addressed. Mice were given 60Co γ-photon radiation followed by skin wounding. Wound trauma exacerbated radiation-induced mortality, body-weight loss, and wound healing. Analyses of DNA damage in bone-marrow cells and peripheral blood mononuclear cells (PBMCs, changes in hematology and cytokine profiles, and fundamental clinical signs were evaluated. Early biomarkers (1 d after RCI vs. irradiation alone included significant decreases in survivin expression in bone marrow cells, enhanced increases in γ-H2AX formation in Lin+ bone marrow cells, enhanced increases in IL-1β, IL-6, IL-8, and G-CSF concentrations in blood, and concomitant decreases in γ-H2AX formation in PBMCs and decreases in numbers of splenocytes, lymphocytes, and neutrophils. Intermediate biomarkers (7 – 10 d after RCI included continuously decreased γ-H2AX formation in PBMC and enhanced increases in IL-1β, IL-6, IL-8, and G-CSF concentrations in blood. The clinical signs evaluated after RCI were increased water consumption, decreased body weight, and decreased wound healing rate and survival rate. Late clinical signs (30 d after RCI included poor survival and wound healing. Conclusion Results suggest that confounding factors such as wounding alters ionizing radiation dose assessment and agents inhibiting these responses may prove therapeutic for radiation combined

  13. Preliminary dose assessment of the Chernobyl accident

    From the major accident at Unit 4 of the Chernobyl nuclear power station, a plume of airborne radioactive fission products was initially carried northwesterly toward Poland, thence toward Scandinavia and into Central Europe. Reports of the levels of radioactivity in a variety of media and of external radiation levels were collected in the Department of Energy's Emergency Operations Center and compiled into a data bank. Portions of these and other data which were obtained directly from published and official reports were utilized to make a preliminary assessment of the extent and magnitude of the external dose to individuals downwind from Chernobyl. Radioactive 131I was the predominant fission product. The time of arrival of the plume and the maximum concentrations of 131I in air, vegetation and milk and the maximum reported depositions and external radiation levels have been tabulated country by country. A large amount of the total activity in the release was apparently carried to a significant elevation. The data suggest that in areas where rainfall occurred, deposition levels were from ten to one-hundred times those observed in nearby ''dry'' locations. Sufficient spectral data were obtained to establish average release fractions and to establish a reference spectra of the other nuclides in the release. Preliminary calculations indicated that the collective dose equivalent to the population in Scandinavia and Central Europe during the first year after the Chernobyl accident would be about 8 x 106 person-rem. From the Soviet report, it appears that a first year population dose of about 2 x 107 person-rem (2 x 105 Sv) will be received by the population who were downwind of Chernobyl within the U.S.S.R. during the accident and its subsequent releases over the following week. 32 refs., 14 figs., 20 tabs

  14. Population dose assessment: characteristics of PC CREAM

    This paper presents the main features of the PC CREAM, a program for performing radiological impact assessments due to radioactive discharges into the environment during the operation of radioactive and nuclear facilities. PC CREAM is a suite of six programs that can be used to estimate individual and collective radiation doses. The methodology of PC CREAM is based on updated environmental and dosimetric models, including ICRP 60 recommendations. The models include several exposure pathways and the input files are easy to access. The ergonomics of the program improves the user interaction and makes easier the input of local data. This program is useful for performing sensitivity analysis, siting studies and validation of model comparing the activity concentration output data with environmental monitoring data. The methodology of each module is described as well as the output data. (author)

  15. Italian intercomparison exercise on internal dose assessment

    In 2001, the Radiation Protection Institute of ENEA promoted an Italian intercomparison exercise on internal dose assessment addressed to the qualified experts in radiation protection, following the coming into force in Italian law of the EURATOM 96/29 Directive. Five case studies of occupational exposure related to the Italian situation are used. The considered radioisotopes are: 60Co, 89Sr, 125I, 131I, and 222Rn + NORM (238U-235U-232Th). Data related to WBC, thyroid and urine excretion measurements, as well as radionuclide air concentration in the workplace are provided to the participants. The results related to medical, industrial and Rn occupational exposure are well represented as means of log-normal distributions with values of the geometric standard deviation less than 2. A wider spread of results is present for the evaluation of occupational exposure to NORM. (author)

  16. Construction of average adult Japanese voxel phantoms for dose assessment

    The International Commission on Radiological Protection (ICRP) adopted the adult reference voxel phantoms based on the physiological and anatomical reference data of Caucasian on October, 2007. The organs and tissues of these phantoms were segmented on the basis of ICRP Publication 103. In future, the dose coefficients for internal dose and dose conversion coefficients for external dose calculated using the adult reference voxel phantoms will be widely used for the radiation protection fields. On the other hand, the body sizes and organ masses of adult Japanese are generally smaller than those of adult Caucasian. In addition, there are some cases that the anatomical characteristics such as body sizes, organ masses and postures of subjects influence the organ doses in dose assessment for medical treatments and radiation accident. Therefore, it was needed to use human phantoms with average anatomical characteristics of Japanese. The authors constructed the averaged adult Japanese male and female voxel phantoms by modifying the previously developed high-resolution adult male (JM) and female (JF) voxel phantoms. It has been modified in the following three aspects: (1) The heights and weights were agreed with the Japanese averages; (2) The masses of organs and tissues were adjusted to the Japanese averages within 10%; (3) The organs and tissues, which were newly added for evaluation of the effective dose in ICRP Publication 103, were modeled. In this study, the organ masses, distances between organs, specific absorbed fractions (SAFs) and dose conversion coefficients of these phantoms were compared with those evaluated using the ICRP adult reference voxel phantoms. This report provides valuable information on the anatomical and dosimetric characteristics of the averaged adult Japanese male and female voxel phantoms developed as reference phantoms of adult Japanese. (author)

  17. Assessment of internal doses in emergency situations

    The need for assessing internal radiation doses in emergency situations was demonstrated after accidents in Brazil, Ukraine and other countries. Lately more and more concern has been expressed regarding malevolent use of radiation and radioactive materials. The scenarios for such use are more difficult to predict than for nuclear power plant or weapons accidents. Much of the results of the work done in the IRADES project can be adopted for use in various accidental situations involving radionuclides that are not addressed in this report. If an emergency situation occurs in only one or a few of the Nordic countries, experts from the other countries could be called upon to assist in monitoring. A big advantage is then our common platform. In the Nordic countries much work has been put down on quality assurance of measurements and on training of dose assessment calculations. Attention to this was addressed at the internal dosimetry course in October 2005. Nordic emergency preparedness exercises have so far not included training of direct measurements of people in the early phase of an emergency. The aim of the IRADES project was to improve the preparedness especially for thyroid measurements. The modest financial support did not enable the participants to make big efforts but certainly acted as a much appreciated reminder of the importance of being prepared also to handle situations with malevolent use of radioactive materials. It was left to each country to decide to which extent to improve the practical skills. There is still a need for detailed national implementation plans. Measurement strategies need to be developed in each country separately taking into account national regulations, local circumstances and resources. End users of the IRADES report are the radiation protection authorities. (au)

  18. Radiation exposure due to bedside chest radiography during intensive care. Cumulative dose and additional morbidity risk of long term therapy

    Purpose: Assessment of the additional morbidity risk due to repeated bedside chest radiography according to ICRP 60 during intensive care. Material and Methods: Ventral surface doses were recorded by thermoluminescence dosimetry in 2 man and 7 women, mean age 36±12 years, mean height 169±5 cm, mean weight 74±8 kg, receiving long-term ventilation therapy due to Adult Respiratory Distress Syndrome (ARDS). Results: From 18 to 126 days duration of therapy 9 patients received a total of 348 bedside chest radiographs, mean 39±22 radiographs per patient. 217 chest radiographs yielded 217 surface doses and 217 gonadal doses. Patient's mean surface dose varys between at least 0,31±0,12 mGy and at most 0,56±0,09 mGy. The surface dose representing gonadal exposure is less than 0,03 mGy per exposure. The mean effective dose is about 0,15 mSv per exposure. The cumulative effective dose Heff ranges between 2,49 mSv and 14,09 mSv, thus estimating the additional individual cancer risk ranges between 0,01% and 0,07%. Conclusion: In comparison with the decreased prognosis of severely ill long-term ventilated patients the additional morbidity risk due to chest radiographs is a negligible quantity. (orig.)

  19. Estimation of the resident's additional dose in bone-coal mining areas of the five provinces

    JIANG Shan; ZHANG Liang; YE Ji-Da; KONG Ling-Li; LI Ying; SHI Jin-Hua; WU Zong-Mei

    2005-01-01

    This paper introduces the resident's additional dose in bone-coal mining areas. The increase of the annual additional effective doses accepted by the residents living in the carbide-brick houses, the staffs working in the carbide-brick houses and the miners working in the bone-coal mining areas of Hubei, Hunan, Jiangxi, Zhejiang and Anhui Provinces is caused by the rising of environmental radioactive level. The investigation of natural background radiation in the bone-coal mining areas indicated that both mining and utilizing bone-coal cause the rise of environmental radioactive level. The ranges of the annual additional effective dose accepted by the residents, staffs and miners is 1.9-6.8 mSv, 0.5-2.0 mSv and 8.2-71 mSv, and with an average of 3.8 mSv, 1 mSv and 40 mSv, respectively. The annual additional effective doses accepted by part residents and staffs exceed the dose limit of 1 mSv for public exposure, and part miners exceed the dose limit of 20 mSv for occupational exposure. And the contribution of dose caused by inhaled radon to the total additional effective dose is over 76%.

  20. Estimation of the resident's additional dose in bone-coal mining areas of the five provinces

    This paper introduces the resident's additional dose in bone-coal mining areas. The increase of the annual additional effective doses accepted by the residents living in the carbide-brick houses, the staffs working in the carbide-brick houses and the miners working in the bone-coal mining areas of Hubei, Hunan, Jiangxi, Zhejiang and Anhui Provinces is caused by the rising of environmental radioactive level. The investigation of natural background radiation in the bone-coal mining areas indicated that both mining and utilizing bone-coal cause the rise of environ- mental radioactive level. The ranges of the annual additional effective dose accepted by the residents, staffs and miners is 1.9-6.8 mSv, 0.5-2.0 mSv and 8.2-71 mSv, and with an average of 3.8 mSv, 1 mSv and 40 mSv, respectively. The annual additional effective doses accepted by part residents and staffs exceed the dose limit of 1 mSv for public exposure, and part miners exceed the dose limit of 20 mSv for occupational exposure. And the contribution of dose caused by inhaled radon to the total additional effective dose is over 76%. (authors)

  1. The refinement of dose assessment of the THOR BNCT beam

    A refined dose assessment method has been used now in the THOR BNCT facility, which takes into account more delicate corrections, carefully handled calibration factors, and the spectrum- and kerma-weighted kt value. The refined method solved the previous problem of negative derived neutron dose in phantom at deeper positions. With the improved dose assessment, the calculated and measured gamma-ray dose rates match perfectly in a 15×15×15 cm3 PMMA phantom.

  2. Radiation fields and dose assessments in Korean nuclear power plants.

    Kim, Hee Geun; Kong, Tae Young; Jeong, Woo Tae; Kim, Seok Tae

    2011-07-01

    In the primary systems of nuclear power plants (NPPs), various radionuclides including fission products and corrosion products are generated due to the complex water chemistry conditions. In particular, (3)H, (14)C, (58)Co, (60)Co, (137)Cs, and (131)I are important or potential radionuclides with respect to dose assessment for workers and the management of radioactive effluents or dose assessment for the public. In this paper, the dominant contributors to the dose for workers and the public were reviewed and the process of dose assessment attributable to those contributors was investigated. Furthermore, an analysis was carried out on some examples of dose to workers during NPP operation. PMID:21498858

  3. Development of radiation dose assessment system for radiation accident (RADARAC)

    The possibility of radiation accident is very rare, but cannot be regarded as zero. Medical treatments are quite essential for a heavily exposed person in an occurrence of a radiation accident. Radiation dose distribution in a human body is useful information to carry out effectively the medical treatments. A radiation transport calculation utilizing the Monte Carlo method has an advantageous in the analysis of radiation dose inside of the body, which cannot be measured. An input file, which describes models for the accident condition and quantities of interest, should be prepared to execute the radiation transport calculation. Since the accident situation, however, cannot be prospected, many complicated procedures are needed to make effectively the input file soon after the occurrence of the accident. In addition, the calculated doses are to be given in output files, which usually include much information concerning the radiation transport calculation. Thus, Radiation Dose Assessment system for Radiation Accident (RADARAC) was developed to derive effectively radiation dose by using the MCNPX or MCNP code. RADARAC mainly consists of two parts. One part is RADARAC-INPUT, which involves three programs. A user can interactively set up necessary resources to make input files for the codes, with graphical user interfaces in a personnel computer. The input file includes information concerning the geometric structure of the radiation source and the exposed person, emission of radiations during the accident, physical quantities of interest and so on. The other part is RADARAC-DOSE, which has one program. The results of radiation doses can be effectively indicated with numerical tables, graphs and color figures visibly depicting dose distribution by using this program. These results are obtained from the outputs of the radiation transport calculations. It is confirmed that the system can effectively make input files with a few thousand lines and indicate more than 20

  4. Indoor radon dose assessment for Osijek

    After ten years' investigation of radon's seasonal variation at three very different locations, as well as radon concentration measurements in kindergartens, schools, air-raid shelters and cellars, systematic indoor radon measurements were undertaken in dwellings (residential buildings) of Osijek (East Croatia, 130andpuncsp; omitted000 citizens). Indoor radon was measured by means of the LR-115 SSNT detector at 48 town locations that gave an arithmetic mean of 71.6 Bq/m3, standard deviation of 44.0 Bq/m3 and geometric mean of 60.1 Bq/m3, for the radon concentration range from 22.7 to 185.6 Bq/m3. Radon measurements, performed by the silicon Radhome detector, did not differ significantly. The empirical frequency distribution of radon concentrations, with the class width of 20 Bq/m3, was in accordance with the theoretical log-normal distribution which was shown with the χ2-test. The radon map pointed out a region of higher radon concentrations (central part of the town) that was ascribed to the geological soil structure. The average equilibrium factor for radon and its progeny in the mentioned dwellings was 0.44. The effective dose equivalent assessment for a few radon models was near 2 mSv/year. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  5. Dose assessments in nuclear power plant siting

    This document is mainly intended to provide information on dose estimations and assessments for the purpose of nuclear power plant (NPP) siting. It is not aimed at giving radiation protection guidance, criteria or procedures to be applied during the process of NPP siting nor even to provide recommendations on this subject matter. The document may however be of help for implementing some of the Nuclear Safety Standards (NUSS) documents on siting. The document was prepared before April 26, 1986, when a severe accident at the Unit 4 of Chernobyl NPP in the USSR had occurred. It should be emphasized that this document does not bridge the gap which exists in the NUSS programme as far as radiation protection guidance for the specific case of siting of NPP is concerned. The Agency will continue to work on this subject with the aim to prepare a safety series document on radiation protection requirements for NPP siting. This document could serve as a working document for this purpose. Refs, figs and tabs

  6. Program for rapid dose assessment in criticality accident, RADAPAS

    In a criticality accident, a person near fissile material can receive extremely high dose which can cause acute health effect. For such a case, medical treatment should be carried out for the exposed person, according to severity of the exposure. Then, radiation dose should be rapidly assessed soon after an outbreak of an accident. Dose assessment based upon the quantity of induced 24Na in human body through neutron exposure is expected as one of useful dosimetry techniques in a criticality accident. A dose assessment program, called RADAPAS (RApid Dose Assessment Program from Activated Sodium in Criticality Accidents), was therefore developed to assess rapidly radiation dose to exposed persons from activity of induced 24Na. RADAPAS consists of two parts; one is a database part and the other is a part for execution of dose calculation. The database contains data compendiums of energy spectra and dose conversion coefficients from specific activity of 24Na induced in human body, which had been derived in a previous analysis using Monte Carlo calculation code. Information for criticality configuration or characteristics of radiation in the accident field is to be interactively given with interface displays in the dose calculation. RADAPAS can rapidly derive radiation dose to the exposed person from the given information and measured 24Na specific activity by using the conversion coefficient in database. This report describes data for dose conversions and dose calculation in RADAPAS and explains how to use the program. (author)

  7. Assessment of a new p-Mosfet usable as a dose rate insensitive gamma dose sensor

    Dosimetric response of unbiased MOS devices has been assessed at dose rates greater than 2000 cGy/h. Application have been made to a personal dosemeter / dose rate meter to measure the absorbed tissue dose received in the case of acute external irradiation. (D.L.)

  8. Relationships between exposure dose and additional filter thickness in the X-ray diagnosis

    For the purpose of reduction of exposure dose in the X-ray diagnosis, authors examined the effect of additional filter thickness on the dose. The apparatus was Toshiba KXO-30F with filter thickness of 2.3 mm Al. For the additional filters, aluminium plates of 0.5 mm and 1.0 mm thickness were used. Dosimetry was done with VICTOREEN RADOCON 500 and with the ionization chambers VICTOREEN RADOCON 550-5 and 30-330, and X-ray analysis for measuring effective energy, with KYOKKO MODEL 100. Phantoms were polystyrene plates and manikin (Kyotokagakuhyohon PB-10). The incident surface dose and irradiation time were examined with varied phantom thickness. Further, the influence of the additional filter thickness was examined on the half-value thickness and effective energy of tube voltage. When the additional filter thickness was more than 10 mm Al, the incident surface dose was found hardly changed and irradiation time was 2 times as long. At 10.0 mm Al thickness, the thicker was the phantom, the smaller were the exposure dose and irradiation time. The thicker was the additional filter, the lower was the resolution of the site necessary to enhance the contrast, such as bone. Thus, the reduction of the dose requires the appropriate selection of the suitable tube voltage, additional filter thickness and sensitive film. (K.H.)

  9. Effective additional gamma dose for general population and workers from a Mexican radioactive waste site

    The environmental effective gamma-dose rate has been determined at the Mexican Storage Centre for Radioactive Waste (SCRW) and surrounding communities. Soil samples were analysed for 226Ra, 235U, 137Cs and 40K concentration activities. The outdoor effective gamma dose rate was higher at the SCRW where industrial radioactive sources and uranium ore piles were stored in the past. Some nearby locations, where the action of the rain on the piles promoted the transport and surface migration of 226Ra, 235U and 137Cs, also showed an increased gamma dose rate. The gamma dose rate at distant communities (local background) was evaluated with data obtained along 10 years measurements. The additional effective external dose for the general public at the 200 m neighbouring zone of the site, was two times higher than that from the local background. The outdoor average external effective dose for workers due to the SCRW operation was 20 times than for the local background

  10. The effect of additional high dose carbon implantation on the tribological properties of titanium implanted steel

    The tribological properties and the structural changes of hardened steel implanted with titanium followed by carbon were investigated as a function of additional carbon dose. The dose of Ti was 5.1017 Ti cm-2 and the additional C doses were 0, 4.1017, 8.1017 and 1.2.1018 Ccm-2. After Ti implantation, the steel surface transformed to a Fe-Ti-C ternary amorphous phase. Additional implantation of carbon to a dose of 4.1017 Ccm-2 produced fine TiC precipitates dispersed in the ternary amorphous matrix. When the additional C dose exceeded 8.1017 Ccm-2, very fine graphite precipitates appeared in the ternary amorphous phase. The steel surface with very fine graphite precipitates exhibited superior tribological properties. The benefits provided by additional high dose carbon implantation are considered as follows: strengthening of the amorphous phase, thickening of the modified layer, dispersion strengthening of the implanted layer by very fine graphite precipitates and lubrication effect by graphite particles. Comparing the friction properties of Ti+C implanted steel with that of C implanted steel, the role of Ti implantation is to reduce the friction of the surface during sliding and the role of C implantation is to increase the lifetime of the surface against wear. (orig.)

  11. Interactive Rapid Dose Assessment Model (IRDAM): reactor-accident assessment methods. Vol. 2

    Poeton, R.W.; Moeller, M.P.; Laughlin, G.J.; Desrosiers, A.E.

    1983-05-01

    As part of the continuing emphasis on emergency preparedness, the US Nuclear Regulatory Commission (NRC) sponsored the development of a rapid dose assessment system by Pacific Northwest Laboratory (PNL). This system, the Interactive Rapid Dose Assessment Model (IRDAM) is a micro-computer based program for rapidly assessing the radiological impact of accidents at nuclear power plants. This document describes the technical bases for IRDAM including methods, models and assumptions used in calculations. IRDAM calculates whole body (5-cm depth) and infant thyroid doses at six fixed downwind distances between 500 and 20,000 meters. Radionuclides considered primarily consist of noble gases and radioiodines. In order to provide a rapid assessment capability consistent with the capacity of the Osborne-1 computer, certain simplifying approximations and assumptions are made. These are described, along with default values (assumptions used in the absence of specific input) in the text of this document. Two companion volumes to this one provide additional information on IRDAM. The user's Guide (NUREG/CR-3012, Volume 1) describes the setup and operation of equipment necessary to run IRDAM. Scenarios for Comparing Dose Assessment Models (NUREG/CR-3012, Volume 3) provides the results of calculations made by IRDAM and other models for specific accident scenarios.

  12. Interactive Rapid Dose Assessment Model (IRDAM): reactor-accident assessment methods. Vol.2

    As part of the continuing emphasis on emergency preparedness, the US Nuclear Regulatory Commission (NRC) sponsored the development of a rapid dose assessment system by Pacific Northwest Laboratory (PNL). This system, the Interactive Rapid Dose Assessment Model (IRDAM) is a micro-computer based program for rapidly assessing the radiological impact of accidents at nuclear power plants. This document describes the technical bases for IRDAM including methods, models and assumptions used in calculations. IRDAM calculates whole body (5-cm depth) and infant thyroid doses at six fixed downwind distances between 500 and 20,000 meters. Radionuclides considered primarily consist of noble gases and radioiodines. In order to provide a rapid assessment capability consistent with the capacity of the Osborne-1 computer, certain simplifying approximations and assumptions are made. These are described, along with default values (assumptions used in the absence of specific input) in the text of this document. Two companion volumes to this one provide additional information on IRDAM. The user's Guide (NUREG/CR-3012, Volume 1) describes the setup and operation of equipment necessary to run IRDAM. Scenarios for Comparing Dose Assessment Models (NUREG/CR-3012, Volume 3) provides the results of calculations made by IRDAM and other models for specific accident scenarios

  13. Simple DVH parameter addition as compared to deformable registration for bladder dose accumulation in cervix cancer brachytherapy

    Andersen, Else Stougård; Noe, Karsten Østergaaard; Sørensen, Thomas Sangild; Nielsen, Søren Kynde; LU, Fokdal; Paludan, Merete; Lindegaard, Jacob Christian; Tanderup, Kari

    2013-01-01

    Background and purpose: Variations in organ position, shape, and volume cause uncertainties in dose assessment for brachytherapy (BT) in cervix cancer. The purpose of this study was to evaluate uncertainties associated with bladder dose accumulation based on DVH parameter addition (previously...... called "the worst case assumption") in fractionated BT. Materials and methods: Forty-seven patients treated for locally advanced cervical cancer were included. All patients received EBRT combined with two individually planned 3D image-guided adaptive BT fractions. D2 and D0.1 were estimated by DVH...

  14. Metrics, Dose, and Dose Concept: The Need for a Proper Dose Concept in the Risk Assessment of Nanoparticles

    Myrtill Simkó; Dietmar Nosske; Kreyling, Wolfgang G

    2014-01-01

    In: International Journal of Environmental Research and Public Health, Vol. 11 (2014), No. 4, 4026-4048; DOI: 10.3390/ijerph110404026In order to calculate the dose for nanoparticles (NP), (i) relevant information about the dose metrics and (ii) a proper dose concept are crucial. Since the appropriate metrics for NP toxicity are yet to be elaborated, a general dose calculation model for nanomaterials is not available. Here we propose how to develop a dose assessment model for NP in analogy to ...

  15. Dose assessment in pediatric computerized tomography

    The objective of this work was the evaluation of radiation doses in paediatric computed tomography scans, considering the high doses usually involved and the absence of any previous evaluation in Brazil. Dose values were determined for skull and abdomen examinations, for different age ranges, by using the radiographic techniques routinely used in the clinical centers investigated. Measurements were done using pencil shape ionization chambers inserted in polymethylmethacrylate (PMMA) phantoms. These were compact phantoms of different diameters were specially designed and constructed for this work, which simulate different age ranges. Comparison of results with published values showed that doses were lower than the diagnostic reference levels established to adults exams by the European Commission. Nevertheless, doses in paediatric phantoms were higher than those obtained in adult phantoms. The paediatric dose values obtained in Hospitals A and B were lower than the reference level (DRL) adopted by SHIMPTON for different age ranges. In the range 0 - 0.5 year (neonatal), the values of DLP in Hospital B were 94 por cent superior to the DRL For the 10 years old children the values of CTDIw obtained were inferior in 89 por cent for skull and 83 por cent for abdomen examinations, compared to the values published by SHRIMPTON and WALL. Our measured CTDIw values were inferior to the values presented for SHRIMPTON and HUDA, for all the age ranges and types of examinations. It was observed that the normalized dose descriptors values in children in the neonatal range were always superior to the values of doses for the adult patient. In abdomen examinations, the difference was approximately 90% for the effective dose (E) and of 57%.for CTDIw . (author)

  16. Radionuclide transport and dose assessment modelling in biosphere assessment 2009

    Following the guidelines set forth by the Ministry of Trade and Industry (now Ministry of Employment and Economy), Posiva is preparing to submit a construction license application for the final disposal spent nuclear fuel at the Olkiluoto site, Finland, by the end of the year 2012. Disposal will take place in a geological repository implemented according to the KBS-3 method. The long-term safety section supporting the license application will be based on a safety case that, according to the internationally adopted definition, will be a compilation of the evidence, analyses and arguments that quantify and substantiate the safety and the level of expert confidence in the safety of the planned repository. This report documents in detail the conceptual and mathematical models and key data used in the landscape model set-up, radionuclide transport modelling, and radiological consequences analysis applied in the 2009 biosphere assessment. Resulting environmental activity concentrations in landscape model due to constant unit geosphere release rates, and the corresponding annual doses, are also calculated and presented in this report. This provides the basis for understanding the behaviour of the applied landscape model and subsequent dose calculations. (orig.)

  17. CANISTER HANDLING FACILITY WORKER DOSE ASSESSMENT

    D.T. Dexheimer

    2004-02-27

    The purpose of this calculation is to estimate radiation doses received by personnel working in the Canister Handling Facility (CHF) performing operations to receive transportation casks, transfer wastes, prepare waste packages, perform associated equipment maintenance. The specific scope of work contained in this calculation covers individual worker group doses on an annual basis, and includes the contributions due to external and internal radiation. The results of this calculation will be used to support the design of the CHF and provide occupational dose estimates for the License Application.

  18. CANISTER HANDLING FACILITY WORKER DOSE ASSESSMENT

    The purpose of this calculation is to estimate radiation doses received by personnel working in the Canister Handling Facility (CHF) performing operations to receive transportation casks, transfer wastes, prepare waste packages, perform associated equipment maintenance. The specific scope of work contained in this calculation covers individual worker group doses on an annual basis, and includes the contributions due to external and internal radiation. The results of this calculation will be used to support the design of the CHF and provide occupational dose estimates for the License Application

  19. FUEL HANDLING FACILITY WORKER DOSE ASSESSMENT

    The purpose of this design calculation is to estimate radiation doses received by personnel working in the Fuel Handling Facility (FHF) of the Monitored Geological Repository (MGR). The FHF is a surface facility supporting waste handling operations i.e. receive transportation casks, transfer wastes, prepare waste packages, and ship out loaded waste packages and empty casks. The specific scope of work contained in this calculation covers both collective doses and individual worker group doses on an annual basis, and includes the contributions due to external and internal radiation. The results are also limited to normal operations only. Results of this calculation will be used to support the FHF design and License Application

  20. MESORAD dose assessment of the Chernobyl reactor accident

    An accident involving Unit 4 of the Chernobylskaya Atomic Energy Station resulted in the release of a large amount of radioactive material to the atmosphere. This report describes the results of an assessment of the doses near the site (within 80 km) made at the Pacific Northwest Laboratory using the MESORAD Dose Assessment model. 6 refs., 10 figs., 5 tabs

  1. Eye dose assessment and management: overview.

    Rehani, M M

    2015-07-01

    Some publications have shown that Hp(0.07) or even Hp(10) can be used as good operational quantities for X-rays in view of difficulties with Hp(3). With increasing awareness, there is tendency to use whatever dosimeter is available with correction factor to estimate eye lens dose. The best position for an eye lens dosimeter has been reported to be at the side of the head nearest to the radiation source, close to the eye. Recent studies have reported eye doses with cone beam CT (CBCT) both for patients and staff, and there are many papers reporting eye lens doses to staff in nuclear medicine. To minimise the dose to eyes, the user can take advantage of a feature of CBCT of projections acquired over an angular span of 180° plus cone angle of the X-ray tube and with tube under scan arcs. PMID:25813481

  2. Eye dose assessment and management: overview

    Some publications have shown that Hp(0.07) or even Hp(10) can be used as good operational quantities for X-rays in view of difficulties with Hp(3). With increasing awareness, there is tendency to use whatever dosimeter is available with correction factor to estimate eye lens dose. The best position for an eye lens dosimeter has been reported to be at the side of the head nearest to the radiation source, close to the eye. Recent studies have reported eye doses with cone beam CT (CBCT) both for patients and staff, and there are many papers reporting eye lens doses to staff in nuclear medicine. To minimise the dose to eyes, the user can take advantage of a feature of CBCT of projections acquired over an angular span of 1808 plus cone angle of the X-ray tube and with tube under scan arcs. (authors)

  3. A review of occupational dose assessment uncertainties and approaches

    The Radiological Protection Practitioner (RPP) will spend a considerable proportion of his time predicting or assessing retrospective radiation exposures to occupational personnel for different purposes. The assessments can be for a variety of purposes, such as to predict doses for occupational dose control, or project design purposes or to make retrospective estimates for the dose record, or account for dosemeters which have been lost or damaged. There are other less frequent occasions when dose assessment will be required such as to support legal cases and compensation claims and to provide the detailed dose information for epidemiological studies. It is important that the level of detail, justification and supporting evidence in the dose assessment is suitable for the requirements. So for instance, day to day operational dose assessments often rely mainly on the knowledge of the RPP in discussion with operators whilst at the other end of the spectrum a historical dose assessment for a legal case will require substantial research and supporting evidence for the estimate to withstand forensic challenge. The robustness of the assessment will depend on many factors including a knowledge of the work activities, the radiation dose uptake and field characteristics; all of which are affected by factors such as the time elapsed, the memory of operators and the dosemeters employed. This paper reviews the various options and uncertainties in dose assessments ranging from use of personal dosimetry results to the development of upper bound assessments. The level of assessment, the extent of research and the evidence adduced should then be appropriate to the end use of the estimate. (Author)

  4. IAEA/IDEAS intercomparison exercise on internal dose assessment

    An Internet based intercomparison exercise on assessment of occupational exposure due to intakes of radionuclides has been performed to check the applicability of the 'General Guidelines for the Assessment of Internal Dose from Monitoring Data' developed by the IDEAS group. There were six intake cases presented on the Internet and 81 participants worldwide reported solutions to these cases. Results of the exercise indicate that the guidelines have a positive influence on the methodologies applied for dose assessments and, if correctly applied, improve the harmonisation of assessed doses. (authors)

  5. DRY TRANSFER FACILITY WORKER DOSE ASSESSMENT

    The purpose of this calculation is to estimate radiation doses received by personnel working in the Dry Transfer Facility No.1 (DTF-1) performing operations to receive transportation casks, transfer wastes, prepare waste packages, and ship out loaded waste packages and empty casks. Doses received by workers due to maintenance operations are also included in this revision. The specific scope of work contained in this calculation covers both collective doses and individual worker group doses on an annual basis, and includes the contributions due to external and internal radiation from normal operation, excluding the remediation area of the building. The results of this calculation will be used to support the design of the DTF-1 and to provide occupational dose estimates for the License Application. The calculations contained in this document were developed by Environmental and Nuclear Engineering of the Design and Engineering Organization and are intended solely for the use of the Design and Engineering Organization in its work regarding facility operation. Yucca Mountain Project personnel from the Environmental and Nuclear Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than authorized personnel in the Environmental and Nuclear Engineering

  6. Assessment of radiation dose awareness among pediatricians

    Thomas, Karen E.; Parnell-Parmley, June E.; Charkot, Ellen; BenDavid, Guila; Krajewski, Connie [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto, Ontario (Canada); Haidar, Salwa [Mubarak Al-Kabeer Hospital, Department of Radiology, Salmiya (Kuwait); Moineddin, Rahim [University of Toronto, Department of Family and Community Medicine, Toronto (Canada)

    2006-08-15

    There is increasing awareness among pediatric radiologists of the potential risks associated with ionizing radiation in medical imaging. However, it is not known whether there has been a corresponding increase in awareness among pediatricians. To establish the level of awareness among pediatricians of the recent publicity on radiation risks in children, knowledge of the relative doses of radiological investigations, current practice regarding parent/patient discussions, and the sources of educational input. Multiple-choice survey. Of 220 respondents, 105 (48%) were aware of the 2001 American Journal of Roentgenology articles on pediatric CT and radiation, though only 6% were correct in their estimate of the quoted lifetime excess cancer risk associated with radiation doses equivalent to pediatric CT. A sustained or transient increase in parent questioning regarding radiation doses had been noticed by 31%. When estimating the effective doses of various pediatric radiological investigations in chest radiograph (CXR) equivalents, 87% of all responses (and 94% of CT estimates) were underestimates. Only 15% of respondents were familiar with the ALARA principle. Only 14% of pediatricians recalled any relevant formal teaching during their specialty training. The survey response rate was 40%. Awareness of radiation protection issues among pediatricians is generally low, with widespread underestimation of relative doses and risks. (orig.)

  7. Assessment of radiation dose awareness among pediatricians

    There is increasing awareness among pediatric radiologists of the potential risks associated with ionizing radiation in medical imaging. However, it is not known whether there has been a corresponding increase in awareness among pediatricians. To establish the level of awareness among pediatricians of the recent publicity on radiation risks in children, knowledge of the relative doses of radiological investigations, current practice regarding parent/patient discussions, and the sources of educational input. Multiple-choice survey. Of 220 respondents, 105 (48%) were aware of the 2001 American Journal of Roentgenology articles on pediatric CT and radiation, though only 6% were correct in their estimate of the quoted lifetime excess cancer risk associated with radiation doses equivalent to pediatric CT. A sustained or transient increase in parent questioning regarding radiation doses had been noticed by 31%. When estimating the effective doses of various pediatric radiological investigations in chest radiograph (CXR) equivalents, 87% of all responses (and 94% of CT estimates) were underestimates. Only 15% of respondents were familiar with the ALARA principle. Only 14% of pediatricians recalled any relevant formal teaching during their specialty training. The survey response rate was 40%. Awareness of radiation protection issues among pediatricians is generally low, with widespread underestimation of relative doses and risks. (orig.)

  8. Assessment of doses due to secondary neutrons received by patient treated by proton therapy

    Proton therapy is a specific technique of radiotherapy which aims at destroying cancerous cells by irradiating them with a proton beam. Nuclear reactions in the device and in the patient himself induce secondary radiations involving mainly neutrons which contribute to an additional dose for the patient. The author reports a study aimed at the assessment of these doses due to secondary neutrons in the case of ophthalmological and intra-cranial treatments. He presents a Monte Carlo simulation of the room and of the apparatus, reports the experimental validation of the model (dose deposited by protons in a water phantom, ambient dose equivalent due to neutrons in the treatment room, absorbed dose due to secondary particles in an anthropomorphic phantom), and the assessment with a mathematical phantom of doses dues to secondary neutrons received by organs during an ophthalmological treatment. He finally evokes current works of calculation of doses due to secondary neutrons in the case of intra-cranial treatments

  9. Simple DVH parameter addition as compared to deformable registration for bladder dose accumulation in cervix cancer brachytherapy

    Background and purpose: Variations in organ position, shape, and volume cause uncertainties in dose assessment for brachytherapy (BT) in cervix cancer. The purpose of this study was to evaluate uncertainties associated with bladder dose accumulation based on DVH parameter addition (previously called “the worst case assumption”) in fractionated BT. Materials and methods: Forty-seven patients treated for locally advanced cervical cancer were included. All patients received EBRT combined with two individually planned 3D image-guided adaptive BT fractions. D2cm3 and D0.1cm3were estimated by DVH parameter addition and compared to dose accumulations based on an in-house developed biomechanical deformable image registration (DIR) algorithm. Results: DIR-based DVH analysis was possible in 42/47 patients. DVH parameter addition resulted in mean dose deviations relative to DIR of 0.4 ± 0.3 Gyαβ3 (1.5 ± 1.8%) and 1.9 ± 1.6 Gyαβ3 (5.2 ± 4.2%) for D2cm3 and D0.1cm3, respectively. Dose deviations greater than 5% occurred in 2% and 38% of the patients for D2cm3 and D0.1cm3, respectively. Visual inspection of the dose distributions showed that hotspots were located in the same region of the bladder during both BT fractions for the majority of patients. Conclusion: DVH parameter addition provides a good estimate for D2cm3, whereas D0.1cm3 is less robust to this approximation

  10. Dose assessment in panoramic dental radiography

    In this paper author deals with the problem of dosimetry at panoramic radiography. Panoramic radiography is a rather complex technique, based on the simultaneous movement of an X-ray tube and an image receptor. A panoramic exposure is acquired by rotating the x-ray tube in an arc around the patients jaw. A thin X-ray beam oriented perpendicular to direction of the motion passes through the jaws at a slight upward angulation with respect to the occlusal plane. Due to this geometry of an examination, it is not straightforward, how to express a dose delivered to a patient during the examination. Because of a similarity with CT examinations, a dose descriptor product of kerma and length PKL is used in panoramic radiology also. However, the way of measurement is different. Currently, no dose descriptor in panoramic radiography is measured in the Czech Republic during the quality control measurements. Therefore, it would be appropriate to accept the product of kerma and length as a standard dose descriptor for panoramic radiography. This measurement should be included in QC procedures as well. Methods of dosimetry at panoramic radiography are discussed. (author)

  11. Radiation dose assessment in nuclear medicine

    Radionuclides are used in nuclear medicine in a variety of diagnostic and therapeutic procedures. Recently, interest has grown in therapeutic agents for a number of applications in nuclear medicine. Internal dose models and methods have been in use for many years, are well established and can give radiation doses to stylized models representing reference individuals. Kinetic analyses need to be carefully planned, and dose conversion factors should be chosen that are most similar to the subject in question and that can then be tailored to be more patient specific. Such calculations, however, are currently not relevant in patient management in internal emitter therapy, as they are not sufficiently accurate or detailed to guide clinical decision making. Great strides are being made at many centres regarding the use of patient image data to construct individualized voxel based models for more detailed and patient specific dose calculations.These recent advances make it likely that the relevance will soon change to be more similar to that of external beam treatment planning. (author)

  12. Dose assessment for decontamination in Goiania

    Shortly after the accident at Goiania, the need arose to set derived intervention levels for the various exposure pathways to guide and optimise clean up measures. For the members of the critical group an intervention level of 5 mSv for the total effective dose in the first year after the accident was chosen, which then was subdivided into values of 1 mSv due to the contribution of external irradiation indoors, 3 mSv from external irradiation while being outdoors, and 1 mSv due to incorporation of resuspended particles and ingestion of locally produced food. The clean up indoors could be directed such that a pre-described ambient dose rate was no longer exceeded. These exposure levels and effective doses to the critical groups predicted in 1988 are compared to actual measurements made in 1988 to 1993 in a local house near one primary contamination foci, and best estimate. It can be shown that the actual doses received by members of the public living in the affected areas were significantly lower. The various reasons for this overprediction will be discussed. (author)

  13. Assessment of patient dose in diagnostic radiology: A new dose concept for the lymphatic tissue

    Diagnostic radiography is a leading cause of man-made radiation exposure to the population. Individual risk assessment and analytic epidemiologic studies likewise require retrospective assessment of lifelong exposure from medical sources. Typical schemes attempt to determine accumulated doses of specific 'critical organs'. The organ dose to the red bone marrow is relevant in studies of diseases like leukemias and malignant lymphomas and there are comprehensive data bases to determine the red bone marrow organ dose of typical radiologic examinations. On the other hand a considerable proportion of the non-Hodgkin's lymphomas are assumed to develop outside the bone marrow compartment. For these a new dose concept for the lymphatic tissue was derived. Tables with conversion factors for typical examinations in diagnostic radiology (conventional radiography, functional radiography with contrast media and computed tomography) are provided that allow the calculation of the doses of the lymphatic tissue from doses of the red bone marrow. (author)

  14. Chemical Mixture Risk Assessment Additivity-Based Approaches

    Powerpoint presentation includes additivity-based chemical mixture risk assessment methods. Basic concepts, theory and example calculations are included. Several slides discuss the use of "common adverse outcomes" in analyzing phthalate mixtures.

  15. Radiation dose assessments for materials with elevated natural radioactivity

    The report provides practical information needed for evaluating the radiation dose to the general public and workers caused by materials containing elevated levels of natural radionuclides. The report presents criteria, exposure scenarios and calculations used to assess dose with respect to the safety requirements set for construction materials in accordance with the Finnish Radiation Act. A method for calculating external gamma exposure from building materials is presented in detail. The results for most typical cases are given as specific dose rates in table form to enable doses to be assessed without computer calculation. A number of such dose assessments is presented, as is the corresponding computer code. Practical investigation levels for the radioactivity of materials are defined. (23 refs.)

  16. Thyroid-Hormone–Disrupting Chemicals: Evidence for Dose-Dependent Additivity or Synergism

    Crofton, Kevin M.; Craft, Elena S.; Hedge, Joan M.; Gennings, Chris; Simmons, Jane E.; Carchman, Richard A.; Carter, W Hans; DeVito, Michael J.

    2005-01-01

    Endocrine disruption from environmental contaminants has been linked to a broad spectrum of adverse outcomes. One concern about endocrine-disrupting xenobiotics is the potential for additive or synergistic (i.e., greater-than-additive) effects of mixtures. A short-term dosing model to examine the effects of environmental mixtures on thyroid homeostasis has been developed. Prototypic thyroid-disrupting chemicals (TDCs) such as dioxins, polychlorinated biphenyls (PCBs), and poly-brominated diph...

  17. Detection and original dose assessment of egg powders subjected to gamma irradiation by using ESR technique

    ESR (electron spin resonance) techniques were applied for detection and original dose estimation to radiation-processed egg powders. The un-irradiated (control) egg powders showed a single resonance line centered at g=2.0086±0.0005, 2.0081±0.0005, 2.0082±0.0005 (native signal) for yolk, white and whole egg, respectively. Irradiation induced at least one additional intense singlet overlapping to the control signal and caused a significant increase in signal intensity without any changes in spectral patterns. Responses of egg powders to different gamma radiation doses in the range 0–10 kGy were examined. The stability of the radiation-induced ESR signal of irradiated egg powders were investigated over a storage period of about 5 months. Additive reirradiation of the egg powders produces a reproducible dose response function, which can be used to assess the initial dose by back-extrapolation. The additive dose method gives an estimation of the original dose within ±12% at the end of the 720 h storage period. - Highlights: • This is the first study on original gamma dose estimation of egg powders using ESR technique. • Dose additive can be used for estimation of the absorbed dose in powder eggs. • The original gamma dose determined with ±12% error at the end of 720 h storage periods. • Powder egg white has good radical yield or radiation sensitivities

  18. Dose reduction in thorax radiography in simulated neonates with additional filtration and digital luminescence radiography

    Purpose: To determine the minimum acceptable radiation dose for an adequate image quality in thorax a.p. radiographs of neonates using mobile X-ray equipment. Material and Methods: The influence of additional filtration (1.0 mm Al+0.1 mm Cu) on image quality and radiation dose was determined for the speed class 400 screen-film system (SFS) and digital luminescence radiography (DLR) by making radiographs of a test phantom. Conventional and digital thorax a.p. radiographs of a rabbit were produced using various tube current-time products. The quality of the rabbit radiographs was judged by eight radiologists applying image quality criteria according to the German guidelines and the recommendations of the European Community. Results: The added filter resulted in a dose reduction of 39% at 66 kV. DLR gave a further dose reduction of 25% in comparison to the speed class 400 SFS while maintaining adequate image quality, i.e. the radiographs were clinically acceptable with regard to quality criteria. Conclusion: The radiation dose resulting from thorax a.p. radiographs of neonates can be reduced by approximately 50% with the use of additional filtration and DLR. (orig.)

  19. Additional safety assessment of ITER - Addition safety investigation of the INB ITER

    This assessment aims at re-assessing safety margins in the light of events which occurred in Fukushima Daiichi, i.e. extreme natural events challenging the safety of installations. After a presentation of some characteristics of the ITER installation (location, activities, buildings, premise detritiation systems, electric supply, handling means, radioactive materials, chemical products, nuclear risks, specific risks), the report addresses the installation robustness by identifying cliff-edge effect risks which can be related to a loss of confinement of radioactive materials, explosions, a significant increase of exposure level, a possible effect on water sheets, and so on. The next part addresses the various aspects related to a seismic risk: installation sizing (assessment methodology, seismic risk characterization in Cadarache), sizing protection measures, installation compliance, and margin assessment. External flooding is the next addressed risk: installation sizing with respect to this specific risk, protection measures, installation compliance, margin assessment, and studied additional measures. Other extreme natural phenomena are considered (meteorological conditions, earthquake and flood) which may have effects on other installations (dam, canal). Then, the report addresses technical risks like the loss of electric supplies and cooling systems, the way a crisis is managed in terms of technical and human means and organization in different typical accidental cases. Subcontracting practices are also discussed. A synthesis proposes an overview of this additional safety assessment and discusses the impact which could have additional measures which could be implemented

  20. IAEA/IDEAS intercomparison exercise on internal dose assessment

    Full text: There were several intercomparison exercises organized already at national and international levels for the assessment of occupational exposure due to intakes of radionuclides. These exercises revealed significant differences in the approach, methods and assumptions, and consequently in the results obtained by participating laboratories. A new intercomparison exercise is being performed in the frame of the IDEAS project 'General Guidelines for the Evaluation of Incorporation Monitoring Data', launched within the 5th EU Framework Programme. Originally, it was planned to organize this new intercomparison exercise on a European scale. However, because of the relevance of the issue for the whole community of internal dosimetrists, it was decided to organize it on a broader scale together with the International Atomic Energy Agency. The new intercomparison exercise would especially focus on the effect of the guidelines for harmonization of internal dosimetry. In addition, it would also consider the following aspects: to provide possibilities for participating laboratories to check the quality of their internal dose assessment methods in applying the recent ICRP recommendations (new respiratory tract model, etc.); to compare different approaches in interpretation of internal contamination monitoring data; to quantify the differences in internal dose assessment based on the new guidelines or on other procedures, respectively; to provide some figures of the influence of the input parameters on the monitoring results, and to provide a broad forum for information exchange. Several cases have been selected for the exercise with the aim to cover a wide range of practices in the nuclear fuel cycle and medical applications, namely: acute intake of HTO; acute inhalation of fission products 137Cs and 90Sr; intake of 60Co; repeated intakes of 131I; intake of enriched uranium; single intake of Pu radionuclides and 241Am. A web-based approach is being used for the

  1. Development of Landscape Dose Factors for dose assessments in SR-Can

    discrete events, by substituting one model by another. All radionuclides of relevance for safety assessments, except for C-14, are included in the study. Predictions of the long-term distribution in the landscape resulting from unit continuous release rates with groundwater discharges are presented for each studied radionuclide. In the main calculation variant, the releases are assumed to start at the beginning of the simulation period; and distributed between the landscape objects according to release fractions obtained from analyses of the results of the hydrological modelling. Additionally, to study the effect of the start time and location of the releases, a series of complementary simulation variants are carried out in different environmental media, comprising soils, waters and sediments. The predictions of the distribution of the radionuclides in the landscape per unit release rates are used to derive time-dependent dose conversion factors for each landscape object and for the whole landscape. To ensure that the dose to a representative member of the public in the population is identified, calculations of the dose rate are made for population groups taken to occupying a single landscape object and obtain all their resources from that object. The number of individuals that can be sustained by a landscape object is calculated for each time period by dividing the potential food production by the yearly food demand of a reference adult person. The average Dose Conversion Factors, i.e. the LDFs, for different groups in the landscape, including the most exposed group are derived, which take into account the distribution of radionuclides in the whole landscape. For each radionuclide derived maximum LDF values are given for the two studied sites, Forsmark and Laxemar. The derived maximum LDF values estimate effective dose rates to the most exposed population group per unit release of activity from a repository. By multiplying these factors by estimates of the release rates

  2. The dose-area product and assessment of the occupational dose in interventional radiology

    This study used dose-area product (DAP) data to determine the relationship between the dose received by radiologists and the DAP. The working conditions were simulated by phantom measurements. The doses of scattered radiation were measured using various scattering angles, distances and tube voltages. The calculated doses of scattered radiation were compared with the measured doses of scattered radiation. To test the validity of using such data for assessing occupational doses, the scatter dose on the radiologist or cardiologist was calculated from the DAP using the measured scatter factors. The dose to the lenses of the eyes may exceed the annual limit, and may therefore restrict the number of interventional procedures. A relation between the DAP and the occupational dose is difficult to establish, especially because staff doses are associated with the use of protective devices, positions of projections with respect to the patient, and working methods. However, the DAP may provide a good reference value for the dosimetric monitoring of staff. (author)

  3. Assessment of doses to game animals in Finland

    A study was carried out to assess the dose rates to game animals in Finland affected by the radioactive caesium deposition that occurred after the accident at the Chernobyl nuclear power plant in Ukraine in 1986. The aim of this assessment was to obtain new information on the dose rates to mammals and birds under Finnish conditions. Dose rates were calculated using the ERICA Assessment Tool developed within the EC 6th Framework Programme. The input data consisted of measured activity concentrations of 137Cs and 134Cs in soil and lake water samples and in flesh samples of selected animal species obtained for environmental monitoring. The study sites were located in the municipality of Lammi, Southern Finland, where the average 137Cs deposition was 46.5 kBq m−2 (1 October 1987). The study sites represented the areas receiving the highest deposition in Finland after the Chernobyl accident. The selected species included moose (Alces alces), arctic hare (Lepus timidus) and several bird species: black grouse (Tetrao tetrix), hazel hen (Bonasia bonasia), mallard (Anas platurhynchos), goldeneye (Bucephala clangula) and teal (Anas crecca). For moose, dose rates were calculated for the years 1986–1990 and for the 2000s. For all other species, maximal measured activity concentrations were used. The results showed that the dose rates to these species did not exceed the default screening level of 10 μGy h−1 used as a protection criterion. The highest total dose rate (internal and external summed), 3.7 μGy h−1, was observed for the arctic hare in 1986. Although the dose rate of 3.7 μGy h−1 cannot be considered negligible given the uncertainties involved in predicting the dose rates, the possible harmful effects related to this dose rate are too small to be assessed based on current knowledge on the biological effects of low doses in mammals

  4. PCDOSE-ESTSC, Radioactive Dose Assessment and NRC Verification

    1 - Description of program or function: PCDOSE was developed for the Nuclear Regulatory Commission (NRC) to perform calculations to determine radioactive dose due to the annual averaged offsite release of liquid and gaseous effluent by U.S. commercial nuclear power facilities. Using NRC approved dose assessment methodologies, it acts as an inspector's tool for verifying the compliance of the facility's dose assessment software. PCDOSE duplicates the calculations of the GASPAR II mainframe code as well as calculations using the methodologies of Reg. Guide 1.109 Rev. 1 and NUREG-0133 by optional choice. 2 - Method of solution: PCDOSE uses spread-sheet models of the dose assessment mathematical equations. The results appear in table format. 3 - Restrictions on the complexity of the problem: PCDOSE requires Lotus 1-2-3 software

  5. Additional diagnostic value of low dose CT in ventilation/perfusion hybrid SPECT for pulmonary embolism

    Objective: To evaluate the assistant diagnostic value of low dose CT in patients with pulmonary embolism (PE) based on ventilation/perfusion (V/Q) SPECT imaging. Methods: One hundred and two patients with clinical suspected PE had been enrolled for this retrospective study. The final diagnosis of PE was made according to the 2008 guidelines of European Society of Cardiology (ESC). All patients underwent V/Q SPECT/CT (Hawkeye 4, GE). The imaging findings from low dose CT lung window were used for differential diagnoses of abnormal regions in SPECT imaging. The diagnostic efficiency of V/Q SPECT alone was compared with that of V/Q SPECT combined with low dose CT scan. Crosstabs χ2 test was performed using SPSS 13.0 software. Results: Twenty-nine patients (28.43%, 29/102) were finally diagnosed as PE. V/Q SPECT alone had a sensitivity of 93.10% (27/29), a specificity of 90.41% (66/73), and an accuracy of 91.18% (93/102). With additional diagnostic information from low dose CT, the diagnostic specificity increased to 95.89% (70/73, χ2=1.72, P>0.05), and the accuracy increased to 95.10% (97/102, χ2=1.23, P>0.05) though the sensitivity remained the same. Conclusion: Imaging information from low dose CT in hybrid SPECT/CT may enhance V/Q diagnostic accuracy for PE. (authors)

  6. Research on additional external exposure dose rate measurement by in-situ HPGe γ spectrometer

    A spectrometric method for additional exposure dose rate (external dose rate due to γ-ray emitted by artificial nuclides) measurement is introduced. The principle of this method is that: strip off the spectrum attributed to the natural radionuclides from the gamma spectrum collected by in situ HPGe spectrometer, and get the spectrum attributed to the artificial radionuclides, then integrate the stripped spectrum with corresponding spectrum-dose conversion function (G(E) function) values to acquire additional exposure dose rate. Standard spectrums attributed to nuclides in U series, Th series and 40K were calibrated by in situ HPGe spectrometer at airborne pads, and the interference caused by other nuclides was eliminated by the inverse matrix calculations. The natural compositions in the spectrum is stripped according to the standard spectrums. Six standard γ-ray sources were used to acquire the response functions of the HPGe spectrometer, then the G(E) function was calculated by the least square method. Finally, the utility of this method was verified by in situ experiment, and the factors that influence the precision of the results are discussed. (author)

  7. Life cycle assessment and additives: state of knowledge

    identify research needs within this area focusing on both risk assessment (RA) and life cycle assessment (LCA). Besides the sectors on paper and plastics also lubricants, textiles, electronics and leather are included in RiskCycle. On plastics a literature review regarding the state of knowledge on......, solvents, metals, AOX and biocides may play a very significant role in the impact profile of printed matter. Regarding the life cycle impact assessment (LCIA) part an investigation of the availability of characterisation factors (aquatic ecotox) for the about 17 additives/impurities to be included in Risk...... additives/impurities in LCA has been performed within RiskCycle. Several inventory databases (LCI data) have been investigated and the result shows that most LCI databases use PlasticsEurope data for plastics production. Most of these data are aggregated and do not include additives. Regarding the...

  8. Mesorad dose assessment model. Volume 1. Technical basis

    MESORAD is a dose assessment model for emergency response applications. Using release data for as many as 50 radionuclides, the model calculates: (1) external doses resulting from exposure to radiation emitted by radionuclides contained in elevated or deposited material; (2) internal dose commitment resulting from inhalation; and (3) total whole-body doses. External doses from airborne material are calculated using semi-infinite and finite cloud approximations. At each stage in model execution, the appropriate approximation is selected after considering the cloud dimensions. Atmospheric processes are represented in MESORAD by a combination of Lagrangian puff and Gaussian plume dispersion models, a source depletion (deposition velocity) dry deposition model, and a wet deposition model using washout coefficients based on precipitation rates

  9. Methemoglobin-Based Biological Dose Assessment for Human Blood.

    Zhang, Xiao-Hong; Hu, Xiao-Dan; Zhao, Su-Ying; Xie, Li-Hua; Miao, Yu-Ji; Li, Qun; Min, Rui; Liu, Pei-Dang; Zhang, Hai-Qian

    2016-07-01

    Methemoglobin is an oxidative form of hemoglobin in erythrocytes. The authors' aim was to develop a new biological dosimeter based on a methemoglobin assay. Methemoglobin in peripheral blood (of females or males) that was exposed to a Co source (0.20 Gy min) was quantified using an enzyme-linked immunosorbent assay. The dose range was 0.5-8.0 Gy. In a time-course experiment, the time points 0, 0.02, 1, 2, 3, 7, 15, 21, and 30 d after 4-Gy irradiation of heparinized peripheral blood were used. Methemoglobin levels in a lysed erythrocyte pellet from the irradiated blood of females and males increased with the increasing dose. Methemoglobin levels in female blood irradiated with γ-doses more than 4 Gy were significantly higher than those in male samples at the same doses. Two dose-response relations were fitted to the straight line: one is with the correlation coefficient of 0.98 for females, and the other is with the correlation coefficient of 0.99 for males. The lower limit of dose assessment based on methemoglobin is about 1 Gy. Methemoglobin levels in blood as a result of auto-oxidation increase after 7-d storage at -20 °C. The upregulation of methemoglobin induced by γ-radiation persists for ∼3 d. The absorbed doses that were estimated using the two dose-response relations were close to the actual doses. The results suggest that methemoglobin can be used as a rapid and accurate biological dosimeter for early assessment of absorbed γ-dose in human blood. PMID:27218292

  10. The assessment of personal dose due to external radiation

    The fundamental basis of thermoluminescent dosimetry (TLD) is discussed and a number of considerations in the measurement of thermoluminescence described, with particular reference to CaSO4:Dy. The steps taken to convert a thermoluminescence measurement to an exposure and then an absorbed dose are outlined. The calculation of effective dose equivalents due to external exposure to γ-radiation in a number of situations commonly encountered in a uranium mine is discussed. Factors which may affect the accuracy of external dose assessments are described

  11. External dose assessment in the Ukraine following the Chernobyl accident

    Frazier, Remi Jordan Lesartre

    While the physiological effects of radiation exposure have been well characterized in general, it remains unclear what the relationship is between large-scale radiological events and psychosocial behavior outcomes in individuals or populations. To investigate this, the National Science Foundation funded a research project in 2008 at the University of Colorado in collaboration with Colorado State University to expand the knowledge of complex interactions between radiation exposure, perception of risk, and psychosocial behavior outcomes by modeling outcomes for a representative sample of the population of the Ukraine which had been exposed to radiocontaminant materials released by the reactor accident at Chernobyl on 26 April 1986. In service of this project, a methodology (based substantially on previously published models specific to the Chernobyl disaster and the Ukrainian population) was developed for daily cumulative effective external dose and dose rate assessment for individuals in the Ukraine for as a result of the Chernobyl disaster. A software platform was designed and produced to estimate effective external dose and dose rate for individuals based on their age, occupation, and location of residence on each day between 26 April 1986 and 31 December 2009. A methodology was developed to transform published 137Cs soil deposition contour maps from the Comprehensive Atlas of Caesium Deposition on Europe after the Chernobyl Accident into a geospatial database to access these data as a radiological source term. Cumulative effective external dose and dose rate were computed for each individual in a 703-member cohort of Ukrainians randomly selected to be representative of the population of the country as a whole. Error was estimated for the resulting individual dose and dose rate values with Monte Carlo simulations. Distributions of input parameters for the dose assessment methodology were compared to computed dose and dose rate estimates to determine which

  12. Development of a real-time radiological dose assessment system

    Han, Moon Hee; Lee, Young Bok; Kim, Eun Han; Suh, Kyung Suk; Hwang, Won Tae; Choi, Young Gil

    1997-07-01

    A radiological dose assessment system named FADAS has been developed. This system is necessary to estimated the radiological consequences against a nuclear accident. Mass-consistent wind field module was adopted for the generation of wind field over the whole domain using the several measured wind data. Random-walk dispersion module is used for the calculation of the distribution of radionuclides in the atmosphere. And volume-equivalent numerical integration method has been developed for the assessment of external gamma exposure given from a randomly distributed radioactive materials and a dose data library has been made for rapid calculation. Field tracer experiments have been carried out for the purpose of analyzing the site-specific meteorological characteristics and increasing the accuracy of wind field generation and atmospheric dispersion module of FADAS. At first, field tracer experiment was carried out over flat terrain covered with rice fields using the gas samplers which were designed and manufactured by the staffs of KAERI. The sampled gas was analyzed using gas chromatograph. SODAR and airsonde were used to measure the upper wind. Korean emergency preparedness system CARE was integrated at Kori 4 nuclear power plants in 1995. One of the main functions of CARE is to estimate the radiological dose. The developed real-time dose assessment system FADAS was adopted in CARE as a tool for the radiological dose assessment. (author). 79 refs., 52 tabs., 94 figs.

  13. Assessment of patient organ dose in CT virtual colonoscopy for bowel cancer screening

    Justification and optimisation form the basic elements for the radiological protection of individuals for medical exposures. Justification includes the assessment of patient organ doses from which radiation risks are deduced. Medical radiation exposures are justified only in the case of a sufficient net benefit. For screening examinations, such as CT virtual colonoscopy, this implies that patient organ doses should be relatively low to minimise the radiation detriment. Image quality should be sufficient to maximise the potential diagnostic benefits. The Medical Exposures Directive places special attention on medical exposures as part of health screening programmes and examinations involving high individual doses to the patient, both of which apply to CT virtual colonoscopy. Technical factors were recorded for a series of patients having virtual colonoscopy on a CT scanner. In addition, the dose-length product was assessed. Patient organ doses were deduced using a CT dose calculation program. The typical effective dose was 7.5 mSv for male patients and 10.2 mSv for female patients. The effective dose is higher for female patients, as some gender-specific organs are irradiated during virtual colonoscopy. Each patient has two series of scans resulting in doses of 15 mSv for male patients and 20 mSv for female patients. (authors)

  14. Assessment of X-ray output dose in the dose calculation of linear accelerators

    Many structural types of MLC (multiple-leaf collimator) are now introduced for linear accelerators and are important factors influencing the exposure dose to patients. In other words, the formula for dose calculation would differ depending on the type which, however, does not always require the different method of dose assessment for different MLC type. Rather, the assessment can be generalized and be applicable in any case of irradiation conditions when the concept of output factors is used. This article described the concept now recognized globally: The output factors consists from field factors and scatter factors, which are further divided in some factors attributable to the apparatus with MLC and irradiation object. The review also demonstrated the effectiveness of the concept by experiments using phantoms under various irradiation conditions. (K.H.)

  15. Internal dose assessment of 99mTc-HTOC

    Full text: Octreotide is a synthetic octapeptide analog of somatostatin. Its major effects inhibit the release of pituitary growth hormone and the endocrine secretions of the pancreas, stomach, and intestine. So it is recommended to control symptoms associated with neuroendocrine tumours. In therapy, it is necessary to estimate patient-specific absorbed dose, especially to dose-limiting risk organs and to the tumour tissue. Kinetic analyses need to be carefully planned, meanwhile absorbed fraction are most similar to the subject in question should be chosen. However, the result of dose assessment is not sufficiently accurate or detailed to guide clinical decision-making, and not well correlated with observed effects on patient's organs and tumours. In this study, 99mTc-HTOC is an excellent indicator that displays the distribution of 188Re- HTOC in patient's body. The kinetic information of 99mTc -HTOC in patient's body can be obtained by SPECT in 1,4 h after injection. The activity in patient's tumours and organs can be calculated by lined the time-activity curve. In the study, the data of 86 cases can be collected. Although the basic formula of dose assessment is based on that of the medical internal radiation dose committee (MIRD), the absorbed fractions have been adjusted to be more patient-specific by patient's CT image and other data. It make internal dose of patients more accurate by the method. (author)

  16. Reducing the shrinkage and setting dose in polyester resins by addition of metal oxides

    To an unsaturated polyester resin, metal oxides (MgO, CaO, BaO) were introduced which reacted with it for 200 h. In this modified resin cured by radiation, considerable reduction of setting dose as well as of the shrinkage of resin were observed in comparison with the unmodified resin. It has been also found that there is an addition of this effect with the previously observed antishrinking action of epoxy resin containing unsaturated bonds. The service properties of the resin modified with metal oxides have not changed, while its thermal stability has increased. (author)

  17. Household energy assessment: integration of approaches and additional factors

    Parikh, J.K.

    1985-01-01

    An appropriate household energy assessment for developing countries which use substantial biomass, requires a coordinated effort between surveyors, experimentalists and analysts. This paper describes the role of each and also the additional factors which need to be considered, recorded, measured and analyzed to account for variations in energy consumption across countries, income classes, etc. These range from seasonal and regional differences, fuel scarcities and coping strategies, dietary and cooking practices, food and fuel processing, to the role of women.

  18. Assessment of doses to biota in the river system

    Doses to aquatic biota in the hydrological system Techa - Ob are estimated.The following water bodies with different levels of radioactive contamination are considered: industrial reservoirs, Techa, Iset, Tobol and Irtysh Rivers. Doses to biota are calculated using the observed data on the content of radionuclides in various environmental components, with consideration for geometric characteristics of the organisms and the exposure sources. The following groups of the river biota are considered: aquatic plants, mollusks and fish. Simplified geometric models (ellipsoids) are used in the internal dose calculations for fish and mollusks. Aquatic plants are approximated either with spheres or with a layer of finite depth. For the external doses assessment the water was considered as an infinite source with the uniform distribution of radionuclides. Sediments were represented as a source with the uniformly distributed activity. Concentration factor of scattered radiation was taken into account for gamma emitters. Sources and levels of radioactive contamination of the Techa - Ob system are analyzed. Data on the activity concentration of radionuclides in water, bottom sediments and aquatic biota are used for the dose assessment. Assessment of doses to biota in the Techa -Ob river system in the period from 1949 to the present time are performed.The highest doses (over 0.01 Gy/day) were received by aquatic organisms in the upper reaches of the Techa River in the period of maximum discharges of radionuclides (1950-1951). In that period, a major contribution to the dose to aquatic organisms was due to the incorporated radionuclides: 89 Sr, 90 Sr, 106 Ru,137 Cs, 144 Ce and others. During 1950-1951, the doses to aquatic organisms were estimated, on average, at 0.003-0.1 Gy/day. After the cessation of intensive radioactive discharges and the construction of a system of protective water bodies, the doses to aquatic biota noticeably decreased. Current levels of exposure to fish in

  19. Additional benefit of higher dose green tea in lowering postprandial blood glucose

    Rita Lahirin

    2015-07-01

    Full Text Available Background: Green tea contains catechins that have inhibitory effects on amylase, sucrase, and sodium-dependent glucose transporter (SGLT which result in lowering of postprandial blood glucose (PBG. This beneficial effect has been widely demonstrated using the usual dose (UD of green tea preparation. Our study was aimed to explore futher lowering of PBG using high dose (HD of green tea in healthy adolescents.Methods: 24 subjects received 100 mL infusion of either 0.67 or 3.33 grams of green tea with test meal. Fasting, PBG at 30, 60, 120 minutes were measured. Subjects were cross-overed after wash out. PBG and its incremental area under the curve (IAUC difference between groups were analyzed with paired T-test. Cathecin contents of tea were measured using high-performance liquid chromatography (HPLC.Results: The PBG of HD group was lower compared to UD (at 60 minutes =113.70 ± 13.20 vs 124.16 ± 8.17 mg/dL, p = 0.005; at 120 minutes = 88.95 ± 6.13 vs 105.25 ± 13.85 mg/dL, p < 0.001. The IAUC of HD was also found to be lower compared to UD (2055.0 vs 3411.9 min.mg/dL, p < 0.001.Conclusion: Additional benefit of lowering PBG can be achieved by using higher dose of green tea. This study recommends preparing higher dose of green tea drinks for better control of PBG.

  20. Integrated Worker Radiation Dose Assessment for the K Basins

    This report documents an assessment of the radiation dose workers at the K Basins are expected to receive in the process of removing spent nuclear fuel from the storage basins. The K Basins (K East and K West) are located in the Hanford 100K Area

  1. Radiological assessment. A textbook on environmental dose analysis

    Radiological assessment is the quantitative process of estimating the consequences to humans resulting from the release of radionuclides to the biosphere. It is a multidisciplinary subject requiring the expertise of a number of individuals in order to predict source terms, describe environmental transport, calculate internal and external dose, and extrapolate dose to health effects. Up to this time there has been available no comprehensive book describing, on a uniform and comprehensive level, the techniques and models used in radiological assessment. Radiological Assessment is based on material presented at the 1980 Health Physics Society Summer School held in Seattle, Washington. The material has been expanded and edited to make it comprehensive in scope and useful as a text. Topics covered include (1) source terms for nuclear facilities and Medical and Industrial sites; (2) transport of radionuclides in the atmosphere; (3) transport of radionuclides in surface waters; (4) transport of radionuclides in groundwater; (5) terrestrial and aquatic food chain pathways; (6) reference man; a system for internal dose calculations; (7) internal dosimetry; (8) external dosimetry; (9) models for special-case radionuclides; (10) calculation of health effects in irradiated populations; (11) evaluation of uncertainties in environmental radiological assessment models; (12) regulatory standards for environmental releases of radionuclides; (13) development of computer codes for radiological assessment; and (14) assessment of accidental releases of radionuclides

  2. Radiological assessment. A textbook on environmental dose analysis

    Till, J.E.; Meyer, H.R. (eds.)

    1983-09-01

    Radiological assessment is the quantitative process of estimating the consequences to humans resulting from the release of radionuclides to the biosphere. It is a multidisciplinary subject requiring the expertise of a number of individuals in order to predict source terms, describe environmental transport, calculate internal and external dose, and extrapolate dose to health effects. Up to this time there has been available no comprehensive book describing, on a uniform and comprehensive level, the techniques and models used in radiological assessment. Radiological Assessment is based on material presented at the 1980 Health Physics Society Summer School held in Seattle, Washington. The material has been expanded and edited to make it comprehensive in scope and useful as a text. Topics covered include (1) source terms for nuclear facilities and Medical and Industrial sites; (2) transport of radionuclides in the atmosphere; (3) transport of radionuclides in surface waters; (4) transport of radionuclides in groundwater; (5) terrestrial and aquatic food chain pathways; (6) reference man; a system for internal dose calculations; (7) internal dosimetry; (8) external dosimetry; (9) models for special-case radionuclides; (10) calculation of health effects in irradiated populations; (11) evaluation of uncertainties in environmental radiological assessment models; (12) regulatory standards for environmental releases of radionuclides; (13) development of computer codes for radiological assessment; and (14) assessment of accidental releases of radionuclides.

  3. Correlation study of effect of additional filter on radiation dose and image quality in digital mammography

    Objective: To explore the effect of different additional filters on radiation dose and image quality in digital mammography. Methods: Hologic company's Selenia digital mammography machine and the post-processing workstations and 5 M high resolution medical monitor were used in this study. Mammography phantoms with the thickness from 1.6 cm to 8.6 cm were used to simulate human breast tissue. The same exposure conditions, pressure, compression thickness, the anode were employed with the additional filters of Mo and Rh under the automatic and manual exposure mode. The image kV, mAs, pressure, filter, average glandular dose (AGD), entrance surface dose (ESD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and image score according to ACR criteria were recorded for the two additional filters. Paired sample t test was performed to compare the indices of Mo and Rh groups by using SPSS 17.0. Results: AGD and ESD of Rh and Mo group were both higher with the increase of the thickness of all the phantoms. AGD, ESD and their increased value of Rh filter(1.484 ± 1.041, 7.969 ± 7.633, 0.423 ± 0.190 and 3.057 ± 2.139) were lower than those of Mo filter (1.915 ± 1.301, 12.516 ± 11.632, 0.539 ±0.246 and 4.731 ± 3.294), in all the phantoms with different thickness (t values were 4.614, 3.209, 3.396 and 3.605, P<0.05). SNR, CNR, and image score of Rh and Mo group both decreased with the increase of the thickness of all the phantoms. There were no statistical difference (P>0.05). Conclusions: Compared with Mo filter, Rh filter could reduce the radiation dose, and this advantage is more obvious in the thicker phantom when the same image quality is required. (authors)

  4. Assessment of organ equivalent doses and effective doses from diagnostic X-ray examinations

    The MIRD-type adult male, female and age 10 phantoms were constructed to evaluate organ equivalent dose and effective dose of patient due to typical diagnostic X-ray examination. These phantoms were constructed with external and internal dimensions of Korean. The X-ray energy spectra were generated with SPEC78. MCNP4B ,the general-purposed Monte Carlo code, was used. Information of chest PA , chest LAT, and abdomen AP diagnostic X-ray procedures was collected on the protocol of domestic hospitals. The results showed that patients pick up approximate 0.02 to 0.18 mSv of effective dose from a single chest PA examination, and 0.01 to 0.19 mSv from a chest LAT examination depending on the ages. From an abdomen AP examination, patients pick up 0.17 to 1.40 mSv of effective dose. Exposure time, organ depth from the entrance surface and X-ray beam field coverage considerably affect the resulting doses. Deviation among medical institutions is somewhat high, and this indicated that medical institutions should interchange their information and the need of education for medical staff. The methodology and the established system can be applied, with some expansion, to dose assessment for other medical procedures accompanying radiation exposure of patients like nuclear medicine or therapeutic radiology

  5. Assessments for High Dose Radionuclide Therapy Treatment Planning

    Advances in the biotechnology of cell-specific targeting of cancer, and the increased number of clinical trials involving treatment of cancer patients with radiolabeled antibodies, peptides, and similar delivery vehicles have led to an increase in the number of high-dose radionuclide therapy procedures. Optimized radionuclide therapy for cancer treatment is based on the concept of absorbed dose to the dose-limiting normal organ or tissue. The limiting normal tissue is often the red marrow, but it may sometimes be lungs, liver, intestinal tract, or kidneys. Appropriate treatment planning requires assessment of radiation dose to several internal organs and tissues, and usually involves biodistribution studies in the patient using a tracer amount of radionuclide bound to the targeting agent and imaged at sequential time points using a planar gamma camera. Time-activity curves are developed from the imaging data for the major organs tissues of concern, for the whole body, and sometimes for selected tumors. Patient-specific factors often require that dose estimates be customized for each patient. The Food and Drug Administration regulates the experimental use of investigational new drugs and requires reasonable calculation of radiation absorbed dose to the whole body and to critical organs using methods prescribed by the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. Review of high-dose studies in the U.S. and elsewhere shows that (1) some studies are conducted with minimal dosimetry, (2) the marrow dose is difficult to establish and is subject to large uncertainties, and (3) despite the general availability of MIRD software, internal dosimetry methods are often inconsistent from one clinical center to another

  6. Assessments for high dose radionuclide therapy treatment planning

    Advances in the biotechnology of cell specific targeting of cancer and the increased number of clinical trials involving treatment of cancer patients with radiolabelled antibodies, peptides, and similar delivery vehicles have led to an increase in the number of high dose radionuclide therapy procedures. Optimised radionuclide therapy for cancer treatment is based on the concept of absorbed dose to the dose limiting normal organ or tissue. The limiting normal tissue is often the red marrow, but it may sometimes be the lungs, liver, intestinal tract, or kidneys. Appropriate treatment planning requires assessment of radiation dose to several internal organs and tissues, and usually involves biodistribution studies in the patient using a tracer amount of radionuclide bound to the targeting agent and imaged at sequential timepoints using a planar gamma camera. Time-activity curves are developed from the imaging data for the major organ tissues of concern, for the whole body and sometimes for selected tumours. Patient specific factors often require that dose estimates be customised for each patient. In the United States, the Food and Drug Administration regulates the experimental use of investigational new drugs and requires 'reasonable calculation of radiation absorbed dose to the whole body and to critical organs' using the methods prescribed by the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. Review of high dose studies shows that some are conducted with minimal dosimetry, that the marrow dose is difficult to establish and is subject to large uncertainties. Despite the general availability of software, internal dosimetry methods often seem to be inconsistent from one clinical centre to another. (author)

  7. Models for dose assessments. Modules for various biosphere types

    Bergstroem, U.; Nordlinder, S.; Aggeryd, I. [Studsvik Eco and Safety AB, Nykoeping (Sweden)

    1999-12-01

    The main objective of this study was to provide a basis for illustrations of yearly dose rates to the most exposed individual from hypothetical leakages of radionuclides from a deep bedrock repository for spent nuclear fuel and other radioactive waste. The results of this study will be used in the safety assessment SR 97 and in a study on the design and long-term safety for a repository planned to contain long-lived low and intermediate level waste. The repositories will be designed to isolate the radionuclides for several hundred thousands of years. In the SR 97 study, however, hypothetical scenarios for leakage are postulated. Radionuclides are hence assumed to be transported in the geosphere by groundwater, and probably discharge into the biosphere. This may occur in several types of ecosystems. A number of categories of such ecosystems were identified, and turnover of radionuclides was modelled separately for each ecosystem. Previous studies had focused on generic models for wells, lakes and coastal areas. These models were, in this study, developed further to use site-specific data. In addition, flows of groundwater, containing radionuclides, to agricultural land and peat bogs were considered. All these categories are referred to as modules in this report. The forest ecosystems were not included, due to a general lack of knowledge of biospheric processes in connection with discharge of groundwater in forested areas. Examples of each type of module were run with the assumption of a continuous annual release into the biosphere of 1 Bq for each radionuclide during 10 000 years. The results are presented as ecosystem specific dose conversion factors (EDFs) for each nuclide at the year 10 000, assuming stationary ecosystems and prevailing living conditions and habits. All calculations were performed with uncertainty analyses included. Simplifications and assumptions in the modelling of biospheric processes are discussed. The use of modules may be seen as a step

  8. Models for dose assessments. Modules for various biosphere types

    The main objective of this study was to provide a basis for illustrations of yearly dose rates to the most exposed individual from hypothetical leakages of radionuclides from a deep bedrock repository for spent nuclear fuel and other radioactive waste. The results of this study will be used in the safety assessment SR 97 and in a study on the design and long-term safety for a repository planned to contain long-lived low and intermediate level waste. The repositories will be designed to isolate the radionuclides for several hundred thousands of years. In the SR 97 study, however, hypothetical scenarios for leakage are postulated. Radionuclides are hence assumed to be transported in the geosphere by groundwater, and probably discharge into the biosphere. This may occur in several types of ecosystems. A number of categories of such ecosystems were identified, and turnover of radionuclides was modelled separately for each ecosystem. Previous studies had focused on generic models for wells, lakes and coastal areas. These models were, in this study, developed further to use site-specific data. In addition, flows of groundwater, containing radionuclides, to agricultural land and peat bogs were considered. All these categories are referred to as modules in this report. The forest ecosystems were not included, due to a general lack of knowledge of biospheric processes in connection with discharge of groundwater in forested areas. Examples of each type of module were run with the assumption of a continuous annual release into the biosphere of 1 Bq for each radionuclide during 10 000 years. The results are presented as ecosystem specific dose conversion factors (EDFs) for each nuclide at the year 10 000, assuming stationary ecosystems and prevailing living conditions and habits. All calculations were performed with uncertainty analyses included. Simplifications and assumptions in the modelling of biospheric processes are discussed. The use of modules may be seen as a step

  9. Identification and dose assessment of irradiated cardamom and cloves by EPR spectrometry

    Beshir, W. B.

    2014-03-01

    The use of electron paramagnetic resonance spectroscopy to accurately distinguish irradiated from unirradiated cardamom and cloves and assesses the absorbed dose to radiation processed cardamom and cloves are examined. The results were successful for identifying both irradiated and unirradiated cardamom and cloves. Additive reirradiation of cardamom and cloves produces reproducible dose-response functions, which can be used to assess the initial dose by back-extrapolation. Third degree polynomial function was used to fit the EPR signal/dose curves. It was found that this 3rd degree polynomial function provides satisfactory results without correction of decay for free radicals. The stability of the radiation induced EPR signal of irradiated cardamom and cloves were studied over a storage period of almost 8 months.

  10. Thoron in the air: assessment of the occupational dose

    The occupational dose due to inhalation of thoron was assessed through the committed effective dose and the committed equivalent dose received by workers exposed to the radionuclide at the nuclear materials storage site and the thorium purification plant of the Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP). The radiation doses were performed by compartmental analysis following the compartmental model of the lung and biokinetic model of the lead, through the thoron equilibrium equivalent concentrations. These values were obtained by gamma ray spectrometry, total alpha count and alpha particle spectrometry of air samples glass fiber filters. The results of the thoron equilibrium equivalent concentration varied from 0.3 to 0,67 Bq/m3 at the nuclear materials storage site and from 0.9 to 249.8 Bq/m3 at the thorium purification plant. The committed effective dose due to thoron inhalation varied from 0.03 mSv/a to 0.67 mSv/a at the nuclear materials storage site and from 0.12 mSv/a to 6.0 mSv/a at the thorium purification plant. The risk assessment of lung cancer and fatal cancers for the workers exposed to thoron at the nuclear materials storage site and the thorium purification plant showed an increment for both risk cancer. (author)

  11. TSD-DOSE: A radiological dose assessment model for treatment, storage, and disposal facilities

    Past practices at US Department of Energy (DOE) field facilities resulted in the presence of trace amounts of radioactive materials in some hazardous chemical wastes shipped from these facilities. In May 1991, the DOE Office of Waste Operations issued a nationwide moratorium on shipping all hazardous waste until procedures could be established to ensure that only nonradioactive hazardous waste would be shipped from DOE facilities to commercial treatment, storage, and disposal (TSD) facilities. To aid in assessing the potential impacts of shipments of mixed radioactive and chemically hazardous wastes, a radiological assessment computer model (or code) was developed on the basis of detailed assessments of potential radiological exposures and doses for eight commercial hazardous waste TSD facilities. The model, called TSD-DOSE, is designed to incorporate waste-specific and site-specific data to estimate potential radiological doses to on-site workers and the off-site public from waste-handling operations at a TSD facility. The code is intended to provide both DOE and commercial TSD facilities with a rapid and cost-effective method for assessing potential human radiation exposures from the processing of chemical wastes contaminated with trace amounts of radionuclides

  12. Application of the ELDO approach to assess cumulative eye lens doses for interventional cardiologists.

    Farah, J; Struelens, L; Auvinen, A; Jacob, S; Koukorava, C; Schnelzer, M; Vanhavere, F; Clairand, I

    2015-04-01

    In preparation of a large European epidemiological study on the relation between eye lens dose and the occurrence of lens opacities, the European ELDO project focused on the development of practical methods to estimate retrospectively cumulative eye lens dose for interventional medical professionals exposed to radiation. The present paper applies one of the ELDO approaches, correlating eye lens dose to whole-body doses, to assess cumulative eye lens dose for 14 different Finnish interventional cardiologists for whom annual whole-body dose records were available for their entire working period. The estimated cumulative left and right eye lens dose ranged from 8 to 264 mSv and 6 to 225 mSv, respectively. In addition, calculations showed annual eye lens doses sometimes exceeding the new ICRP annual limit of 20 mSv. The work also highlights the large uncertainties associated with the application of such an approach proving the need for dedicated dosimetry systems in the routine monitoring of the eye lens dose. PMID:25316910

  13. Application of the ELDO approach to assess cumulative eye lens doses for interventional cardiologists

    In preparation of a large European epidemiological study on the relation between eye lens dose and the occurrence of lens opacities, the European ELDO project focused on the development of practical methods to estimate retrospectively cumulative eye lens dose for interventional medical professionals exposed to radiation. The present paper applies one of the ELDO approaches, correlating eye lens dose to whole-body doses, to assess cumulative eye lens dose for 14 different Finnish interventional cardiologists for whom annual whole-body dose records were available for their entire working period. The estimated cumulative left and right eye lens dose ranged from 8 to 264 mSv and 6 to 225 mSv, respectively. In addition, calculations showed annual eye lens doses sometimes exceeding the new ICRP annual limit of 20 mSv. The work also highlights the large uncertainties associated with the application of such an approach proving the need for dedicated dosimetry systems in the routine monitoring of the eye lens dose. (authors)

  14. Methodology for assessing doses and radiation impact on marine organisms

    Environmental protection is one of the key issues in the prospective policy and strategy of radiation protection. In this context, numerous efforts have been made for developing the framework for the protection of non-human species from ionizing radiation, especially in European countries and Unite States. The present report summarizes knowledge so far attained on the assessment of doses and radiation impact on marine organisms. Special attention was directed to the methodology for calculating absorbed doses of marine organisms, based on which a case study was also carried out for estimating absorbed dose rate of several species of marine organisms inhabiting in the coastal sea off Rokkasho-Mura, Aomori Prefecture where a spent nuclear fuel reprocessing plant came into operation. (author)

  15. Improvement of the following accident dose assessment system

    Kim, Enn Han; Han, Moon Hee; Suh, Kyung Suk; Hwang, Won Tae; Choi, Young Gil [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1999-12-15

    The FADAS has been updates for calculating the real-time wind fields continuously at the nuclear sites in Korea. The system has been constructed to compute the wind fields using its own process for the dummy meteorological data, and dose not effect on the overall wind field module. If the radioactive materials are released into the atmosphere in real situation, the calculations of wind fields and exposure dose in the previous FADAS are performed in the case of the recognition of the above situation in the source term evaluation module. The current version of FADAS includes the program for evaluating the effect of the predicted accident and the assumed scenario together. The dose assessment module is separated into the real-time and the supposed accident respectively.

  16. ASSESSMENT OF COLLECTIVE DOSE FOR TRAVELLERS BY WATERS

    岳清宇; 姜萍; 等

    1995-01-01

    People travelling by air will receive more exposure dose and by water will receive less one.According to statistic data from the Ministry of Communications in 1988,the turnover in that year was about 2×1010 man.km.The total number of fishermen for inshore fishing was nearly two million reported by Ministry of Agriculture,Animal Husbandry and Fishery.Based on measured data on 212 points in six typical shipping lines of inshore lines and inland rivers,and the total voyage is 5625km,the average natural radiation dose rate received by travellers was calculated.From that assessment of collective effective dose for passengers by water and fishermen was derived.The value is 32.7man.Sv for passengers and 265.3man.Sv for fishermen.

  17. Improvement of the following accident dose assessment system

    The FADAS has been updates for calculating the real-time wind fields continuously at the nuclear sites in Korea. The system has been constructed to compute the wind fields using its own process for the dummy meteorological data, and dose not effect on the overall wind field module. If the radioactive materials are released into the atmosphere in real situation, the calculations of wind fields and exposure dose in the previous FADAS are performed in the case of the recognition of the above situation in the source term evaluation module. The current version of FADAS includes the program for evaluating the effect of the predicted accident and the assumed scenario together. The dose assessment module is separated into the real-time and the supposed accident respectively

  18. Additional factors for the estimation of mean glandular breast dose using the UK mammography dosimetry protocol

    The UK and European protocols for mammographic dosimetry use conversion factors that relate incident air kerma to the mean glandular dose (MGD) within the breast. The conversion factors currently used were obtained by computer simulation of a model breast with a composition of 50% adipose and 50% glandular tissues by weight (50% glandularity). Relative conversion factors have been calculated which allow the extension of the protocols to breasts of varying glandularity and for a wider range of mammographic x-ray spectra. The data have also been extended to breasts of a compressed thickness of 11 cm. To facilitate the calculation of MGD in patient surveys, typical breast glandularities are tabulated for women in the age ranges 40-49 and 50-64 years, and for breasts in the thickness range 2-11 cm. In addition, tables of equivalent thickness of polymethyl methacrylate have been provided to allow the simulation for dosimetric purposes of typical breasts of various thicknesses. (author)

  19. Assessment of out-of-field absorbed dose and equivalent dose in proton fields

    Clasie, Ben; Wroe, Andrew; Kooy, Hanne; Depauw, Nicolas; Flanz, Jay; Paganetti, Harald; Rosenfeld, Anatoly [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States); Department of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, California 92354 (United States) and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales, 2522 (Australia); Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales, 2522 (Australia)

    2010-01-15

    . Conclusions: The dose deposited immediately downstream of the primary field, in these cases, is dominated by internally produced neutrons; therefore, scattered and scanned fields may have similar risk of second cancer in this region. The authors confirm that there is a reduction in the out-of-field dose in active scanning but the effect decreases with depth. GEANT4 is suitable for simulating the dose deposited outside the primary field. The agreement with measurements is comparable to or better than the agreement reported for other implementations of Monte Carlo models. Depending on the position, the absorbed dose outside the primary field is dominated by contributions from primary protons that may or may not have scattered in the brass collimating devices. This is noteworthy as the quality factor of the low LET protons is well known and the relative dose risk in this region can thus be assessed accurately.

  20. Error in assessing the absorbed dose from the EPR signal from dental enamel

    Dose measurements from EPR signals from dental enamel were analyzed in a random sampling of 100 teeth extracted in liquidators of the Chernobyl accident aftermath and the EPR spectra of dental enamel of 80 intact teeth from children studied. The mean square deviation of enamel sensitivity to ionizing radiation in some teeth is approximately 0.3 of the mean sensitivity value. The variability of the nature EPR spectrum of dental enamel limits in principle the lower threshold of EPR-measured 60 mGy doses. When assessing the individual absorbed doses from the EPR signal from dental enamel without additional exposure it is necessary to bear in mind the extra error of approximately 6-% at a confidence probability P=0.95 caused by the variability of enamel sensitivity to radiation in some teeth. This additional error may be ruled out by graduated additional exposure of the examined enamel samples

  1. Identification and dose assessment of irradiated cardamom and cloves by EPR spectrometry

    The use of electron paramagnetic resonance spectroscopy to accurately distinguish irradiated from unirradiated cardamom and cloves and assesses the absorbed dose to radiation processed cardamom and cloves are examined. The results were successful for identifying both irradiated and unirradiated cardamom and cloves. Additive reirradiation of cardamom and cloves produces reproducible dose–response functions, which can be used to assess the initial dose by back-extrapolation. Third degree polynomial function was used to fit the EPR signal/dose curves. It was found that this 3rd degree polynomial function provides satisfactory results without correction of decay for free radicals. The stability of the radiation induced EPR signal of irradiated cardamom and cloves were studied over a storage period of almost 8 months. The calculated G-value (The number of radicals per 100 eV of absorbed energy) for cardamom and cloves was found 0.07±0.01 and 0.055±0.01, respectively. - Highlights: • The EPR analysis of cardamom and cloves prove the sample has been irradiated or not. • Dose additive can be used for evaluation of the absorbed dose in cardamom and cloves. • The 3rd polynomial function can be used to fit the data and the estimated dose. • The stability of the radiation induced EPR signal of irradiated cardamom and cloves were studied over 2 months

  2. Biokinetics and dose assessment of radionuclides in juveniles

    In the aftermath of the Chernobyl accident, it becomes evident that dose coefficients for members of the public are necessary. International Commission on Radiological Protection (ICRP) established a task group of Committee 2 charged with the assessment of dose coefficients as a function of an individual's age. However, little data is available on the biokinetics of radionuclides in juvenile and there is a need to develop age-dependent biokinetic models, such as for the gastrointestinal tract. The present paper reviewed an outline on characteristics of biokinetics of radionuclides in juvenile animals focusing on the previous experimental data. The following radionuclides are discussed: 54Mn, 60Co, 65Zn, 75Se, 106Ru, 110mAg, 115mCd, 125Sb, 137Cs, 141Ce, 203Hg and 3H. Generally, intestinal absorption and whole-body retention of radionuclides in juveniles were higher than that of adult. In the case of sucklings, it is very important to study how radionuclides are transferred through the placenta and milk. The transfer rate of radionuclides through the placenta and milk is dependent on the period of gestation at the time of dosing. The IDES(Internal Dose Estimation System) which is based on the ICRP model was used for dose calculation. We modified the IDES using the biokinetic data which was gained animal experiment. The IDES is flexible because the absorbed dose can be calculated by substituting arbitrary physical and physiological parameters and also substituting ingested dose coefficients not only for the ICRP Reference Man, but also for Japanese of 1 year old, 5 years old, 10 years old, 15 years old and the adult, respectively. (author)

  3. Assessment of patient dose in mammography using Monte Carlo simulation

    Breast doses due to mammographic examinations were assessed using a MIRD-type female phantom and Monte Carlo simulations. Clinical mammographic data, which vary according to the age group of the subject undergoing the examinations, were obtained from the Korea Cancer Center Hospital in Seoul. The tube potential was fixed to 26 kVp, most commonly used in the mammographic examination, and the source-film distance was kept constant at 65 cm. The breast tissue was assumed to have an even composition between glandular tissue and adipose tissue. The nominal breast equivalent doses were in the range from 0.6 to 1.8 mSv and the resulting effective doses ranged from 0.06 to 0.19 mSv depending on the age group and the projection modes. Lower doses were resulted at older ages. Contributions of organs other than the breast to the effective doses were negligible as long as the X-ray beam was adequately collimated and aligned to avoid exposure of other part of the body than the breast. This means that a simple breast-only phantom can be used in dosimetric calculations for mammography. (author)

  4. Biological dosimetry: chromosomal aberration analysis for dose assessment

    In view of the growing importance of chromosomal aberration analysis as a biological dosimeter, the present report provides a concise summary of the scientific background of the subject and a comprehensive source of information at the technical level. After a review of the basic principles of radiation dosimetry and radiation biology basic information on the biology of lymphocytes, the structure of chromosomes and the classification of chromosomal aberrations are presented. This is followed by a presentation of techniques for collecting blood, storing, transporting, culturing, making chromosomal preparations and scaring of aberrations. The physical and statistical parameters involved in dose assessment are discussed and examples of actual dose assessments taken from the scientific literature are given

  5. Assessment of dose measurement uncertainty using RisøScan

    Helt-Hansen, J.; Miller, A.

    2006-01-01

    The dose measurement uncertainty of the dosimeter system RisoScan, office scanner and Riso B3 dosimeters has been assessed by comparison with spectrophotometer measurements of the same dosimeters. The reproducibility and the combined uncertainty were found to be approximately 2% and 4%, respectiv......The dose measurement uncertainty of the dosimeter system RisoScan, office scanner and Riso B3 dosimeters has been assessed by comparison with spectrophotometer measurements of the same dosimeters. The reproducibility and the combined uncertainty were found to be approximately 2% and 4......%, respectively, at one standard deviation. The subroutine in RisoScan for electron energy measurement is shown to give results that are equivalent to the measurements with a scanning spectrophotometer. (c) 2006 Elsevier Ltd. All rights reserved....

  6. Equine scintigraphy: assessment of the dose received by the personnel

    Following a request from the Permanent Secretary of the French Commission for Artificial Radioelements (CIREA) engaged to investigate a request for a licence related to a new scintigraphy unit dedicated to equidae, a dosimetric assessment concerning the personnel attending the examination was carried out. This scintigraphy unit depends on the Goustranville Centre for Imaging and Research on the Locomotive Diseases of Equidae (CIRALE) in the Calvados region. The dosimetric assessment was carried out for the different operators during the successive stages of the scintigraphic examination. Assuming 150 examinations per year, the annual equivalent dose to the fingers skin is 150 mSv maximum for the technologist and 2 mSv for the veterinary surgeon; the annual effective dose ranges from 0.15 to 0.45 mSv, depending on the operators. (authors)

  7. Venous thromboembolism: Additional diagnostic value and radiation dose of pelvic CT venography in patients with suspected pulmonary embolism

    Reichert, Miriam, E-mail: Miriam.Reichert@umm.de [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim (Germany); Henzler, Thomas; Krissak, Radko; Apfaltrer, Paul [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim (Germany); Huck, Kurt [1st Department of Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim (Germany); Buesing, Karen [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim (Germany); Sueselbeck, Tim [1st Department of Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim (Germany); Schoenberg, Stefan O.; Fink, Christian [Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim (Germany)

    2011-10-15

    Purpose: To assess the additional diagnostic value of indirect CT venography (CTV) of the pelvis and upper thighs performed after pulmonary CT angiography (CTA) for the diagnosis of venous thromboembolism (VTE). Materials and methods: In a retrospective analysis, the radiology information system entries between January 2003 and December 2007 were searched for patients who received pulmonary CTA and additional CTV of the pelvis and upper thighs. Of those patients, the radiology reports were reviewed for the diagnosis of pulmonary embolism (PE) and deep venous thrombosis (DVT) in the pelvic veins and veins of the upper thighs. In cases with an isolated pelvic thrombosis at CTV (i.e. which only had a thrombosis in the pelvic veins but not in the veins of the upper thigh) ultrasound reports were reviewed for the presence of DVT of the legs. The estimated radiation dose was calculated for pulmonary CTA and for CTV of the pelvis. Results: In the defined period 3670 patients were referred to our institution for exclusion of PE. Of those, 642 patients (353 men, 289 women; mean age, 65 {+-} 15 years, age range 18-98 years) underwent combined pulmonary CTA and CTV. Among them, PE was found in 227 patients (35.4%). In patients without PE CTV was negative in all cases. In patients with PE, CTV demonstrated pelvic thrombosis in 24 patients (3.7%) and thrombosis of the upper thighs in 43 patients (6.6%). Of those patients 14 (2.1%) had DVT in the pelvis and upper thighs. In 10 patients (1.5%) CTV showed an isolated pelvic thrombosis. Of those patients ultrasound reports were available in 7 patients, which revealed DVT of the leg veins in 5 cases (1%). Thus, the estimated prevalence of isolated pelvic thrombosis detected only by pelvic CTV ranges between 1-5/642 patients (0.1-0.7%). Radiation dose ranges between 4.8 and 9.7 mSv for additional CTV of the pelvis. Conclusion: CTV of the pelvis performed after pulmonary CTA is of neglectable additional diagnostic value for the

  8. Methods of assessing total doses integrated across pathways

    Calculated doses for comparison with limits resulting from discharges into the environment should be summed across all relevant pathways and food groups to ensure adequate protection. Current methodology for assessments used in the radioactivity in Food and the Environment (R.I.F.E.) reports separate doses from pathways related to liquid discharges of radioactivity to the environment from those due to gaseous releases. Surveys of local inhabitant food consumption and occupancy rates are conducted in the vicinity of nuclear sites. Information has been recorded in an integrated way, such that the data for each individual is recorded for all pathways of interest. These can include consumption of foods, such as fish, crustaceans, molluscs, fruit and vegetables, milk and meats. Occupancy times over beach sediments and time spent in close proximity to the site is also recorded for inclusion of external and inhalation radiation dose pathways. The integrated habits survey data may be combined with monitored environmental radionuclide concentrations to calculate total dose. The criteria for successful adoption of a method for this calculation were: Reproducibility can others easily use the approach and reassess doses? Rigour and realism how good is the match with reality?Transparency a measure of the ease with which others can understand how the calculations are performed and what they mean. Homogeneity is the group receiving the dose relatively homogeneous with respect to age, diet and those aspects that affect the dose received? Five methods of total dose calculation were compared and ranked according to their suitability. Each method was labelled (A to E) and given a short, relevant name for identification. The methods are described below; A) Individual doses to individuals are calculated and critical group selection is dependent on dose received. B) Individual Plus As in A, but consumption and occupancy rates for high dose is used to derive rates for application in

  9. An airborne dispersion/dose assessment computer program. Phase 1

    The Atomic Energy Control Board (AECB) staff have a need for an airborne dispersion-dose assessment computer programme for a microcomputer. The programme must be capable of analyzing the dispersion of both radioactive and non-radioactive materials. A further requirement of the programme is that it be implemented on the AECB complex of microcomputers and that it have an advanced graphical user interface. A survey of computer programs was conducted to determine which, if any, could meet the AECB's requirements in whole or in part. Ten programmes were selected for detailed review including programs for nuclear and non-radiological emergencies. None of the available programmes for radiation dose assessment meets all the requirements for reasons of user interaction, method of source term estimation or site specificity. It is concluded that the best option for meeting the AECB requirements is to adopt the CAMEO programme (specifically the ALOHA portion) which has a superior graphical user interface and add the necessary models for radiation dose assessment

  10. Assessment and recording of radiation doses to workers

    The assessment and recording of the radiation exposure of workers in activities involving radiation risks are required for demonstrating compliance with institutional dose limitations and for a number of other complementary purposes. A significant proportion of the labor force involved in radiation work is currently represented by those specialised workers who operate as itinerant contractors for different nuclear installations and in different countries. In order to ensure that the exposure of these workers is adequately and consistently controlled and kept within acceptable limits, there is a need for the criteria and methods for dose assessment and recording to be harmonised throughout the different countries. An attempt in that direction has been made in this report, which has been prepared by a group of experts convened by the Committee on Radiation Protection and Public Health of the OECD Nuclear Energy Agency. Its primary purpose is to describe recommended technical procedures for an unified approach to the assessment and recording of worker doses. The report is published under the responsibility of the Secretary-General of the OECD, and does not commit Member governments

  11. Assessment of internal dose from radionuclides - dosimetric and biokinetic models

    For the assessment of annual limits on intakes of radionuclides by workers, and of dose coefficients for intakes of radionuclides by members of the public and patients, the ICRP has developed biokinetic models for the uptake of radionuclides by the gastrointestinal and the respiratory tract as well as for the systemic behaviour of radionuclides and their elimination from the body. The dosimetric and biokinetic models and data used for the assessments are described in detail. Present results and future activities of the ICRP on secondary limits for internal exposure are briefly mentioned. (orig./HP)

  12. Cone beam computed tomography radiation dose and image quality assessments.

    Lofthag-Hansen, Sara

    2010-01-01

    Diagnostic radiology has undergone profound changes in the last 30 years. New technologies are available to the dental field, cone beam computed tomography (CBCT) as one of the most important. CBCT is a catch-all term for a technology comprising a variety of machines differing in many respects: patient positioning, volume size (FOV), radiation quality, image capturing and reconstruction, image resolution and radiation dose. When new technology is introduced one must make sure that diagnostic accuracy is better or at least as good as the one it can be expected to replace. The CBCT brand tested was two versions of Accuitomo (Morita, Japan): 3D Accuitomo with an image intensifier as detector, FOV 3 cm x 4 cm and 3D Accuitomo FPD with a flat panel detector, FOVs 4 cm x 4 cm and 6 cm x 6 cm. The 3D Accuitomo was compared with intra-oral radiography for endodontic diagnosis in 35 patients with 46 teeth analyzed, of which 41 were endodontically treated. Three observers assessed the images by consensus. The result showed that CBCT imaging was superior with a higher number of teeth diagnosed with periapical lesions (42 vs 32 teeth). When evaluating 3D Accuitomo examinations in the posterior mandible in 30 patients, visibility of marginal bone crest and mandibular canal, important anatomic structures for implant planning, was high with good observer agreement among seven observers. Radiographic techniques have to be evaluated concerning radiation dose, which requires well-defined and easy-to-use methods. Two methods: CT dose index (CTDI), prevailing method for CT units, and dose-area product (DAP) were evaluated for calculating effective dose (E) for both units. An asymmetric dose distribution was revealed when a clinical situation was simulated. Hence, the CTDI method was not applicable for these units with small FOVs. Based on DAP values from 90 patient examinations effective dose was estimated for three diagnostic tasks: implant planning in posterior mandible and

  13. Biological dose assessment of 15 victims in Haerbin radiation accident

    unstable aberrations were analyzed and biological dose was assessed according to the dose-effect curves built by our lab member. For micronucleus analysis, blood were added cytochalasin-B after culturing 40 hours. The doses were assessed according to the dose-effect curves built by our lab member. According to a human lymphocyte chromosome aberration and micronucleus analysis, the estimated maximum irradiation dose of 3 exposed patients is lower than 2 Gy, equal to the dose of once uneven total-body irradiation. In vitro dose-response calibration curves for (60)Co gamma rays have been established for unstable chromosome aberrations in human peripheral blood lymphocytes. The observed dose-response data were fitted to a linear quadratic model. The calibration curve parameters were used to estimate the equivalent whole-body dose and dose to the irradiated region in partial body irradiation of cancer patients. The derived partial body doses and fractions of lymphocytes irradiated were in agreement with those estimated from the radiotherapy regimes. (author)

  14. Non-human biota dose assessment. Sensitivity analysis and knowledge quality assessment

    This report provides a summary of a programme of work, commissioned within the BIOPROTA collaborative forum, to assess the quantitative and qualitative elements of uncertainty associated with biota dose assessment of potential impacts of long-term releases from geological disposal facilities (GDF). Quantitative and qualitative aspects of uncertainty were determined through sensitivity and knowledge quality assessments, respectively. Both assessments focused on default assessment parameters within the ERICA assessment approach. The sensitivity analysis was conducted within the EIKOS sensitivity analysis software tool and was run in both generic and test case modes. The knowledge quality assessment involved development of a questionnaire around the ERICA assessment approach, which was distributed to a range of experts in the fields of non-human biota dose assessment and radioactive waste disposal assessments. Combined, these assessments enabled critical model features and parameters that are both sensitive (i.e. have a large influence on model output) and of low knowledge quality to be identified for each of the three test cases. The output of this project is intended to provide information on those parameters that may need to be considered in more detail for prospective site-specific biota dose assessments for GDFs. Such information should help users to enhance the quality of their assessments and build greater confidence in the results. (orig.)

  15. CAP-88, Dose Risk Assessment from Air Emissions of Radionuclides

    1 - Description of program or function: The Clean Air Act Assessment Package-1988 (CAP-88) is designed for assessment of dose and risk from radionuclide emissions to air in compliance with National Emission Standards for Hazardous Air Pollutants (NESHAPs) for Radionuclides. CAP-88 estimates health impacts from the inhalation, ingestion, air immersion and ground surface irradiation pathways, and tabulates results for maximally exposed individuals and regional populations out to 80 kilometers. The system provides risk information in a concise, easy-to-read format and prints an echo of the input. CAP-88 consists of updated versions of the mainframe codes AIRDOS-EPA and DARTAB. Atmospheric dispersion and deposition are calculated by AIRDOS2. Dose and risk assessment tables are calculated by DARTAB2 from the binary output file produced by AIRDOS2 and a file of dose and risk factors calculated by RADRISK. Pre-processors (PREPAR2 and PREDA) for AIRDOS2 and DARTAB2 access data bases of element and nuclide dependent data to simplify the execution of the principal programs. 2 - Method of solution: AIRDOS-EPA implements a long term average Gaussian Plume model. The associated terrestrial model for deposition is based on NRC Regulatory Guide 1.109. The 50-year effective dose equivalent factors for DARTAB2 are calculated by RADRISK and use weighting factors from ICRP-26. Risks are calculated using a linear Life Table model consistent with BEIR-3. The resultant risk factors are 4.0E-4 cancer deaths per rem and 3.6E-4 cancer deaths per person working-level-month exposure to radon decay products. CAP88-PC (CCC-0542/02) is able to use population data and weather data downloaded from mainframe versions of CAP-88. CAP88-PC also comes with sample population arrays from some DOE facilities, and includes weather data from many DOE sites and major U.S. cities. 3 - Restrictions on the complexity of the problem: Programs are limited to 36 radionuclides and to 20 downwind distances for each

  16. ARAC: a flexible real-time dose consequence assessment system

    ARAC (the Atmospheric Release Advisory Capability), an emergency radiological dose assessment capability of the U.S. Government, has been called on to do consequence assessments for releases into the atmosphere of radionuclides and a variety of other substances. Because of the variety of requirements of each unique assessment, ARAC has developed and maintains a flexible system of people, computer software and hardware. A new version of ADPIC that can simulate the transport of any number of radionuclide particulates and gases and all of the decay products that are generated during transport and after deposition. This code will be most suitable for application to nuclear reactor accidents. ARAC has personal computer and advanced computer workstations at approximately 50 remote sites that communicate central system and which can initiate an ARAC response by transmitting time, location and source information about an accident to the central system

  17. Source term calculations for assessing radiation dose to equipment

    This study examines results of analyses performed with the Source Term Code Package to develop updated source terms using NUREG-0956 methods. The updated source terms are to be used to assess the adequacy of current regulatory source terms used as the basis for equipment qualification. Time-dependent locational distributions of radionuclides within a containment following a severe accident have been developed. The Surry reactor has been selected in this study as representative of PWR containment designs. Similarly, the Peach Bottom reactor has been used to examine radionuclide distributions in boiling water reactors. The time-dependent inventory of each key radionuclide is provided in terms of its activity in curies. The data are to be used by Sandia National Laboratories to perform shielding analyses to estimate radiation dose to equipment in each containment design. See NUREG/CR-5175, ''Beta and Gamma Dose Calculations for PWR and BWR Containments.'' 6 refs., 11 tabs

  18. Landscape dose conversion factors used in the safety assessment SR-Site

    Avila, Rodolfo; Ekstroem, Per-Anders; Aastrand, Per-Gustav (Facilia AB (Sweden))

    2010-12-15

    In this report two types of Dose Conversion Factors have been derived: i) a Landscape Dose Conversion Factor (LDF) that is applicable to continuous long-term releases to the biosphere at a constant rate, and ii) a Landscape Dose Conversion Factor for pulse releases (LDF pulse) that is applicable to a radionuclide release that reaches the biosphere in a pulse within years to hundreds of years. In SR-Site these Dose Factors are multiplied with modelled release rates or pulse releases from the geosphere to obtain dose estimates used in assessment of compliance with the regulatory risk criterion. The LDFs were calculated for three different periods of the reference glacial cycle; a period of submerged conditions following the deglaciation, the temperate period, and a prolonged period of periglacial conditions. Additionally, LDFs were calculated for the global warming climate case. The LDF pulse was calculated only for temperate climate conditions. The LDF and LDF pulse can be considered as Best Estimate values, which can be used in calculations of Best Estimate values of doses to a representative individual of the most exposed group from potential releases from a future repository. A systematic analysis of the effects of system, model and parameter uncertainties on the LDFs has been carried out. This analysis has shown that the use of the derived LDF would lead to cautious or realistic dose estimates. The models and methods that were used for derivation of the LDFs and LDF pulse are also described in this report

  19. Monitoring system for the quality assessment in additive manufacturing

    Additive Manufacturing (AM) refers to a process by which a set of digital data -representing a certain complex 3dim design - is used to grow the respective 3dim real structure equal to the corresponding design. For the powder-based EOS manufacturing process a variety of plastic and metal materials can be used. Thereby, AM is in many aspects a very powerful tool as it can help to overcome particular limitations in conventional manufacturing. AM enables more freedom of design, complex, hollow and/or lightweight structures as well as product individualisation and functional integration. As such it is a promising approach with respect to the future design and manufacturing of complex 3dim structures. On the other hand, it certainly calls for new methods and standards in view of quality assessment. In particular, when utilizing AM for the design of complex parts used in aviation and aerospace technologies, appropriate monitoring systems are mandatory. In this respect, recently, sustainable progress has been accomplished by joining the common efforts and concerns of a manufacturer Additive Manufacturing systems and respective materials (EOS), along with those of an operator of such systems (MTU Aero Engines) and experienced application engineers (Carl Metrology), using decent know how in the field of optical and infrared methods regarding non-destructive-examination (NDE). The newly developed technology is best described by a high-resolution layer by layer inspection technique, which allows for a 3D tomography-analysis of the complex part at any time during the manufacturing process. Thereby, inspection costs are kept rather low by using smart image-processing methods as well as CMOS sensors instead of infrared detectors. Moreover, results from conventional physical metallurgy may easily be correlated with the predictive results of the monitoring system which not only allows for improvements of the AM monitoring system, but finally leads to an optimisation of the quality

  20. Monitoring system for the quality assessment in additive manufacturing

    Carl, Volker

    2015-03-01

    Additive Manufacturing (AM) refers to a process by which a set of digital data -representing a certain complex 3dim design - is used to grow the respective 3dim real structure equal to the corresponding design. For the powder-based EOS manufacturing process a variety of plastic and metal materials can be used. Thereby, AM is in many aspects a very powerful tool as it can help to overcome particular limitations in conventional manufacturing. AM enables more freedom of design, complex, hollow and/or lightweight structures as well as product individualisation and functional integration. As such it is a promising approach with respect to the future design and manufacturing of complex 3dim structures. On the other hand, it certainly calls for new methods and standards in view of quality assessment. In particular, when utilizing AM for the design of complex parts used in aviation and aerospace technologies, appropriate monitoring systems are mandatory. In this respect, recently, sustainable progress has been accomplished by joining the common efforts and concerns of a manufacturer Additive Manufacturing systems and respective materials (EOS), along with those of an operator of such systems (MTU Aero Engines) and experienced application engineers (Carl Metrology), using decent know how in the field of optical and infrared methods regarding non-destructive-examination (NDE). The newly developed technology is best described by a high-resolution layer by layer inspection technique, which allows for a 3D tomography-analysis of the complex part at any time during the manufacturing process. Thereby, inspection costs are kept rather low by using smart image-processing methods as well as CMOS sensors instead of infrared detectors. Moreover, results from conventional physical metallurgy may easily be correlated with the predictive results of the monitoring system which not only allows for improvements of the AM monitoring system, but finally leads to an optimisation of the quality

  1. Monitoring system for the quality assessment in additive manufacturing

    Carl, Volker, E-mail: carl@t-zfp.de [Carl Messtechnik, Thyssenstrasse 183a, 46535 Dinslaken (Germany)

    2015-03-31

    Additive Manufacturing (AM) refers to a process by which a set of digital data -representing a certain complex 3dim design - is used to grow the respective 3dim real structure equal to the corresponding design. For the powder-based EOS manufacturing process a variety of plastic and metal materials can be used. Thereby, AM is in many aspects a very powerful tool as it can help to overcome particular limitations in conventional manufacturing. AM enables more freedom of design, complex, hollow and/or lightweight structures as well as product individualisation and functional integration. As such it is a promising approach with respect to the future design and manufacturing of complex 3dim structures. On the other hand, it certainly calls for new methods and standards in view of quality assessment. In particular, when utilizing AM for the design of complex parts used in aviation and aerospace technologies, appropriate monitoring systems are mandatory. In this respect, recently, sustainable progress has been accomplished by joining the common efforts and concerns of a manufacturer Additive Manufacturing systems and respective materials (EOS), along with those of an operator of such systems (MTU Aero Engines) and experienced application engineers (Carl Metrology), using decent know how in the field of optical and infrared methods regarding non-destructive-examination (NDE). The newly developed technology is best described by a high-resolution layer by layer inspection technique, which allows for a 3D tomography-analysis of the complex part at any time during the manufacturing process. Thereby, inspection costs are kept rather low by using smart image-processing methods as well as CMOS sensors instead of infrared detectors. Moreover, results from conventional physical metallurgy may easily be correlated with the predictive results of the monitoring system which not only allows for improvements of the AM monitoring system, but finally leads to an optimisation of the quality

  2. Internal dose assessment in nuclear medicine: fetal doses due to radiopharmaceutical administration to the mother

    The objective of this publication is to present a guideline for the dose assessment through a comprehensive introduction of knowledge on ionizing radiation, radiation protection during pregnancy and fetal dosimetry for physician and other professionals involved in nuclear medicine practices. It contains tables with recommended dose estimates at all stages of pregnancy for many radiopharmaceuticals. Compounds for which some information was available regarding placental crossover are shown in shaded rows. It includes the most common diagnostic and therapy practices in nuclear medicine considering the four radioactive isotopes selected: 99mTc, 131I, 201Tl and 67Ga. There is a special case included, it is when conception occurs after the iodine has been administered. In almost every case, the diagnostic benefit to the mother outweighs the risk of any irradiation of the fetus. However, there is one situation in which severe fetal injury can be incurred from administering a radiopharmaceutical to the mother, and that is use of iodine-131 therapy for ablation of the thyroid in cases of hyperthyroidism or carcinoma. Radioactive iodine readily crosses the placenta and concentrates in the fetal thyroid, where, because of its small organ mass, high radiation doses are received. (author)

  3. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

    Sergio Luevano-Gurrola

    2015-09-01

    Full Text Available Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize.

  4. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-01-01

    Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

  5. Additive manufacturing metrology: State of the art and needs assessment

    Koester, L.; Taheri, H.; Bond, L. J.; Barnard, D.; Gray, J.

    2016-02-01

    Additive manufacturing (AM) is a technology that first emerged in 1987 with stereolithography (SL) of plastic materials from 3D Systems. It saw light use for rapid prototyping and very low volume production for a number of years. However, in the past few years AM of metallic materials has become a practical fabrication technology, use is rapidly increasing and is projected to continue with double digit growth in coming years. The promise and flexibility shown by AM has spurred efforts to begin standardization of this type of process. This paper provides an assessment of the state of the art for in-situ process monitoring of AM processes with an emphasis on the production of metallic components. It is seen that with the implementation of proper process control there is potential to create reliable and reproducible materials and geometries previously unachievable using metal removal based means of production. A reliable methodology for detection and control of microstructure and defects would be of great value in terms of enabling broader AM utilization.

  6. ARAC: a computer-based emergency dose-assessment service

    Over the past 15 years, the Lawrence Livermore National Laboratory's Atmospheric Release Advisory Capability (ARAC) has developed and evolved a computer-based, real-time, radiological-dose-assessment service for the United States Departments of Energy and Defense. This service is built on the integrated components of real-time computer-acquired meteorological data, extensive computer databases, numerical atmospheric-dispersion models, graphical displays, and operational-assessment-staff expertise. The focus of ARAC is the off-site problem where regional meteorology and topography are dominant influences on transport and dispersion. Through application to numerous radiological accidents/releases on scales from small accidental ventings to the Chernobyl reactor disaster, ARAC has developed methods to provide emergency dose assessments from the local to the hemispheric scale. As the power of computers has evolved inversely with respect to cost and size, ARAC has expanded its service and reduced the response time from hours to minutes for an accident within the United States. Concurrently the quality of the assessments has improved as more advanced models have been developed and incorporated into the ARAC system. Over the past six years, the number of directly connected facilities has increased from 6 to 73. All major U.S. Federal agencies now have access to ARAC via the Department of Energy. This assures a level of consistency as well as experience. ARAC maintains its real-time skills by participation in approximately 150 exercises per year; ARAC also continuously validates its modeling systems by application to all available tracer experiments and data sets

  7. Relationship between dose and risk, and assessment of carcinogenic risks associated with low doses of ionizing radiation

    This report raises doubts on the validity of using LNT (linear no-threshold) relationship for evaluating the carcinogenic risk of low doses (< 100 mSv) and even more for very low doses (< 10 mSv). The LNT concept can be a useful pragmatic tool for assessing rules in radioprotection for doses above 10 mSv; however since it is not based on biological concepts of our current knowledge, it should not be used without precaution for assessing by extrapolation the risks associated with low and even more so, with very low doses (< 10 mSv), especially for benefit-risk assessments imposed on radiologists by the European directive 97-43. The biological mechanisms are different for doses lower than a few dozen mSv and for higher doses. The eventual risks in the dose range of radiological examinations (0.1 to 5 mSv, up to 20 mSv for some examinations) must be estimated taking into account radiobiological and experimental data. An empirical relationship which has been just validated for doses higher than 200 mSv may lead to an overestimation of risks (associated with doses one hundred fold lower), and this overestimation could discourage patients from undergoing useful examinations and introduce a bias in radioprotection measures against very low doses (< 10 mSv). Decision makers confronted with problems of radioactive waste or risk of contamination, should re-examine the methodology used for the evaluation of risks associated with very low doses and with doses delivered at a very low dose rate. This report confirms the inappropriateness of the collective dose concept to evaluate population irradiation risks

  8. Committed dose assessment based on background outdoor gamma exposure in Chihuahua City, Mexico

    Full text: Determining ionizing radiation in a geographic area serves to assess its effects on populations health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the committed dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, annual effective dose, and the lifetime cancer risk, 48 sampling points were randomly selected along the Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Muller counter. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th, 40K and their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Outdoor gamma dose rates ranged from 56 to 193 n Gy h-1. Results indicated that lifetime effective dose to inhabitants of Chihuahua City is in average of 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of activity concentrations in soil were 51.8, 73.1, and 1096.5 Bq kg-1, of 226Ra, 232Th and 40K, respectively. From the analysis of the spatial distribution of 232Th, 226Ra, and 40K is to north, to north-center, and to south of city, respectively. In conclusion, natural background gamma dose received by inhabitants of Chihuahua City is high and mainly due to geological characteristics of the zone. (Author)

  9. Committed dose assessment based on background outdoor gamma exposure in Chihuahua City, Mexico

    Luevano G, S.; Perez T, A.; Pinedo A, C.; Renteria V, M. [Universidad Autonoma de Chihuahua, Facultad de Zootecnia y Ecologia, Perif. Francisco R. Almada Km 1, 31415 Chihuahua, Chih. (Mexico); Carrillo F, J.; Montero C, M. E., E-mail: mrenteria@uach.mx [Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, 31136 Chihuahua, Chih. (Mexico)

    2015-10-15

    Full text: Determining ionizing radiation in a geographic area serves to assess its effects on populations health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the committed dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, annual effective dose, and the lifetime cancer risk, 48 sampling points were randomly selected along the Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Muller counter. At the same sites, 48 soil samples were taken to obtain the activity concentrations of {sup 226}Ra, {sup 232}Th, {sup 40}K and their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Outdoor gamma dose rates ranged from 56 to 193 n Gy h{sup -1}. Results indicated that lifetime effective dose to inhabitants of Chihuahua City is in average of 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of activity concentrations in soil were 51.8, 73.1, and 1096.5 Bq kg{sup -1}, of {sup 226}Ra, {sup 232}Th and {sup 40}K, respectively. From the analysis of the spatial distribution of {sup 232}Th, {sup 226}Ra, and {sup 40}K is to north, to north-center, and to south of city, respectively. In conclusion, natural background gamma dose received by inhabitants of Chihuahua City is high and mainly due to geological characteristics of the zone. (Author)

  10. Dose assessment and dose optimisation in decommissioning using the VISIPLAN 3D ALARA planning tool

    The optimisation of radiological protection of the workers in nuclear industry is an important part of the safety culture especially in the field of decommissioning where we are confronted with a radioactive environment that is in the process of constant change. The application of the ALARA concept (to keep exposures As Low As Reasonably Achievable) is not always straightforward in such cases. A good ALARA pre-job study must be performed and should contain predicted doses in the work area and investigate the effects of geometry, material, source or work position changes. This information provides a quantitative basis to select between various alternative work scenario's for a specific operation. In order to handle this information SCK-CEN developed the VISIPLAN 3D ALARA planning tool. This PC-based tool makes it possible to create and edit work scenarios taking into account worker positions and subsequent geometry and source distribution changes in a 3D environment. The presentation will show the current status of the tool and its application to the decommissioning of the BR3 reactor and other installations. New developments will also be presented regarding the geometric and radioactive characterisation of a decommissioning site. The use of human motion simulation tools in ALARA assessment will also be discussed. This will show how new developments of software and measurement tools can help dealing with the new challenges of decommissioning in the field of dose optimization. (authors)

  11. Axillary block duration and related hemodynamic changes: high versus low dose Adrenaline addition to Lidocaine

    Shariat Moharari R

    2009-03-01

    Full Text Available "nBackground: Axillary block is used for inducing anesthesia in outpatient hand and forearm surgeries. Few researches have studied hemodynamic and blockade effects of low doses of Epinephrine. The aim of the present study was to compare the duration of analgesia and hemodynamic changes following the injection of high/low epinephrine doses in such surgeries. "nMethods: The present randomized clinical trial study was conducted on healthy individuals (ASA I-II who were candidates for hand and forearm surgeries. The patients were randomly divided into three groups. The first two groups were allocated to receive lidocaine with low (0.6µg/cc and high (5µg/cc doses of epinephrine whereas lidocaine plus normal saline was injected in the third group. The hemodynamic changes (Mean arterial blood pressure and heart rate and the occurance of any side-effects along with the duration of analgesia and motor block were recorded. "nResults: From among the total of 75 patients, 15 cases were excluded due to incomplete blockade or failure needing general anesthesia. The duration of analgesia and the motor block were longer in the high dose epinephrine group, the difference, however, was not statistically significant. Heart rate changes within the groups was significant in the 4th-7th and 10th minutes. Mean arterial blood pressure changes was only significant in the 4th minute, within the groups. "nConclusions: Administering low doses of epinephrine plus lidocaine as a local anesthetic not only provides acceptable analgesia compared to higher doses of the medication, but also is associated with fewer side effects.

  12. Human intruder dose assessment for deep geological disposal

    Smith, G. M. [GMS Abington Ltd, Abingdon (United Kingdom); Molinero, J.; Delos, A.; Valls, A.; Conesa, A. [Amphos 21, Barcelona (Spain); Smith, K. [RadEcol Consulting Ltd, Abingdon (United Kingdom); Hjerpe, T. [Saanio and Riekkola Oy, Helsinki (Finland)

    2013-07-15

    For near-surface disposal, approaches to assessment of inadvertent human intrusion have been developed through international cooperation within the IAEA's ISAM programme. Other assessments have considered intrusion into deep geological disposal facilities, but comparable international cooperation to develop an approach for deep disposal has not taken place. Accordingly, the BIOPROTA collaboration project presented here (1) examined the technical aspects of why and how deep geological intrusion might occur; (2) considered how and to what degree radiation exposure would arise to the people involved in such intrusion; (3) identified the processes which constrain the uncertainties; and hence (4) developed and documented an approach for evaluation of human intruder doses which addresses the criteria adopted by the IAEA and takes account of other international guidance and human intrusion assessment experience. Models for radiation exposure of the drilling workers and geologists were developed and described together with compilation of relevant input data, taking into account relevant combinations of drilling technique, geological formation and repository material. Consideration has been given also to others who might be exposed to contaminated material left at the site after drilling work has ceased. The models have been designed to be simple and stylised, in accordance with international recommendations. The set of combinations comprises 58 different scenarios which cover a very wide range of human intrusion possibilities via deep drilling. (orig.)

  13. Human intruder dose assessment for deep geological disposal

    For near-surface disposal, approaches to assessment of inadvertent human intrusion have been developed through international cooperation within the IAEA's ISAM programme. Other assessments have considered intrusion into deep geological disposal facilities, but comparable international cooperation to develop an approach for deep disposal has not taken place. Accordingly, the BIOPROTA collaboration project presented here (1) examined the technical aspects of why and how deep geological intrusion might occur; (2) considered how and to what degree radiation exposure would arise to the people involved in such intrusion; (3) identified the processes which constrain the uncertainties; and hence (4) developed and documented an approach for evaluation of human intruder doses which addresses the criteria adopted by the IAEA and takes account of other international guidance and human intrusion assessment experience. Models for radiation exposure of the drilling workers and geologists were developed and described together with compilation of relevant input data, taking into account relevant combinations of drilling technique, geological formation and repository material. Consideration has been given also to others who might be exposed to contaminated material left at the site after drilling work has ceased. The models have been designed to be simple and stylised, in accordance with international recommendations. The set of combinations comprises 58 different scenarios which cover a very wide range of human intrusion possibilities via deep drilling. (orig.)

  14. Addition of low dose hCG to rFSh benefits older women during ovarian stimulation for IVF

    Gomaa Hala

    2012-08-01

    Full Text Available Abstract Background To compare the outcome of IVF cycles in women receiving controlled ovarian stimulation with recFSH or recFSH plus low dose hCG. Methods A retrospective case control study, performed at a private practice affiliated with an academic institute. Patients were infertile women who were treated with IVF/ICSI and controlled ovarian stimulation in a long GnRH agonist protocol using either low dose hCG in addition to recFSH [N = 88] or recFSH alone [N = 99]. Primary outcomes were mean FSH dose, number of mature eggs, number of fertilized eggs, and serum levels of estradiol. Secondary outcomes were endometrial thickness, cycle cancellations and pregnancy rates. Results A significant increase in number of mature and fertilized eggs was observed in women over 40 years of age using low dose hCG in addition to recFSH. The estradiol level was significantly higher on the day of hCG administration and the serum level of FSH on cycle day 7 and on the day of hCG administration were lower. Conclusion Addition of low dose hCG to recFSH compared with recFSH alone significantly modified cycle characteristics in patients >/= 40 years and could be of potential benefit for IVF cycles in older infertile women.

  15. Retrospective assessment of exposure dose from the levels of serum glutamic oxaloacetic and pyruvic transaminases

    Development of a method for retrospective assessment of absorbed dose in humans by the activities of SGOT and SGPT. SGOT and SGPT were measured after Raitmann and Frenkel. The dose-effect curves were measured after Raitmann and Frenkel. The dose-effect curves were based on the results of examinations of 223 liquidators of the Chernobyl accident consequences directly after exposure to super-background ionizing radiation. A dose-effect relationship between SGOT and SGPT activities and the absorbed dose is observed for the dose range of 20-40 sGy. The absorbed dose is assessed from the proposed curves reflecting the correlation and the estimation formula

  16. Collective dose and risk assessment from Brazil nut consumption

    Commercial samples of Brazil nut were analysed to determine the natural radionuclide content and to assess the radiological risk resulting from its ingestion by members of the general public. Mean values of 1.4 ± 0.4 Bq.kg-1 for 238U, 26.3 ± 4.1 Bq.kg-1 for 226Ra, 4.7 ± 1.8 Bq.kg-1 for 210Pb, 16.5 ± 4.3 Bq.kg-1 for 232Th, 31.3 ± 6.4 Bq.kg-1 for 228Ra and 12.3 ± 5.1 Bq.kg-1 for 228Th were found in the samples analysed. Taking into account the annual production of Brazil nuts, the collective committed effective dose resulting from the ingestion of nuts corresponding to one year of production is estimated to be 8.6 x 102 man.Sv. (author)

  17. Dose reconstruction starting from the pre-dose effect of quartz: combined procedure of additive dose and multiple activation; Reconstruccion de dosis a partir del efecto pre-dosis del cuarzo: procedimiento combinado de dosis aditiva y activacion multiple

    Correcher, V.; Gomez R, J. M.; Delgado, A. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Av. Complutense 22, 28040 Madrid (Spain); Garcia G, J. [Consejo Superior de Investigaciones Cientificas, Museo Nacional de Ciencias Naturales, Jose Gutierrez Abascal No. 2, 28006 Madrid (Spain)], e-mail: v.correcher@ciemat.es

    2009-07-01

    The pre-dose effect of the 110 C thermoluminescence (Tl) peak of quartz gives rise to the use of a sensitive technique to estimate of low-level doses under retrospective conditions. However, one can appreciate how aliquots of quartz, from the same mineral fraction, display different sensitivities. In this sense, we herein report on a new measurement protocol based on the aforementioned pre-dose effect. Such procedure includes additive dose and multiple activation steps allows to determine simultaneously the sensitivity changes induced by the thermal activation and the Tl dose dependence. This behaviour let calculate the field accrued dose by interpolation thus permitting an increase of both precision and accuracy. (Author)

  18. Patient dose assessment in different diagnostic procedures in nuclear medicine

    Effective doses have been estimated for 314 patients under diagnostic procedures in a Nuclear Medicine Department using data reported in ICRP-80 and RIDIC (Radiation Internal Dose Information Center). Data on administered activity, radiopharmaceutical and administration route, age and sex of the patients have been collected. Doses in the most exposed critical organ for every protocol, doses in uterus, doses in fetus versus the stage of pregnancy (in case the female patient was pregnant) and doses for nursing infants have been also estimated. Ga-67 studies give the highest effective doses per protocol followed by cardiac SPECT procedures using Tl-201 chloride. Ga-67 studies also give the highest absorbed doses in uterus. Due to not administering different activities, depending on height and weight of adults, women receive doses about 20% higher than men. This would be a practice to modify in the future in order to optimise doses. (author)

  19. Assessment of Gasoline Additive Containing Ditert-butoxypropanol

    West, Brian H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Connatser, Raynella M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lewis, Samuel Arthur [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-04-01

    The Fuels, Engines, and Emissions Research Center completed analysis and testing of the CPS Powershot gasoline additive under the auspices of the Department of Energy’s Technical Assistance for US Small Businesses in Vehicle Technologies. Gas chromatography-mass spectrometry (GC-MS) was used to quantify the makeup of the additive, finding a predominance of 2,3-Ditert-Butoxypropanol, also known as Glyceryl Di-Tert-Butyl Ether (GTBE). Blends of the additive at 2 and 4 volume percent were subjected to a number of standard ASTM tests, including Research Octane Number, Motor Octane Number, distillation, and vapor pressure. Results show a high boiling range and low vapor pressure for the additive, and a very modest octane boosting effect in gasoline with and without ethanol.

  20. Low dose powdered activated carbon addition at high sludge retention times to reduce fouling in membrane bioreactors

    Remy, Maxime; Marel, van der Perry; Zwijnenburg, Arie; Rulkens, Wim; Temmink, Hardy

    2009-01-01

    The addition of a low concentration of PAC (0.5 g L−1 of sludge, i.e. a dose of 4 mg L−1 of wastewater), in combination with a relatively long SRT (50 days), to improve membrane filtration performance was investigated in two pilot-scale MBRs treating real municipal wastewater. Continuous filterabili

  1. Low dose powdered activated carbon addition at high sludge retention times to reduce fouling in membrane bioreactors

    Remy, M.J.J.; Marel, van der P.; Zwijnenburg, A.; Rulkens, W.H.; Temmink, B.G.

    2009-01-01

    The addition of a low concentration of PAC (0.5 g L-1 of sludge, i.e. a dose of 4 mg L-1 of wastewater), in combination with a relatively long SRT (50 days), to improve membrane filtration performance was investigated in two pilot-scale MBRs treating real municipal wastewater. Continuous filterabili

  2. Technology Assessment and Roadmap for the Emergency Radiation Dose Assessment Program

    A Joint Interagency Working Group (JIWG) under the auspices of the Department of Homeland Security Office of Research and Development conducted a technology assessment of emergency radiological dose assessment capabilities as part of the overall need for rapid emergency medical response in the event of a radiological terrorist event in the United States. The goal of the evaluation is to identify gaps and recommend general research and development needs to better prepare the Country for mitigating the effects of such an event. Given the capabilities and roles for responding to a radiological event extend across many agencies, a consensus of gaps and suggested development plans was a major goal of this evaluation and road-mapping effort. The working group consisted of experts representing the Departments of Homeland Security, Health and Human Services (Centers for Disease Control and the National Institutes of Health), Food and Drug Administration, Department of Defense and the Department of Energy's National Laboratories (see appendix A for participants). The specific goals of this Technology Assessment and Roadmap were to: (1) Describe the general context for deployment of emergency radiation dose assessment tools following terrorist use of a radiological or nuclear device; (2) Assess current and emerging dose assessment technologies; and (3) Put forward a consensus high-level technology roadmap for interagency research and development in this area. This report provides a summary of the consensus of needs, gaps and recommendations for a research program in the area of radiation dosimetry for early response, followed by a summary of the technologies available and on the near-term horizon. We then present a roadmap for a research program to bring present and emerging near-term technologies to bear on the gaps in radiation dose assessment and triage. Finally we present detailed supporting discussion on the nature of the threats we considered, the status of technology

  3. Technology Assessment and Roadmap for the Emergency Radiation Dose Assessment Program

    Turteltaub, K W; Hartman-Siantar, C; Easterly, C; Blakely, W

    2005-10-03

    A Joint Interagency Working Group (JIWG) under the auspices of the Department of Homeland Security Office of Research and Development conducted a technology assessment of emergency radiological dose assessment capabilities as part of the overall need for rapid emergency medical response in the event of a radiological terrorist event in the United States. The goal of the evaluation is to identify gaps and recommend general research and development needs to better prepare the Country for mitigating the effects of such an event. Given the capabilities and roles for responding to a radiological event extend across many agencies, a consensus of gaps and suggested development plans was a major goal of this evaluation and road-mapping effort. The working group consisted of experts representing the Departments of Homeland Security, Health and Human Services (Centers for Disease Control and the National Institutes of Health), Food and Drug Administration, Department of Defense and the Department of Energy's National Laboratories (see appendix A for participants). The specific goals of this Technology Assessment and Roadmap were to: (1) Describe the general context for deployment of emergency radiation dose assessment tools following terrorist use of a radiological or nuclear device; (2) Assess current and emerging dose assessment technologies; and (3) Put forward a consensus high-level technology roadmap for interagency research and development in this area. This report provides a summary of the consensus of needs, gaps and recommendations for a research program in the area of radiation dosimetry for early response, followed by a summary of the technologies available and on the near-term horizon. We then present a roadmap for a research program to bring present and emerging near-term technologies to bear on the gaps in radiation dose assessment and triage. Finally we present detailed supporting discussion on the nature of the threats we considered, the status of

  4. Efficacy of a high-dose in addition to daily low-dose vitamin A in children suffering from severe acute malnutrition with other illnesses.

    Samima Sattar

    Full Text Available BACKGROUND: Efficacy of high-dose vitamin A (VA in children suffering from severe acute malnutrition (SAM has recently been questioned. This study compared the efficacy of a single high-dose (200,000 IU in addition to daily low-dose (5000 IU VA in the management of children suffering from SAM with diarrhea and/or acute lower respiratory tract infection (ALRI. METHODS: In a randomized, double-blind, controlled clinical trial in icddr,b, Bangladesh during 2005-07, children aged 6-59 months with weight-for-height <-3 Z-score and/or bipedal edema (SAM received either a high-dose VA or placebo on admission day. Both the groups received 5,000 IU/day VA in a multivitamins drop for 15 days and other standard treatment which is similar to WHO guidelines. RESULTS: A total 260 children (130 in each group were enrolled. All had diarrhea, 54% had concomitant ALRI, 50% had edema, 48.5% were girl with a mean±SD age of 16±10 months. None had clinical signs of VA deficiency. Mean±SD baseline serum retinol was 13.15±9.28 µg/dl, retinol binding protein was 1.27±0.95 mg/dl, and pre-albumin was 7.97±3.96 mg/dl. Median (inter quartile range of C-reactive protein was 7.8 (2.1, 22.2 mg/L. Children of the two groups did not differ in any baseline characteristic. Over the 15 days treatment period resolution of diarrhea, ALRI, edema, anthropometric changes, and biochemical indicators of VA were similar between the groups. The high-dose VA supplementation in children with SAM did not show any adverse event. CONCLUSIONS: Efficacy of daily low-dose VA compared to an additional single high-dose was not observed to be better in the management of children suffering from SAM with other acute illnesses. A single high-dose VA may be given especially where the children with SAM may leave the hospital/treatment center early. TRIAL REGISTRATION: ClinicalTrials.gov NCT00388921.

  5. Mammography radiation dose: Initial results from Serbia based on mean glandular dose assessment for phantoms and patients

    The primary objective of this study is to investigate the actual mammography dose levels in Serbia and establish a baseline dose database for the future screening programme. The mean glandular dose (MGD) was assessed for standard size breast substituted by 45 mm polymethyl methacrylate (PMMA) phantom and imaged under typical clinical conditions at 30 screen film mammography facilities. Average MGD was (1.9 ± 1.0) mGy, with a range of 0.12-5.2 mGy. These results were used for the calculation of the initial diagnostic reference levels in mammography in Serbia, which was set to 2.1 mGy for a standard breast. At some facilities, high doses were observed and the assessed MGD was supplemented by a patient dose survey. MGD was measured for 53 women having a diagnostic mammography in cranio-caudal (CC) and medio-lateral oblique (MLO) projections at the largest mammography facilities in Serbia. The parameters recorded were: age, compressed breast thickness, tube potential (in kV), tube loading (in mAs) and the MLO projection angle. The average MGD per image was 2.8 mGy for the CC projection and 4.3 mGy for the MLO projection. Dose to breast was compared with dose for PMMA phantoms of various sizes, assessed at the same facilities. The results have indicated that phantom dose values can assist in setting optimisation activities in mammography. Both phantom and patient dose values indicated unnecessary high doses in facilities with an extremely high mammography workload. For these facilities, urgent dose-reduction measures and follow-up actions were recommended. (authors)

  6. Pantex Plant Cell 12-44-1 tritium release: Re-assessment of environmental doses for 1990 to 1992

    A release of tritium gas occurred within Cell 12-44-1 at the Pantex Plant on May 17, 1989. The release was the result of a nuclear component containment failure. This document summarizes past assessments and characterization of the release. From 1990 to 1992, the average annual dose to the offsite maximally exposed individual (MEI), re-assessed using updated methods and data, ranged from 9E-6 to 2E-4 mrem/y. Doses at this level are well below the regulatory dose limit and support the discontinuation of the distinct calculation of the MEI doses from the cell's tritium releases in future Pantex Annual Site Environmental Reports. Additional information provides guidance for the evaluation of similar releases in the future. Improved Environmental Protection Department sampling plans and assessment goals will increase the value of the data collected during future incidents

  7. Epistemological limits for risk assessments at low radiation doses

    The author discusses the epistemological question of whether there are real limits to knowledge in radio biology and suggests that effects at low doses are one such area. Topics raised are dominant and non-dominant doses, interpolated risks from observed effects at high doses and other epidemiological data; the discussion is illustrated by examples from the Swedish experience. (UK)

  8. Evaluation of two intracavitary high-dose-rate brachytherapy devices for irradiating additional and irregularly shaped volumes of breast tissue

    Lu, Sharon M., E-mail: sharonlu@ucsd.edu [Department of Radiation Oncology and Center for Advanced Radiotherapy Technologies (CART), University of California, San Diego, La Jolla, CA (United States); Scanderbeg, Daniel J.; Barna, Patrick; Yashar, William; Yashar, Catheryn [Department of Radiation Oncology and Center for Advanced Radiotherapy Technologies (CART), University of California, San Diego, La Jolla, CA (United States)

    2012-04-01

    The SAVI and Contura breast brachytherapy applicators represent 2 recent advancements in brachytherapy technology that have expanded the number of women eligible for accelerated partial breast irradiation in the treatment of early-stage breast cancer. Early clinical experience with these 2 single-entry, multichannel high-dose-rate brachytherapy devices confirms their ease of use and dosimetric versatility. However, current clinical guidelines for SAVI and Contura brachytherapy may result in a smaller or less optimal volume of treated tissue compared with traditional interstitial brachytherapy. This study evaluates the feasibility of using the SAVI and Contura to irradiate larger and irregularly shaped target volumes, approaching what is treatable with the interstitial technique. To investigate whether additional tissue can be treated, 17 patients treated with the SAVI and 3 with the Contura were selected. For each patient, the planning target volume (PTV) was modified to extend 1.1 cm, 1.3 cm, and 1.5 cm beyond the tumor bed cavity. To evaluate dose conformance to an irregularly shaped target volume, 9 patients treated with the SAVI and 3 with the Contura were selected from the original 20 patients. The following asymmetric PTV margin combinations were assessed for each patient: 1.5/0.3, 1.3/0.3, and 1.1/0.3 cm. For all patients, treatment planning was performed, adopting the National Surgical Adjuvant Breast and Bowel Project guidelines, and dosimetric comparisons were made. The 6-1 and 8-1 SAVI devices can theoretically treat a maximal tissue margin of 1.5 cm and an asymmetric PTV with margins ranging from 0.3 to 1.5 cm. The 10-1 SAVI and Contura can treat a maximal margin of 1.3 cm and 1.1 cm, respectively, and asymmetric PTV with margins ranging from 0.3-1.3 cm. Compared with the Contura, the SAVI demonstrated greater dosimetric flexibility. Risk of developing excessive hot spots increased with the size of the SAVI device. Both the SAVI and Contura appear

  9. Lack of benefit for the addition of androgen deprivation therapy to dose-escalated radiotherapy in the treatment of intermediate- and high-risk prostate cancer.

    Krauss, Daniel

    2012-02-01

    PURPOSE: Assessment of androgen deprivation therapy (ADT) benefits for prostate cancer treated with dose-escalated radiotherapy (RT). METHODS AND MATERIALS: From 1991 to 2004, 1,044 patients with intermediate- (n = 782) or high-risk (n = 262) prostate cancer were treated with dose-escalated RT at William Beaumont Hospital. Patients received external-beam RT (EBRT) alone, brachytherapy (high or low dose rate), or high dose rate brachytherapy plus pelvic EBRT. Intermediate-risk patients had Gleason score 7, prostate-specific antigen (PSA) 10.0-19.9 ng\\/mL, or Stage T2b-T2c. High-risk patients had Gleason score 8-10, PSA >\\/=20, or Stage T3. Patients were additionally divided specifically by Gleason score, presence of palpable disease, and PSA level to further define subgroups benefitting from ADT. RESULTS: Median follow-up was 5 years; 420 patients received ADT + dose-escalated RT, and 624 received dose-escalated RT alone. For all patients, no advantages in any clinical endpoints at 8 years were associated with ADT administration. No differences in any endpoints were associated with ADT administration based on intermediate- vs. high-risk group or RT modality when analyzed separately. Patients with palpable disease plus Gleason >\\/=8 demonstrated improved clinical failure rates and a trend toward improved survival with ADT. Intermediate-risk patients treated with brachytherapy alone had improved biochemical control when ADT was given. CONCLUSION: Benefits of ADT in the setting of dose-escalated RT remain poorly defined. This question must continue to be addressed in prospective study.

  10. Radionuclides in Animal Feed (Poultry) 'Assessment of Radiation Dose'

    In this work a comprehensive study has been carried out for the determination of presents evaluation of effective dose due to consumption of chicken fed by fodders collected from four major Sudanese companies (Hader, Koudjs, Wifi and Preconex SPN.V). The concentrations of radionuclides in the thirty two (32) feed samples have been determined by gamma spectrometry using NaI(Tl) detector. Radionuclides observed were: Pb-212 (daughter of Th-238), Pb-214, Bi-214 (daughters of U-238), Cs-137 and K-40 concentration. In additives the activity concentration of these radionuclides has found in the following ranges: 0.81 - 22.06 Bq/kg, 0.59 - 32.07 Bq/kg, 0.64 - 15.77 Bq/kg, 0.01 - 2.02 Bq/kg and 33.58 - 204.61 Bq/kg respectively. In feed concentrates activity concentration ranges has: 0.73 - 13.79 Bq/kg, 0.33 - 20.04 Bq/kg, 0.01 - 1.67 Bq/kg, 0.01 - 0.28 Bq/kg, 26.86 - 99.21 Bq/kg respectively. In fodders the activity concentration ranges has: 1.25 - 1.52 Bq/kg, 0.12 - 1.24 Bq/kg, 0.51 - 1.25 Bq/kg, 0.01 - 0.61 Bq/kg, 11.94 - 127.88 Bq/kg respectively. The 'animal product' activity concentration ranges has: 0.31 - 1.65 Bq/kg, 0.22 - 1.11 Bq/kg, 0.26 - 1.07 Bq/kg, 0.03 - 0.51 Bq/kg, 14.07 - 79.93 Bq/kg respectively. High concentrations (233.3 Bq/Kg) has typically found in toxo(additive); the lowest concentration (27.9 Bq/Kg ) has found in concentrate for layers and animal product. The total average effective dose due to the different feed-stuff has estimated and found to be 5.89x10-6±3.11x10-6mSv/y and 13.9 x 10-7 ± 7.24 x 10-7mSv/y for age categories 7-12 y and >17 y respectively. If compared with the limits - Radioactivity Levels Permitted in foodstuffs Part 1 the Saudi Standards, Metrology and quality (300 Bq/Kg) and ICRP,FAO organization (5 mSv/y) - these values are very low. Document available in abstract form only. (authors)

  11. Investigation and dose assessment of the radioactive level in buildings made of cinder bricks of Xiangxi gold mine

    The investigation results of the radioactive level in the houses made of cinder bricks of Xiangxi Gold Mine was presented. The measured results and dose assessment shows that the mean of γ external penetrating radiation dose rate including cosmic radiation in houses of cinder bricks is 33.4 x 10-8 Gyh-1 because the bricks have a higher concentration of natural radionuclide 226Ra. The additional annual collective effective dose equivalent to∼5250 persons in such houses is 20.9 man·Sv

  12. Radiation dose assessment of musa acuminata - triploid (AAA)

    Bananas are radioactive due to the presence of the radioisotope-40K. This imposes a possible health risk to the general public. This study intended to assess the annual equivalent dosages and the annual effective dosage committed by the body. This seeks to benefit the general public, students and researchers, and entrepreneurs. Using atomic absorption spectrophotometry, lakatan banana (Musa acuminata-triploid (AAA), the most purchased variety cultivated in Barangay Adlawon, Cebu City, Philippines, was found to contain 0.53 g of total potassium for every 100 g of its fresh fruit wherein 6.2 x 10-5 g of which is potassium-40. Based on its 40K content banana was calculated to have a radioactivity of 16 Bq/100 g. it was found out that the body is exposed to radiation dosages ranging from 2.8 x 10-3 rem annually by eating 100 g of lakatan bananas everyday. Conversely, it is equivalent to the annual effective dosage of 0.0043 rem; the amount at which the body of an individual is uniformly exposed. However, no or extremely minute health risk was determined by just eating bananas. In fact, to exceed the radiation dose limits set by the International Commission on Radiation Protection, an individual may eat 116 kg of lakatan bananas everyday for a year. Fertilizers may be the major source of the radioisotope - 40K and assimilated by the plants. (author)

  13. Imaging dose assessment for IGRT in particle beam therapy

    Introduction: Image-guided advanced photon and particle beam treatments are promising options for improving lung treatments. Extensive use of imaging increases the overall patient dose. The aim of this study was to determine the imaging dose for different IGRT solutions used in photon and particle beam therapy. Material and methods: Measurements were performed in an Alderson phantom with TLDs. Clinically applied protocols for orthogonal planar kV imaging, stereoscopic imaging, CT scout views, fluoroscopy, CT, 4D-CT and CBCT were investigated at five ion beam centers and one conventional radiotherapy department. The overall imaging dose was determined for a patient undergoing a lung tumor irradiation with institute specific protocols. Results: OAR doses depended on imaging modality and OAR position. Dose values were in the order of 1 mGy for planar and stereoscopic imaging and 10–50 mGy for volumetric imaging, except for one CBCT device leading to lower doses. The highest dose per exam (up to 150 mGy to the skin) was recorded for a 3-min fluoroscopy. Discussion: Modalities like planar kV or stereoscopic imaging result in very low doses (∼1 mGy) to the patient. Imaging a moving target during irradiation, low-dose protocols and protocol optimization can reduce the imaging dose to the patient substantially

  14. Food chain modelling and dose assessment in RODOS

    All radiation exposure pathways which are considered in the RODOS food chain and dose modules are described. For each of them, the principal processes controlling the exposure are discussed, showing up the input data requirements. Emphasis is put on those data which vary from region to region and thus require the adaptation of model parameters if RODOS is to be applied for regions with different conditions. Calculation of individual doses as well as estimation of collective doses are reflected. Possibilities for improving the dose estimations by consideration of measured data are discussed. The deposition onto different kinds of surfaces (e.g., soil, plant canopies, urban areas) can be improved by means of gamma dose rate measurements, vegetation samples, in situ gamma spectrometry etc. Measurements of concentrations of activity in feed and foodstuffs, whole body burdens, personal dosemeters etc. can help to improve the predicted internal and external doses. (orig.)

  15. A novel approach to pharmacodynamic assessment of antimicrobial agents: new insights to dosing regimen design.

    Vincent H Tam

    Full Text Available Pharmacodynamic modeling has been increasingly used as a decision support tool to guide dosing regimen selection, both in the drug development and clinical settings. Killing by antimicrobial agents has been traditionally classified categorically as concentration-dependent (which would favor less fractionating regimens or time-dependent (for which more frequent dosing is preferred. While intuitive and useful to explain empiric data, a more informative approach is necessary to provide a robust assessment of pharmacodynamic profiles in situations other than the extremes of the spectrum (e.g., agents which exhibit partial concentration-dependent killing. A quantitative approach to describe the interaction of an antimicrobial agent and a pathogen is proposed to fill this unmet need. A hypothetic antimicrobial agent with linear pharmacokinetics is used for illustrative purposes. A non-linear functional form (sigmoid Emax of killing consisted of 3 parameters is used. Using different parameter values in conjunction with the relative growth rate of the pathogen and antimicrobial agent concentration ranges, various conventional pharmacodynamic surrogate indices (e.g., AUC/MIC, Cmax/MIC, %T>MIC could be satisfactorily linked to outcomes. In addition, the dosing intensity represented by the average kill rate of a dosing regimen can be derived, which could be used for quantitative comparison. The relevance of our approach is further supported by experimental data from our previous investigations using a variety of gram-negative bacteria and antimicrobial agents (moxifloxacin, levofloxacin, gentamicin, amikacin and meropenem. The pharmacodynamic profiles of a wide range of antimicrobial agents can be assessed by a more flexible computational tool to support dosing selection.

  16. Specific gamma-ray dose constants for nuclides important to dosimetry and radiological assessment

    Tables of specific gamma-ray dose constants (the unshielded gamma-ray dose equivalent rate at 1 m from a point source) have been computed for approximately 500 nuclides important to dosimetry and radiological assessment. The half life, the mean attenuation coefficient, and thickness for a lead shield providing 95% dose equivalent attenuation are also listed

  17. Study, assessment of radioactive dose on China's population

    Ziqiang, P.

    1984-05-10

    The national population dose is defined as the radioactive dose from both natural and artificial sources which is received by the entire Chinese population. The necessity and prospects for developing ways to assess China's national population dose and some noteworthy problems in this area are described.

  18. Dose assessment in pediatric computerized tomography; Avaliacao de doses em tomografia computadorizada pediatrica

    Vilarinho, Luisa Maria Auredine Lima

    2004-07-01

    The objective of this work was the evaluation of radiation doses in paediatric computed tomography scans, considering the high doses usually involved and the absence of any previous evaluation in Brazil. Dose values were determined for skull and abdomen examinations, for different age ranges, by using the radiographic techniques routinely used in the clinical centers investigated. Measurements were done using pencil shape ionization chambers inserted in polymethylmethacrylate (PMMA) phantoms. These were compact phantoms of different diameters were specially designed and constructed for this work, which simulate different age ranges. Comparison of results with published values showed that doses were lower than the diagnostic reference levels established to adults exams by the European Commission. Nevertheless, doses in paediatric phantoms were higher than those obtained in adult phantoms. The paediatric dose values obtained in Hospitals A and B were lower than the reference level (DRL) adopted by SHIMPTON for different age ranges. In the range 0 - 0.5 year (neonatal), the values of DLP in Hospital B were 94 por cent superior to the DRL For the 10 years old children the values of CTDI{sub w} obtained were inferior in 89 por cent for skull and 83 por cent for abdomen examinations, compared to the values published by SHRIMPTON and WALL. Our measured CTDI{sub w} values were inferior to the values presented for SHRIMPTON and HUDA, for all the age ranges and types of examinations. It was observed that the normalized dose descriptors values in children in the neonatal range were always superior to the values of doses for the adult patient. In abdomen examinations, the difference was approximately 90% for the effective dose (E) and of 57%.for CTDI{sub w} . (author)

  19. Assessment of genetically significant doses to the Sofia population from natural gamma background

    Genetically significant dose to the population of Sofia city was assessed within a program covering larger urban communities in the country. Measurements were made of gamma background exposure rates in the gonadal region. Gonad doses were estimated using a screening factor of 0.73. Based on statistical data for total number of inhabitants and number of people of reproductive age, and on the mean annual gonad doses derived, calculations were made of genetically significant dose to the Sofia population. Base-line data were thus provided for an assessment of extra radiation dose resulting from occupational radiation exposure. (author)

  20. KREAM: Korean Radiation Exposure Assessment Model for Aviation Route Dose

    Hwang, J.; Dokgo, K.; Choi, E. J.; Kim, K. C.; Kim, H. P.; Cho, K. S. F.

    2014-12-01

    Since Korean Air has begun to use the polar route from Seoul/ICN airport to New York/JFK airport on August 2006, there are explosive needs for the estimation and prediction against cosmic radiation exposure for Korean aircrew and passengers in South Korea from public. To keep pace with those needs of public, Korean government made the law on safety standards and managements of cosmic radiation for the flight attendants and the pilots in 2013. And we have begun to develop our own Korean Radiation Exposure Assessment Model (KREAM) for aviation route dose since last year funded by Korea Meteorological Administration (KMA). GEANT4 model and NRLMSIS 00 model are used for calculation of the energetic particles' transport in the atmosphere and for obtaining the background atmospheric neutral densities depending on altitude. For prediction the radiation exposure in many routes depending on the various space weather effects, we constructed a database from pre-arranged simulations using all possible combinations of R, S, and G, which are the space weather effect scales provided by the National Oceanic and Atmospheric Administration (NOAA). To get the solar energetic particles' spectrum at the 100 km altitude which we set as a top of the atmospheric layers in the KREAM, we use ACE and GOES satellites' proton flux observations. We compare the results between KREAM and the other cosmic radiation estimation programs such as CARI-6M which is provided by the Federal Aviation Agency (FAA). We also validate KREAM's results by comparison with the measurement from Liulin-6K LET spectrometer onboard Korean commercial flights and Korean Air Force reconnaissance flights.

  1. The Northern Marshall Islands radiological survey: Data and dose assessments

    Fallout from atmospheric nuclear tests, especially from those conducted at the Pacific Proving Grounds between 1946 and 1958, contaminated areas of the Northern Marshall Islands. A radiological survey at some Northern Marshall Islands was conducted from September through November 1978 to evaluate the extent of residual radioactive contamination. The atolls included in the Northern Marshall Islands Radiological Survey (NMIRS) were Likiep, Ailuk, Utirik, Wotho, Ujelang, Taka, Rongelap, Rongerik, Bikar, Ailinginae, and Mejit and Jemo Islands. The original test sites, Bikini and Enewetak Atolls, were also visited on the survey. An aerial survey was conducted to determine the external gamma exposure rate. Terrestrial (soil, food crops, animals, and native vegetation), cistern and well water samples, and marine (sediment, seawater, fish and clams) samples were collected to evaluate radionuclide concentrations in the atoll environment. Samples were processed and analyzed for 137Cs, 90Sr, 239+240Pu and 241Am. The dose from the ingestion pathway was calculated using the radionuclide concentration data and a diet model for local food, marine, and water consumption. The ingestion pathway contributes 70% to 90% of the estimated dose. Approximately 95% of the dose is from 137Cs accounts for about 10% to 30% of the dose. 239+240Pu and 241Am are the major contributors to dose via the inhalation pathway; however, inhalation accounts for only about 1% of the total estimated dose, based on surface soil levels and resuspension studies. All doses are computed for concentrations decay corrected to 1996. The maximum annual effective dose from manmade radionuclides at these atolls ranges from .02 mSv y-1. The background dose in the Marshall Islands is estimated to be 2.4 mSv y-1 to 4.5 mSv y-1. The 50-y integral dose ranges from 0.5 to 65 mSv. 35 refs., 2 figs., 9 tabs

  2. The Northern Marshall Islands radiological survey: Data and dose assessments

    Robison, W.L.; Noshkin, V.E.; Conrado, C.L. [Lawrence Livermore National Lab., CA (United States)] [and others

    1997-07-01

    Fallout from atmospheric nuclear tests, especially from those conducted at the Pacific Proving Grounds between 1946 and 1958, contaminated areas of the Northern Marshall Islands. A radiological survey at some Northern Marshall Islands was conducted from September through November 1978 to evaluate the extent of residual radioactive contamination. The atolls included in the Northern Marshall Islands Radiological Survey (NMIRS) were Likiep, Ailuk, Utirik, Wotho, Ujelang, Taka, Rongelap, Rongerik, Bikar, Ailinginae, and Mejit and Jemo Islands. The original test sites, Bikini and Enewetak Atolls, were also visited on the survey. An aerial survey was conducted to determine the external gamma exposure rate. Terrestrial (soil, food crops, animals, and native vegetation), cistern and well water samples, and marine (sediment, seawater, fish and clams) samples were collected to evaluate radionuclide concentrations in the atoll environment. Samples were processed and analyzed for {sup 137}Cs, {sup 90}Sr, {sup 239+240}Pu and {sup 241}Am. The dose from the ingestion pathway was calculated using the radionuclide concentration data and a diet model for local food, marine, and water consumption. The ingestion pathway contributes 70% to 90% of the estimated dose. Approximately 95% of the dose is from {sup 137}Cs accounts for about 10% to 30% of the dose. {sup 239+240}Pu and {sup 241}Am are the major contributors to dose via the inhalation pathway; however, inhalation accounts for only about 1% of the total estimated dose, based on surface soil levels and resuspension studies. All doses are computed for concentrations decay corrected to 1996. The maximum annual effective dose from manmade radionuclides at these atolls ranges from .02 mSv y{sup -1}. The background dose in the Marshall Islands is estimated to be 2.4 mSv y{sup -1} to 4.5 mSv y{sup -1}. The 50-y integral dose ranges from 0.5 to 65 mSv. 35 refs., 2 figs., 9 tabs.

  3. Assessment of prospective foodchain doses from radioactive discharges from BNFL Sellafield

    This paper presents the method used by the UK Food Standards Agency (FSA) to assess the potential impact of proposed radioactive discharges from the Sellafield nuclear site on food and determine their acceptability. It explains aspects of a cautious method that has been adopted to reflect the UK government policy and uncertainties related to people's habits with regard to food production and consumption. Two types of ingestion doses are considered in this method: 'possible' and 'probable' doses. The method is specifically applied to Sellafield discharge limits and calculated possible and probable ingestion doses are presented and discussed. Estimated critical group ingestion doses are below the dose limit and constraint set for members of the public. The method may be subject to future amendments to take account of changes in government policy and the outcome of a recent Consultative Exercise on Dose Assessments carried out by FSA. Uncertainties inherent in dose assessments are discussed and quantified wherever possible

  4. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  5. Emergency preparedness for Tarapur site: environmental gamma dose rate assessment - continuous on-line dose rate data collection and analysis

    Continuous recording of environmental dose rates around the Nuclear Power Plants (NPPs) and its routine analysis is essential to assess the impact of the operation of these facilities on the public residing in the vicinity of the plants. During the normal operation of a NPP, releases into the atmosphere will be in small quantity. But a major nuclear accident may result in an uncontrolled release through the stack or at ground level causing radiation hazard to the public in the vicinity of the plant. The continuously recorded environmental dose rate data in the Emergency Planning Zone (EPZ) of the NPPs will form a baseline data which will be of great use in assessing the radiological impact during an emergency situation. With this aim, environmental dose rate data around Tarapur site are being collected continuously using various automatic stand alone or manual systems. This paper presents the analysis of the gamma dose rate data collected within the EPZ of Tarapur site during the last six years (1994-1999). The study is carried out using the state of the art systems. The extensive monitoring carried out in and around Tarapur site and the analysis of the data collected shows that radiological impact due to the operation of TAPS and other nuclear facilities at Tarapur on the surrounding environment is insignificant. Assessment of the environmental dose rate in the public domain helps in strengthening the emergency preparedness programme of our NPPs. (author)

  6. Electronic dose conversion technique using a NaI(Tl) detector for assessment of exposure dose rate from environmental radiation

    An electronic dose conversion technique to assess the exposure dose rate due to environmental radiation especially from terrestrial sources was developed. For a 2 x 2 inch cylindrical NaI(Tl) scintillation detector, pulse-height spectra were obtained for gamma-rays of energy up to 3 MeV by Monte Carlo simulation. Based on the simulation results and the experimentally fitted energy resolution, dose conversion factors were calculated by a numerical decomposition method. These calculated dose conversion factors were, then, electronically implemented to a developed dose conversion unit (DCU) which is a microprocessor-controlled single channel analyzer (SCA) with variable discrimination levels. The simulated spectra were confirmed by measurement of several monoenergetic gamma spectra with a multichannel analyzer (MCA). The converted exposure dose rates from the implemented dose conversion algorithm in the DCU were also evaluated for a field test in the vicinity of the nuclear power plant at Kori as well as for several standard sources, and the results were in good agreement with separate measurement by a high pressure ionization chamber (HPIC) within a 6.4% deviation

  7. A dose reconstruction case study - the retrospective assessment of neutron dose for workers on the Windscale Piles at Sellafield

    The Windscale Piles were air-cooled reactors which started operation in 1951 to irradiate natural uranium fuel elements. It is now nearly 40 years since the Windscale Piles ceased operation after a fire during the release of Wigner energy in Reactor 1 on 10 October 1957. The spotlight returned to the Windscale Piles during the recent childhood leukaemia cases because the two fathers concerned worked there during the 1950s. Operators working on the Piles wore film badges and QFEs, but no suitable personal neutron dosemeter was available at that time and no neutron doses were entered onto dose records. For the purposes of litigation, a major dose reconstruction exercise was carried out to retrospectively assess the likely neutron doses received by the two individuals. The paper describes the main steps and processes required to carry out the reconstruction exercise. Within the overall exercise, two technical aspects required particular attention. Firstly, expert interpretation was used to convert contemporary survey measurements into useable data requiring some knowledge of the neutron spectrum and the capabilities of the early neutron instruments. Secondly, it was necessary to model the reactors to predict neutron dose rates for key scenarios identified in the dose reconstruction process for which archive survey information was not located. Finally, the methodology used to convert the survey data and model predictions into neutron doses for the individuals concerned is discussed and contrasted with other potential approaches. (author)

  8. Radiation Dose-Response Relationships and Risk Assessment

    The notion of a dose-response relationship was probably invented shortly after the discovery of poisons, the invention of alcoholic beverages, and the bringing of fire into a confined space in the forgotten depths of ancient prehistory. The amount of poison or medicine ingested can easily be observed to affect the behavior, health, or sickness outcome. Threshold effects, such as death, could be easily understood for intoxicants, medicine, and poisons. As Paracelsus (1493-1541), the 'father' of modern toxicology said, 'It is the dose that makes the poison.' Perhaps less obvious is the fact that implicit in such dose-response relationships is also the notion of dose rate. Usually, the dose is administered fairly acutely, in a single injection, pill, or swallow; a few puffs on a pipe; or a meal of eating or drinking. The same amount of intoxicants, medicine, or poisons administered over a week or month might have little or no observable effect. Thus, before the discovery of ionizing radiation in the late 19th century, toxicology ('the science of poisons') and pharmacology had deeply ingrained notions of dose-response relationships. This chapter demonstrates that the notion of a dose-response relationship for ionizing radiation is hopelessly simplistic from a scientific standpoint. While useful from a policy or regulatory standpoint, dose-response relationships cannot possibly convey enough information to describe the problem from a quantitative view of radiation biology, nor can they address societal values. Three sections of this chapter address the concepts, observations, and theories that contribute to the scientific input to the practice of managing risks from exposure to ionizing radiation. The presentation begins with irradiation regimes, followed by responses to high and low doses of ionizing radiation, and a discussion of how all of this can inform radiation risk management. The knowledge that is really needed for prediction of individual risk is presented

  9. Ambient dose assessment around TRACY using deterministic methods

    Ambient dose was measured in the Transient Experiment Critical Facility (TRACY) supercritical experiments. In the analyses, The DORT code, the ANISN code and the MCNP code were used. Ambient dose equivalent calculated with DORT and ANSIN were compared to results calculated with MCNP. So we found that ambient dose equivalents calculated with DORT and ANISN, is larger than ones of MCNP, by 7∼50%. As a cause of this difference, we estimate that it is the difference of calculated source distribution inside the fuel solution, and that it is reflecting effect in wall. In following study, examination concerning this point is necessary. (author)

  10. Radiological dose assessment related to management of naturally occurring radioactive materials generated by the petroleum industry

    A preliminary radiological dose assessment related to equipment decontamination, subsurface disposal, landspreading, equipment smelting, and equipment burial was conducted to address concerns regarding the presence of naturally occurring radioactive materials in production waste streams. The assessment evaluated the relative dose of these activities and included a sensitivity analysis of certain input parameters. Future studies and potential policy actions are recommended

  11. Dose assessment of an accidental exposure at the IPNS

    Seven different methods were used to estimate the dose rate to a female worker who was accidentally exposed in the neutron PHOENIX beamline at the IPNS. Theoretical and measured entrance dose ranged from 550 mrem/min to 2850 mrem/min. Theoretical estimates were based on a Monte Carlo simulation of a spectrum provided by IPNS (Crawford Spectrum). Dose measurements were made with TLDs on phantoms and with ionization chambers in a water phantom. Estimates of the whole body total effective dose equivalent (TEDE) rate ranged from 5.2 mrem/min to 840 mrem/min. Assumed and measured quality factors ranged from 2.6 to 11.8. Cytogenetic analyses of blood samples detected no positive exposure. The recommended TEDE rate was 158 mrem/min. The TEDE was 750 mrem

  12. Assessment of radiation dose in digital storage phosphor radiography

    This paper reports on digital storage phosphor radiography that is able to produce images of constant optical density over a wide range of exposure dose by adjusting reading sensitivity. Since overexposed images are not as-readily recognized as with the conventional film-screen technique, a method capable of determining radiation dose is necessary to detect overexposures (due to, e.g., handling errors or technical defects). A formula was designed that calculates the radiation dose in the film plane from image sensitivity (S-factor), latitude (L-factor), and average gray value over the region of interest. To verify the formula, 106 measurements with variation of dose, L-factor, S-factor, and the readout algorithm were made with the Digiscan storage phosphor system (Siemens)

  13. The Northern Marshall Islands Radiological Survey: data and dose assessments.

    Robison, W L; Noshkin, V E; Conrado, C L; Eagle, R J; Brunk, J L; Jokela, T A; Mount, M E; Phillips, W A; Stoker, A C; Stuart, M L; Wong, K M

    1997-07-01

    Fallout from atmospheric nuclear tests, especially from those conducted at the Pacific Proving Grounds between 1946 and 1958, contaminated areas of the Northern Marshall Islands. A radiological survey at some Northern Marshall Islands was conducted from September through November 1978 to evaluate the extent of residual radioactive contamination. The atolls included in the Northern Marshall Islands Radiological Survey (NMIRS) were Likiep, Ailuk, Utirik, Wotho, Ujelang, Taka, Rongelap, Rongerik, Bikar, Ailinginae, and Mejit and Jemo Islands. The original test sites, Bikini and Enewetak Atolls, were also visited on the survey. An aerial survey was conducted to determine the external gamma exposure rate. Terrestrial (soil, food crops, animals, and native vegetation), cistern and well water samples, and marine (sediment, seawater, fish and clams) samples were collected to evaluate radionuclide concentrations in the atoll environment. Samples were processed and analyzed for 137Cs, 90Sr, 239+240Pu and 241Am. The dose from the ingestion pathway was calculated using the radionuclide concentration data and a diet model for local food, marine, and water consumption. The ingestion pathway contributes 70% to 90% of the estimated dose. Approximately 95% of the dose is from 137Cs. 90Sr is the second most significant radionuclide via ingestion. External gamma exposure from 137Cs accounts for about 10% to 30% of the dose. 239+240Pu and 241Am are the major contributors to dose via the inhalation pathway; however, inhalation accounts for only about 1% of the total estimated dose, based on surface soil levels and resuspension studies. All doses are computed for concentrations decay corrected to 1996. The maximum annual effective dose from manmade radionuclides at these atolls ranges from .02 mSv y(-1) to 2.1 mSv y(-1). The background dose in the Marshall Islands is estimated to be 2.4 mSv y(-1). The combined dose from both background and bomb related radionuclides ranges from slightly

  14. Fetal and maternal dose assessment for diagnostic scans during pregnancy

    Rafat Motavalli, Laleh; Miri Hakimabad, Hashem; Hoseinian Azghadi, Elie

    2016-05-01

    Despite the concerns about prenatal exposure to ionizing radiation, the number of nuclear medicine examinations performed for pregnant women increased in the past decade. This study attempts to better quantify radiation doses due to diagnostic nuclear medicine procedures during pregnancy with the help of our recently developed 3, 6, and 9 month pregnant hybrid phantoms. The reference pregnant models represent the adult female international commission on radiological protection (ICRP) reference phantom as a base template with a fetus in her gravid uterus. Six diagnostic scintigraphy scans using different radiopharmaceuticals were selected as typical diagnostic nuclear medicine procedures. Furthermore, the biokinetic data of radioiodine was updated in this study. A compartment representing iodide in fetal thyroid was addressed explicitly in the biokinetic model. Calculations were performed using the Monte Carlo transport method. Tabulated dose coefficients for both maternal and fetal organs are provided. The comparison was made with the previously published fetal doses calculated for stylized pregnant female phantoms. In general, the fetal dose in previous studies suffers from an underestimation of up to 100% compared to fetal dose at organ level in this study. A maximum of difference in dose was observed for the fetal thyroid compared to the previous studies, in which the traditional models did not contain the fetal thyroid. Cumulated activities of major source organs are primarily responsible for the discrepancies in the organ doses. The differences in fetal dose depend on several other factors including chord length distribution between fetal organs and maternal major source organs, and anatomical differences according to gestation periods. Finally, considering the results of this study, which was based on the realistic pregnant female phantoms, a more informed evaluation of the risks and benefits of the different procedures could be made.

  15. Initial assessment of image quality for low-dose PET: evaluation of lesion detectability

    Schaefferkoetter, Joshua D.; Yan, Jianhua; Townsend, David W.; Conti, Maurizio

    2015-07-01

    In the context of investigating the potential of low-dose PET imaging for screening applications, we developed methods to assess small lesion detectability as a function of the number of counts in the scan. We present here our methods and preliminary validation using tuberculosis cases. FDG-PET data from seventeen patients presenting diffuse hyper-metabolic lung lesions were selected for the study, to include a wide range of lesion sizes and contrasts. Reduced doses were simulated by randomly discarding events in the PET list mode, and ten realizations at each simulated dose were generated and reconstructed. The data were grouped into 9 categories determined by the number of included true events, from  >40 M to  <250 k counts. The images reconstructed from the original full statistical set were used to identify lung lesions, and each was, at every simulated dose, quantified by 6 parameters: lesion metabolic volume, lesion-to-background contrast, mean lesion tracer uptake, standard deviation of activity measurements (across realizations), lesion signal-to-noise ratio (SNR), and Hotelling observer SNR. Additionally, a lesion-detection task including 550 images was presented to several experienced image readers for qualitative assessment. Human observer performances were ranked using receiver operating characteristic analysis. The observer results were correlated with the lesion image measurements and used to train mathematical observer models. Absolute sensitivities and specificities of the human observers, as well as the area under the ROC curve, showed clustering and performance similarities among images produced from 5 million or greater counts. The results presented here are from a clinically realistic but highly constrained experiment, and more work is needed to validate these findings with a larger patient population.

  16. Initial assessment of image quality for low-dose PET: evaluation of lesion detectability

    In the context of investigating the potential of low-dose PET imaging for screening applications, we developed methods to assess small lesion detectability as a function of the number of counts in the scan. We present here our methods and preliminary validation using tuberculosis cases. FDG-PET data from seventeen patients presenting diffuse hyper-metabolic lung lesions were selected for the study, to include a wide range of lesion sizes and contrasts. Reduced doses were simulated by randomly discarding events in the PET list mode, and ten realizations at each simulated dose were generated and reconstructed. The data were grouped into 9 categories determined by the number of included true events, from  >40 M to  <250 k counts. The images reconstructed from the original full statistical set were used to identify lung lesions, and each was, at every simulated dose, quantified by 6 parameters: lesion metabolic volume, lesion-to-background contrast, mean lesion tracer uptake, standard deviation of activity measurements (across realizations), lesion signal-to-noise ratio (SNR), and Hotelling observer SNR. Additionally, a lesion-detection task including 550 images was presented to several experienced image readers for qualitative assessment. Human observer performances were ranked using receiver operating characteristic analysis. The observer results were correlated with the lesion image measurements and used to train mathematical observer models. Absolute sensitivities and specificities of the human observers, as well as the area under the ROC curve, showed clustering and performance similarities among images produced from 5 million or greater counts. The results presented here are from a clinically realistic but highly constrained experiment, and more work is needed to validate these findings with a larger patient population. (paper)

  17. Assessment of patients' skin dose during interventional cardiology procedures

    During the last 30 years the use of Interventional Cardiology (IC) procedures has increased significantly, mainly due to the benefits and advantages of the method that offers more accurate diagnosis and treatment along with less complications and hospitalization. However, IC procedures are based on the use of x-ray radiation, mostly localized at certain areas of patient's body and for extended periods of time. Consequently, patient may receive high radiation dose and deterministic effects, such as erythema, epilation or even dermal necrosis may be observed. Therefore, the need for reducing radiation dose is highly important. In order to achieve this, good knowledge of the dose levels delivered to the patient during IC procedures is essential since radiation effects are known to increase with dose. It is of great interest to know the point where the maximum skin dose (MSD) is noted since individual sensitivity may vary. MSDs greater than 1 Gy should be recorded. Patient dosimetry during IC procedures is a complex task since these type of procedures depend on various factors, such as complexity and severity of case, different specifications of x-ray equipment and patient's physical characteristics. Moreover, cardiologist's experience plays an important role. For these reasons, Food and Drug Administration (FDA), the International Commission on Radiological Protection (ICRP) as well as the World Health Organization (WHO), have published documents on radiation safety and ways to reduce skin injuries during IC procedures. Various methods have been proposed for measuring MSD such as the use of slow radiotherapy films, thermoluminescent detectors (TLD), scintillation detectors, Dose-Area Product (DAP) meter, as well as a combination of DAP and air kerma. A literature review on MSDs measured during IC procedures showed that doses ranged from 300 to 43000 mGy

  18. Researches and Applications of ESR Dosimetry for Radiation Accident Dose Assessment

    The aim of this work was to establish methods suitable for practical dose assessment of people involved in ionising radiation accidents. Some biological materials of the human body and materials possibly carried or worn by people were taken as detection samples. By using electron spin resonance (ESR) techniques, the basic dosimetric properties of selected materials were investigated in the range above the threshold dose of human acute haemopoietic radiation syndrome. The dosimetric properties involved included dose response properties of ESR signals, signal stabilities, distribution of background signals, the lowest detectable dose value, radiation conditions, environmental effects on the detecting process, etc. Several practical dose analytical indexes and detecting methods were set up. Some of them (bone, watch glass and tooth enamel) had also been successfully used in the dose assessment of people involved in three radiation accidents, including the Chernobyl reactor accident. This work further proves the important role of ESR techniques in radiation accident dose estimation. (author)

  19. Radiation dose from Chernobyl forests: assessment using the 'forestpath' model

    Contaminated forests can contribute significantly to human radiation dose for a few decades after initial contamination. Exposure occurs through harvesting the trees, manufacture and use of forest products for construction materials and paper production, and the consumption of food harvested from forests. Certain groups of the population, such as wild animal hunters and harvesters of berries, herbs and mushrooms, can have particularly large intakes of radionuclides from natural food products. Forestry workers have been found to receive radiation doses several times higher than other groups in the same area. The generic radionuclide cycling model 'forestpath' is being applied to evaluate the human radiation dose and risks to population groups resulting from living and working near the contaminated forests. The model enables calculations to be made to predict the internal and external radiation doses at specific times following the accident. The model can be easily adjusted for dose calculations from other contamination scenarios (such as radionuclide deposition at a low and constant rate as well as complex deposition patterns). Experimental data collected in the forests of Southern Belarus are presented. These data, together with the results of epidemiological studies, are used for model calibration and validation

  20. Epistemological problems in assessing cancer risks at low radiation doses

    Historically, biology has not been subjected to any epistemological analysis as has been the case with mathematics and physics. Our knowledge of the effects in biological systems of various stimuli proves to be dualistic in a complementary (although not mutually exclusive) way, which bears resemblance to the knowledge of phenomena in quantum physics. The dualistic limbs of biological knowledge are the action of stimuli and the response of the exposed, biological system. With regard to radiogenic cancer, this corresponds to the action of the ionizations and the response of the exposed mammal to that action, respectively. The following conclusions can be drawn from the present analysis: Predictions as to radiogenic cancer seem often if not always to have neglected the response variability (variations in radiosensitivity) in individuals or among individuals in populations, i.e. the predictions have been based exclusively on radiation doses and exposure conditions. The exposed individual or population, however, must be considered an open statistical system, i.e. a system in which predictions as to the effect of an agent are only conditionally possible. The knowledge is inverse to the size of the dose or concentration of the active agent. On epistemological grounds, we can not gain knowledge about the carcinogenic capacity of very low (non-dominant) radiation doses. Based on the same principle, we can not predict cancer risks at very low (non-dominant) radiation doses merely on the basis of models, or otherwise interpolated or extrapolated high-dose effects, observed under special exposure conditions

  1. Improvements in extremity dose assessment for ionising radiation medical applications

    This study aims at testing the INTE ring dosemeter based on MCP-Ns and TLD-100 detectors on users from the field of medical applications, namely radio-pharmacists, personnel at a cyclotron facility with corresponding FDG synthesis cells, interventional radiology technologists and radiologists. These users were chosen due to the fact that they have a significantly high risk of exposure to their hands. Following previous results, MCP-Ns TL thin material was used for radiology measurements, whereas TLD-100 was preferred for other applications. The dosemeters were tested to make sure that they were waterproof and that they could be sterilised properly prior to use. Results confirm the need to implement finger dosimetry, mainly for interventional radiologists as finger dose can be >50 times higher than whole-body dose and 3 times higher than wrist dose. (authors)

  2. Computational assessment of effective dose and patient specific doses for kilovoltage stereotactic radiosurgery of wet age-related macular degeneration

    Hanlon, Justin Mitchell

    Age-related macular degeneration (AMD) is a leading cause of vision loss and a major health problem for people over the age of 50 in industrialized nations. The current standard of care, ranibizumab, is used to help slow and in some cases stabilize the process of AMD, but requires frequent invasive injections into the eye. Interest continues for stereotactic radiosurgery (SRS), an option that provides a non-invasive treatment for the wet form of AMD, through the development of the IRay(TM) (Oraya Therapeutics, Inc., Newark, CA). The goal of this modality is to destroy choroidal neovascularization beneath the pigment epithelium via delivery of three 100 kVp photon beams entering through the sclera and overlapping on the macula delivering up to 24 Gy of therapeutic dose over a span of approximately 5 minutes. The divergent x-ray beams targeting the fovea are robotically positioned and the eye is gently immobilized by a suction-enabled contact lens. Device development requires assessment of patient effective dose, reference patient mean absorbed doses to radiosensitive tissues, and patient specific doses to the lens and optic nerve. A series of head phantoms, including both reference and patient specific, was derived from CT data and employed in conjunction with the MCNPX 2.5.0 radiation transport code to simulate treatment and evaluate absorbed doses to potential tissues-at-risk. The reference phantoms were used to evaluate effective dose and mean absorbed doses to several radiosensitive tissues. The optic nerve was modeled with changeable positions based on individual patient variability seen in a review of head CT scans gathered. Patient specific phantoms were used to determine the effect of varying anatomy and gaze. The results showed that absorbed doses to the non-targeted tissues were below the threshold levels for serious complications; specifically the development of radiogenic cataracts and radiation induced optic neuropathy (RON). The effective dose

  3. Retrospective study on the dose assessment in Algeria over a period 1998-2002

    Full text: In Algeria, the assessment of individual doses of workers occupationally exposed to external radiations is made by the national individual monitoring service at the Nuclear Research Center of Algiers (N.R.C.A.) with photographic dosimeter. In this paper, we have undertaken a retrospective study on dose assessment of workers exposed to external radiations involved in medical and industrial activities according to the new occupational dose limits over a period of five consecutive years (1998 2002). This survey has permitted to observe the impact that would have new dose limits once adopted by our legislation. (author)

  4. A preliminary assessment of individual doses in the environs of Berkeley, Gloucestershire, following the Chernobyl nuclear reactor accident

    A preliminary assessment has been made of the individual doses to critical group members of the public in the environs of Berkeley arising from fallout resulting from the Chernobyl accident. The assessment was based on measurements of airborne radionuclide concentrations, ground deposition and nuclide concentrations in rainwater, tapwater, grass, milk and green vegetables. The committed effective dose-equivalent was found to be as follows:- Adult - 200 μSv, 1 year old child - 500 μSv, the 10 year old child receiving a dose intermediate between these two values. The estimate accounts only for the nuclides measured and the specific exposure routes considered namely ingestion of milk and vegetables, inhalation and external exposure. However, it is believed that the inclusion of a range of other nuclides of potential significance, which may have been present but not measured, and potential intakes from additional routes is unlikely to increase the above estimates by more than a factor of 2. (author)

  5. Ultrasound attenuation computed tomography assessment of PAGAT gel dose

    Ultrasound has been previously investigated as an alternative readout method for irradiated polymer gel dosimeters, with authors reporting varying dose responses. We extend previous work utilizing a new computed tomography ultrasound scanner comprising of two identical 5 MHz, 128-element linear-array ultrasound transducers, co-axially aligned and submerged in water as a coupling agent, with rotational of the gel dosimeter between the transducers facilitated by a robotic arm. We have investigated the dose-dependence of both ultrasound bulk attenuation and broadband ultrasound attenuation (BUA) for the PAGAT gel dosimeter. The ultrasound bulk attenuation dose sensitivity was found to be 1.46  ±  0.04 dB m −1 Gy −1, being in agreement with previously published results for PAG and MAGIC gels. BUA was also found to be dose dependent and was measured to be 0.024  ±  0.003 dB MHz −1 Gy −1; the advantage of BUA being its insensitivity to frequency-independent attenuation mechanisms including reflection and refraction, thereby minimizing image reconstruction artefacts. (note)

  6. Assessment of dose level of ionizing radiation in army scrap

    Radiation protection is the science of protecting people and the environment from the harmful effects of ionizing radiation, which includes both particle radiation and high energy radiation. Ionizing radiation is widely used in industry and medicine. Any human activity of nuclear technologies should be linked to the foundation of scientific methodology and baseline radiation culture to avoid risk of radiation and should be working with radioactive materials and expertise to understand, control practices in order to avoid risks that could cause harm to human and environment. The study was conducted in warehouses and building of Sudan air force Khartoum basic air force during September 2010. The goal of this study to estimate the radiation dose and measurement of radioactive contamination of aircraft scrap equipment and increase the culture of radiological safety as well as the concept of radiation protection. The results showed that there is no pollution observed in the contents of the aircraft and the spire part stores outside, levels of radiation dose for the all contents of the aircraft and spire part within the excitable level, except temperature sensors estimated radiation dose about 43 μSv/h outside of the shielding and 12 μSv/h inside the shielding that exceeded the internationally recommended dose level. One of the most important of the identification of eighteen (18) radiation sources used in temperature and fuel level sensors. These are separated from the scrap, collected and stored in safe place. (Author)

  7. Improvements in extremity dose assessment in ionizing radiation medical applications

    Full text: Whole-body personal dosimetry is well established for the individual monitoring of radiation workers. Legal dosimetry is usually based on TL or film passive dosimeters worn on the trunk and evaluated by an authorised dosimetric service. However, although extremity and skin dosimetry is required by law for any practice where extremities or skin are the critical organs, the development of extremity dosemetry has not been as well established. Only a few European dosimetry services offer this service. Moreover, there is hardly any recommendation on the most suitable place for wearing this type of dosemeter. The present paper aims at testing the INTE-UPC ring dosemeter based on MCPNs and TLD-100 detectors on some users from the field of medicine, namely manual brachytherapy operators, nuclear medicine technologists from a radiopharmaceutical unit, personnel at a cyclotron facility with the corresponding FDG synthesis cells, radiographers and surgeons participating in interventional radiology. The staff were chosen due to the fact that they had a significantly high risk of exposure to their hands. According to previous results, MCPNs TL thin material is used in the radiology measurements, whereas TLD100 is preferred for the other applications. Prior to use, the dosemeters were tested for waterproof and cold sterilisation sensitivity. Preliminary results confirm the need to implement extremity dosimetry in the above- mentioned jobs, where finger dose can be of the order of 40 times the whole body dose and 3 times the wrist dose. Selection of an appropriate dosemeter can mean changes in the classification of the worker as category A or B. The study shows good correlation between workload and integrated dose, and small differences between experienced workers' dose. As a conclusion, some guidelines for radiation protection optimization are presented. (author)

  8. Variability of a peripheral dose among various linac geometries for second cancer risk assessment

    Joosten, A.; Bochud, F.; Baechler, S.; Levi, F.; Mirimanoff, R.-O.; Moeckli, R.

    2011-08-01

    Second cancer risk assessment for radiotherapy is controversial due to the large uncertainties of the dose-response relationship. This could be improved by a better assessment of the peripheral doses to healthy organs in future epidemiological studies. In this framework, we developed a simple Monte Carlo (MC) model of the Siemens Primus 6 MV linac for both open and wedged fields that we then validated with dose profiles measured in a water tank up to 30 cm from the central axis. The differences between the measured and calculated doses were comparable to other more complex MC models and never exceeded 50%. We then compared our simple MC model with the peripheral dose profiles of five different linacs with different collimation systems. We found that the peripheral dose between two linacs could differ up to a factor of 9 for small fields (5 × 5 cm2) and up to a factor of 10 for wedged fields. Considering that an uncertainty of 50% in dose estimation could be acceptable in the context of risk assessment, the MC model can be used as a generic model for large open fields (>=10 × 10 cm2) only. The uncertainties in peripheral doses should be considered in future epidemiological studies when designing the width of the dose bins to stratify the risk as a function of the dose.

  9. A rapid dose assessment and display system applicable to PWR accident

    The necessity of developing a rapid dose assessment system has been emphasized for an effective emergency response of mitigation of off-site radiological consequences. A microcomputer program based on a rapid dose assessment model of the off-site radiological consequences is developed for various accident sinarios for the Nuclear Power Plants in Korea. This model, which is consists of the user answering-question input format as a menu driven method and the output format of table and graphic types, is helpful to decision-making on Emergency Preparedness by being more rapidly able to implement the off-site dose assessment and to interpret the result. (Author)

  10. Improvement of Off-site Dose Assessment Code for Operating Nuclear Power Plant

    XOQDOQ code which calculates atmospheric Dispersion factor was included into INDAC also. A research on the improvement of off-site dose assessment system for an operating nuclear power plant was performed by KINS in 2011. As a result, following improvements were derived: - Separation of dose assessment for new and existing facilities - Update of food ingestion data - Consideration of multi-unit operation and so on In order to reflect the results, INDAC is under modification. INDAC is an integrated dose assessment code for an operating nuclear power plant and consists of three main modules: XOQDOQ, GASDOS and LIQDOS. The modules are under modification in order to improve the accuracy of assessment and usability. Assessment points for multi-unit release can be calculated through the improved code and the method on dose assessment for multi-unit release has been modified, so that the dose assessment result of multi-unit site becomes more realistic by relieving excessive conservatism. Finally, as the accuracy of calculation modules has been improved, the reliability of dose assessment result has been strengthened

  11. Using the Monte Carlo method for assessing the tissue and organ doses of patients in dental radiography

    Makarevich, K. O.; Minenko, V. F.; Verenich, K. A.; Kuten, S. A.

    2016-05-01

    This work is dedicated to modeling dental radiographic examinations to assess the absorbed doses of patients and effective doses. For simulating X-ray spectra, the TASMIP empirical model is used. Doses are assessed on the basis of the Monte Carlo method by using MCNP code for voxel phantoms of ICRP. The results of the assessment of doses to individual organs and effective doses for different types of dental examinations and features of X-ray tube are presented.

  12. Application of probabilistic quantitative ecological risk assessment to radiological dose

    Probabilistic ERA is becoming more accepted and applied in evaluations of environmental impacts worldwide. In a previous paper we have shown that the process can be applied in practice to routine effluent releases from a nuclear facility. However, there are practical issues that need to be addressed prior to its regulatory application for criteria setting or for site-specific ERA. Among these issues are a) appropriate data selection for both exposure and dose-response input, because there is a need to carefully characterise and filter the available dose-response data for its ecological relevance, b) A coherent approach is required to the choice of exposure scenarios, and c) there are various questions associated with treatment of exposure to mixed nuclides. In this paper we will evaluate and discuss aspects of these issues, using an illustrative case study approach. (author)

  13. Dose Assessment of Natural Radioactivity in Ancient Egyptian Monuments

    Within an environmental radiation investigation of the ancient Egyptian monuments sites, 151 environmental samples were analyzed using γ-ray spectrometers based on HPGe detectors. The results show that the activity concentration values of the naturally occurring radionuclides; 238U (22'6Ra), 232Th, and 40K respectively, are within the world average ranges.Two models for calculation of absorbed dose rate due to gamma emission from radionuclides in the studied soil, limestone and adobe samples were evaluated. The first model was established based on constant value of sample density. The second model takes the density variation into consideration. Two sets of conversion factors were evaluated. A comparison between the results of calculation of the absorbed dose of the studied samples based on the model adopted by UNSCEAR and on our two models was carried out and discussed. (authors)

  14. Establishment of exposure dose assessment laboratory in National Radiation Emergency Medical Center (NREMC)

    As unclear industry grown, 432 of the nuclear power plants are operating and 52 of NPPs are under construction currently. Increasing use of radiation or radioisotopes in the field of industry, medical purpose and research such as non-destructive examination, computed tomography and x-ray, etc. constantly. With use of nuclear or radiation has incidence possibility for example the Fukushima NPP incident, the Goiania accident and the Chernobyl Nuclear accident. Also the risk of terror by radioactive material such as Radiological Dispersal Device(RDD) etc. In Korea, since the 'Law on protection of nuclear facilities and countermeasure for radioactive preparedness was enacted in 2003, the Korean institute of Radiological and Medical Sciences(KIRAMS) was established for the radiation emergency medical response in radiological disaster due to nuclear accident, radioactive terror and so on. Especially National Radiation Emergency Medical Center(NREMC) has the duty that is protect citizens from nuclear, radiological accidents or radiological terrors through the emergency medical preparedness. The NREMC was established by the 39-article law on physical protection of nuclear material and facilities and measures for radiological emergencies. Dose assessment or contamination survey should be performed which provide the radiological information for medical response. For this reason, the NREMC establish and re-organized dose assessment system based on the existing dose assessment system of the NREMC recently. The exposure dose could be measured by physical and biological method. With these two methods, we can have conservative dose assessment result. Therefore the NREMC established the exposure dose assessment laboratory which was re-organized laboratory space and introduced specialized equipment for dose assessment. This paper will report the establishment and operation of exposure dose assessment laboratory for radiological emergency response and discuss how to enhance

  15. Assessment of cumulative external beam and intracavitary brachytherapy organ doses in gynecologic cancers using deformable dose summation

    Purpose: Due to inter-fraction variation in applicator position, organ displacement and deformation, doses to targets and normal tissues may not be accurately represented by adding the doses from external beam radiation therapy (EBRT) and intracavitary brachytherapy (ICBT) using rigid image registration. Deformable image registration permits organ and applicators to be spatially matched in 3D, enabling more accurate tracking of the accumulated volumetric dose to the target as well as organs at risk (OAR). This study assesses the dosimetric impact of using deformable image registration to determine the cumulative EBRT and ICBT doses to the rectum and bladder. Methods and materials: Data from 20 patients with stage IB1-IVA cervical cancer were analyzed. Nine of the patients were treated with ICBT and EBRT which included a nodal or parametrium boost while eleven were treated with ICBT and EBRT with no boost. Dose summation was performed in two stages. For the first stage, only the ICBT fractional doses were added using both “parameter adding” and deformable registration techniques. In the second stage, the ICBT and EBRT doses were combined using “parameter adding” in two ways. Partial “parameter adding” considers the cumulative ICBT dose from deformable registration as one parameter while full “parameter adding” uses fractional ICBT parameters. The cumulative minimum doses to 2cc (D2cc) of the rectum and bladder were compared between deformable registration and “parameter adding” techniques. Results: Dose summation of ICBT fractions only using deformable registration yielded D2cc values that were (10.1 ± 9.5)% lower for the rectum and (7.2 ± 6.3)% lower for the bladder compared to “parameter adding”. When ICBT and EBRT doses were summed deformably, the group without EBRT boost had D2cc that were (0.0 ± 4.6)% and (−1.2 ± 2.9)% lower for the rectum and bladder respectively compared to partial “parameter adding”. With EBRT boost, the

  16. Assessment of vitamin A metabolism with a multiple dose technique

    A rat model has been developed to study vitamin A turnover and metabolism during physiological conditions. Body pools of vitamin A of young adult male rats were replaced with radioactive vitamin A. The effect of daily ingestion and withdrawal of 20 μg of tritiated retinyl acetate was examined on the excretion of radioactivity in urine and feces. During conditions of constant excretion, 35% of dose radioactivity was excreted daily in urine and feces, feces representing the major route of excretion. After discontinuation of daily oral administration of vitamin A, proportionally smaller amounts of radioactivity were excreted both in urine and feces on each subsequent day. Urinary excretion of radioactivity decreased at a constant rate of 0.08 micrograms per day of labeled metabolites, while fecal excretion decreased more rapidly (0.22 μg/d). Significant fecal radioactivity is associated with the processing of daily dietary vitamin A and represents the metabolism of newly absorbed and unabsorbed vitamin A. Radioactivity excreted in urine is not greatly affected by elimination of daily ingestion of vitamin A and appears to reflect the functional metabolism of this vitamin in tissues. The s.a. of circulatory retinol was similar to that of the dose, while that of liver retinyl esters was 10-30% that of the dose during the 8 day period subsequent to removal of dietary vitamin A

  17. Assessment and interpretation of internal doses: uncertainty and variability.

    Paquet, F; Bailey, M R; Leggett, R W; Harrison, J D

    2016-06-01

    Internal doses are calculated on the basis of knowledge of intakes and/or measurements of activity in bioassay samples, typically using reference biokinetic and dosimetric models recommended by the International Commission on Radiological Protection (ICRP). These models describe the behaviour of the radionuclides after ingestion, inhalation, and absorption to the blood, and the absorption of the energy resulting from their nuclear transformations. They are intended to be used mainly for the purpose of radiological protection: that is, optimisation and demonstration of compliance with dose limits. These models and parameter values are fixed by convention and are not subject to uncertainty. Over the past few years, ICRP has devoted a considerable amount of effort to the revision and improvement of models to make them more physiologically realistic. ICRP models are now sufficiently sophisticated for calculating organ and tissue absorbed doses for scientific purposes, and in many other areas, including toxicology, pharmacology and medicine. In these specific cases, uncertainties in parameters and variability between individuals need to be taken into account. PMID:27044362

  18. WAYS TO INCREASE ACCURACY AND RELIABILITY OF INDIVIDUAL DOSES ASSESSMENTS IN PERSONNEL WITHIN THERMOLUMINESCENCE TECHNIQUE

    G. N. Kaydanovskiy

    2015-09-01

    Full Text Available The paper analyses the main sources of measurement errors of individual doses in personnel performed within the thermoluminescence technique and gives recommendations to minimize these errors. The reasons that reduce reliability of effective dose assessments derived from measured values of personal dose equivalent are imperfections of guidance documents. Changes to the Guidelines «Organization and implementation of individual dosimetric control. Staff of health institutions» are justified.

  19. WAYS TO INCREASE ACCURACY AND RELIABILITY OF INDIVIDUAL DOSES ASSESSMENTS IN PERSONNEL WITHIN THERMOLUMINESCENCE TECHNIQUE

    G. N. Kaydanovskiy; E. N. Pirogova

    2015-01-01

    The paper analyses the main sources of measurement errors of individual doses in personnel performed within the thermoluminescence technique and gives recommendations to minimize these errors. The reasons that reduce reliability of effective dose assessments derived from measured values of personal dose equivalent are imperfections of guidance documents. Changes to the Guidelines «Organization and implementation of individual dosimetric control. Staff of health institutions» are justified.

  20. Assessing doses to terrestrial wildlife at a radioactive waste disposal site: Inter-comparison of modelling approaches

    Johansen, M.P., E-mail: mathew.johansen@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW, 2232 (Australia); Barnett, C.L., E-mail: clb@ceh.ac.uk [Centre for Ecology and Hydrology, Lancaster (United Kingdom); Beresford, N.A., E-mail: nab@ceh.ac.uk [Centre for Ecology and Hydrology, Lancaster (United Kingdom); Brown, J.E., E-mail: justin.brown@nrpa.no [Norwegian Radiation Protection Authority, Oesteraas (Norway); Cerne, M., E-mail: marko.cerne@ijs.si [Jozef Stefan Institute, Ljubljana (Slovenia); Howard, B.J., E-mail: bjho@ceh.ac.uk [Centre for Ecology and Hydrology, Lancaster (United Kingdom); Kamboj, S., E-mail: skamboj@anl.gov [Argonne National Laboratory, IL (United States); Keum, D.-K., E-mail: dkkeum@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Smodis, B. [Jozef Stefan Institute, Ljubljana (Slovenia); Twining, J.R., E-mail: jrt@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW, 2232 (Australia); Vandenhove, H., E-mail: hvandenh@sckcen.be [Belgian Nuclear Research Centre, Mol (Belgium); Vives i Batlle, J., E-mail: jvbatll@sckcen.be [Belgian Nuclear Research Centre, Mol (Belgium); Wood, M.D., E-mail: m.d.wood@salford.ac.uk [University of Salford, Manchester (United Kingdom); Yu, C., E-mail: cyu@anl.gov [Argonne National Laboratory, IL (United States)

    2012-06-15

    Radiological doses to terrestrial wildlife were examined in this model inter-comparison study that emphasised factors causing variability in dose estimation. The study participants used varying modelling approaches and information sources to estimate dose rates and tissue concentrations for a range of biota types exposed to soil contamination at a shallow radionuclide waste burial site in Australia. Results indicated that the dominant factor causing variation in dose rate estimates (up to three orders of magnitude on mean total dose rates) was the soil-to-organism transfer of radionuclides that included variation in transfer parameter values as well as transfer calculation methods. Additional variation was associated with other modelling factors including: how participants conceptualised and modelled the exposure configurations (two orders of magnitude); which progeny to include with the parent radionuclide (typically less than one order of magnitude); and dose calculation parameters, including radiation weighting factors and dose conversion coefficients (typically less than one order of magnitude). Probabilistic approaches to model parameterisation were used to encompass and describe variable model parameters and outcomes. The study confirms the need for continued evaluation of the underlying mechanisms governing soil-to-organism transfer of radionuclides to improve estimation of dose rates to terrestrial wildlife. The exposure pathways and configurations available in most current codes are limited when considering instances where organisms access subsurface contamination through rooting, burrowing, or using different localised waste areas as part of their habitual routines. - Highlights: Black-Right-Pointing-Pointer Assessment of modelled dose rates to terrestrial biota from radionuclides. Black-Right-Pointing-Pointer The substantial variation among current approaches is quantifiable. Black-Right-Pointing-Pointer The dominant variable was soil

  1. Assessing doses to terrestrial wildlife at a radioactive waste disposal site: Inter-comparison of modelling approaches

    Radiological doses to terrestrial wildlife were examined in this model inter-comparison study that emphasised factors causing variability in dose estimation. The study participants used varying modelling approaches and information sources to estimate dose rates and tissue concentrations for a range of biota types exposed to soil contamination at a shallow radionuclide waste burial site in Australia. Results indicated that the dominant factor causing variation in dose rate estimates (up to three orders of magnitude on mean total dose rates) was the soil-to-organism transfer of radionuclides that included variation in transfer parameter values as well as transfer calculation methods. Additional variation was associated with other modelling factors including: how participants conceptualised and modelled the exposure configurations (two orders of magnitude); which progeny to include with the parent radionuclide (typically less than one order of magnitude); and dose calculation parameters, including radiation weighting factors and dose conversion coefficients (typically less than one order of magnitude). Probabilistic approaches to model parameterisation were used to encompass and describe variable model parameters and outcomes. The study confirms the need for continued evaluation of the underlying mechanisms governing soil-to-organism transfer of radionuclides to improve estimation of dose rates to terrestrial wildlife. The exposure pathways and configurations available in most current codes are limited when considering instances where organisms access subsurface contamination through rooting, burrowing, or using different localised waste areas as part of their habitual routines. - Highlights: ► Assessment of modelled dose rates to terrestrial biota from radionuclides. ► The substantial variation among current approaches is quantifiable. ► The dominant variable was soil-to-organism transfer. ► Variation also from exposure configuration, progeny, and dose

  2. Changes in friction characteristics and microstructure of steel by ion implantation of titanium and additional carbon in various doses (II)

    It is well known that Ti and Ti+C implantation improves the tribological properties of steels. The surface implanted with Ti+C exhibits superior performance in comparison with that implanted with Ti only. In this study, the difference in the microstructure and friction properties between Ti-implanted and Ti+C-implanted steel is investigated through transmission electron microscopy (TEM). After the implantation of Ti to a dose of 5x1017ionscm-2, the steel surface transformed to the amorphous phase only. On the contrary, the surface implanted with 5x1017 Ticm-2 followed by C implantation to a dose of 4x1017ionscm-2 transformed to the amorphous phase embedded with very fine TiC precipitates. After the dry sliding tests, wear tracks were studied by TEM. In Ti-implanted specimens, local damage via the loss of the amorphous layer and oxidation were observed in the wear track. On the contrary, in Ti+C-implanted specimens, uniform wear with very fine stripes was observed. This difference in the wear mode between Ti-implanted specimens and Ti+C-implanted specimens is interpreted in terms of the strength of the implanted layer and the chemical stability of the amorphous phase made by the additional C implantation. ((orig.))

  3. Measurement and assessment of doses from external radiations required for revised radiation protection regulations

    Radiation protection regulations based on the 1990 recommendations of ICRP have been revised and will take effect from Apr., 2001. The major changes concerning on the measurement and assessment of doses from external radiations are as follows. (1) Personal dose equivalent and ambient dose equivalent stated in ICRP Publication 74 are introduced as quantities to be measured with personal dosimeters and survey instruments, respectively. (2) For multiple dosimetry for workers, the compartment weighting factors used for a realistic assessment of effective dose are markedly changed. In advance of the introduction of the new radiation protection regulations, the impacts on workplace and personal monitoring for external radiations by these revisions were investigated. The following results were obtained. (1) A new ambient dose equivalent to neutrons is higher with a factor of 1.2 than the old one for moderated fission neutron spectra. Therefore, neutron dose equivalent monitors for workplace monitoring at MOX fuel for facilities should be recalibrated for measurement of the new ambient dose equivalent. (2) Annual effective doses of workers were estimated by applying new calibration factors to readings of personal dosimeters, worn by workers. Differences between effective doses and effective dose equivalents are small for workers engaged in the fabrication process of MOX fuel. (author)

  4. EMP Attachment 3 DOE-SC PNNL Site Dose Assessment Guidance

    Snyder, Sandra F.

    2011-12-21

    This Dose Assessment Guidance (DAG) describes methods to use to determine the Maximally-Exposed Individual (MEI) location and to estimate dose impact to that individual under the U.S. Department of Energy Office of Science (DOE-SC) Pacific Northwest National Laboratory (PNNL) Site Environmental Monitoring Plan (EMP). This guidance applies to public dose from radioactive material releases to the air from PNNL Site operations. This document is an attachment to the Pacific Northwest National Laboratory (PNNL) Environmental Monitoring Plan (EMP) and describes dose assessment guidance for radiological air emissions. The impact of radiological air emissions from the U.S. Department of Energy Office of Science (DOE-SC) PNNL Site is indicated by dose estimates to a maximally exposed member of the public, referred to as the maximally exposed individual (MEI). Reporting requirements associated with dose to members of the public from radiological air emissions are in 40 CFR Part 61.94, WAC 246-247-080, and DOE Order 458.1. The DOE Order and state standards for dose from radioactive air emissions are consistent with U.S. Environmental Protection Agency (EPA) dose standards in 40 CFR 61.92 (i.e., 10 mrem/yr to a MEI). Despite the fact that the current Contract Requirements Document (CRD) for the DOE-SC PNNL Site operations does not include the requirement to meet DOE CRD 458.1, paragraph 2.b, public dose limits, the DOE dose limits would be met when EPA limits are met.

  5. PCBS: CANCER DOSE-RESPONSE ASSESSMENT AND APPLICATION TO ENVIRONMENTAL MIXTURES (1996)

    This report updates the cancer dose-response assessment for polychlorinated biphenyls (PCBs) and shows how information on toxicity, disposition, and environmental processes can be considered together to evaluate health risks from PCB mixtures in the environment. Processes that ch...

  6. Assessment of individual and population doses from releases into rivers

    Members of the C.E.N., Fontenay aux Roses, France have made an evaluation of individual and population doses resulting from releases from an installation situated on the Rhone, 120 km from its mouth on the Mediterranean. Results are presented for CO60, Sr90, Ru106 and Cs137 for which a release of 1 Bq s-1 was assumed. The following pathways were studied, for which results are presented: 1) Ingestion of drinking water. 2) Consumption of fish. 3) Consumption of food products such as vegetables irrigated by river water. 4) External radiation received from river bed sediments and from the river banks. (U.K.)

  7. Atmospheric diffusion and dose estimation for habitability assessments

    The assessment of Emergency Centre has a bearing on the implementing of Emergency plan, and is of great significance. So the calculation procedure and models concerning the normalized concentration (X/Q) in the building wakes are becoming very important. A model which is different from the currently used is used to assess the habitability of Emergency Centre of a certain power plant in China. (4 figs., 3 tabs.)

  8. Boron Diffused Thermoluminescent Surface Layer in LiF TLDs for Skin Dose Assessments

    Christensen, Poul; Majborn, Benny

    1980-01-01

    A new high-temperature glow peak produced in a thin surface layer of LiF TLDs by diffusion of boron into the LiF material has been studied for skin dose assessments in personnel dosimetry.......A new high-temperature glow peak produced in a thin surface layer of LiF TLDs by diffusion of boron into the LiF material has been studied for skin dose assessments in personnel dosimetry....

  9. Radiation dose assessment from ingestion pathway in Saudi Arabia

    Abdul-Majid, S.; Abdul-Fattah, A.R.A.F.; Abulfaraj, W.H. (King Abdulaziz Univ., Jeddah (Saudi Arabia))

    1992-01-01

    Levels of radioactivities in foodstuffs in the local market have been measured for the period from November 1987 until end of June 1988. Out of the 674 samples analyzed there were 83 milk powder, 85 infant milk powder, 54 infant cereals, 89 meat, 16 lentils, 14 wheat, and 26 macaroni samples. The average radioactivity concentration of {sup 137}Cs and {sup 134}Cs, in these samples in Bq/kg were 19, 13, 18, 6, 10, 25 and 13 respectively. The rest adults and infant foodstuffs had negligible radioactivity levels. The calculated annual doses from ingestion pathway due to {sup 137}Cs and {sup 134}Cs for adults were 3.13 {times} 10{sup {minus}5} Sv and 2.1 {times} 10{sup {minus}5} Sv while for one year old infant they were 12 {times} 10{sup {minus}5} Sv and 8 {times} 10{sup {minus}5} Sv respectively. The estimated accumulated dose for 50 years from {sup 90}Sr due to one year food ingestion for adults and one year old infants were 3.76 {times} 3.76 {times} 10{sup {minus}5} Sv and 5.2 {times} 10{sup {minus}5} Sv respectively.

  10. TRANSPORTATION CASK RECEIPT AND RETURN FACILITY WORKER DOSE ASSESSMENT

    The purpose of this design calculation is to estimate radiation doses received by personnel working in the Transportation Cask Receipt and Return Facility (TCRRF) of the repository including the personnel at the security gate and cask staging areas. This calculation is required to support the preclosure safety analysis (PCSA) to ensure that the predicted doses are within the regulatory limits prescribed by the U.S. Nuclear Regulatory Commission (NRC). The Cask Receipt and Return Facility receives NRC licensed transportation casks loaded with spent nuclear fuel (SNF) and high-level radioactive waste (HLW). The TCRRF operation starts with the receipt, inspection, and survey of the casks at the security gate and the staging areas, and proceeds to the process facilities. The transportation casks arrive at the site via rail cars or trucks under the guidance of the national transportation system. This calculation was developed by the Environmental and Nuclear Engineering organization and is intended solely for the use of Design and Engineering in work regarding facility design. Environmental and Nuclear Engineering personnel should be consulted before using this calculation for purposes other than those stated herein or for use by individuals other than authorized personnel in the Environmental and Nuclear Engineering organization

  11. Facial exposure dose assessment during intraoral radiography by radiological technologists

    The study examined the changes in the decreased facial exposure dose for radiological technologists depending on increased distance between the workers and the X-ray tube head during intraoral radiography. First, the facial phantom similar to the human tissues was manufactured. The shooting examination was configured to the maxillary molars for adults (60 kVp, 10 mA, 50 msec) and for children (60 kVp, 10 mA, 20 msec), and the chamber was fixed where the facial part of the radiation worker would be placed using the intraoral radiography equipment. The distances between the X-ray tube head and the phantom were set to 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, 35 cm, and 40 cm. The phantom was radiated 20 times with each examination condition and the average scattered doses were examined. The rate at the distance of 40 cm decreased by about 92.6% to 7.43% based on the scattered rays radiated at the distance of 10 cm under the adult conditions. The rate at the distance of 40 cm decreased by about 97.6% to 2.58% based on the scattered rays radiated at the distance of 10 cm under the children conditions. Protection from the radiation exposure was required during the dental radiographic examination

  12. Facial exposure dose assessment during intraoral radiography by radiological technologists

    Yu, Hwan; Yang, Han Joon [Dept. of International Radiological Science, Hallym University of Graduate Studies, Chuncheon (Korea, Republic of)

    2014-09-15

    The study examined the changes in the decreased facial exposure dose for radiological technologists depending on increased distance between the workers and the X-ray tube head during intraoral radiography. First, the facial phantom similar to the human tissues was manufactured. The shooting examination was configured to the maxillary molars for adults (60 kVp, 10 mA, 50 msec) and for children (60 kVp, 10 mA, 20 msec), and the chamber was fixed where the facial part of the radiation worker would be placed using the intraoral radiography equipment. The distances between the X-ray tube head and the phantom were set to 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, 35 cm, and 40 cm. The phantom was radiated 20 times with each examination condition and the average scattered doses were examined. The rate at the distance of 40 cm decreased by about 92.6% to 7.43% based on the scattered rays radiated at the distance of 10 cm under the adult conditions. The rate at the distance of 40 cm decreased by about 97.6% to 2.58% based on the scattered rays radiated at the distance of 10 cm under the children conditions. Protection from the radiation exposure was required during the dental radiographic examination.

  13. Evaluation of the use of ICRP 60 dose conversion factors in a postclosure assessment of a deep geological disposal system

    An Environmental Impact Statement (EIS) of the concept for disposal of Canada's nuclear fuel waste was completed in 1994 and is currently under review by an independent Review Panel. This EIS included a postclosure assessment case study to estimate the annual effective dose equivalent in sieverts per year to members of the public; these estimates were obtained using dose conversion factors (DCFS) based on the 1977 recommendations of the International Commission on Radiation Protection (ICRP). However, in 1990 the ICRP revised these recommendations based on additional biological information and developments in radiation protection. This report describes a study of how the more recent recommendations of the ICRP would affect the results of the postclosure assessment case study presented in the EIS. The report includes a theoretical description of how DCFs are used and a comparison of results from computer simulations using the 1977 and the 1990 ICRP recommendations. In the EIS case study, which was based on the 1977 ICRP recommendations, the total dose rate to a member of the critical group is more than six orders of magnitude below the dose rate associated with the regulatory criterion for individual radiological risk. The total dose rate to 104 years is dominated by 129I, with smaller contributions from 36C1 and 14C. If the 1990 ICRP recommendations were implemented, the total dose rate would be mostly affected by the new DCF for 129I, and would increase by about 67%. Even with this increase, the total dose rate would still remain many orders of magnitude lower than the dose rate associated with the regulatory risk criterion. (author)

  14. Assessment of potential doses to workers during postulated accident conditions at the Waste Isolation Pilot Plant

    Hoover, M.D.; Farrell, R.F. [DOE, Carlsbad, NM (United States); Newton, G.J.

    1995-12-01

    The recent 1995 WIPP Safety Analysis Report (SAR) Update provided detailed analyses of potential radiation doses to members of the public at the site boundary during postulated accident scenarios at the U.S. Department of Energy`s Waste Isolation Pilot Plant (WIPP). The SAR Update addressed the complete spectrum of potential accidents associated with handling and emplacing transuranic waste at WIPP, including damage to waste drums from fires, punctures, drops, and other disruptions. The report focused on the adequacy of the multiple layers of safety practice ({open_quotes}defense-in-depth{close_quotes}) at WIPP, which are designed to (1) reduce the likelihood of accidents and (2) limit the consequences of those accidents. The safeguards which contribute to defense-in-depth at WIPP include a substantial array of inherent design features, engineered controls, and administrative procedures. The SAR Update confirmed that the defense-in-depth at WIPP is adequate to assure the protection of the public and environment. As a supplement to the 1995 SAR Update, we have conducted additional analyses to confirm that these controls will also provide adequate protection to workers at the WIPP. The approaches and results of the worker dose assessment are summarized here. In conformance with the guidance of DOE Standard 3009-94, we emphasize that use of these evaluation guidelines is not intended to imply that these numbers constitute acceptable limits for worker exposures under accident conditions. However, in conjunction with the extensive safety assessment in the 1995 SAR Update, these results indicate that the Carlsbad Area Office strategy for the assessment of hazards and accidents assures the protection of workers, members of the public, and the environment.

  15. An assessment of non-linear dose response in chemiluminescence dosimetry

    Jun, J.S. [Department of Physics, Chungnam National University, Taejon (Korea); Dalheimer, A.; Guggenberger, R. [Institute of Applied Radiation Protection, Federal Office of Radiation Protection, Oberschleissheim (Germany)

    2000-05-01

    Sugar and sorbite are well known to be convenient and suitable materials for chemiluminescence (CL) as well as electron spin resonance (ESR) dosimetry, in particular for retrospective dose assessment in an emergency and/or accident situation, mainly because of their close tissue-equivalence. In practice, however, the dose-CL response of those materials are not always shown to be satisfactorily linear. An attempt was made in this study to evaluate and correct the early supralinear dose-CL relationship appeared in the sugar and sorbite samples irradiated to gamma-ray doses of 0.5 to 10 Gy. In consideration of a similarity of the non-linear CL-dose relationship with the initial supralinearity shown in TL-dose response as depicted by Aitken, several recently proposed methods of expressing non-linear dose responses of TL, ESR or CL outputs were examined and investigated in order to look for a fittest means for the assessment of our supralinear dose-CL response of sugar and sorbite. As a result of an extensive study, merits and demerits of each method of representing non-linear dose response could be figured out in the light of our particular dose-CL relationship appeared in the sugar and sorbite samples. It is concluded that the 'supralinearity index', f(D), defined as a function of dose by Chen and McKeever is the most suitable function for expressing and correcting the non-linear dose-CL response shown in the initial low dose range of our irradiated sugar sorbite samples. The CL outputs corrected by use of f(D) are compared with those uncorrected, and the resultant CL sensitivities of the samples are numerically given together with re-evaluated dispersion of the sensitivities in terms of standard deviation. (author)

  16. Improvement and testing of radiation source models in DecDose for public dose assessments during decommissioning of nuclear facilities

    Radiation source models in a code called DecDose were improved in this study. DecDose had been developed for assessing public and worker exposure doses during the decommissioning of nuclear facilities. A segmentation model evaluating the length, volume, and surface area of kerfs in the object to be dismantled was improved to deal with seven shapes of objects simulating most of the components and the structures in nuclear facilities, while the previous model could treat only two of them. Models for the evaluation of the external dose by direct and skyshine radiation were also improved to deal with the distribution of waste containers temporarily placed in the building and the quantity of radionuclides stored in the individual container. Good agreement was observed between actual and calculated kerf volumes in cutting the reactor pressure vessel, the waste collector tank, and the channel box of the Japan Power Demonstration Reactor (JPDR). It is an indication of the validity of the model improved in this study. On the other hand, some discrepancies were observed between actual and calculated quantities of radionuclides discharged into the ocean during the JPDR dismantling project, indicating the necessity of further validation of the model. (author)

  17. Dosimetry experiences and lessons learned for radiation dose assessment in Korean nuclear power plants.

    Choi, Jong Rak; Kim, Hee Geun; Kong, Tae Young; Son, Jung Kwon

    2013-07-01

    Since the first Korean nuclear power plant (NPP), Kori 1, commenced operation in 1978, a total of 21 NPPs had been put into operation in Korea by the end of 2011. Radiation doses of NPP workers have been periodically evaluated and controlled within the prescribed dose limit. Radiation dose assessment is carried out monthly by reading personal dosemeters for external radiation exposure, which have traceability in compliance with strict technical guidelines. In the case of the internal radiation exposure, workers who have access to the possible area of polluted air are also evaluated for their internal dose after maintenance task. In this article, the overall situation and experience for the assessment and distribution of radiation doses in Korean NPPs is described. PMID:23204558

  18. Assessment of radiation dose commitment in Europe due to the Chernobyl accident

    The meeting in Bilthoven was held to make a preliminary assessment of the radiation dose commitment in Europe and to compare meteorological simulation models. Today, one year after the accident at Chernobyl, a much better data base and more precise dose estimates are available. Yet we are still publishing this report as we feel that it is of interest to compare the first dose assessments (external irradiation, inhalation, ingestion) with later ones to get an idea of the reliability of early dose predictions. Consequently the figures in the report reflect the state of knowledge in June 1986. Since last summer data from many extensive measuring programmes have been available to compile maps showing the local dose rates for most European countries. These now may be compared with the early meteorological calculations. This comparison should help scientists to improve their prognostic statements after widespread accidental releases. (orig./HP)

  19. Feasibility study for the assessment of the exposed dose with TENORM added in consumer products

    Consumer products including naturally occurring radioactive material have been distributed widely in human life. The potential hazard of the excessively added technically enhanced naturally occurring radioactive material (TENORM) in consumer products should be assessed. The aim of this study is to evaluate the organ equivalent dose and the annual effective dose with the usage of the TENORM added in paints. The activities of gammas emitted from natural radionuclides in the five types of paints were measured with the high-purity germanium detector, and the annual effective dose was assessed with the computational human phantom and the Monte Carlo method. The results show that uranium and thorium series were mainly measured over the five paints. Based on the exposure scenario of the paints in the room, the highest effective dose was evaluated as <1 mSv y-1 of the public dose limit. (authors)

  20. Assessment of radiation doses to the population in the environment of a nuclear power plant

    This guide sets forth the principles to be followed in the assessment of the radiation exposure of the surrounding population of a nuclear power plant. The requirements of this guide apply to transient and safety analyses conducted in accordance with Guide YVL 2.2; to analyses assessing exposure from releases during normal operation; and to analyses in connection with emergency preparedness. In addition, they may be applied to other analyses for the operation of a nuclear power plant. This guide may be applied to other nuclear facilities as well. Guide YVL 7.3 deals with evaluation of the dispersion of radioactive substances in relation to radiation dose assessment. According to Recommendation 91/4/Euratom issued by the Commission of the European Communities on the application of Article 37 of the EURATOM Treaty, the member states shall provide the Commission with information about the environmental impacts of the use of nuclear energy. If need be, the Radiation and Nuclear Safety Authority will instruct separately on the application of the Recommendation. The licensee may use a simplified model that deviates from the detailed requirements of this guide. It shall then be justifiably demonstrated that the model is conservative

  1. A review of transfer factors for assessing the dose from radionuclides in agricultural products

    The dose to man from radionuclides released to the environment is generally assessed with mathematical models that require transfer factors as input parameters to predict the concentration of radionuclides in foodstuffs. This article summarizes recent attempts to review the worldwide literature and derive updated transfer factors to predict concentrations of radionuclides in terrestrial foods using equilibrium models. Updated transfer coefficients to predict the concentration of a radionuclide in cow's milk and other animal products from that in feed are presented as well as concentration factors to predict the concentration of a nuclide in a food or feed crop from that in soil. Comparing the updated transfer coefficients with those in existing tables leads to suggested changes in the transfer coefficients for milk and beef. Soil-to-plant concentration factors are extremely variable, which limits the usefulness of a single concentration factor to predict the uptake of a radionuclide into crops from soil. The potentially large uncertainty associated with predicting the uptake of radionuclides by plants from soil at a particular location may be reduced by considering the dominant crops and soil types in the area and how various soil properties affect the concentration factor. The updated transfer factors may be useful in assessing transport through terrestrial food chains when site-specific information is not available. In addition, they provide a basis for systematically updating existing tables of transfer factors for generic assessments

  2. Review on Population Projection Methodology for Radiological Dose Assessment

    Jang, M. S.; Kang, H. S.; Kim, S. R. [NESS, Daejeon (Korea, Republic of); Hwang, W. T. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yang, Y. H. [KHNP, Daejeon (Korea, Republic of)

    2015-05-15

    Radiation environment report (RER), one of the essential documents in plant operating license or continuous operation license, includes population projection. Population estimates are utilized in determining the collective dose at the operation or restart time of nuclear power plant. Many population projection models are suggested and also under development. We carried out the sensitivity analysis on various population projection models to Daejeon city as a target. Daejeon city showed the increase or decrease in the cross-sectional population, because of the development of Sejong city, Doan new town and etc. We analyzed the population of Daejeon city using statistical ARIMA model and various simple population projection models. It is important to determine the population limit in Modified exponential model but it is not easy. Therefore, the various properties of the area such as the decrease and increase of population, new town development plan, social and natural environment change and etc., should be carefully reviewed to estimate the future population of any area.

  3. Contamination of Japanese foodstuffs of terrestrial origin after the Fukushima nuclear accident and related dose assessment - Part 2: ingestion dose assessments for the first year after the accident

    This article proposes an assessment of the ingestion doses potentially received by people living in the Japanese areas most severely affected by the radioactive deposits due to the Fukushima nuclear accident. The assessment distinguishes two consecutive periods: the first 2 months (March 15 to May 15 2011) and the rest of the year 2011, according to the two main foodstuff contamination periods identified (Renaud et al., 2013). On the basis of the worst- case hypothesis that can reasonably be made, the estimated doses are much lower than they might have been in other circumstances, on account of generally moderate levels of contamination for most foods, early evacuation of the most severely affected areas and the consumption bans ordered by the Japanese authorities. Thus, a single ingestion of 100 g of leafy vegetables in the early days by a one-year-old child living in non-evacuated localities near Iitate and Kawamata could have led to an equivalent dose to the thyroid of about 25 mSv; and to a thyroid dose of about 140 mSv for the rather unrealistic scenario of a daily consumption. Because of the rapid decrease in the contamination of vegetables and a much weaker contamination of other crops, and thanks to measures taken by the authorities (prohibition of consumption, use of certain fodder, etc.), the ingestion doses potentially received during the remainder of the year 2011 are estimated to be below 1 mSv. In the event that sales limits would have been ignored, only repeated consumption of mushrooms would have led to doses above that level. Even with the worst-case hypotheses, the doses potentially caused by ingestion are much lower than those resulting from outdoor exposure to radioactive deposits: approximately several milli-sieverts in a year for the population living in the non-evacuated localities near Iitate and Kawamata. (authors)

  4. Development of environmental dose assessment system (EDAS) code of PC version

    Taki, M; Kobayashi, H; Yamaguchi, T

    2003-01-01

    A computer code (EDAS) was developed to assess the public dose for the safety assessment to get the license of nuclear reactor operation. This code system is used for the safety analysis of public around the nuclear reactor in normal operation and severe accident. This code was revised and composed for personal computer user according to the Nuclear Safety Guidelines reflected the ICRP1990 recommendation. These guidelines are revised by Nuclear Safety Commission on March, 2001, which are 'Weather analysis guideline for the safety assessment of nuclear power reactor', 'Public dose around the facility assessment guideline corresponding to the objective value for nuclear power light water reactor' and 'Public dose assessment guideline for safety review of nuclear power light water reactor'. This code has been already opened for public user by JAERI, and English version code and user manual are also prepared. This English version code is helpful for international cooperation concerning the nuclear safety assessme...

  5. EPR spectrum deconvolution and dose assessment of fossil tooth enamel using maximum likelihood common factor analysis

    In order to determine the components which give rise to the EPR spectrum around g = 2 we have applied Maximum Likelihood Common Factor Analysis (MLCFA) on the EPR spectra of enamel sample 1126 which has previously been analysed by continuous wave and pulsed EPR as well as EPR microscopy. MLCFA yielded agreeing results on three sets of X-band spectra and the following components were identified: an orthorhombic component attributed to CO-2, an axial component CO3-3, as well as four isotropic components, three of which could be attributed to SO-2, a tumbling CO-2 and a central line of a dimethyl radical. The X-band results were confirmed by analysis of Q-band spectra where three additional isotropic lines were found, however, these three components could not be attributed to known radicals. The orthorhombic component was used to establish dose response curves for the assessment of the past radiation dose, DE. The results appear to be more reliable than those based on conventional peak-to-peak EPR intensity measurements or simple Gaussian deconvolution methods

  6. Problems with application of Hp(10) and approach to assessment of effective dose

    Monte Carlo simulation with an anthropomorphic phantom was used for calculation of effective doses and doses in multiple individual dosimeters placed on the surface of the phantom for various geometries of irradiation. A direction of parallel photon beam varied within 4π solid angle, photon energies varied from 20 to 600 keV. Obtained dependences of conversion coefficient from personal equivalent Hp(10) to effective dose as a function of irradiation geometry, photon energy and dosimeter position demonstrate that using Hp(10) for estimation of effective dose in strongly anisotropic radiation field could result in essential underestimation or overestimation of effective doses. Several options of assessment of the effective dose by use of multiple dosimeters were analyzed and an optimization of weighted sum of dosimeter readout is proposed. Optimum weighting parameters for simultaneous use of 4 dosimeters were derived under the assumption of energy spectrum typical for Chernobyl 'Object Shelter' conditions. (author)

  7. Reduced-dose CT protocol for the assessment of cerebral vasospasm

    Bricout, N.; Estrade, L.; Boustia, F.; Kalsoum, E.; Pruvo, J.P.; Leclerc, X. [Hopital Roger Salengro, CHRU de Lille, Department of Neuroradiology, Universite Lille Nord de France, Lille cedex (France)

    2015-12-15

    Despite the increased radiation dose, multimodal CT including noncontrast CT (NCT), CT angiography (CTA), and perfusion CT (PCT) remains a useful tool for the diagnosis of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH). The aim of this study was to assess the radiation dose and the image quality between a standard-dose and a reduced-dose multimodal CT protocol. The study group consisted of 26 aSAH patients with a suspicion of DCI on clinical examination and transcranial doppler. Two different CT protocols were used: a standard-dose protocol (NCT 120 kV, 350 mAs; CTA 100 kV, 250 mAs; PCT 80 kV, 200 mAs) from August 2011 to October 2013 (n = 13) and a reduced-dose protocol (NCT 100 kV, 400 mAs; CTA 100 kV, 220 mAs; PCT 80 kV, 180 mAs) from November 2013 to May 2014 (n = 13). Dose-length product (DLP), effective dose, volume CT dose index (CTDI), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and overall image quality were determined for each examination. The overall image quality was judged as good or excellent in all cases. The reduced-dose protocol allowed a 15 % decrease in both the median total DLP (2438 vs 2898 mGy cm, p < 0.0001) and the effective dose as well as a significant decrease in median CTDI of 23, 31, and 10 % for NCT, CTA, and CTP, respectively. This dose reduction did not result in significant alteration of SNR (except for NCT) or CNR between groups. The present study showed that the reduced-dose multimodal CT protocol enabled a significant reduction of radiation dose without image quality impairment. (orig.)

  8. Assessment of eye lens doses for workers during interventional radiology procedures.

    Urboniene, A; Sadzeviciene, E; Ziliukas, J

    2015-07-01

    The assessment of eye lens doses for workers during interventional radiology (IR) procedures was performed using a new eye lens dosemeter. In parallel, the results of routine individual monitoring were analysed and compared with the results obtained from measurements with a new eye lens dosemeter. The eye lens doses were assessed using Hp(3) measured at the level of the eyes and were compared with Hp(10) measured with the whole-body dosemeter above the lead collar. The information about use of protective measures, the number of performed interventional procedures per month and their fluoroscopy time was also collected. The assessment of doses to the lens of the eye was done for 50 IR workers at 9 Lithuanian hospitals for the period of 2012-2013. If the use of lead glasses is not taken into account, the estimated maximum annual dose equivalent to the lens of the eye was 82 mSv. PMID:25877533

  9. ANDROS: A code for Assessment of Nuclide Doses and Risks with Option Selection

    Begovich, C.L.; Sjoreen, A.L.; Ohr, S.Y.; Chester, R.O.

    1986-11-01

    ANDROS (Assessment of Nuclide Doses and Risks with Option Selection) is a computer code written to compute doses and health effects from atmospheric releases of radionuclides. ANDROS has been designed as an integral part of the CRRIS (Computerized Radiological Risk Investigation System). ANDROS reads air concentrations and environmental concentrations of radionuclides to produce tables of specified doses and health effects to selected organs via selected pathways (e.g., ingestion or air immersion). The calculation may be done for an individual at a specific location or for the population of the whole assessment grid. The user may request tables of specific effects for every assessment grid location. Along with the radionuclide concentrations, the code requires radionuclide decay data, dose and risk factors, and location-specific data, all of which are available within the CRRIS. This document is a user manual for ANDROS and presents the methodology used in this code.

  10. ANDROS: A code for Assessment of Nuclide Doses and Risks with Option Selection

    ANDROS (Assessment of Nuclide Doses and Risks with Option Selection) is a computer code written to compute doses and health effects from atmospheric releases of radionuclides. ANDROS has been designed as an integral part of the CRRIS (Computerized Radiological Risk Investigation System). ANDROS reads air concentrations and environmental concentrations of radionuclides to produce tables of specified doses and health effects to selected organs via selected pathways (e.g., ingestion or air immersion). The calculation may be done for an individual at a specific location or for the population of the whole assessment grid. The user may request tables of specific effects for every assessment grid location. Along with the radionuclide concentrations, the code requires radionuclide decay data, dose and risk factors, and location-specific data, all of which are available within the CRRIS. This document is a user manual for ANDROS and presents the methodology used in this code

  11. Assessment of eye lens doses for workers during interventional radiology procedures

    The assessment of eye lens doses for workers during interventional radiology (IR) procedures was performed using a new eye lens dosemeter. In parallel, the results of routine individual monitoring were analysed and compared with the results obtained from measurements with a new eye lens dosemeter. The eye lens doses were assessed using Hp(3) measured at the level of the eyes and were compared with Hp(10) measured with the whole-body dosemeter above the lead collar. The information about use of protective measures, the number of performed interventional procedures per month and their fluoroscopy time was also collected. The assessment of doses to the lens of the eye was done for 50 IR workers at 9 Lithuanian hospitals for the period of 2012-2013. If the use of lead glasses is not taken into account, the estimated maximum annual dose equivalent to the lens of the eye was 82 mSv. (authors)

  12. Early treatment with addition of low dose prednisolone to methotrexate improves therapeutic outcome in severe psoriatic arthritis

    Vikram K Mahajan

    2013-01-01

    Full Text Available Psoriatic arthritis (PsA is increasingly being recognized to cause progressive joint damage and disability. PsA unresponsive to non-steroidal anti-inflammatory drugs (NSAIDs, the conventional first-line choice of treatment, is usually managed with disease-modifying antirheumatic drugs (DMARDs especially methotrexate. An 18-year-old HIV-negative male had progressively severe PsA of 4-month duration that was nearly confining him to a wheel chair. He did not respond to multiple NSAIDs, alone or in combination with methotrexate (15 mg/week, given for 4 weeks. Addition of prednisolone (10 mg on alternate days controlled his symptoms within a week. The NSAIDs could be withdrawn after 4 weeks as the treatment progressed. The doses were tapered for methotrexate (5 mg/week and prednisolone (2.5 mg on alternate days every 8 weekly subsequently during 15 months of follow-up without recurrence/deformities or drug toxicity. For years, the use of corticosteroids in psoriasis has been criticized for their propensity to exacerbate the skin disease on withdrawal. However, monitored use of corticosteroids, even in low doses, combined with DMARDs may be a good therapeutic option in early stage of the PsA rather than ′steroid rescue′ later. This will help in early control of joint inflammation, prevent joint damage and maintain long-term good functional capacity and quality of life. This may be useful when the cost or availability of biologics precludes their use. However, we discourage the use of corticosteroids as monotherapy.

  13. Assessment of image quality and radiation dose on a modern flat panel angiography system

    Full text: Angiographic procedures are often associated with high patient and staff dose that can be reduced without image quality deterioration. This work is on assessment of image quality and patient doses on a modern flat panel angiography unit. Because of the limited number of digital systems in Bulgaria, quality control protocol for testing these units does not exist currently and this work is aimed to develop and test the methodology. Methods and materials. A GE Innova 4100 Flat Panel Detector angiography unit was examined. Low and high contrast resolutions were assessed using FL18 test object placed at the isocentre between the sheets of a PMMA phantom with total thickness varying from 16 to 30 cm for FOV of 16 to 40 cm at pulsed fluoro mode of 30 frames/s. The image detector was set up at 5 cm above the 30 cm PMAA phantom. The Entrance Surface Dose Rate was measured by Mult-O-Meter dosimeter (Unfors, Sweden). The Incident Dose rate and Dose Area Product were measured with Diamentor M4-KDK (PTW, Germany) for the same FOVs and phantom thicknesses. The quality of images at acquisition mode was examined also using DIGI 13 test object (Wellhofer, Germany). The homogeneity, dynamic range, alignment, high contrast spatial resolution and low contrast resolution and signal-to-noise ratio were measured. The digital subtraction angiography image quality was examined using RoVi-8 test tool (Wellhofer, Germany). Results and discussion. The Entrance Surface Dose Rate measured for 20 cm PMAA and the 40 cm FOV, 30 frames/s was 11,29 mGy.min-1 and 5,58 mGy.min-1 for the 'normal' and 'low' mode, respectively. The dosimetric results obtained via both dosimeters are used for calculation of calibration coefficients for the DAP and ESD values shown by the system on the display monitor at the control console. The low contrast sensitivity varies from 1,6% to 6,6% depending on the thickness of PMAA phantom and FOV, as the limiting spatial resolution is changing from 2,24 to 1,12 lp

  14. Assessment of subject doses in mammography and its implication in the screening practice

    The aim of this paper is to evaluate the equivalent dose to breasts and effective dose from typical mammographic procedure. To calculate the contribution to effective dose from scattered radiation was used an MIRD-type whole body phantom of adult female. In this study, transformed the original MIRD female breast model to simulate the compressed breast. To determine the size of breast, mammographic procedure data were collected from the Korea Cancer Center Hospital in Seoul. These values were applied to the geometrical modeling of compressed breast. Mammographic units chosen for modeling are GE Senographe 600T and LORAD M-IV. Dose assessment was conducted for breast material of gland, homogeneous 50:50 mixture of adipose and glandular tissue, and sole adipose. Patient doses were calculated using the general-purposed Monte Carlo code, MCNPX. The X-ray spectra provided by the SPEC 78 data library were used. The difference in breast dose due to the different breast material compositions and different units was small. The equivalent doses to the breast were decreased aat other ages to became 2.25 mSv for patients undergoing craniocaudal in their 20's and the lowest dose is 0.68 mSv undergoing craniocaudal in their 60's. Similar trend was observed in the mediolateral projections. The contribution of other organ doses to effective does is found negligible so that the effective doses were approximately one-tenth the breast dose. The result of assessment of subject doses in mammography may provide reference of screening practice and groundwork for the national health in radiology

  15. 4D cone beam CT-based dose assessment for SBRT lung cancer treatment

    Cai, Weixing; Dhou, Salam; Cifter, Fulya; Myronakis, Marios; Hurwitz, Martina H.; Williams, Christopher L.; Berbeco, Ross I.; Seco, Joao; Lewis, John H.

    2016-01-01

    The purpose of this research is to develop a 4DCBCT-based dose assessment method for calculating actual delivered dose for patients with significant respiratory motion or anatomical changes during the course of SBRT. To address the limitation of 4DCT-based dose assessment, we propose to calculate the delivered dose using time-varying (‘fluoroscopic’) 3D patient images generated from a 4DCBCT-based motion model. The method includes four steps: (1) before each treatment, 4DCBCT data is acquired with the patient in treatment position, based on which a patient-specific motion model is created using a principal components analysis algorithm. (2) During treatment, 2D time-varying kV projection images are continuously acquired, from which time-varying ‘fluoroscopic’ 3D images of the patient are reconstructed using the motion model. (3) Lateral truncation artifacts are corrected using planning 4DCT images. (4) The 3D dose distribution is computed for each timepoint in the set of 3D fluoroscopic images, from which the total effective 3D delivered dose is calculated by accumulating deformed dose distributions. This approach is validated using six modified XCAT phantoms with lung tumors and different respiratory motions derived from patient data. The estimated doses are compared to that calculated using ground-truth XCAT phantoms. For each XCAT phantom, the calculated delivered tumor dose values generally follow the same trend as that of the ground truth and at most timepoints the difference is less than 5%. For the overall delivered dose, the normalized error of calculated 3D dose distribution is generally less than 3% and the tumor D95 error is less than 1.5%. XCAT phantom studies indicate the potential of the proposed method to accurately estimate 3D tumor dose distributions for SBRT lung treatment based on 4DCBCT imaging and motion modeling. Further research is necessary to investigate its performance for clinical patient data.

  16. Experimental assessment of gold nanoparticle-mediated dose enhancement in radiation therapy beams using electron spin resonance dosimetry

    In this work, we aim to experimentally assess increments of dose due to nanoparticle-radiation interactions via electron spin resonance (ESR) dosimetry performed with a biological-equivalent sensitive material.We employed 2-Methyl-Alanine (2MA) in powder form to compose the radiation sensitive medium embedding gold nanoparticles (AuNPs) 5 nm in diameter. Dosimeters manufactured with 0.1% w/w of AuNPs or no nanoparticles were irradiated with clinically utilized 250 kVp orthovoltage or 6 MV linac x-rays in dosimetric conditions. Amplitude peak-to-peak (App) at the central ESR spectral line was used for dosimetry. Dose-response curves were obtained for samples with or without nanoparticles and each energy beam. Dose increments due to nanoparticles were analyzed in terms of absolute dose enhancements (DEs), calculated as App ratios for each dose/beam condition, or relative dose enhancement factors (DEFs) calculated as the slopes of the dose-response curves.Dose enhancements were observed to present an amplified behavior for small doses (between 0.1–0.5 Gy), with this effect being more prominent with the kV beam. For doses between 0.5–5 Gy, dose-independent trends were observed for both beams, stable around (2.1   ±   0.7) and (1.3   ±   0.4) for kV and MV beams, respectively. We found DEFs of (1.62   ±   0.04) or (1.27   ±   0.03) for the same beams. Additionally, we measured no interference between AuNPs and the ESR apparatus, including the excitation microwaves, the magnetic fields and the paramagnetic radicals.2MA was demonstrated to be a feasible paramagnetic radiation-sensitive material for dosimetry in the presence of AuNPs, and ESR dosimetry a powerful experimental method for further verifications of increments in nanoparticle-mediated doses of biological interest. Ultimately, gold nanoparticles can cause significant and detectable dose enhancements in biological-like samples irradiated at both

  17. Assessment of coverage levels of single dose measles vaccine

    Objective: To study the consequences of low coverage levels of a single dose of measles vaccine. Results: mean age observed in measles cases was 2 years and 8 months with a range from 3 months to 8 years. Maximum number of cases reported were <1 year of age (n=22,32%). Fifty percent of cases were seen among vaccinated children. Seventy-five percent (n=51) had history of contact with a measles case. Pneumonia was the commonest complication followed by acute gastroenteritis, encephalitis, febrile convulsions, oral ulcers, oral thrush, eye changes of vitamin-A deficiency and pulmonary tuberculosis (T.B.) in descending order of frequency. Fifty four cases were successfully treated for complications of measles and discharged. Nine cases left against medical advice. Five patients died all of them had encephalitis either alone (n=1) or in combination with pneumonia and acute gastroenteritis (n=4). Conclusion: There is a dire need to increase the immunization coverage to reduce the rate of vaccine failure and achieve effective control of measles.(author)

  18. Dose assessment studies at former nuclear weapons test sites in Australia

    Field and laboratory measurements are described and data presented which enable a dose assessment for the inhalation of artificial radionuclides at Maralinga and Emu, the sites of United kingdom atomic weapons tests between 1953 and 1963. Dose assessments for the inhalation of artificial radionuclides are presented for all remaining contaminated areas at Maralinga and Emu. In the case of Aborigines, these doses are estimated assuming inhalable dust loadings of 1 mg/m3 for adults and 1.5 mg/m3 for children and infants. Particle size is taken to be 5 μm AMAD. Plutonium and americium are taken to be represented by solubility Class Y for major trial sites and 25% Class W and 75% Class Y for all minor trial sites. For other radionuclides, where no data are available, the most conservative dose intake conversion factor values are used. All calculations of dose assume 100% occupancy. The results indicate that doses to children are higher than doses to adults and infants. This is a consequence of children being subjected to higher dust concentrations than adults because of their play activities and because of generally higher dose intake conversion factor values than adults, which more than offset their smaller breathing rates. Thus children form the critical group. With the exception of one site which is contaminated with uranium, at all other sites it is only the inhalation of plutonium and americium that contributes significantly to the dose, and of these 239Pu is the largest contributor. Therefore, having regard to the long half lives of the radionuclides concerned, the inhalation problems highlighted by this dose assessment will not diminish significantly within any reasonable period of time and hence management strategies must be developed to deal with them. (author). 35 refs, 1 fig., 2 tabs

  19. Development of a real-time radiological dose assessment system

    Han, Moon Hee; Lee, Young Bok; Kim, Eun Han; Suh, Kyung Suk; Hwang, Won Tae

    1997-01-01

    Inspection and repair of tower structure and lift, instrument calibration have been done. Wireless data transmission to MIPS (Meteorological Information Processing System) has been done after collection in the DAS where environmental assessment can be done by the developed simulation programs in both cases of normal operation and emergency. Wind direction, wind speed, temperature, humidity at 67m, 27m, and 10m height and temperature, humidity, atmospheric pressure, solar radiation, precipitation, and visibility at surface have been measured analyzed with statistical methods. At the site, the prevailing wind directions were SW in spring and summer, NNW in winter season. (author). 6 refs., 9 tabs., 4 figs.

  20. Development of a real-time radiological dose assessment system

    Inspection and repair of tower structure and lift, instrument calibration have been done. Wireless data transmission to MIPS (Meteorological Information Processing System) has been done after collection in the DAS where environmental assessment can be done by the developed simulation programs in both cases of normal operation and emergency. Wind direction, wind speed, temperature, humidity at 67m, 27m, and 10m height and temperature, humidity, atmospheric pressure, solar radiation, precipitation, and visibility at surface have been measured analyzed with statistical methods. At the site, the prevailing wind directions were SW in spring and summer, NNW in winter season. (author). 6 refs., 9 tabs., 4 figs

  1. Distribution of radionuclides in potato tubers. Implication for dose assessments

    A study of the distribution of 137Cs, 90Sr, Pu and Am in potato tubers has been carried out. Cesium-137 was essentially uniformly distributed throughout the tuber, whereas up to about 50% of the 90Sr activity was found in the peel. Results for actinides indicated that most of the activity would be found in the peel and of this more than half would be located in the thin outermost skin. When account is taken of the form in which potatoes are consumed in the UK, the values of soil-plant transfer factors currently assumed in the NRPB model FARMLAND are reasonable for general assessment purposes. (author)

  2. Integrated numerical platforms for environmental dose assessments of large tritium inventory facilities

    Related with a prospected new scenario of large inventory tritium facilities [KATRIN at TLK, CANDUs, ITER, EAST, other coming] the prescribed dosimetric limits by ICRP-60 for tritium committed-doses are under discussion requiring, in parallel, to surmount the highly conservative assessments by increasing the refinement of dosimetric-assessments in many aspects. Precise Lagrangian-computations of dosimetric cloud-evolution after standardized (normal/incidental/SBO) tritium cloud emissions are today numerically open to the perfect match of real-time meteorological-data, and patterns data at diverse scales for prompt/early and chronic tritium dose assessments. The trends towards integrated-numerical-platforms for environmental-dose assessments of large tritium inventory facilities under development.

  3. Displaying 3D radiation dose on endoscopic video for therapeutic assessment and surgical guidance

    We have developed a method to register and display 3D parametric data, in particular radiation dose, on two-dimensional endoscopic images. This registration of radiation dose to endoscopic or optical imaging may be valuable in assessment of normal tissue response to radiation, and visualization of radiated tissues in patients receiving post-radiation surgery. Electromagnetic sensors embedded in a flexible endoscope were used to track the position and orientation of the endoscope allowing registration of 2D endoscopic images to CT volumetric images and radiation doses planned with respect to these images. A surface was rendered from the CT image based on the air/tissue threshold, creating a virtual endoscopic view analogous to the real endoscopic view. Radiation dose at the surface or at known depth below the surface was assigned to each segment of the virtual surface. Dose could be displayed as either a colorwash on this surface or surface isodose lines. By assigning transparency levels to each surface segment based on dose or isoline location, the virtual dose display was overlaid onto the real endoscope image. Spatial accuracy of the dose display was tested using a cylindrical phantom with a treatment plan created for the phantom that matched dose levels with grid lines on the phantom surface. The accuracy of the dose display in these phantoms was 0.8–0.99 mm. To demonstrate clinical feasibility of this approach, the dose display was also tested on clinical data of a patient with laryngeal cancer treated with radiation therapy, with estimated display accuracy of ∼2–3 mm. The utility of the dose display for registration of radiation dose information to the surgical field was further demonstrated in a mock sarcoma case using a leg phantom. With direct overlay of radiation dose on endoscopic imaging, tissue toxicities and tumor response in endoluminal organs can be directly correlated with the actual tissue dose, offering a more nuanced assessment of normal

  4. Screening methodology for dose assessment to seawater organisms in baltic sea

    Determination of radionuclides in Baltic Sea environment in the frame of MORS programme gives opportunity to evaluate doses for aquatic organisms from the Southern Baltic Sea. The available environmental data from the last few years included concentrations of 137Cs (bomb-tests-fallout and Chernobyl origin), 226Ra (natural radionuclide) and 239,240Pu (bomb-tests-fallout) in biota, bottom sediment and water. The doses assessment of 137Cs, 226Ra and 239,240Pu for aquatic animals was performed, based on the screening methodology elaborated by U.S. Department of Energy. Baltic Sea fish (cod, sprat, herring, plaice) and crustaceans (Sanduria entomon and Mytilus edulis) were taken in to consideration and the annual doses from 137Cs, 226Ra and 239Pu to organisms were calculated at average concentrations of these radionuclides observed in water, concentration of radionuclides determined in bottom sediments from two sub-areas (Gdansk Basin and Bornholm Basin) and average concentrations of radionuclides in animal tissues. The total maximal annual doses for seawater organisms do not exceed a one percent of recommended dose limits however, the dominate contribution to the total dose depends on analysed radionuclide. For 137Cs a maximum contribution to the total dose gives external dose from bottom sediment (about 0.5 mGy y-1). Only about 1% of the total 137Cs dose is derived from internal dose however animal-water ratio obtained from measurements is much lower (in a range 30-300 L kg-1) comparing with recommended by DOE Standard value (22000 L kg-1). For 226Ra internal doses for fish and Mytilus are similar (0.2 mGy y-1, 0.6 mGy y-1 respectively) and they are comparable with external doses from sediment (0.3 mGy y-1) whereas internal dose for Sanduria is about 10 times higher (7 mGy y-1). A measured animal- water ratios (20 - 500 L kg-1) differs remarkably from default DOE Standard value (3200 L kg-1). For plutonium 239Pu the maximum contribution to the total dose gives

  5. Radiological dose assessments at the Kennedy Space Center

    This paper discusses the application of an atmospheric transport and diffusion model for launch window and safety risk assessment studies in support of the Galileo (which is scheduled for the October/November 1989 period) and Ulysses (scheduled for ∼1 yr after Galileo) missions at the Kennedy Space Center (KSC). The model is resident in the EMERGE software system developed by NUS Corporation and modified for the U.S. Department of Energy (DOE) to provide real-time and safety analyses report support for the launches. The application is unique in that the model accommodates the varied amount of meteorological data at KSC and Cape Canaveral and includes a site-specific algorithm to account for local-scale circulations. This paper focuses on the Galileo mission application, including discussions of the use of the meteorological data available at KSC, integration of the EMERGE sea-breeze algorithm, and examples of real-time and safety analyses report assessments. The Galileo spacecraft is to be launched toward Jupiter using the space shuttle

  6. Objective assessment of image quality and dose reduction in CT iterative reconstruction

    Vaishnav, J. Y., E-mail: jay.vaishnav@fda.hhs.gov; Jung, W. C. [Diagnostic X-Ray Systems Branch, Office of In Vitro Diagnostic Devices and Radiological Health, Center for Devices and Radiological Health, United States Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States); Popescu, L. M.; Zeng, R.; Myers, K. J. [Division of Imaging and Applied Mathematics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States)

    2014-07-15

    Purpose: Iterative reconstruction (IR) algorithms have the potential to reduce radiation dose in CT diagnostic imaging. As these algorithms become available on the market, a standardizable method of quantifying the dose reduction that a particular IR method can achieve would be valuable. Such a method would assist manufacturers in making promotional claims about dose reduction, buyers in comparing different devices, physicists in independently validating the claims, and the United States Food and Drug Administration in regulating the labeling of CT devices. However, the nonlinear nature of commercially available IR algorithms poses challenges to objectively assessing image quality, a necessary step in establishing the amount of dose reduction that a given IR algorithm can achieve without compromising that image quality. This review paper seeks to consolidate information relevant to objectively assessing the quality of CT IR images, and thereby measuring the level of dose reduction that a given IR algorithm can achieve. Methods: The authors discuss task-based methods for assessing the quality of CT IR images and evaluating dose reduction. Results: The authors explain and review recent literature on signal detection and localization tasks in CT IR image quality assessment, the design of an appropriate phantom for these tasks, possible choices of observers (including human and model observers), and methods of evaluating observer performance. Conclusions: Standardizing the measurement of dose reduction is a problem of broad interest to the CT community and to public health. A necessary step in the process is the objective assessment of CT image quality, for which various task-based methods may be suitable. This paper attempts to consolidate recent literature that is relevant to the development and implementation of task-based methods for the assessment of CT IR image quality.

  7. Objective assessment of image quality and dose reduction in CT iterative reconstruction

    Purpose: Iterative reconstruction (IR) algorithms have the potential to reduce radiation dose in CT diagnostic imaging. As these algorithms become available on the market, a standardizable method of quantifying the dose reduction that a particular IR method can achieve would be valuable. Such a method would assist manufacturers in making promotional claims about dose reduction, buyers in comparing different devices, physicists in independently validating the claims, and the United States Food and Drug Administration in regulating the labeling of CT devices. However, the nonlinear nature of commercially available IR algorithms poses challenges to objectively assessing image quality, a necessary step in establishing the amount of dose reduction that a given IR algorithm can achieve without compromising that image quality. This review paper seeks to consolidate information relevant to objectively assessing the quality of CT IR images, and thereby measuring the level of dose reduction that a given IR algorithm can achieve. Methods: The authors discuss task-based methods for assessing the quality of CT IR images and evaluating dose reduction. Results: The authors explain and review recent literature on signal detection and localization tasks in CT IR image quality assessment, the design of an appropriate phantom for these tasks, possible choices of observers (including human and model observers), and methods of evaluating observer performance. Conclusions: Standardizing the measurement of dose reduction is a problem of broad interest to the CT community and to public health. A necessary step in the process is the objective assessment of CT image quality, for which various task-based methods may be suitable. This paper attempts to consolidate recent literature that is relevant to the development and implementation of task-based methods for the assessment of CT IR image quality

  8. Radiological dose assessment related to management of naturally occurring radioactive materials generated by the petroleum industry

    A preliminary radiological dose assessment of equipment decontamination, subsurface disposal, landspreading, equipment smelting, and equipment burial was conducted to address concerns regarding the presence of naturally occurring radioactive materials (NORM) in production waste streams. The assessment estimated maximum individual dose equivalents for workers and the general public. Sensitivity analyses of certain input parameters also were conducted. On the basis of this assessment, it is concluded that (1) regulations requiring workers to wear respiratory protection during equipment cleaning operations are likely to result in lower worker doses, (2) underground injection and downhole encapsulation of NORM wastes present a negligible risk to the general public, and (3) potential doses to workers and the general public related to smelting NORM-contaminated equipment can be controlled by limiting the contamination level of the initial feed. It is recommended that (1) NORM wastes be further characterized to improve studies of potential radiological doses; (2) states be encouraged to permit subsurface disposal of NORM more readily, provided further assessments support this study; results; (3) further assessment of landspreading NORM wastes be conducted; and (4) the political, economic, sociological, and nonradiological issues related to smelting NORM-contaminated equipment be studied to fully examine the feasibility of this disposal option

  9. ARN Training Course on Advance Methods for Internal Dose Assessment: Application of Ideas Guidelines

    Dose assessment in case of internal exposure involves the estimation of committed effective dose based on the interpretation of bioassay measurement, and the assumptions of hypotheses on the characteristics of the radioactive material and the time pattern and the pathway of intake. The IDEAS Guidelines provide a method to harmonize dose evaluations using criteria and flow chart procedures to be followed step by step. The EURADOS Working Group 7 'Internal Dosimetry', in collaboration with IAEA and Czech Technical University (CTU) in Prague, promoted the 'EURADOS/IAEA Regional Training Course on Advanced Methods for Internal Dose Assessment: Application of IDEAS Guidelines' to broaden and encourage the use of IDEAS Guidelines, which took place in Prague (Czech Republic) from 2-6 February 2009. The ARN identified the relevance of this training and asked for a place for participating on this activity. After that, the first training course in Argentina took place from 24-28 August for training local internal dosimetry experts. (authors)

  10. Dose assessment, radioecology and community interaction at former nuclear test sites

    The United States of America conducted a nuclear testing programme at Bikini and Enewetak atolls in the Marshall Islands from 1946 through 1958. We have conducted an experimental, monitoring, and dose assessment programme at atolls in the northern Marshall Islands for the past 20 years. The goals have been to: determine the radiological conditions at the atolls; provide dose assessments for resettlement options and alternative living patterns; develop and evaluate remedial measures to reduce the dose to people re-inhabiting the atolls; discuss our results with each of the communities and Government officials of the Marshall Islands to help them understand the data as a basis for resettlement decisions. The remaining radionuclides at the atolls that contribute any significant dose are 137Cs, 90Sr, 239+240Pu and 241Am. 4 refs, 1 fig., 2 tabs

  11. Assessment of effective dose in X ray imaging in view of the proposed ICRP risk factors

    The uncertainty related to the remaining organs in assessing effective dose equivalent (HE) according to ICRP 26 has been overcome when ICRP specified the new concept of the effective dose (E). The calculation method and phantom model for assessing HE and E in X ray examinations are presented. The phantom model is based on the Alderson Rando phantom, ICRP Reference Man and a topographic atlas. It includes 23 organs, amongst them the organs included in the new ICRP 60 report. The calculation method, based on semi-empirical depth dose data, allows free selection of exposure parameters, examination geometry, examination type and projections. Effective dose E calculated according to ICRP 60 is about 30-40% higher than HE in AP projections, but about 5-20% lower in lateral projections

  12. Assessment of effective dose in X ray imaging in view of the proposed ICRP risk factors

    The uncertainty related to the remaining organs in assessing effective dose equivalent (HE) according to ICRP 26 has been overcome when ICRP specified the new concept of the effective dose (E). The calculation method and phantom model for assessing HE and E in X ray examinations are presented. The phantom model is based on the Alderson Rando phantom, ICRP Reference Man and a topographic atlas. It includes 23 organs, amongst them the organs included in the new ICRP 60 report. The calculation method, based on semi-empirical depth dose data, allows free selection of exposure parameters, examination geometry, examination type and projections. Effective dose E calculated according to ICRP 60 is about 30-40% higher than HE in AP projections, but about 5-20% lower in lateral projections. (author)

  13. General guidelines for the harmonisation of internal dose assessment: the Ideas Project

    The determination of internal doses is an essential component of individual monitoring programmes for workers. Assessment of internal doses can be divided into two phases: 1. determination of the amount of radioactive material in the human body by direct measurements and/or by indirect methods and 2. the interpretation of monitoring data in terms of intake and/or internal dose taking into account many influencing factors and assumptions, such as the physical and chemical characteristics of the radioactive substances, the mode of intake, the biokinetic and energy absorption processes, the individual parameters, etc. This second phase is particularly important because of the number of variables and uncertainties involved. Although the International Commission on Radiological Protection (ICRP) and International Atomic Energy Agency (IAEA) have published extensive tables of dose per unit intake (dose coefficients), these are default values based on assumptions about the intake parameters that may not be valid in specific situations

  14. Assessment of the dose from radon and its decay products in the Bozkov dolomite cave

    The dose from radon and its progeny remains a frequently discussed problem. ICRP 65 provides a commonly used methodology to calculate the dose from radon. Our work focuses on a cave environment and on assessing the doses in public open caves. The differences in conditions (aerosol size distribution, humidity, radon and its progeny ratio, etc.) are described by the so-called cave factor j. The cave factor is used to correct the dose for workers which is calculated using the ICRP 65 recommendation. In this work, the authors have brought together measured data of aerosol size distribution, unattached and attached fraction activity, and have calculated the so-called cave factor for the Bozkov dolomite cave environment. The dose conversion factors based on measured data and used for evaluating the cave factor were calculated by LUDEP software, which implements HRTM ICRP66. (authors)

  15. Assessment of potential doses at the Maralinga and Emu test sites

    An assessment has been undertaken of potential doses to future aboriginal inhabitants of the Maralinga and Emu areas of South Australia, where nuclear weapons tests in the 1950s and 1960s have resulted in residual radioactive contamination. Radioactive material due to this programme of tests and other experiments is still detectable several tens of kilometres from some of the test sites, and continued occupancy by individuals following and Aboriginal lifestyle could give rise to annual effective dose equivalents of several millisieverts within contours enclosing areas of several hundred square kilometres. The most significant dose pathways are calculated to be the inhalation of resuspended activity and ingestion of soil by infants. An analysis of the effects of uncertainties in the dose calculation has indicated the uncertainty distribution on predicted doses from the inhalation pathway. (author). 15 refs, 3 figs, 5 tabs

  16. Development of a extremity thermoluminescence dosemeter for photon dose equivalent assessment

    An extremely thermoluminescence dosimeter, to be used when the extremity may become the limiting organ, based on CaSO4:Dy pellet was developed to be worn as wristlet by technicians who work with unsealed sources or handle radioactive materials. This system permits photon dose equivalent assessment as well as the effective energy determination. Such dosemeter has to be worn in addition to a whole-body dosemeter. The system consists of two pieces of polyethylene with dimensions of 40 mm x 20 mm x 10 mm that can be superimposed and three discs of CaSO4:Dy plus Teflon (PTFE), as sensitive material, between different filters. The detectors are produced by the Dosimetric Materials Laboratory of IPEN and have diameter of 6.0 mm and a thickness of 0.8 mm. One detector is placed between plastic filters of 3.0 mm thickness that guarantees electronic equilibrium for 60Co gamma rays. Another detector is located between 1.0 mm thick lead filters plus 3.0 mm plastic filters. A third detector is sandwiched between filters of lead 0.8 mm thick with a central hole of 2.0 mm diameter and plastic filters of 3.0 mm thickness. The detectors are sealed in a plastic film 20 mg.cm-2 thick. All TL detectors are in contact with filters. The filter area is a little larger than the TL detector. The validation of the proposed dosimetric system was performed for 60Co gamma doses between 0.1 and 200 mGy. In this range the relationship dose-response is linear. The energy response of the dosimetric system was evaluated for an energy range between 30 and 662 keV. The maximum, relative to 60Co, energy dependence TL response is observed at 31.2 keV (factor 10.2). To obtain the dose equivalent and the effective energy from the correlation between the three TL readings was developed an algorithm. Taking into account the results obtained in simulated laboratory comparisons, better than ±5%, we conclude that the proposed dosimetric system agrees with the requirements for its application as extremity

  17. Realistic retrospective dose assessments to members of the public around Spanish nuclear facilities

    Jimenez, M.A., E-mail: majg@csn.es [Consejo de Seguridad Nuclear (CSN), Pedro Justo Dorado Dellmans 11, E-28040 Madrid (Spain); Martin-Valdepenas, J.M.; Garcia-Talavera, M.; Martin-Matarranz, J.L.; Salas, M.R.; Serrano, J.I.; Ramos, L.M. [Consejo de Seguridad Nuclear (CSN), Pedro Justo Dorado Dellmans 11, E-28040 Madrid (Spain)

    2011-11-15

    In the frame of an epidemiological study carried out in the influence areas around the Spanish nuclear facilities (ISCIII-CSN, 2009. Epidemiological Study of The Possible Effect of Ionizing Radiations Deriving from The Operation of Spanish Nuclear Fuel Cycle Facilities on The Health of The Population Living in Their Vicinity. Final report December 2009. Ministerio de Ciencia e Innovacion, Instituto de Salud Carlos III, Consejo de Seguridad Nuclear. Madrid. Available from: (http://www.csn.es/images/stories/actualidad{sub d}atos/especiales/epidemiologico/epidemiological{sub s}tudy.pdf)), annual effective doses to public have been assessed by the Spanish Nuclear Safety Council (CSN) for over 45 years using a retrospective realistic-dose methodology. These values are compared with data from natural radiation exposure. For the affected population, natural radiation effective doses are in average 2300 times higher than effective doses due to the operation of nuclear installations (nuclear power stations and fuel cycle facilities). When considering the impact on the whole Spanish population, effective doses attributable to nuclear facilities represent in average 3.5 x 10{sup -5} mSv/y, in contrast to 1.6 mSv/y from natural radiation or 1.3 mSv/y from medical exposures. - Highlights: > Most comprehensive dose assessment to public by nuclear facilities ever done in Spain. > Dose to public is dominated by liquid effluent pathways for the power stations. > Dose to public is dominated by Rn inhalation for milling and mining facilities. > Average annual doses to public in influence areas are negligible (10 {mu}Sv/y or less). > Doses from facilities average 3.5 x 10{sup -2} {mu}Sv/y per person onto whole Spanish population.

  18. Development of dose assessment code for release of tritium during normal operation of nuclear power plants

    A computer code PTMHTO has been developed to assess tritium doses to the general public. The code enables to simulate the behavior of tritium in the environment released into the atmosphere under normal operation of nuclear power plants. Code can calculate the doses for the three chemical and physical forms: tritium gas (HT), tritiated water vapor and water drops (HTO). The models in this code consist of the tritium transfer model including oxidation of HT to HTO and reemission of HTO from soil to the atmosphere, and the dose calculation model

  19. Dose assessment and radioprotective medical evaluation of prenatal radiation exposures to diagnostic X-rays

    The 2nd to 15th weeks after conception are assessed to be the critical time period for the induction of teratogenic radiation damage. In the GDR, women having incurred fetal doses in excess of 100 mGy are recommended to interrupt pregnancy. Of 275 patients advised in the National Board for Atomic Safety and Radiation Protection between 1978 and 1988, approximately 90% were found to have received fetal doses below 20 mGy. Only 4 women had been exposed to doses above 100 mGy. Exposure data were given in the form of tables, and discussed. (author)

  20. Revised series of stylized anthropometric phantoms for internal and external radiation dose assessment

    Han, Eunyoung

    At present, the dosimetry systems of both the International Commission on Radiological Protection, and the Society of Nuclear Medicine's Medical Internal Radiation Dose Committee utilize a series of stylized or mathematical anthropometric models of patient anatomy developed in 1987 at the Oak Ridge National Laboratory (ORNL). In this study, substantial revisions to the ORNL phantom series are reported with tissue compositions, tissue densities, and organ masses adjusted to match their most recent values in the literature. In addition, both the ICRP and MIRD systems of internal dosimetry implicitly consider that electron and beta-particle energy emitted within the source organs of the patient are fully deposited within these organs. With the development of the revised ORNL phantom series, three additional applications were explored as part of this dissertation research. First, the phantoms were used in combination to assess external radiation exposures to family members caring or interacting with patients released from the hospital following radionuclide therapy with I-131. Values of family member effective dose are then compared to values obtained using NRC guidance and based on a simple point-source methodology which ignores the effects of photon attenuation and scatter within both the source individual (patient) and the target individual (family member). Second, the anatomical structures of the extrathoracic airways and thoracic airways (exclusive of the lungs themselves) have been included in the entire revised ORNL phantom series of pediatric individuals. Values of cross-region photon dose are explored for use in radioactive aerosol inhalation exposures to members of the general public, and comparisons are made to values given by the ICRP in which surrogate organ assignments were made in the absence of explicit models of these airways. Finally, the revised ORNL phantoms of the adult male and adult female are used to determine internal photon exposures to

  1. Radiological assessment of worker doses during sludge mobilization and removal at the Melton Valley storage tanks

    This report presents an assessment of potential radiation doses to workers during mobilization and removal of contaminated sludges from the Melton Valley Storage Tanks at Oak Ridge National Laboratory. The assessment is based on (1) measurements of radionuclide concentrations in sludge and supernatant liquid samples from the waste storage tanks, (2) measurements of gamma radiation levels in various areas that will be accessed by workers during normal activities, (3) calculations of gamma radiation levels for particular exposure situations, especially when the available measurements are not applicable, and (4) assumed scenarios for worker activities in radiation areas. Only doses from external exposure are estimated in this assessment. Doses from internal exposure are assumed to be controlled by containment of radioactive materials or respiratory protection of workers and are not estimated

  2. An Analysis Of Tensile Test Results to Assess the Innovation Risk for an Additive Manufacturing Technology

    Adamczak Stanisław; Bochnia Jerzy; Kaczmarska Bożena

    2015-01-01

    The aim of this study was to assess the innovation risk for an additive manufacturing process. The analysis was based on the results of static tensile tests obtained for specimens made of photocured resin. The assessment involved analyzing the measurement uncertainty by applying the FMEA method. The structure of the causes and effects of the discrepancies was illustrated using the Ishikawa diagram. The risk priority numbers were calculated. The uncertainty of the tensile test measurement was ...

  3. Assessing the Clinical Impact of Approximations in Analytical Dose Calculations for Proton Therapy

    Schuemann, Jan, E-mail: jschuemann@mgh.harvard.edu; Giantsoudi, Drosoula; Grassberger, Clemens; Moteabbed, Maryam; Min, Chul Hee; Paganetti, Harald

    2015-08-01

    Purpose: To assess the impact of approximations in current analytical dose calculation methods (ADCs) on tumor control probability (TCP) in proton therapy. Methods: Dose distributions planned with ADC were compared with delivered dose distributions as determined by Monte Carlo simulations. A total of 50 patients were investigated in this analysis with 10 patients per site for 5 treatment sites (head and neck, lung, breast, prostate, liver). Differences were evaluated using dosimetric indices based on a dose-volume histogram analysis, a γ-index analysis, and estimations of TCP. Results: We found that ADC overestimated the target doses on average by 1% to 2% for all patients considered. The mean dose, D95, D50, and D02 (the dose value covering 95%, 50% and 2% of the target volume, respectively) were predicted within 5% of the delivered dose. The γ-index passing rate for target volumes was above 96% for a 3%/3 mm criterion. Differences in TCP were up to 2%, 2.5%, 6%, 6.5%, and 11% for liver and breast, prostate, head and neck, and lung patients, respectively. Differences in normal tissue complication probabilities for bladder and anterior rectum of prostate patients were less than 3%. Conclusion: Our results indicate that current dose calculation algorithms lead to underdosage of the target by as much as 5%, resulting in differences in TCP of up to 11%. To ensure full target coverage, advanced dose calculation methods like Monte Carlo simulations may be necessary in proton therapy. Monte Carlo simulations may also be required to avoid biases resulting from systematic discrepancies in calculated dose distributions for clinical trials comparing proton therapy with conventional radiation therapy.

  4. Dose assessment for medical exposure from diagnostic X-rays using a human voxel model

    Korean voxel model, KORMAN, segmented from whole-body MR data of an adult male, was used to calculate organ equivalent doses and effective doses due to diagnostic X-ray examinations. Calculated doses were normalized to entrance air kerma and compared with those derived using a stylized mathematical model, MIRD5. General purposed Monte Carlo code, MCNPX 2.3 was used for simulation of X-ray procedure. Korean voxel model picked up 0.048 Sv/Gy of effective dose per unit air kerma from a single chest PA examination, and 0.277 Sv/Gy from abdomen AP examination. These calculated results are higher than those MIRD5. The difference of effective doses between Korean voxel model and MIRD5 was within 32%, which were caused by significant discrepancies of organ equivalent doses between the two models. As MIRD5 is representing reference man, whereas KORMAN is segmented from specific individual MR data, it is recognized that variation among individuals could be significant for dose assessment in X-ray examination. Substantial differences in calculated doses between voxel and mathematical models suggested that existing mathematical models should be revised. (author)

  5. The role of uncertainty analysis in dose reconstruction and risk assessment

    Dose reconstruction and risk assessment rely heavily on the use of mathematical models to extrapolate information beyond the realm of direct observation. Because models are merely approximations of real systems, their predictions are inherently uncertain. As a result, full disclosure of uncertainty in dose and risk estimates is essential to achieve scientific credibility and to build public trust. The need for formal analysis of uncertainty in model predictions was presented during the nineteenth annual meeting of the NCRP. At that time, quantitative uncertainty analysis was considered a relatively new and difficult subject practiced by only a few investigators. Today, uncertainty analysis has become synonymous with the assessment process itself. When an uncertainty analysis is used iteratively within the assessment process, it can guide experimental research to refine dose and risk estimates, deferring potentially high cost or high consequence decisions until uncertainty is either acceptable or irreducible. Uncertainty analysis is now mandated for all ongoing dose reconstruction projects within the United States, a fact that distinguishes dose reconstruction from other types of exposure and risk assessments. 64 refs., 6 figs., 1 tab

  6. Assessment of Organ Doses for a Glovebox Worker Using Realistic Postures with PIMAL and VOXMAT

    In an earlier effort, the Oak Ridge National Laboratory (ORNL) mathematical phantom has been revised to enable assessment of radiation dose for different postures in occupational exposures by enabling freely positioning arms and legs. The revised phantom is called PIMAL: Phantom wIth Moving Arms and Legs. Further, to assist the analyst with input preparation and output manipulation for different postures, a graphical user interface has been developed. Also, at ORNL a hybrid computational phantom, which uses a combination of voxelized and stylized geometry, for radiation dose assessment was recently developed. This phantom is based on the International Commission on Radiological Protection's (ICRP's) male phantom model and is called VOXMAT. For VOXMAT, the head and torso, which contain significant anatomical details, were described using voxel geometry. The arms and legs, which contain less-detailed anatomical structures, were modeled using the mathematical equations (stylized approach). With this approach the number of voxels was reduced from 7 million to 2.3 million, which translated into a proportional reduction in computational time and memory requirements. More importantly, VOXMAT allows easy the movement of arms and legs for radiation dose assessment for realistic postures. To determine/demonstrate the importance of the realistic posture for a case study, PIMAL and VOXMAT are applied to assess the dose to a glovebox worker. In this paper, the comparative computational results for the estimated dose are presented.

  7. An updated dose assessment for a U.S. Nuclear Test Site - Bikini Atoll

    On March 1, 1954, a nuclear weapon test, code-named BRAVO, conducted at Bikini Atoll in the northern Marshall Islands contaminated the major residence island. There has been a continuing effort since 1977 to refine dose assessments for resettlement options at Bikini Atoll. Here we provide a radiological dose assessment for the main residence island, Bikini, using extensive radionuclide concentration data derived from analysis of food crops, ground water, cistern water, fish and other marine species, animals, air, and soil collected at Bikini Island as part of our continuing research and monitoring program that began in 1975. The unique composition of coral soil greatly alters the relative contribution of cesium-137 (137Cs) and strontium-90 (90Sr) to the total estimated dose relative to expectations based on North American and European soils. Without counter measures, cesium-137 produces 96% of the estimated dose for returning residents, mostly through uptake from the soil to terrestrial food crops but also from external gamma exposure. The doses are calculated assuming a resettlement date of 1999. The estimated maximum annual effective dose for current island conditions is 4.0 mSv when imported foods, which are now an established part of the diet, are available. The corresponding 30-, 50-, and 70-y integral effective doses are 9.1 cSv, 13 cSv, and 15 cSv, respectively. A corresponding uncertainty analysis showed that after about 5 y of residence, the 95% confidence limits on population-average dose would be ±35% of its expected value. We have evaluated various countermeasures to reduce 137Cs in food crops. Treatment with potassium reduces the uptake of 137Cs into food crops, and therefore the ingestion dose, to about 5% of pretreatment levels and has essentially no negative environmental consequences

  8. Environmental dose rate assessment of ITER using the Monte Carlo method

    Karimian Alireza

    2014-01-01

    Full Text Available Exposure to radiation is one of the main sources of risk to staff employed in reactor facilities. The staff of a tokamak is exposed to a wide range of neutrons and photons around the tokamak hall. The International Thermonuclear Experimental Reactor (ITER is a nuclear fusion engineering project and the most advanced experimental tokamak in the world. From the radiobiological point of view, ITER dose rates assessment is particularly important. The aim of this study is the assessment of the amount of radiation in ITER during its normal operation in a radial direction from the plasma chamber to the tokamak hall. To achieve this goal, the ITER system and its components were simulated by the Monte Carlo method using the MCNPX 2.6.0 code. Furthermore, the equivalent dose rates of some radiosensitive organs of the human body were calculated by using the medical internal radiation dose phantom. Our study is based on the deuterium-tritium plasma burning by 14.1 MeV neutron production and also photon radiation due to neutron activation. As our results show, the total equivalent dose rate on the outside of the bioshield wall of the tokamak hall is about 1 mSv per year, which is less than the annual occupational dose rate limit during the normal operation of ITER. Also, equivalent dose rates of radiosensitive organs have shown that the maximum dose rate belongs to the kidney. The data may help calculate how long the staff can stay in such an environment, before the equivalent dose rates reach the whole-body dose limits.

  9. An updated dose assessment for a U.S. Nuclear Test Site - Bikini Atoll

    Robison, W.L.; Bogen, K.T.; Conrado, C.L.

    1995-10-01

    On March 1, 1954, a nuclear weapon test, code-named BRAVO, conducted at Bikini Atoll in the northern Marshall Islands contaminated the major residence island. There has been a continuing effort since 1977 to refine dose assessments for resettlement options at Bikini Atoll. Here we provide a radiological dose assessment for the main residence island, Bikini, using extensive radionuclide concentration data derived from analysis of food crops, ground water, cistern water, fish and other marine species, animals, air, and soil collected at Bikini Island as part of our continuing research and monitoring program that began in 1975. The unique composition of coral soil greatly alters the relative contribution of cesium-137 ({sup 137}Cs) and strontium-90 ({sup 90}Sr) to the total estimated dose relative to expectations based on North American and European soils. Without counter measures, cesium-137 produces 96% of the estimated dose for returning residents, mostly through uptake from the soil to terrestrial food crops but also from external gamma exposure. The doses are calculated assuming a resettlement date of 1999. The estimated maximum annual effective dose for current island conditions is 4.0 mSv when imported foods, which are now an established part of the diet, are available. The corresponding 30-, 50-, and 70-y integral effective doses are 9.1 cSv, 13 cSv, and 15 cSv, respectively. A corresponding uncertainty analysis showed that after about 5 y of residence, the 95% confidence limits on population-average dose would be {plus_minus}35% of its expected value. We have evaluated various countermeasures to reduce {sup 137}Cs in food crops. Treatment with potassium reduces the uptake of {sup 137}Cs into food crops, and therefore the ingestion dose, to about 5% of pretreatment levels and has essentially no negative environmental consequences.

  10. Computed tomography dose assessment for a 160 mm wide, 320 detector row, cone beam CT scanner

    Computed tomography (CT) dosimetry should be adapted to the rapid developments in CT technology. Recently a 160 mm wide, 320 detector row, cone beam CT scanner that challenges the existing Computed Tomography Dose Index (CTDI) dosimetry paradigm was introduced. The purpose of this study was to assess dosimetric characteristics of this cone beam scanner, to study the appropriateness of existing CT dose metrics and to suggest a pragmatic approach for CT dosimetry for cone beam scanners. Dose measurements with a small Farmer-type ionization chamber and with 100 mm and 300 mm long pencil ionization chambers were performed free in air to characterize the cone beam. According to the most common dose metric in CT, namely CTDI, measurements were also performed in 150 mm and 350 mm long CT head and CT body dose phantoms with 100 mm and 300 mm long pencil ionization chambers, respectively. To explore effects that cannot be measured with ionization chambers, Monte Carlo (MC) simulations of the dose distribution in 150 mm, 350 mm and 700 mm long CT head and CT body phantoms were performed. To overcome inconsistencies in the definition of CTDI100 for the 160 mm wide cone beam CT scanner, doses were also expressed as the average absorbed dose within the pencil chamber (D-bar100). Measurements free in air revealed excellent correspondence between CTDI300air and D-bar100air, while CTDI100air substantially underestimates CTDI300air. Results of measurements in CT dose phantoms and corresponding MC simulations at centre and peripheral positions were weighted and revealed good agreement between CTDI300w, D-bar100w and CTDI600w, while CTDI100w substantially underestimates CTDI300w. D-bar100w provides a pragmatic metric for characterizing the dose of the 160 mm wide cone beam CT scanner. This quantity can be measured with the widely available 100 mm pencil ionization chamber within 150 mm long CT dose phantoms. CTDI300w measured in 350 mm long CT dose phantoms serves as an appropriate

  11. Updated radiological dose assessment of Bikini and Eneu Islands at Bikini Atoll

    This report is part of a continuing effort to refine dose assessments for resettlement options at Bikini Atoll. Radionuclide concentration data developed at Bikini Atoll since 1977 have been used in conjunction with recent dietary information and current dose models to develop the annual dose rate and 30- and 50-y integral doses presented here for Bikini and Eneu Island living patterns. The terrestrial food chain is the most significant exposure pathway--it contributes more than 50% of the total dose--and external gamma exposure is the second most significant pathway. Other pathways evaluated are the marine food chain, drinking water, and inhalation. Cesium-137 produces more than 85% of the predicted dose; 90Sr is the second most significant radionuclide; 60Co contributes to the external gamma exposure in varying degrees, but is a small part of the total predicted dose; the transuranic radionuclides contribute a small portion of the total predicted lung and bone doses but do present a long-term source of exposure. Maximum annual dose rates for Bikini Island are about 1 rem/y for the whole body and bone marrow when imported foods are available and about 1.9 rem/y when imports are unavailable. Maximum annual dose rates for Eneu Island when imports are available are 130 mrem/y for the whole body and 136 mrem/y for bone marrow. Similar doses when imported foods are unavailable are 245 and 263 mrem/y, respectively. The 30-y integral doses for Bikini Island are about 23 rem for whole body and bone marrow when imported foods are available and more than 40 rem when imports are unavailable. The Eneu Island 30-y integral doses for whole body and bone marrow are about 3 rem when imports are available and 5.5 and 6.1 rem, respectively, when imports are unavailable. Doses from living patterns involving some combination of Bikini and Eneu Islands fall between the doses listed above for each island separately

  12. Scoping assessment of groundwater doses to biota at the Sellafield site, UK

    In the current climate of investigating the impact of discharges from the nuclear industry on non-human biota, much attention has been given to biota in marine and terrestrial environments in receipt of authorised discharges of liquid and gaseous effluent. Relatively little attention to date has been given to the exposure of biota to groundwater containing man-made radio-nuclides. This area of interest is growing especially in the field of nuclear waste repositories. A scoping assessment has been performed here to determine the impacts due to radiological contamination on organisms living within or coming into contact with groundwater at the Sellafield site, UK. The following potential exposure routes to biota were identified: 1) Organisms living within groundwater; 2) Groundwater discharges to the surface at beach springs (i.e. emerging above the low water line; 3) Groundwater discharges to nearby surface water bodies (e.g. rivers); 4) Groundwater discharges directly to the Irish Sea.. In order to evaluate impacts on organisms living within, contacting or ingesting groundwater, it was necessary to determine the activity concentration of radio-nuclides in the groundwater. For time periods up to 2120, modeling of contaminant release from in-ground inventories and transport in groundwater was carried out for this scoping study using a relatively simple assessment methodology with the MONDRIAN modeling suite. Screening assessments of radiological impacts upon wildlife have been performed for liquid discharges to groundwater from the Sellafield Ltd reprocessing plant at Sellafield, Cumbria. Impacts have been considered for biota at sites within reach of the groundwater flow network. Most calculated total weighted absorbed doses appear to be of no radiological significance whatsoever in relation to the new Environment Agency freshwater ecosystem trigger level (40 microGy h-1), thereby obviating the need to conduct further investigations. The one exception to this is for

  13. Effect of low-dose CT and iterative reconstruction on trabecular bone microstructure assessment

    Kopp, Felix K.; Baum, Thomas; Nasirudin, Radin A.; Mei, Kai; Garcia, Eduardo G.; Burgkart, Rainer; Rummeny, Ernst J.; Bauer, Jan S.; Noël, Peter B.

    2016-03-01

    The trabecular bone microstructure is an important factor in the development of osteoporosis. It is well known that its deterioration is one effect when osteoporosis occurs. Previous research showed that the analysis of trabecular bone microstructure enables more precise diagnoses of osteoporosis compared to a sole measurement of the mineral density. Microstructure parameters are assessed on volumetric images of the bone acquired either with high-resolution magnetic resonance imaging, high-resolution peripheral quantitative computed tomography or high-resolution computed tomography (CT), with only CT being applicable to the spine, which is one of clinically most relevant fracture sites. However, due to the high radiation exposure for imaging the whole spine these measurements are not applicable in current clinical routine. In this work, twelve vertebrae from three different donors were scanned with standard and low radiation dose. Trabecular bone microstructure parameters were assessed for CT images reconstructed with statistical iterative reconstruction (SIR) and analytical filtered backprojection (FBP). The resulting structure parameters were correlated to the biomechanically determined fracture load of each vertebra. Microstructure parameters assessed for low-dose data reconstructed with SIR significantly correlated with fracture loads as well as parameters assessed for standard-dose data reconstructed with FBP. Ideal results were achieved with low to zero regularization strength yielding microstructure parameters not significantly different from those assessed for standard-dose FPB data. Moreover, in comparison to other approaches, superior noise-resolution trade-offs can be found with the proposed methods.

  14. Only minor additional metabolic health benefits of high as opposed to moderate dose physical exercise in young, moderately overweight men

    Reichkendler, M H; Larsen, Mads Rosenkilde; Auerbach, P L;

    2014-01-01

    living (sedentary control group; n = 18), moderate (moderate dose training group [MOD]: 300 kcal/day, n = 21), or high (high dose training group [HIGH]: 600 kcal/day, n = 22) dose physical exercise for 11 weeks. RESULTS: The return rate for post-intervention testing was 82-94% across groups. Weekly......OBJECTIVE: The dose-response effects of exercise training on insulin sensitivity, metabolic risk, and quality of life were examined. METHODS: Sixty-one healthy, sedentary (VO₂max: 35 ± 5 ml/kg/min), moderately overweight (BMI: 27.9 ± 1.8), young (age: 29 ± 6 years) men were randomized to sedentary...... exercise amounted to 2,004 ± 24 and 3,774 ± 68 kcal, respectively, in MOD and HIGH. Cardiorespiratory fitness increased (P exercise groups (MOD: 32 ± 1 to 29 ± 1%; HIGH: 30 ± 1 to 27 ± 1%). Peripheral...

  15. The Thule accident: Assessment of radiation doses from terrestrial radioactive contamination

    Ulbak, K. (National Institute of Radiation Protection, Herlev (Denmark))

    2011-12-15

    Risoe DTU has carried out research on the terrestrial contamination in the Thule area after the radioactive contents of four nuclear weapons were dispersed following the crash of an American B-52 bomber in 1968. The results of Risoe DTU's studies are described in the report Thule-2007 - Investigation of radioactive pollution on land, which covers all measurements that were carried out on land in Thule in the years 2003, 2006, 2007 and 2008. The present report uses Risoe DTU's report as a basis for assessing radiation doses and consequently the risk for individuals as a result of terrestrial radioactive contamination in the Thule area. The assessment of radiation doses involves a number of conservative assumptions, estimates, and measurements, all of which are subject to considerable uncertainty. In some cases, models have been used based on experiences from other contaminated areas elsewhere in the world, which are subject to climatic and other conditions that diverge from those in the Thule area. The calculated doses are thus associated with considerable uncertainty, which must be taken into account when the results are used for comparison and when the risks of staying in the Thule area are assessed. It has therefore been chosen to provide the assessed radiation doses in the form of indicative orders of magnitude, which are applicable to everyone who might stay in the area, across various age groups. If the estimated doses in this report are combined with the National Institute of Radiation Protection's recommended reference level for contamination as a result of the Thule Accident of 1 mSv/year, the assessed magnitudes of radiation doses for inhalation and ingestion as exposure pathways are many orders of magnitude below the reference level (10,000-10 million times smaller). The wound contamination exposure pathway has a magnitude of radiation dose that is smaller than the reference level by a factor of 10-1000, and it should be recalled that the

  16. RADIATION HYGIENIC MONITORING AND ASSESSMENT OF POPULATION DOSES IN RADIOACTIVELY CONTAMINATED AREAS OF TULA REGION

    T. M. Chichura

    2016-01-01

    Full Text Available The goal. The analyses of radiation hygienic monitoring conducted in Tula region territories affected by the Chernobyl NPP accident regarding cesium-137 and strontium- 90 in the local foodstuffs and the analyses of populational annual effective dose. The materials and methods. The survey was conducted in Tula Region since 1997 to 2015. Over that period, more than fifty thousand samples of the main foodstuffs from the post-Chernobyl contaminated area were analyzed. Simultaneously with that, the external gamma - radiation dose rate was measured in the fixed control points. The dynamics of cesium -137 and strontium-90 content in foodstuffs were assessed along with the maximum values of the mean annual effective doses to the population and the contribution of the collective dose from medical exposures into the structure of the annual effective collective dose to the population. The results. The amount of cesium-137 and strontium -90 in the local foodstuffs was identified. The external gamma- radiation dose rate values were found to be stable and not exceeding the natural fluctuations range typical for the middle latitudes of Russia’s European territory. The maximum mean annual effective dose to the population reflects the stable radiation situation and does not exceed the permissible value of 1 mSv. The contribution of the collective dose from medical exposures of the population has been continuously reducing as well as the average individual dose to the population per one medical treatment under the annual increase of the medical treatments quantities. The conclusion. There is no exceedance of the admissible levels of cesium-137 and strontium- 90 content in the local foodstuffs. The mean annual effective dose to the population has decreased which makes it possible to transfer the settlements affected by the Chernobyl NPP accident to normal life style. This is covered by the draft concept of the settlements’ transfer to normal life style.

  17. Quantifying remarks to the question of uncertainties of the 'general dose assessment fundamentals'

    Dose prediction models are always subject to uncertainties due to a number of factors including deficiencies in the model structure and uncertainties of the model input parameter values. In lieu of validation experiments the evaluation of these uncertainties is restricted to scientific judgement. Several attempts have been made in the literature to evaluate the uncertainties of the current dose assessment models resulting from uncertainties of the model input parameter values using stochastic approaches. Less attention, however, has been paid to potential sources of systematic over- and underestimations of the predicted doses due to deficiencies in the model structure. The present study addresses this aspect with regard to dose assessment models currently used for regulatory purposes. The influence of a number of basic simplifications and conservative assumptions has been investigated. Our systematic approach is exemplified by a comparison of doses evaluated on the basis of the regulatory guide model and a more realistic model respectively. This is done for 3 critical exposure pathways. As a result of this comparison it can be concluded that the currently used regularoty-type models include significant safety factors resulting in a systematic overprediction of dose to man up to two orders of magnitude. For this reason there are some indications that these models usually more than compensate the bulk of the stochastic uncertainties caused by the variability of the input parameter values. (orig.)

  18. Assessment of patient doses and image quality in X-ray diagnostics in Norway

    Results from other industrialized countries indicate that the annual number of diagnostic procedures approaches one for every member of the population, and in many cases the individual radiation doses are higher than from any other human activity. Furthermore, the doses to patients for the same type of examination differ widely from place to place, suggesting that there is a considerable potential for dose reduction. This motivated an investigation of the diagnostic use of X-rays in Norway. The trends in the number of X-ray examinations performed annually have been studied. The patient doses (all diagnostics) and image quality (mammography and computed tomography) have been assessed for various radiological procedures. This form the basis for the assessment of total collective effective dose (CED) from X-rays in Norway, and further risk estimates. The radiological practice has then been evaluated according to the radiation protection principles of justification and optimisation. Based on the 1993 examination frequency, the total CED was assessed to 3400 manSv (0.78 mSv/inhabitant). It is estimated that this radiation burden may cause about 100 excess cancer deaths annually. The frequency of CT examination has doubled every fifth year, and did in 1993 represent 7% of the total number of examinations and 30% of the total CED. 129 refs

  19. Assessment of patient doses and image quality in X-ray diagnostics in Norway

    Olerud, H.M.

    1998-06-01

    Results from other industrialized countries indicate that the annual number of diagnostic procedures approaches one for every member of the population, and in many cases the individual radiation doses are higher than from any other human activity. Furthermore, the doses to patients for the same type of examination differ widely from place to place, suggesting that there is a considerable potential for dose reduction. This motivated an investigation of the diagnostic use of X-rays in Norway. The trends in the number of X-ray examinations performed annually have been studied. The patient doses (all diagnostics) and image quality (mammography and computed tomography) have been assessed for various radiological procedures. This form the basis for the assessment of total collective effective dose (CED) from X-rays in Norway, and further risk estimates. The radiological practice has then been evaluated according to the radiation protection principles of justification and optimisation. Based on the 1993 examination frequency, the total CED was assessed to 3400 manSv (0.78 mSv/inhabitant). It is estimated that this radiation burden may cause about 100 excess cancer deaths annually. The frequency of CT examination has doubled every fifth year, and did in 1993 represent 7% of the total number of examinations and 30% of the total CED. 129 refs.

  20. MOSFET assessment of radiation dose delivered to mice using the Small Animal Radiation Research Platform (SARRP).

    Ngwa, Wilfred; Korideck, Houari; Chin, Lee M; Makrigiorgos, G Mike; Berbeco, Ross I

    2011-12-01

    The Small Animal Radiation Research Platform (SARRP) is a novel isocentric irradiation system that enables state-of-the-art image-guided radiotherapy research to be performed with animal models. This paper reports the results obtained from investigations assessing the radiation dose delivered by the SARRP to different anatomical target volumes in mice. Surgically implanted metal oxide semiconductor field effect transistors (MOSFET) dosimeters were employed for the dose assessment. The results reveal differences between the calculated and measured dose of -3.5 to 0.5%, -5.2 to -0.7%, -3.9 to 0.5%, -5.9 to 2.5%, -5.5 to 0.5%, and -4.3 to 0% for the left kidney, liver, pancreas, prostate, left lung, and brain, respectively. Overall, the findings show less than 6% difference between the delivered and calculated dose, without tissue heterogeneity corrections. These results provide a useful assessment of the need for tissue heterogeneity corrections in SARRP dose calculations for clinically relevant tumor model sites. PMID:21962005

  1. Revisions to US EPA Superfund Risk and Dose Assessment Models and Guidance - 13403

    The U.S. Environmental Protection Agency (EPA) Superfund program's six Preliminary Remediation Goal (PRG) and Dose Compliance Concentration (DCC) internet based calculators for risk and dose assessment at Superfund sites are being revised to reflect better science, revisions to existing exposure scenarios and new scenarios, and changes to match up more closely with the EPA chemical regional screening level calculator. A revised version of the 1999 guidance document that provides an overview for the Superfund risk assessment process at radioactively contaminated sites, 'Radiation Risk Assessment At CERCLA Sites: Q and A', is being completed that will reflect Superfund recommended guidance and other technical documents issued over the past 13 years. EPA is also issuing a series of fact sheets in the document 'Superfund Radiation Risk Assessment: A Community Tool-kit'. This presentation would go over those changes that are expected to be finished by this spring. (authors)

  2. Intake estimation and dose assessment of 90Sr, 137Cs around QNPP base

    90Sr and 137Cs are important radionuclides in environmental investigation related to nuclear power stations. A mode of intake estimation and dose assessment via various food chains is made in this paper. Based on daily food consumption and dietary composition for Chinese reference man and for man of Zhejiang province and the concentration of 137Cs and 90Sr around QNPP Base, the intake estimation and dose of 90Sr and 137Cs around QNPP Base are calculated. It shows that the main food sources of intake of 90Sr and 137Cs are rice,vegetable and aquatic product. Also the public average annual committed effective dose of 90Sr(2.5 μSv)is obviously higher than the contribution of dose of the 137Cs(0.36 μSv). A practical estimation method was made by taking QNPP Base as an example in this paper, while no background change occurs after its commercial operation. (authors)

  3. Dental radiography: tooth enamel EPR dose assessment from Rando phantom measurements

    Electron paramagnetic resonance dosimetry of tooth enamel is now established as a suitable method for individual dose reconstruction following radiation accidents. The accuracy of the method is limited by some confounding factors, among which is the dose received due to medical x-ray irradiation. In the present paper the EPR response of tooth enamel to endoral examination was experimentally evaluated using an anthropomorphic phantom. The dose to enamel for a single exposure of a typical dental examination performed with a new x-ray generation unit working at 65 kVp gave rise to a CO2-signal of intensity similar to that induced by a dose of about 2 mGy of 60Co. EPR measurements were performed on the entire tooth with no attempt to separate buccal and lingual components. Also the dose to enamel for an orthopantomography exam was estimated. It was derived from TLD measurements as equivalent to 0.2 mGy of 60Co. In view of application to risk assessment analysis, in the present work the value for the ratio of the reference dose at the phantom surface measured with TLD to the dose at the tooth measured with EPR was determined. (author)

  4. Eye lens radiation exposure to interventional cardiologists: A retrospective assessment of cumulative doses

    Radiation dose to the eye lens is a crucial issue for interventional cardiologists (ICs) who are exposed during the procedures they perform. This paper presents a retrospective assessment of the cumulative eye lens doses of ICs enrolled in the O'CLOC study for Occupational Cataracts and Lens Opacities in interventional Cardiology. Information on the workload in the catheterisation laboratory, radiation protection equipment, eye lens dose per procedure and dose reduction factors associated with eye-protective equipment were considered. For the 129 ICs at an average age of 51 who had worked for an average period of 22 years, the estimated cumulative eye lens dose ranged from 25 mSv to more than 1600 mSv; the mean + SD was 423+359 mSv. After several years of practice, without eye protection, ICs may exceed the new ICRP lifetime eye dose threshold of 500 mSv and be at high risk of developing early radiation-induced cataracts. Radiation protection equipment can reduce these doses and should be used routinely. (authors)

  5. Assessment of doses and risks posed to the Bailiwick of Guernsey by the nuclear industry

    A study has been undertaken at NRPB on behalf of the States of Guernsey Civil Defence Committee to assess effective doses and risks to the Bailiwick of Guernsey arising from the nuclear facilities on the Cotentin peninsular in France. The French nuclear facilities considered were the nuclear waste reprocessing plant at Cap de la Hague and the pressurised water reactors at Flamanville. The doses arising from the marine transport of nuclear waste were also considered, as were those arising from the dumping of waste in the sea to the northwest of Guernsey (the Hurd Deep site). Also presented in the report at the request of the States Civil Defence Committee is a review of international insurance arrangements in the event of a nuclear emergency. It is concluded that the estimated effective doses arising from routine discharges and the waste disposal site at Hurd Deep are very low indeed. Three potential accidental releases were considered in the report, and for these accidents doses in the first year are predicted to be at most a few tens of microsieverts up to a few hundred microsieverts, levels which would not justify consideration of emergency countermeasures. However, these three potential accidents may require the imposition of food restrictions for short periods. Pessimistic calculations of the doses arising from potential accidents occurring during marine transport of waste have been made; for a 1% release, potential maximum doses of around 3 mSv y-1 are indicated, but it is most unlikely that these doses would actually be realised. (author)

  6. Dental radiography: tooth enamel EPR dose assessment from Rando phantom measurements

    Aragno, D.; Fattibene, P.; Onori, S.; Aragno, D.; Fattibene, P.

    2000-09-01

    Electron paramagnetic resonance dosimetry of tooth enamel is now established as a suitable method for individual dose reconstruction following radiation accidents. The accuracy of the method is limited by some confounding factors, among which is the dose received due to medical x-ray irradiation. In the present paper the EPR response of tooth enamel to endoral examination was experimentally evaluated using an anthropomorphic phantom. The dose to enamel for a single exposure of a typical dental examination performed with a new x-ray generation unit working at 65 kVp gave rise to a CO2- signal of intensity similar to that induced by a dose of about 2 mGy of 60Co. EPR measurements were performed on the entire tooth with no attempt to separate buccal and lingual components. Also the dose to enamel for an orthopantomography exam was estimated. It was derived from TLD measurements as equivalent to 0.2 mGy of 60Co. In view of application to risk assessment analysis, in the present work the value for the ratio of the reference dose at the phantom surface measured with TLD to the dose at the tooth measured with EPR was determined.

  7. ACUTRI a computer code for assessing doses to the general public due to acute tritium releases

    Yokoyama, S; Noguchi, H; Ryufuku, S; Sasaki, T

    2002-01-01

    Tritium, which is used as a fuel of a D-T burning fusion reactor, is the most important radionuclide for the safety assessment of a nuclear fusion experimental reactor such as ITER. Thus, a computer code, ACUTRI, which calculates the radiological impact of tritium released accidentally to the atmosphere, has been developed, aiming to be of use in a discussion of licensing of a fusion experimental reactor and an environmental safety evaluation method in Japan. ACUTRI calculates an individual tritium dose based on transfer models specific to tritium in the environment and ICRP dose models. In this calculation it is also possible to analyze statistically on meteorology in the same way as a conventional dose assessment method according to the meteorological guide of the Nuclear Safety Commission of Japan. A Gaussian plume model is used for calculating the atmospheric dispersion of tritium gas (HT) and/or tritiated water (HTO). The environmental pathway model in ACUTRI considers the following internal exposures: i...

  8. Review of Cl-36 behaviour in the biosphere and implications for long-term dose assessment

    Cl-36 is an important contributor to potential radiation doses in the long term, arising from release into the biosphere from radioactive waste disposal facilities. Its special attributes include its long half-life, high mobility in many environmental conditions, and potentially high uptake into plants and hence accumulation in the food-chain. Review has shown very wide ranges of Cl-36 values of parameters commonly employed in models used for long term doses. Accordingly, a workshop was held recently within the aegis of the international collaboration project BIOPROTA, to consider the causes of such variation, and in particular: to provide an open forum for presentation and discussion of environmental processes involved in Cl-36 migration and accumulation, and on how to model them, and to develop recommendations for the direction of continuing research as input to long-term radiological assessment. Participation in the workshop included specialists and contributions from North America, Europe and Japan in environmental behaviour of chlorine, radioecology of Cl-36 and long term dose assessment. This paper will present the output from that workshop in the context of the wider aspects of performance assessment, taking into account information about: waste types for which Cl-36 is a significant component of the total Cl-36 inventory; data requirements for the dose assessment models, notably concerning uptake from soils into food crops which may lead to higher doses than direct consumption of contaminated drinking water; critical data weaknesses which may lead to overly pessimistic dose estimates; time dependent factors within a single growing season which can affect final concentrations in food crops for animals and humans; alternative conceptual models for the behaviour of Cl-36 in the environment, notably models structured as other trace radionuclide dose assessment models as opposed to models which are based specifically on chlorine behaviour which should take

  9. Assessment of radiation dose in nuclear cardiovascular imaging using realistic computational models

    Xie, Tianwu; Lee, Choonsik; Bolch, Wesley E.; Zaidi, Habib

    2015-01-01

    Purpose: Nuclear cardiology plays an important role in clinical assessment and has enormous impact on the management of a variety of cardiovascular diseases. Pediatric patients at different age groups are exposed to a spectrum of radiation dose levels and associated cancer risks different from those

  10. Dose assessment and approach to the safety for the public in the emergency. Proceedings

    This issue is the collection of the papers presented at the 21st NIRS seminar on Dose Assessment and Approach to the Safety for the Public in the Emergency. The 16 of the presented papers are indexed individually. (J.P.N.)

  11. Development of environmental dose assessment system (EDAS) code of PC version

    Taki, Mitsumasa; Kikuchi, Masamitsu; Kobayashi, Hideo; Yamaguchi, Takenori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-05-01

    A computer code (EDAS) was developed to assess the public dose for the safety assessment to get the license of nuclear reactor operation. This code system is used for the safety analysis of public around the nuclear reactor in normal operation and severe accident. This code was revised and composed for personal computer user according to the Nuclear Safety Guidelines reflected the ICRP1990 recommendation. These guidelines are revised by Nuclear Safety Commission on March, 2001, which are 'Weather analysis guideline for the safety assessment of nuclear power reactor', 'Public dose around the facility assessment guideline corresponding to the objective value for nuclear power light water reactor' and 'Public dose assessment guideline for safety review of nuclear power light water reactor'. This code has been already opened for public user by JAERI, and English version code and user manual are also prepared. This English version code is helpful for international cooperation concerning the nuclear safety assessment with JAERI. (author)

  12. Integrity assessment of pipelines - additional remarks; Avaliacao da integridade de dutos - observacoes adicionais

    Alves, Luis F.C. [PETROBRAS S.A., Salvador, BA (Brazil). Unidade de Negocios. Exploracao e Producao

    2005-07-01

    Integrity assessment of pipelines is part of a process that aims to enhance the operating safety of pipelines. During this task, questions related to the interpretation of inspection reports and the way of regarding the impact of several parameters on the pipeline integrity normally come up. In order to satisfactorily answer such questions, the integrity assessment team must be able to suitably approach different subjects such as corrosion control and monitoring, assessment of metal loss and geometric anomalies, and third party activities. This paper presents additional remarks on some of these questions based on the integrity assessment of almost fifty pipelines that has been done at PETROBRAS/E and P Bahia over the past eight years. (author)

  13. Prospective radiological dose assessment. Amersham plc (Amersham site) variation application December 1998

    Amersham plc (previously Nycomed-Amersham plc) submitted an application to the Environment Agency in December 1998 for a variation to their radioactive waste discharge authorisations granted under the Radioactive Substances Act 1993. The application requested a reduction in the discharge limits for certain radionuclides and no change for the remaining radionuclides. Amersham plc undertook a further review of their discharge requirements and submitted a new assessment for revised limits in January 2001. This report provides an assessment of the radiological implications of discharges at these revised limits requested by Amersham plc and the limits proposed by the Agency. It has been prepared by the National Compliance Assessment Service at the request of Thames Region to support their determination of the application. Four candidate critical groups were identified who could be exposed to discharges from the Amersham site: 1) Sewage workers at the Maple Lodge sewage works who might be exposed to external radiation from discharges contained within sewage and inadvertently inhale or ingest sewage. 2) Anglers on the Grand Union Canal who eat a small proportion of their annual catch of freshwater fish, who drink water abstracted solely from the River Colne and eat vegetables irrigated by water from the canal. 3) Persons living closest to site who eat locally produced food. 4) Dog walkers living near to site who eat locally produced food. For continuous discharges at the Agency's proposed annual limits, the highest dose of 160 μSv/y is predicted to be received by infants who live closest to the site and eat locally produced food. Therefore, this has been identified as the critical group. Children and adults living at the same location and eating locally produced food receive doses of 140 μSv/y and 130 μSv/y respectively. The critical group dose is less than the source constraint of 300 μSv/y. The dose is dominated by direct radiation from the site (110 μSv/y) and the

  14. Radioiodine (I-131) treatment for uncomplicated hyperthyroidism: An assessment of optimal dose and cost-effectiveness

    Aim: Radioiodine (I-131) is increasingly being considered for the treatment of hyperthyroidism but there is no general agreement for the initial dose. To determine the cost-effectiveness and optimal dose of I-131 to cure disease, we prospectively studied the outcome of radioiodine therapy of 423 patients. Material and Methods: Any of the fixed doses of 6, 8, 10, 12 or 15 mCi of I-131 was administered to the patients relating to thyroid gland size. The individual was excluded from this study who had multinodular goitre and autonomous toxic nodule. Patients were classified as cured if the clinical and biochemical status was either euthyroid or hypothyroid at one year without further treatment by antithyroid drugs or radioiodine. The costs were assessed by analyzing the total cost of care including office visit, laboratory testing, radioiodine treatment, average conveyance and income loss of patient and attendant and thyroxine replacement for a period of 2 years from the day of I-131 administration. Results: The results showed a progressive increase of cure rate from the doses of 6, 8 and 10 mCi by 67%, 76.5% and 85.7% respectively but the cure rate for the doses of 12 and 15 mCi was 87.9% and 88.8% respectively. Cure was directly related to the dose between 6 and 10 mCi but at higher doses the cure rate was increased marginally at the expense of increased total body radiation. There was little variation in total costs, but was higher for low dose-therapy and the cost proportion between the 6 mCi regimen and 10 mCi regimen was 1.04:1. Conclusion: We could conclude that an initial 10 mCi of I-131 may be the optimal dose for curing hyperthyroidism and will also limit the total costs

  15. A dose assessment for a U.S. nuclear test site -- Bikini Atoll

    On March 1, 1954, a nuclear weapon test, code-named BRAVO, conducted at Bikini Atoll in the northern Marshall Islands contaminated the major residence island. Here the authors provide a radiological dose assessment for the main residence island, Bikini, using extensive radionuclide concentration data derived from analysis of food crops, ground water, cistern water, fish and other marine species, animals, air, and soil collected at Bikini Island. The unique composition of coral soil greatly alters the relative contribution of cesium-137 and strontium-90 to the total estimated dose relative to expectations based on North American and European soils. Cesium-137 produces 96% of the estimated dose for returning residents, mostly through uptake from the soil to terrestrial food crops but also from external gamma exposure. The estimated maximum annual effective dose is 4.4 mSv y-1 when imported foods, which are now an established part of the diet, are available. The 30-, 50-, and 70-y integral effective doses are 10 cSv, 14 cSv, and 16 cSv, respectively. An analysis of interindividual variability in 0- to 30-y expected integral dose indicates that 95% of Bikini residents would have expected doses within a factor of 3.4 above and 4.8 below the population-average value. A corresponding uncertainty analysis showed that after about 5 y of residence, the 95% confidence limits on population-average dose would be ±35% of its expected value. The authors have evaluated various countermeasures to reduce 137Cs in food crops. Treatment with potassium reduces the uptake of 137Cs into food crops, and therefore the ingestion dose, to less than 10% of pretreatment levels and has essentially no negative environmental consequences

  16. A dose assessment for a U.S. nuclear test site -- Bikini Atoll

    Robison, W.L.; Bogen, K.T.; Conrado, C.L.

    1993-07-01

    On March 1, 1954, a nuclear weapon test, code-named BRAVO, conducted at Bikini Atoll in the northern Marshall Islands contaminated the major residence island. Here the authors provide a radiological dose assessment for the main residence island, Bikini, using extensive radionuclide concentration data derived from analysis of food crops, ground water, cistern water, fish and other marine species, animals, air, and soil collected at Bikini Island. The unique composition of coral soil greatly alters the relative contribution of cesium-137 and strontium-90 to the total estimated dose relative to expectations based on North American and European soils. Cesium-137 produces 96% of the estimated dose for returning residents, mostly through uptake from the soil to terrestrial food crops but also from external gamma exposure. The estimated maximum annual effective dose is 4.4 mSv y{sup {minus}1} when imported foods, which are now an established part of the diet, are available. The 30-, 50-, and 70-y integral effective doses are 10 cSv, 14 cSv, and 16 cSv, respectively. An analysis of interindividual variability in 0- to 30-y expected integral dose indicates that 95% of Bikini residents would have expected doses within a factor of 3.4 above and 4.8 below the population-average value. A corresponding uncertainty analysis showed that after about 5 y of residence, the 95% confidence limits on population-average dose would be {+-}35% of its expected value. The authors have evaluated various countermeasures to reduce {sup 137}Cs in food crops. Treatment with potassium reduces the uptake of {sup 137}Cs into food crops, and therefore the ingestion dose, to less than 10% of pretreatment levels and has essentially no negative environmental consequences.

  17. Assessment of thyroid doses due to 131I from atmospheric nuclear weapons tests in Nevada

    About 100 of the atmospheric nuclear weapons tests carried out at the Nevada Test Site (NTS) resulted in off-site detection of radioactive materials. These tests released about 5 EBq of 131I in the atmosphere, predominantly in 1952, 1953, 1955 and 1957. Radioiodine was deposited across the United States of America, with the highest values immediately downwind of the NTS and the lowest values of the west coast. In the 1980s, three major dose reconstruction studies were undertaken in order to address the assessment of thyroid doses due to 131I fallout from the NTS: (1) the ORERP study of the US Department of Energy; (2) the Utah thyroid cohort study; and (3) the NCI thyroid study. The first two studies are concerned with doses received by 'local' populations (less than 800 km from the NTS), while the third study deals with the estimation of thyroid doses received by populations across the continental USA. In all three studies, uncertainty estimates were attached to the calculated doses. The second and third studies specifically addressed the assessment of thyroid doses from radioiodines, whereas the first study has a much wider scope, in that it considers both external and internal irradiation of the main organs and tissues of the body from all radionuclides produced by nuclear weapons tests. The thyroid doses from NTS fallout resulted essentially from the ingestion of milk contaminated with 131I; other, usually less important, pathways of exposure are the consumption of leafy vegetables and eggs. Because children generally drink more milk than adults, and because of the smaller mass of their thyroid gland, children received higher doses than adults for a given deposition of 131I. The thyroid doses are estimated to have ranged up to a few grays for small children in south-western Utah who drank milk from a family owned goat. A preliminary estimate of the collective thyroid dose to the US population from NTS fallout is 4 x 106 man·Gy, corresponding to a per capita

  18. A dose assessment for a US nuclear test site - Bikini atoll

    On March 1, 1954, a nuclear weapon test, code-named BRAVO, conducted at Bikini Atoll in the northern Marshall Islands contaminated the major residence island. There has been a continuing effort since 1977 to refine dose assessments for resettlement options at Bikini Atoll. Here we provide a radiological dose assessment for the main residence island, Bikini, using extensive radionuclide concentration data derived from analysis of food crops, ground water, cistern water, fish and other marine species, animals, air, and soil collected at Bikini Island as a part of our continuing research and monitoring program that began in 1975. The unique composition of coral soil greatly alters the relative contribution of cesium-137 (137Cs) and strontium-90 (90Sr) to the total estimated dose relative to expectations based on North American and European soils. Cesium-137 produces 96% of the estimated dose for returning residents, mostly through uptake from the soil to terrestrial food crops but also from external gamma exposure. The doses are calculated assuming a resettlement date of 1996. The estimated maximum annual effective dose is 4.4 mSv y-1 when imported foods, which are now an established part of the diet, are available. The 30-, 50-, and 70-y integral effective doses are 10 cSv, 14 cSv, and 16 cSv, respectively. An analysis of interindividual variability in 0- to 30-y expected integral dose indicates that 95% of Bikini residents would have expected doses within a factor of 3.4 above and 4.8 below the population-average value. A corresponding uncertainty analysis showed that after about 5 y of residence, the 95% confidence limits on population-average dose would be ± 35% of its expected value. We have evaluated various countermeasures to reduce 137Cs in food crops. Treatment with potassium reduces the uptake of 137Cs into food crops, and therefore the indigestion dose, to less than 10% of pretreatment levels and has essentially no negative environmental consequences

  19. Real-time assessment of exposure dose to workers in radiological environments during decommissioning of nuclear facilities

    Highlights: • The method of exposure dose assessment to workers during decommissioning of nuclear facilities. • The environments of simulation were designed under a virtual reality. • To assess exposure dose to workers, human model was developed within a virtual reality. - Abstract: This objective of this paper is to develop a method to simulate and assess the exposure dose to workers during decommissioning of nuclear facilities. To simulate several scenarios, decommissioning environments were designed using virtual reality. To assess exposure dose to workers, a human model was also developed using virtual reality. The exposure dose was measured and assessed under the principle of ALARA in accordance with radiological environmental change. This method will make it possible to plan for the exposure dose to workers during decommissioning of nuclear facilities

  20. Information on Hydrologic Conceptual Models, Parameters, Uncertainty Analysis, and Data Sources for Dose Assessments at Decommissioning Sites

    Meyer, Philip D.; Gee, Glendon W.; Nicholson, Thomas J.

    2000-02-28

    This report addresses issues related to the analysis of uncertainty in dose assessments conducted as part of decommissioning analyses. The analysis is limited to the hydrologic aspects of the exposure pathway involving infiltration of water at the ground surface, leaching of contaminants, and transport of contaminants through the groundwater to a point of exposure. The basic conceptual models and mathematical implementations of three dose assessment codes are outlined along with the site-specific conditions under which the codes may provide inaccurate, potentially nonconservative results. In addition, the hydrologic parameters of the codes are identified and compared. A methodology for parameter uncertainty assessment is outlined that considers the potential data limitations and modeling needs of decommissioning analyses. This methodology uses generic parameter distributions based on national or regional databases, sensitivity analysis, probabilistic modeling, and Bayesian updating to incorporate site-specific information. Data sources for best-estimate parameter values and parameter uncertainty information are also reviewed. A follow-on report will illustrate the uncertainty assessment methodology using decommissioning test cases.

  1. Information on Hydrologic Conceptual Models, Parameters, Uncertainty Analysis, and Data Sources for Dose Assessments at Decommissioning Sites

    This report addresses issues related to the analysis of uncertainty in dose assessments conducted as part of decommissioning analyses. The analysis is limited to the hydrologic aspects of the exposure pathway involving infiltration of water at the ground surface, leaching of contaminants, and transport of contaminants through the groundwater to a point of exposure. The basic conceptual models and mathematical implementations of three dose assessment codes are outlined along with the site-specific conditions under which the codes may provide inaccurate, potentially nonconservative results. In addition, the hydrologic parameters of the codes are identified and compared. A methodology for parameter uncertainty assessment is outlined that considers the potential data limitations and modeling needs of decommissioning analyses. This methodology uses generic parameter distributions based on national or regional databases, sensitivity analysis, probabilistic modeling, and Bayesian updating to incorporate site-specific information. Data sources for best-estimate parameter values and parameter uncertainty information are also reviewed. A follow-on report will illustrate the uncertainty assessment methodology using decommissioning test cases

  2. An Analysis Of Tensile Test Results to Assess the Innovation Risk for an Additive Manufacturing Technology

    Adamczak Stanisław

    2015-03-01

    Full Text Available The aim of this study was to assess the innovation risk for an additive manufacturing process. The analysis was based on the results of static tensile tests obtained for specimens made of photocured resin. The assessment involved analyzing the measurement uncertainty by applying the FMEA method. The structure of the causes and effects of the discrepancies was illustrated using the Ishikawa diagram. The risk priority numbers were calculated. The uncertainty of the tensile test measurement was determined for three printing orientations. The results suggest that the material used to fabricate the tensile specimens shows clear anisotropy of the properties in relation to the printing direction.

  3. Assessment of the Low Alloy Cast Steel Inoculation Effects with Chosen Additives

    D. Bartocha

    2012-04-01

    Full Text Available Structure, and thus the mechanical properties of steel are primarily a function of chemical composition and the solidification process which can be influenced by the application of the inoculation treatment. This effect depends on the modifier used. The article presents the results of studies designed to assess the effects of structural low alloy steel inoculation by selected modifying additives. The study was performed on nine casts modeled with different inoculants, assessment of the procedure impact was based on the macrostructure of made castings. The ratio of surface area equivalent to the axial zone of the crystals and columnar crystals zone was adopted as a measure of the inoculation effect.

  4. Application of GIS for population dose assessment in the Chernobyl accident area

    The development of updated approaches to evaluating the long-term consequences of the Chernobyl accident is based on the experience of authors in assessing population doses and in creating Decision Support Systems (DSS) in radioecology with the use of GIS technologies. 'Dose block' is a key component of the PRANA GIS-DSS on rehabilitation of contaminated territories after Chernobyl accident. When estimating internal and external doses to the local population the following components of PRANA are used: electronic maps for territories under investigation (5 contaminated districts of Bryansk reg.); databases (including database associated with polygons of vector electronic maps, and database for model and other input parameters); updated and modified mathematical models for assessing external and internal doses to the local population (from 137Cs and 90Sr); corresponding computer modules and user interface. Library of electronic maps includes different layers of vector maps of landuse for territories under consideration. Map of landuse for each district comprises all elements of land use: agricultural fields (arable lands, pastures and hayfields), forests, gardens, settlements, swamps and water bodies. Databases associated with polygons of vector maps include the following main monitoring data for each polygon: for fields - soil contamination density with 137Cs and 90Sr, soil type, mechanical and chemical composition, crop rotation; for settlements - contamination density, monitoring data of internal and external doses, local diet, behaviour and location and other factors, demographic data, etc. Other databases include all the parameters necessary for assessing contamination of agricultural products and internal/external doses: various transfer factors, parameters of countermeasures, productivity and/or production of agricultural crops, milk and meat (both for private and farm production), etc. Special attention was paid to developing and adjusting to elements of GIS

  5. Radioactivity in food and the environment: calculations of UK radiation doses using integrated assessment methods

    A new method for estimating radiation doses to UK critical groups is proposed for discussion. Amongst others, the Food Standards Agency (FSA) and the Scottish Environment Protection Agency (SEPA) undertake surveillance of UK food and the environment as a check on the effect of discharges of radioactive wastes. Discharges in gaseous and liquid form are made under authorisation by the Environment Agency and SEPA under powers in the Radioactive Substance Act. Results of surveillance by the FSA and SEPA are published in the Radioactivity in Food and the Environment (RIFE) report series. In these reports, doses to critical groups are normally estimated separately for gaseous and liquid discharge pathways. Simple summation of these doses would tend to overestimate doses actually received. Three different methods of combining the effects of both types of discharge in an integrated assessment are considered and ranked according to their ease of application, transparency, scientific rigour and presentational issues. A single integrated assessment method is then chosen for further study. Doses are calculated for surveillance data for the calendar year 2000 and compared with those from the existing RIFE method

  6. Quantification of micronuclei in blood lymphocytes of patients exposed to gamma radiation for dose absorbed assessment

    Dose assessment in an important step to evaluate biological effects as a result of individual exposure to ionizing radiation. The use of cytogenetic dosimetry based on the quantification of micronuclei in lymphocytes is very important to complement physical dosimetry, since the measurement of absorbed dose cannot be always performed. In this research, the quantification of micronuclei was carried out in order to evaluate absorbed dose as a result of radiotherapy with 60Co, using peripheral blood samples from 5 patients with cervical uterine cancer. For this purpose, an aliquot of whole blood from the individual patients was added in culture medium RPMI 1640 supplemented with fetal calf serum and phytohaemagglutinin. The culture was incubated for 44 hours. Henceforth, cytochalasin B was added to block the dividing lymphocytes in cytokinesis. The culture was returned to the incubator for further of 28 hours. Thus, cells were harvested, processed and analyzed. Values obtained considering micronuclei frequency after pelvis irradiation with absorption of 0,08 Gy and 1,8 Gy were, respectively, 0,0021 and 0,052. These results are in agreement with some recent researches that provided some standard values related to micronuclei frequency induced by gamma radiation exposure in different exposed areas for the human body. The results presented in this report emphasizes biological dosimetry as an important tool for dose assessment of either total or partial-body exposure to ionizing radiation, mainly in retrospective dose investigation. (author)

  7. A user friendly database for use in ALARA job dose assessment

    The pressurized water reactor (PWR) design chosen for adoption by Nuclear Electric plc was based on the Westinghouse Standard Nuclear Unit Power Plant (SNUPPS). This design was developed to meet the United Kingdom requirements and these improvements are embodied in the Sizewell B plant which will start commercial operation in 1994. A user-friendly database was developed to assist the station in the dose and ALARP assessments of the work expected to be carried out during station operation and outage. The database stores the information in an easily accessible form and enables updating, editing, retrieval, and searches of the information. The database contains job-related information such as job locations, number of workers required, job times, and the expected plant doserates. It also contains the means to flag job requirements such as requirements for temporary shielding, flushing, scaffolding, etc. Typical uses of the database are envisaged to be in the prediction of occupational doses, the identification of high collective and individual dose jobs, use in ALARP assessments, setting of dose targets, monitoring of dose control performance, and others

  8. Transmission scans using Gd-153 line sources in cardiac SPECT studies: What is the additional patient radiation dose burden?

    Aim: To determine the contribution of transmission scan acquisition obtained for attenuation/scatter correction to total patient effective dose from cardiac SPECT studies. Materials and Methods: A dual-headed L-shaped gamma camera equipped with a transmission scan acquisition system based on two 153Gd line sources was used. Transmission scan acquisition was performed on a humanoid phantom. Thermoluminescence dosimeters were used to directly monitor the dose to 550 measuring points in the phantom. Patient effective dose and associated risk from transmission scans acquisition were estimated and compared to those associated to the radiopharmaceutical injected. Results: The maximum effective dose from a typical transmission measurements acquisition was 1.3 μSv and 1.9 μSv for male and female patients, respectively. The contribution of the typical transmission scans acquisition to total patient radiation risk from a cardiac SPECT study was less than 10-3. Conclusion: Radiation exposure may not be considered as a limiting factor for the clinical application of attenuation correction methods based on transmission measurements in cardiac SPECT

  9. Comparison of conventional Injection Mould Inserts to Additively Manufactured Inserts using Life Cycle Assessment

    Hofstätter, Thomas; Bey, Niki; Mischkot, Michael;

    2016-01-01

    Polymer Additive Manufacturing can be used to produce soft tooling inserts for injection moulding. Compared to conventional tooling, the energy and time consumption during production are significantly lower. As the life time of such inserts is significantly shorter than the life time of traditional...... potential environmental impact and yield throughout the development and pilot phase. Insert geometry is particularly advantageous for pilot production and small production sizes. In this research, Life Cycle Assessment is used to compare the environmental impact of soft tooling by Additive Manufacturing...

  10. Assessment of radiation dose in nuclear cardiovascular imaging using realistic computational models

    Purpose: Nuclear cardiology plays an important role in clinical assessment and has enormous impact on the management of a variety of cardiovascular diseases. Pediatric patients at different age groups are exposed to a spectrum of radiation dose levels and associated cancer risks different from those of adults in diagnostic nuclear medicine procedures. Therefore, comprehensive radiation dosimetry evaluations for commonly used myocardial perfusion imaging (MPI) and viability radiotracers in target population (children and adults) at different age groups are highly desired. Methods: Using Monte Carlo calculations and biological effects of ionizing radiation VII model, we calculate the S-values for a number of radionuclides (Tl-201, Tc-99m, I-123, C-11, N-13, O-15, F-18, and Rb-82) and estimate the absorbed dose and effective dose for 12 MPI radiotracers in computational models including the newborn, 1-, 5-, 10-, 15-yr-old, and adult male and female computational phantoms. Results: For most organs, 201Tl produces the highest absorbed dose whereas 82Rb and 15O-water produce the lowest absorbed dose. For the newborn baby and adult patient, the effective dose of 82Rb is 48% and 77% lower than that of 99mTc-tetrofosmin (rest), respectively. Conclusions: 82Rb results in lower effective dose in adults compared to 99mTc-labeled tracers. However, this advantage is less apparent in children. The produced dosimetric databases for various radiotracers used in cardiovascular imaging, using new generation of computational models, can be used for risk-benefit assessment of a spectrum of patient population in clinical nuclear cardiology practice

  11. Assessment of radiation dose in nuclear cardiovascular imaging using realistic computational models

    Xie, Tianwu [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 4 CH-1211 (Switzerland); Lee, Choonsik [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, Maryland 20852 (United States); Bolch, Wesley E. [Departments of Nuclear and Radiological and Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States); Zaidi, Habib, E-mail: habib.zaidi@hcuge.ch [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 4 CH-1211 (Switzerland); Geneva Neuroscience Center, Geneva University, Geneva CH-1205 (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen 9700 RB (Netherlands)

    2015-06-15

    Purpose: Nuclear cardiology plays an important role in clinical assessment and has enormous impact on the management of a variety of cardiovascular diseases. Pediatric patients at different age groups are exposed to a spectrum of radiation dose levels and associated cancer risks different from those of adults in diagnostic nuclear medicine procedures. Therefore, comprehensive radiation dosimetry evaluations for commonly used myocardial perfusion imaging (MPI) and viability radiotracers in target population (children and adults) at different age groups are highly desired. Methods: Using Monte Carlo calculations and biological effects of ionizing radiation VII model, we calculate the S-values for a number of radionuclides (Tl-201, Tc-99m, I-123, C-11, N-13, O-15, F-18, and Rb-82) and estimate the absorbed dose and effective dose for 12 MPI radiotracers in computational models including the newborn, 1-, 5-, 10-, 15-yr-old, and adult male and female computational phantoms. Results: For most organs, {sup 201}Tl produces the highest absorbed dose whereas {sup 82}Rb and {sup 15}O-water produce the lowest absorbed dose. For the newborn baby and adult patient, the effective dose of {sup 82}Rb is 48% and 77% lower than that of {sup 99m}Tc-tetrofosmin (rest), respectively. Conclusions: {sup 82}Rb results in lower effective dose in adults compared to {sup 99m}Tc-labeled tracers. However, this advantage is less apparent in children. The produced dosimetric databases for various radiotracers used in cardiovascular imaging, using new generation of computational models, can be used for risk-benefit assessment of a spectrum of patient population in clinical nuclear cardiology practice.

  12. Chernobyl accident. Assessment of the Collective thyroid dose for the Belarusian population

    As a consequence of the Chernobyl accident, a widespread radioactive contamination occurred over the territory of the Republic of Belarus. During the first few weeks after the accident, the intake of 131I, due essentially to the consumption of contaminated milk, resulted in substantial thyroid exposures for many Belarusians. The sharp increase of thyroid cancer cases among children that has been observed since the early 1990s has triggered many studies on the comparison between the levels of thyroid exposure among children and the number of cancer cases. In 1996, we estimated the collective thyroid dose to the Belarusian population to be about 510,000 person Gy (including 130,000 person Gy for the children up to 7 years old at the time of the accident). Since 1996, we have improved the dose assessment model used for 7.3 million residents (73%) of Belarus. Two models will be to assess thyroid doses for rural inhabitants: the first one is based on relationship between mean adult-thyroid dose and the deposition density of 131I or 137Cs in the settlements where lived a sufficient number of residents whose thyroids were measured in vivo in May through beginning of June 1986; the second one is an environmental transfer model making use of the available measurements of 131I in fallout, grass, and milk. For the other 2.7 million residents we will estimate the collective dose based on doses obtained by residents of corresponding settlements or areas, whose thyroids were measured in 1986. The associated uncertainties will be discussed. The magnitude of the collective dose will be compared to the number of observed thyroid cancer cases among children, Oblast by Oblast. The variations observed in various Oblasts of Belarus will be analyzed. (author)

  13. European project for developing general guidelines for harmonising internal dose assessment procedures (IDEAS)

    Several international intercomparison exercises on intake and internal dose assessments from monitoring data led to the conclusion that the results calculated by different participants varied significantly mainly because of the wide variety of methods and assumptions applied in the assessment procedure. Based on these experiences the need for harmonisation of the procedures has been formulated as an EU research project under the 5th Framework Programme (2001-2005), with the aim of developing general guidelines for standardising assessments of intakes and internal doses. In the IDEAS project eight institutions from seven European countries are participating using inputs also from internal dosimetry professionals from across Europe to ensure broad consensus in the outcome of the project. The IDEAS project is explained

  14. Assessment of dose conversion factors in a generic biosphere of a Korea HLW repository

    Radioactive species released from a waste repository migrate through engineered and natural barriers and eventually reach the biosphere. Once entered the biosphere, contaminants transport various exposure pathways and finally reach a human. In this study the full RES matrix explaining the key compartments in the biosphere and their interactions is introduced considering the characteristics of the Korean biosphere. Then the three exposure groups are identified based on the compartments of interest. The full exposure pathways and corresponding mathematical expression for mass transfer coefficients and etc are developed and applied to assess the dose conversion factors of nuclides for a specific exposure group. Dose conversion factors assessed in this study will be used for total system performance assessment of a potential Korean HLW repository

  15. The use of caffeine to assess high dose exposures to ionising radiation by dicentric analysis

    Dicentric analysis is considered as a 'gold standard' method for biological dosimetry. However, due to the radiation-induced mitotic delay or inability to reach mitosis of heavily damaged cells, the analysis of dicentrics is restricted to doses up to 4-5 Gy. For higher doses, the analysis by premature chromosome condensation technique has been proposed. Here, it is presented a preliminary study is presented in which an alternative method to analyse dicentrics after high dose exposures to ionising radiation (IR) is evaluated. The method is based on the effect of caffeine in preventing the G2/M checkpoint allowing damaged cells to reach mitosis. The results obtained indicate that the co-treatment with Colcemide and caffeine increases significantly increases the mitotic index, and hence allows a more feasible analysis of dicentrics. Moreover in the dose range analysed, from 0 to 15 Gy, the dicentric cell distribution followed the Poisson distribution, and a simulated partial-body exposure has been clearly detected. Overall, the results presented here suggest that caffeine has a great potential to be used for dose-assessment after high dose exposure to IR. (authors)

  16. Influence of dosemeter position for the assessment of eye lens dose during interventional cardiology.

    Principi, Sara; Ginjaume, Mercè; Duch, Maria Amor; Sánchez, Roberto M; Fernández, Jose M; Vano, Eliseo

    2015-04-01

    The equivalent dose limit for the eye lens for occupational exposure recommended by the ICRP has been reduced to 20 mSv y(-1) averaged over defined periods of 5 y, with no single year exceeding 50 mSv. The compliance with this new requirement could not be easy in some workplace such as interventional radiology and cardiology. The aim of this study is to evaluate different possible approaches in order to have a good estimate of the eye lens dose during interventional procedures. Measurements were performed with an X-ray system Philips Allura FD-10, using a PMMA phantom to simulate the patient scattered radiation and a Rando phantom to simulate the cardiologist. Thermoluminescence (TL) whole-body and TL eye lens dosemeters together with Philips DoseAware active dosemeters were located on different positions of the Rando phantom to estimate the eye lens dose in typical cardiology procedures. The results show that, for the studied conditions, any of the analysed dosemeter positions are suitable for eye lens dose assessment. However, the centre of the thyroid collar and the left ear position provide a better estimate. Furthermore, in practice, improper use of the ceiling-suspended screen can produce partial protection of some parts of the body, and thus large differences between the measured doses and the actual exposure of the eye could arise if the dosemeter is not situated close to the eye. PMID:25514919

  17. Nuclear plant's virtual simulation for on-line radioactive environment monitoring and dose assessment for personnel

    This paper reports the use of nuclear plant's simulation for online dose rate monitoring and dose assessment for personnel, using virtual reality technology. The platform used for virtual simulation was adapted from a low cost game engine, taking advantage of all its image rendering capabilities, as well as the physics for movement and collision, and networking capabilities for multi-user interactive navigation. A real nuclear plant was virtually modeled and simulated, so that a number of users can navigate simultaneously in this virtual environment in first or third person view, each one receiving visual information about both the radiation dose rate in each actual position, and the radiation dose received. Currently, this research and development activity has been extended to consider also on-line measurements collected from radiation monitors installed in the real plant that feed the simulation platform with dose rate data, through a TCP/IP network. Results are shown and commented, and other improvements are discussed, as the execution of a more detailed dose rate mapping campaign.

  18. Influence of dosemeter position for the assessment of eye lens dose during interventional cardiology

    The equivalent dose limit for the eye lens for occupational exposure recommended by the ICRP has been reduced to 20 mSv y-1 averaged over defined periods of 5 y, with no single year exceeding 50 mSv. The compliance with this new requirement could not be easy in some workplace such as interventional radiology and cardiology. The aim of this study is to evaluate different possible approaches in order to have a good estimate of the eye lens dose during interventional procedures. Measurements were performed with an X-ray system Philips Allura FD-10, using a PMMA phantom to simulate the patient scattered radiation and a Rando phantom to simulate the cardiologist. Thermoluminescence (TL) whole-body and TL eye lens dosemeters together with Philips DoseAware active dosemeters were located on different positions of the Rando phantom to estimate the eye lens dose in typical cardiology procedures. The results show that, for the studied conditions, any of the analysed dosemeter positions are suitable for eye lens dose assessment. However, the centre of the thyroid collar and the left ear position provide a better estimate. Furthermore, in practice, improper use of the ceiling-suspended screen can produce partial protection of some parts of the body, and thus large differences between the measured doses and the actual exposure of the eye could arise if the dosemeter is not situated close to the eye. (authors)

  19. Assessment of undesirable dose to eye-melanoma patients after proton radiotherapy

    Radiotherapy with a proton beam of initial energy 55-80 MeV is presently the clinically recommended therapy for some cases of intraocular melanoma such as large melanomas or tumours adjacent to critical organs. Evaluation and optimization of radiation doses outside the treatment volume may contribute to reducing undesirable side-effects and decreasing the risk of occurrence of secondary cancers, particularly for paediatric patients. In this work the undesired doses to organs were assessed basing on Monte Carlo calculation of secondary radiation transport and on results of measurements of neutron and γ-ray doses at the proton therapy facility of the Institute of Nuclear Physics at Krakow. Dosimetry was performed using a He-3-based FHT 762 neutron monitor (Wendi II), a FH40G proportional counter (for γ-rays), and MTS-7 (LiF:Mg,Ti) thermoluminescence detectors (TLDs). Organ doses were calculated in the ADAM anthropomorphic phantom using the MCNPX Monte Carlo transport code and partly verified, for γ-ray doses, with TLD measurements in the RANDO Anderson anthropomorphic phantom. The effective dose due to undesired radiation, including exposure from scattered radiation during the entire process of proton radiotherapy and patient positioning using X-rays, does not exceed 1 mSv.

  20. WAZA-ARI. A dose assessment system for patients in CT scan

    The Japan Atomic Energy Agency (JAEA) are now developing WAZA-ARI for improvement of management of exposure doses due to CT examination under the joint research with the Oita University of Nursing and Health Sciences. The trial version of WAZA-ARI has been released on 21 December 2012. In trial version, users can perform dose assessment by using organ dose database based on the average adult Japanese male (JM-103) and female (JF-103) voxel phantoms and a 4 years old female voxel phantom (UFF4). The homepage of WAZA-ARI has been accessed over 1000 times per month and 28421 times by the end of September 2014. We are developing WAZA-ARI version 2 as the extension version of dose calculation functions of WAZA-ARI. WAZA-ARI version 2 will be released by the end of March 2015. In WAZA-ARI version 2. Users can upload dose calculation results to WAZA-ARI version 2 server, and utilize improvement of the dose management of patients and the optimization of CT scan conditions. (author)

  1. A study on the dose assessment methodology using the probabilistic characteristics of TL element response

    Characteristics of element responses of Panasonic UD802 personnel dosimeters in the X, β, γ, γ/X,γ/β and γ/neutron mixed fields were assessed. A dose-response algorithm has been developed to decide the high probability of a radiation type and energy by using the distribution in all six ratios of the multi-element TLD. To calculate the 4-element response factors and ratios between te elements of the Panasonic TLDs in the X,β, and γ radiation fields, Panasonic's UD802 TLDs were irradiated with KINS's reference irradiation facility. In the photon radiation field, this study confirms that element-3 (E3) and element-4 (E4) of the Panasonic TLDs show energy dependent both in low-and intermediate-energy range, while element-1 (E1) and element-2 (E2) show little energy dependency in the entire whole range. The algorithm, which was developed in this study, was applied to the Panasonic personnel dosimetry system with UD716AGL reader and UD802 TLDs. Performance tests of the algorithm developed was conducted according to the standards and criteria recommended in the ANSI N13.11. The sum of biases and standard deviations was less than 0.232. The values of biases and standard deviations are distributed within a triangle of a lateral value of 0.3 in the ordinate and abscissa. With the above algorithm, Panasonic TLDs satisfactorily perform optimum dose assessment even under an abnormal response of the TLD elements to the energy imparted. This algorithm can be applied to a more rigorous dose assessment by distinguishing an unexpected dose from the planned dose for the most practical purposes, and is useful in conducting an effective personnel dose control program

  2. A study on the dose assessment methodology using the probabilistic characteristics of TL element response

    Cho, Dae Hyung; Oh, Jang Jin; Han, Seung Jae; Na, Seong Ho; Kwang, Won Guk [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of); Lee, Won Keun [Kyunghee Univ., Seoul (Korea, Republic of)

    1998-09-01

    Characteristics of element responses of Panasonic UD802 personnel dosimeters in the X, {beta}, {gamma}, {gamma}/X,{gamma}/{beta} and {gamma}/neutron mixed fields were assessed. A dose-response algorithm has been developed to decide the high probability of a radiation type and energy by using the distribution in all six ratios of the multi-element TLD. To calculate the 4-element response factors and ratios between te elements of the Panasonic TLDs in the X,{beta}, and {gamma} radiation fields, Panasonic's UD802 TLDs were irradiated with KINS's reference irradiation facility. In the photon radiation field, this study confirms that element-3 (E3) and element-4 (E4) of the Panasonic TLDs show energy dependent both in low-and intermediate-energy range, while element-1 (E1) and element-2 (E2) show little energy dependency in the entire whole range. The algorithm, which was developed in this study, was applied to the Panasonic personnel dosimetry system with UD716AGL reader and UD802 TLDs. Performance tests of the algorithm developed was conducted according to the standards and criteria recommended in the ANSI N13.11. The sum of biases and standard deviations was less than 0.232. The values of biases and standard deviations are distributed within a triangle of a lateral value of 0.3 in the ordinate and abscissa. With the above algorithm, Panasonic TLDs satisfactorily perform optimum dose assessment even under an abnormal response of the TLD elements to the energy imparted. This algorithm can be applied to a more rigorous dose assessment by distinguishing an unexpected dose from the planned dose for the most practical purposes, and is useful in conducting an effective personnel dose control program.

  3. Addition of a third field significantly increases dose to the brachial plexus for patients undergoing tangential whole-breast therapy after lumpectomy

    Our goal was to evaluate brachial plexus (BP) dose with and without the use of supraclavicular (SCL) irradiation in patients undergoing breast-conserving therapy with whole-breast radiation therapy (RT) after lumpectomy. Using the standardized Radiation Therapy Oncology Group (RTOG)–endorsed guidelines delineation, we contoured the BP for 10 postlumpectomy breast cancer patients. The radiation dose to the whole breast was 50.4 Gy using tangential fields in 1.8-Gy fractions, followed by a conedown to the operative bed using electrons (10 Gy). The prescription dose to the SCL field was 50.4 Gy, delivered to 3-cm depth. The mean BP volume was 14.5 ± 1.5 cm3. With tangential fields alone, the median mean dose to the BP was 0.57 Gy, the median maximum dose was 1.93 Gy, and the irradiated volume of the BP receiving 40, 45, and 50 Gy was 0%. When the third (SCL field) was added, the dose to the BP was significantly increased (P = .01): the median mean dose to the BP was 40.60 Gy, and the median maximum dose was 52.22 Gy. With 3-field RT, the median irradiated volume of the BP receiving 40, 45, and 50 Gy was 83.5%, 68.5%, and 24.6%, respectively. The addition of the SCL field significantly increases dose to the BP. The possibility of increasing the risk of BP morbidity should be considered in the context of clinical decision making.

  4. Addition of a third field significantly increases dose to the brachial plexus for patients undergoing tangential whole-breast therapy after lumpectomy

    Stanic, Sinisa; Mathai, Mathew; Mayadev, Jyoti S.; Do, Ly V.; Purdy, James A. [Department of Radiation Oncology, University of California, Davis, Sacramento, CA (United States); Chen, Allen M., E-mail: allen.chen@ucdmc.ucdavis.edu [Department of Radiation Oncology, University of California, Davis, Sacramento, CA (United States)

    2012-07-01

    Our goal was to evaluate brachial plexus (BP) dose with and without the use of supraclavicular (SCL) irradiation in patients undergoing breast-conserving therapy with whole-breast radiation therapy (RT) after lumpectomy. Using the standardized Radiation Therapy Oncology Group (RTOG)-endorsed guidelines delineation, we contoured the BP for 10 postlumpectomy breast cancer patients. The radiation dose to the whole breast was 50.4 Gy using tangential fields in 1.8-Gy fractions, followed by a conedown to the operative bed using electrons (10 Gy). The prescription dose to the SCL field was 50.4 Gy, delivered to 3-cm depth. The mean BP volume was 14.5 {+-} 1.5 cm{sup 3}. With tangential fields alone, the median mean dose to the BP was 0.57 Gy, the median maximum dose was 1.93 Gy, and the irradiated volume of the BP receiving 40, 45, and 50 Gy was 0%. When the third (SCL field) was added, the dose to the BP was significantly increased (P = .01): the median mean dose to the BP was 40.60 Gy, and the median maximum dose was 52.22 Gy. With 3-field RT, the median irradiated volume of the BP receiving 40, 45, and 50 Gy was 83.5%, 68.5%, and 24.6%, respectively. The addition of the SCL field significantly increases dose to the BP. The possibility of increasing the risk of BP morbidity should be considered in the context of clinical decision making.

  5. Granulometric determinations and inhalation dose assessment for atmospheric aerosol contaminated by 137Cs

    During the redevelopment of Brescia freight-yard a measurement campaign of atmospheric aerosol was carried out: in fact a 137Cs ground contamination, caused by the permanence of wagons carrying iron materials contaminated by this radionuclide, had been found out. During the redevelopment phases of excavation and can filling the workers were exposed to the danger of radioactive aerosol inhalation. The aim of the measurement campaign was to test the aerosol sampling and granulometric analysis methodologies with their sensitivity related to the inhalation dose assessments. The results of both aerosuspended mass and activity, evaluated by means of a portable cascade impactor, are presented. The granulometries have been interpolated with a log normal distribution using an iterative routine minimizing the square deviation between the calculated and experimental data. The results related to the dose assessments are also presented. These evaluations have been carried out using both the granulometric information obtained and the more recent models (ICRP 66) both the total concentration data and the dose coefficients referring to the standard conditions of ICRP 68 and of the Italian law (D.Lgs. 230/95). Furthermore the significance and the reliability of the dose assessments referring to the different methodologies are discussed, also in relation to the possibility of using this sampling methodologies for other radionuclides and different exposure conditions

  6. Internal dose assessment due to large area contamination: Main lessons drawn from the Chernobyl accident

    Andrasi, A. [KFKI Atomic Energy Research Inst., Budapest (Hungary)

    1997-03-01

    The reactor accident at Chernobyl in 1986 beside its serious and tragic consequences provided also an excellent opportunity to check, test and validate all kind of environmental models and calculation tools which were available in the emergency preparedness systems of different countries. Assessment of internal and external doses due to the accident has been carried out for the population all over Europe using different methods. Dose predictions based on environmental model calculation considering various pathways have been compared with those obtained by more direct monitoring methods. One study from Hungary and one from the TAEA is presented shortly. (orig./DG)

  7. Explanation of specification for assessment of intakes and internal doses of radionuclides

    National occupational health standard-Specification for Assessments of Intakes and Internal Doses of Radionuclides has been approved and issued by the Ministry of Health. Based on the extensive research of literature, systematic study of the relevant laws and regulations related to the specification, this specification was enacted according to the principles about it. It is mainly used for estimating the occupational radiation internal dose, This article explained the important technical content and proposed suggestions for the publicity and implementation of the standard. (authors)

  8. Internal dose assessment due to large area contamination: Main lessons drawn from the Chernobyl accident

    The reactor accident at Chernobyl in 1986 beside its serious and tragic consequences provided also an excellent opportunity to check, test and validate all kind of environmental models and calculation tools which were available in the emergency preparedness systems of different countries. Assessment of internal and external doses due to the accident has been carried out for the population all over Europe using different methods. Dose predictions based on environmental model calculation considering various pathways have been compared with those obtained by more direct monitoring methods. One study from Hungary and one from the TAEA is presented shortly. (orig./DG)

  9. Refined exposure assessment of ethyl lauroyl arginate based on revised proposed uses as a food additive

    European Food Safety Authority

    2013-01-01

    Following a request from the European Commission, the European Food Safety Authority (EFSA) carried out a refined exposure assessment of ethyl lauroyl arginate (LAE) from its use as a food additive, for children and adults, based on revised proposed uses. Refined exposure estimates have been calculated with revised proposed use levels and individual food consumption data from the EFSA Comprehensive Database, according to five different scenarios. The anticipated dietary exposure to LAE for sc...

  10. An assessment of thyroid dose of patient and staff performing barium swallow and upper gastrointestinal fluoroscopy examinations

    Introduction: Fluoroscopy is an important diagnostic technique in medicine. Among fluoroscopic procedures barium swallow and upper gastrointestinal account for a large number of examinations. During these procedures. the thyroid of patients is normally irradiated by the primary and scatter ionizing radiation causing both the deterministic and hazardous effects on this tissue. Therefore, the assessment of absorbed doses to the thyroid from these examinations becomes necessary. In addition, to perform these examinations. it is normally required that the radiologists and other radiation workers and paramedics stay in the fluoroscopic room. This puts the clinicians body and their various organs/ tissues, especially their thyroid, under the secondary/ scatter ionizing radiation. This research was carried out to estimate the thyroid absorbed doses of patient and radiation workers involved in fluoroscopic examinations at four different large scale genera hospitals in Tehran. Materials and Methods: To assess the pate int and radiation worker thyroid doses, Li-F thermoluminescent dosimeters were used which are known as thermoluminescent dosimeters -100 and made by Harshaw Company. The thermoluminescent dosimeters cubic chips were first annealed and read out using an appropriate consistent oven to make their background stored counts free. Then, they were exposed to know various amounts of radiation at Karaj Secondary Standard Dosimetry Laboratory of Iran, enabling us to determine a calibration curve for them over the range of exposure common in fluoroscopic procedures. The results of this dose assessment were also compared with those obtained in other countries and with the reference dose levels recommended by some radiation protection organizations. Results: The results indicated an average absorbed dose to the thyroid of patients of 7.89 mGy SE: 1.33) and 2.97 mGy for the barium swallow and upper gastrointestinal fluoroscopic examinations respectively. Corresponding values

  11. Assessment of organ-specific neutron equivalent doses in proton therapy using computational whole-body age-dependent voxel phantoms

    Proton beams used for radiotherapy will produce neutrons when interacting with matter. The purpose of this study was to quantify the equivalent dose to tissue due to secondary neutrons in pediatric and adult patients treated by proton therapy for brain lesions. Assessment of the equivalent dose to organs away from the target requires whole-body geometrical information. Furthermore, because the patient geometry depends on age at exposure, age-dependent representations are also needed. We implemented age-dependent phantoms into our proton Monte Carlo dose calculation environment. We considered eight typical radiation fields, two of which had been previously used to treat pediatric patients. The other six fields were additionally considered to allow a systematic study of equivalent doses as a function of field parameters. For all phantoms and all fields, we simulated organ-specific equivalent neutron doses and analyzed for each organ (1) the equivalent dose due to neutrons as a function of distance to the target; (2) the equivalent dose due to neutrons as a function of patient age; (3) the equivalent dose due to neutrons as a function of field parameters; and (4) the ratio of contributions to secondary dose from the treatment head versus the contribution from the patient's body tissues. This work reports organ-specific equivalent neutron doses for up to 48 organs in a patient. We demonstrate quantitatively how organ equivalent doses for adult and pediatric patients vary as a function of patient's age, organ and field parameters. Neutron doses increase with increasing range and modulation width but decrease with field size (as defined by the aperture). We analyzed the ratio of neutron dose contributions from the patient and from the treatment head, and found that neutron-equivalent doses fall off rapidly as a function of distance from the target, in agreement with experimental data. It appears that for the fields used in this study, the neutron dose lateral to the

  12. Assessing the effect, on animal model, of mixture of food additives, on the water balance

    Mariola Friedrich

    2013-03-01

    Full Text Available Purpose. The purpose of this study was to determine, on the animal model, the effect of modifi cation of diet composition and administration of selected food additives on water balance in the body. Material and methods. The study was conducted with 48 males and 48 females (separately for each sex of Wistar strain rats divided into four groups. For drinking, the animals from groups I and III were receiving water, whereas the animals from groups II and IV were administered 5 ml of a solution of selected food additives (potassium nitrate – E 252, sodium nitrite – E 250, benzoic acid – E 210, sorbic acid – E 200, and monosodium glutamate – E 621. Doses of the administered food additives were computed taking into account the average intake by men, expressed per body mass unit. Having drunk the solution, the animals were provided water for drinking. Results. The mixture of selected food additives applied in the experiment was found to facilitate water retention in the body both in the case of both male and female rats, and differences observed between the volume of ingested fl uids and the volume of excreted urine were statistically signifi cant in the animals fed the basal diet. The type of feed mixture provided to the animals affected the site of water retention – in the case of animals receiving the basal diet analyses demonstrated a signifi cant increase in water content in the liver tissue, whereas in the animals fed the modifi ed diet water was observed to accumulate in the vascular bed. Conclusion. Taking into account the fact of water retention in the vascular bed, the effects of food additives intake may be more adverse in the case of females.

  13. Low-Dose and Standard-Dose Unenhanced Helical Computed Tomography for the Assessment of Acute Renal Colic: Prospective Comparative Study

    Kim, Bong Soo; Hwang, Im Kyung; Choi, Yo Won; Namkung, Sook; Kim, Heung Cheol; Hwang, Woo Cheol; Choi, Kuk Myung; Park, Ji Kang; Han, Tae Il; Kang, Weechang [Cheju National Univ. College of Medicine, Jeju (Korea, Republic of). Dept. of Diagnostic Radiology

    2005-11-01

    Purpose: To compare the efficacy of low-dose and standard-dose computed tomography (CT) for the diagnosis of ureteral stones. Material and Methods: Unenhanced helical CT was performed with both a standard dose (260 mAs, pitch 1.5) and a low dose (50 mAs, pitch 1.5) in 121 patients suspected of having acute renal colic. The two studies were prospectively and independently interpreted for the presence and location of ureteral stones, abnormalities unrelated to stone disease, identification of secondary signs, i.e. hydronephrosis and perinephric stranding, and tissue rim sign. The standard-dose CT images were interpreted by one reviewer and the low-dose CT images independently by two reviewers unaware of the standard-dose CT findings. The findings of the standard and low-dose CT scans were compared with the exact McNemar test. Interobserver agreements were assessed with kappa analysis. The effective radiation doses resulting from two different protocols were calculated by means of commercially available software to which the Monte-Carlo phantom model was given. Results: The sensitivity, specificity, and accuracy of standard-dose CT for detecting ureteral stones were 99%, 93%, and 98%, respectively, whereas for the two reviewers the sensitivity of low-dose CT was 93% and 95%, specificity 86%, and accuracy 92% and 94%. We found no significant differences between standard-dose and low-dose CT in the sensitivity and specificity for diagnosing ureter stones ( P >0.05 for both). However, the sensitivity of low-dose CT for detection of 19 stones less than or equal to 2 mm in diameter was 79% and 68%, respectively, for the two reviewers. Low-dose CT was comparable to standard-dose CT in visualizing hydronephrosis and the tissue rim sign. Perinephric stranding was far less clear on low-dose CT. Low-dose CT had the same diagnostic performance as standard-dose CT in diagnosing alternative diseases. Interobserver agreement between the two low-dose CT reviewers in the diagnosis of

  14. Assessing Boundary Film Forming Behavior of Phosphonium Ionic Liquids as Engine Lubricant Additives

    Mayank Anand

    2016-05-01

    Full Text Available The reduction of friction and wear losses in boundary lubrication regime of a piston ring-cylinder liner tribo-system has always been a challenge for engine and lubricant manufacturers. One way is to use lubricant additives, which can form boundary film quickly and reduce the direct contact between asperities. This article focuses on the assessment of boundary film forming behavior of two phosphonium-based ionic liquids (ILs as additives in engine-aged lubricant to further improve its film forming capabilities and hence reduce friction and wear of contacting surfaces. A reciprocating piston ring segment-on-flat coupon under fully flooded lubrication conditions at room temperature (approx. 25 °C was employed. The trihexyltetradecyl phosphonium bis(2-ethylhexyl phosphate and trihexyltetradecyl phosphonium bis(2,4,4-tri-methylpentyl phosphinate ionic liquids were used as additives in 6 vol. % quantity. Benchmark tests were conducted using fully formulated new lubricant of same grade (with and without ILs. Results revealed that the addition of phosphonium ILs to engine-aged lubricant led to quicker initiation of boundary film forming process. In addition, friction and wear performance of engine-aged lubricant improved by the addition of both ILs and these mixtures outperformed the fresh fully formulated oil. Chemical analysis showed higher concentration of phosphorus element on the worn surface indicating presence of ILs in the formed tribofilms.

  15. SU-E-J-06: Additional Imaging Guidance Dose to Patient Organs Resulting From X-Ray Tubes Used in CyberKnife Image Guidance System

    Purpose: The use of image-guided radiation therapy (IGRT) has become increasingly common, but the additional radiation exposure resulting from repeated image guidance procedures raises concerns. Although there are many studies reporting imaging dose from different image guidance devices, imaging dose for the CyberKnife Robotic Radiosurgery System is not available. This study provides estimated organ doses resulting from image guidance procedures on the CyberKnife system. Methods: Commercially available Monte Carlo software, PCXMC, was used to calculate average organ doses resulting from x-ray tubes used in the CyberKnife system. There are seven imaging protocols with kVp ranging from 60 – 120 kV and 15 mAs for treatment sites in the Cranium, Head and Neck, Thorax, and Abdomen. The output of each image protocol was measured at treatment isocenter. For each site and protocol, Adult body sizes ranging from anorexic to extremely obese were simulated since organ dose depends on patient size. Doses for all organs within the imaging field-of-view of each site were calculated for a single image acquisition from both of the orthogonal x-ray tubes. Results: Average organ doses were <1.0 mGy for every treatment site and imaging protocol. For a given organ, dose increases as kV increases or body size decreases. Higher doses are typically reported for skeletal components, such as the skull, ribs, or clavicles, than for softtissue organs. Typical organ doses due to a single exposure are estimated as 0.23 mGy to the brain, 0.29 mGy to the heart, 0.08 mGy to the kidneys, etc., depending on the imaging protocol and site. Conclusion: The organ doses vary with treatment site, imaging protocol and patient size. Although the organ dose from a single image acquisition resulting from two orthogonal beams is generally insignificant, the sum of repeated image acquisitions (>100) could reach 10–20 cGy for a typical treatment fraction

  16. SU-E-J-06: Additional Imaging Guidance Dose to Patient Organs Resulting From X-Ray Tubes Used in CyberKnife Image Guidance System

    Sullivan, A; Ding, G [Vanderbilt University, Nashville, TN (United States)

    2015-06-15

    Purpose: The use of image-guided radiation therapy (IGRT) has become increasingly common, but the additional radiation exposure resulting from repeated image guidance procedures raises concerns. Although there are many studies reporting imaging dose from different image guidance devices, imaging dose for the CyberKnife Robotic Radiosurgery System is not available. This study provides estimated organ doses resulting from image guidance procedures on the CyberKnife system. Methods: Commercially available Monte Carlo software, PCXMC, was used to calculate average organ doses resulting from x-ray tubes used in the CyberKnife system. There are seven imaging protocols with kVp ranging from 60 – 120 kV and 15 mAs for treatment sites in the Cranium, Head and Neck, Thorax, and Abdomen. The output of each image protocol was measured at treatment isocenter. For each site and protocol, Adult body sizes ranging from anorexic to extremely obese were simulated since organ dose depends on patient size. Doses for all organs within the imaging field-of-view of each site were calculated for a single image acquisition from both of the orthogonal x-ray tubes. Results: Average organ doses were <1.0 mGy for every treatment site and imaging protocol. For a given organ, dose increases as kV increases or body size decreases. Higher doses are typically reported for skeletal components, such as the skull, ribs, or clavicles, than for softtissue organs. Typical organ doses due to a single exposure are estimated as 0.23 mGy to the brain, 0.29 mGy to the heart, 0.08 mGy to the kidneys, etc., depending on the imaging protocol and site. Conclusion: The organ doses vary with treatment site, imaging protocol and patient size. Although the organ dose from a single image acquisition resulting from two orthogonal beams is generally insignificant, the sum of repeated image acquisitions (>100) could reach 10–20 cGy for a typical treatment fraction.

  17. Additional Interventions to Enhance the Effectiveness of Individual Placement and Support: A Rapid Evidence Assessment

    Naomi Boycott

    2012-01-01

    Full Text Available Topic. Additional interventions used to enhance the effectiveness of individual placement and support (IPS. Aim. To establish whether additional interventions improve the vocational outcomes of IPS alone for people with severe mental illness. Method. A rapid evidence assessment of the literature was conducted for studies where behavioural or psychological interventions have been used to supplement standard IPS. Published and unpublished empirical studies of IPS with additional interventions were considered for inclusion. Conclusions. Six published studies were found which compared IPS alone to IPS plus a supplementary intervention. Of these, three used skills training and three used cognitive remediation. The contribution of each discrete intervention is difficult to establish. Some evidence suggests that work-related social skills and cognitive training are effective adjuncts, but this is an area where large RCTs are required to yield conclusive evidence.

  18. Dose related risk and effect assessment model (DREAM) -- A more realistic approach to risk assessment of offshore discharges

    Risk assessment of discharges from offshore oil and gas production to the marine environment features determination of potential environmental concentration (PEC) levels and no observed effect concentration (NOEC) levels. The PEC values are normally based on dilution of chemical components in the actual discharge source in the recipient, while the NOEC values are determined by applying a safety factor to acute toxic effects from laboratory tests. The DREAM concept focuses on realistic exposure doses as function of contact time and dilution, rather than fixed exposure concentrations of chemicals in long time exposure regimes. In its present state, the DREAM model is based on a number of assumptions with respect to the link between real life exposure doses and effects observed in laboratory tests. A research project has recently been initiated to develop the concept further, with special focus on chronic effects of different chemical compounds on the marine ecosystem. One of the questions that will be addressed is the link between exposure time, dose, concentration and effect. Validation of the safety factors applied for transforming acute toxic data into NOEC values will also be included. The DREAM model has been used by Statoil for risk assessment of discharges from new and existing offshore oil and gas production fields, and has been found to give a much more realistic results than conventional risk assessment tools. The presentation outlines the background for the DREAM approach, describes the model in its present state, discusses further developments and applications, and shows a number of examples on the performance of DREAM

  19. Assessment of the occupational radiation exposure doses to workers at INMOL Pakistan (2007-11)

    The assessment of occupationally exposed medical radiation workers at the Institute of Nuclear Medicine and Oncology (INMOL) (Pakistan)) has been performed. The whole-body radiation exposure doses of 120 workers in nuclear medicine (NM), radiotherapy (RT) and diagnostic radiology (DR) were measured by using the film badge dosimetry technique for the time interval (2007-11) and their results presented. The annual average effective doses in NM, RT and DR were found to be well below the permissible annual limit of 20 mSv (averaged over a period of 5 consecutive y). The declining trend observed in the annual average dose values during the time interval (2007-11) is an indication of ameliorated radiation protection practices at INMOL (Pakistan)). (authors)

  20. Blast overpressure and fallout radiation dose models for casualty assessment and other purposes. Rev. ed.

    The determination of blast overpressures and fallout radiation doses at points on a sufficiently fine grid, for any part or for the whole of the UK, and for any postulated attack, is an essential element in the systematic assessment of casualties, the estimation of numbers of homeless, and the evaluation of life-saving measures generally. Models are described which provide the required blast and dose values and which are intended to supersede existing models which were introduced in 1971. The factors which affect blast and, more particularly, dose values are discussed, and the way in which various factors are modelled is described. The models are incorporated into separate computer programs which are described, the outputs of which are stored on magnetic tape for subsequent use as required. (author)

  1. A preliminary assessment of potential doses to man from radioactive waste dumped in the Arctic Sea

    This report describes a preliminary radiological assessment of collective doses to the world population from radioactive material dumped in the Barents and Kara Seas in the period 1961-1991. Information on the dumped waste and the rates of release of radionuclides have been available from Russian sources and from the International Atomic Energy Agency. A box model has been used to simulate the dispersion of radionuclides in the marine environment and to calculate the contamination of seafood and the subsequent radiation doses to man. Two release scenarios have been adopted. The worst-case release scenario which ignores the presence of barriers between spent nuclear fuel and seawater is estimated to give rise to about 10 mansieverts calculated to 1000 years from the time of release. A more realistic release scenario is estimated to cause about 3 mansieverts. In both cases exposure from the radionuclide 137Cs is found to dominate the doses. (au) 8 tabs., 56 ills., 19 refs

  2. A preliminary assessment of potential doses to man from radioactive waste dumped in the Arctic sea

    This report describes a preliminary radiological assessment of collective doses to the world population from radioactive material dumped in the Kara and Barents Seas in the period 1961-1991. Information on the dumped waste and the rates of release of radionuclides have been available from Russian sources and from the International Atomic Energy Agency. A box model has been used to simulate the dispersion of radionuclides in the marine environment and to calculate the contamination of seafood and the subsequent radiation doses to man. Two release scenarios have been adopted. The worst-case release scenario, which ignores the presence of barriers between spent nuclear fuel and seawater, is estimated to give rise to about 10 mansievert calculated to 1000 years from the time of release. A more realistic release scenario is estimated to cause about 3 mansieverts. In both cases exposure from the radionuclide 137Cs is found to dominate the doses. 19 refs., 56 figs., 8 tabs

  3. EPR-assessment of soils radiation doses for Semipalatinsk test site's north-east trace

    The dose loads are an important characteristics of potential damage assessment for health of population suffered from nuclear incidents. Technique of retrospective dosimetry allows to evaluate of these loads, if to find in the soils samples the radiation detector - for example, some mineral - in which in the locality conditions the radiation defects are accumulating and keeping and giving the EPR signal. In the paper the results of searching of such detector to Semipalatinsk test site soils samples are expounded.The samples were taken along the north-east trace of radioactive cloud (step ∼2 km) on the distance 0.7-112 km from the air thermonuclear explosion epicenter. Te EPR performances were studied on the ESP 300E spectrometer of Brucker company (Germany). The tested methodic is perspective for determination of dose loads of soils with integral irradiation dose does not exceeds 10-15 kGy

  4. Shutdown dose rate assessment with the Advanced D1S method: Development, applications and validation

    Villari, R., E-mail: rosaria.villari@enea.it [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Fischer, U. [Karlsruhe Institute of Technology KIT, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Moro, F. [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Pereslavtsev, P. [Karlsruhe Institute of Technology KIT, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Petrizzi, L. [European Commission, DG Research and Innovation K5, CDMA 00/030, B-1049 Brussels (Belgium); Podda, S. [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Serikov, A. [Karlsruhe Institute of Technology KIT, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2014-10-15

    Highlights: Development of Advanced-D1S for shutdown dose rate calculations; Recent applications of the tool to tokamaks; Summary of the results of benchmarking with measurements and R2S calculations; Limitations and further development. Abstract: The present paper addresses the recent developments and applications of Advanced-D1S to the calculations of shutdown dose rate in tokamak devices. Results of benchmarking with measurements and Rigorous 2-Step (R2S) calculations are summarized and discussed as well as limitations and further developments. The outcomes confirm the essential role of the Advanced-D1S methodology and the evidence for its complementary use with the R2Smesh approach for the reliable assessment of shutdown dose rates and related statistical uncertainties in present and future fusion devices.

  5. Shutdown dose rate assessment with the Advanced D1S method: Development, applications and validation

    Highlights: •Development of Advanced-D1S for shutdown dose rate calculations. •Recent applications of the tool to tokamaks. •Summary of the results of benchmarking with measurements and R2S calculations. •Limitations and further development. -- Abstract: The present paper addresses the recent developments and applications of Advanced-D1S to the calculations of shutdown dose rate in tokamak devices. Results of benchmarking with measurements and Rigorous 2-Step (R2S) calculations are summarized and discussed as well as limitations and further developments. The outcomes confirm the essential role of the Advanced-D1S methodology and the evidence for its complementary use with the R2Smesh approach for the reliable assessment of shutdown dose rates and related statistical uncertainties in present and future fusion devices

  6. 3D delivered dose assessment using a 4DCT-based motion model

    Cai, Weixing; Hurwitz, Martina H.; Williams, Christopher L.; Dhou, Salam; Berbeco, Ross I.; Mishra, Pankaj, E-mail: wcai@lroc.harvard.edu, E-mail: jhlewis@lroc.harvard.edu; Lewis, John H., E-mail: wcai@lroc.harvard.edu, E-mail: jhlewis@lroc.harvard.edu [Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115 (United States); Seco, Joao [Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02115 (United States)

    2015-06-15

    reconstructed from kV and MV projections compared to the ground truth, which is clinically comparable to 4DCT (0.093%). For the second XCAT phantom that has an irregular breathing pattern, the errors are 0.81% and 1.75% for kV and MV reconstructions, both of which are better than that of 4DCT (4.01%). In the case of real patient, although it is impossible to obtain the actual delivered dose, the dose estimation is clinically reasonable and demonstrates differences between 4DCT and MV reconstruction-based dose estimates. Conclusions: With the availability of kV or MV projection images, the proposed approach is able to assess delivered doses for all respiratory phases during treatment. Compared to the planning dose based on 4DCT, the dose estimation using reconstructed 3D fluoroscopic images was as good as 4DCT for regular respiratory pattern and was a better dose estimation for the irregular respiratory pattern.

  7. In vivo assessment of catheter positioning accuracy and prolonged irradiation time on liver tolerance dose after single-fraction 192Ir high-dose-rate brachytherapy

    To assess brachytherapy catheter positioning accuracy and to evaluate the effects of prolonged irradiation time on the tolerance dose of normal liver parenchyma following single-fraction irradiation with 192 Ir. Fifty patients with 76 malignant liver tumors treated by computed tomography (CT)-guided high-dose-rate brachytherapy (HDR-BT) were included in the study. The prescribed radiation dose was delivered by 1 - 11 catheters with exposure times in the range of 844 - 4432 seconds. Magnetic resonance imaging (MRI) datasets for assessing irradiation effects on normal liver tissue, edema, and hepatocyte dysfunction, obtained 6 and 12 weeks after HDR-BT, were merged with 3D dosimetry data. The isodose of the treatment plan covering the same volume as the irradiation effect was taken as a surrogate for the liver tissue tolerance dose. Catheter positioning accuracy was assessed by calculating the shift between the 3D center coordinates of the irradiation effect volume and the tolerance dose volume for 38 irradiation effects in 30 patients induced by catheters implanted in nearly parallel arrangement. Effects of prolonged irradiation were assessed in areas where the irradiation effect volume and tolerance dose volume did not overlap (mismatch areas) by using a catheter contribution index. This index was calculated for 48 irradiation effects induced by at least two catheters in 44 patients. Positioning accuracy of the brachytherapy catheters was 5-6 mm. The orthogonal and axial shifts between the center coordinates of the irradiation effect volume and the tolerance dose volume in relation to the direction vector of catheter implantation were highly correlated and in first approximation identically in the T1-w and T2-w MRI sequences (p = 0.003 and p < 0.001, respectively), as were the shifts between 6 and 12 weeks examinations (p = 0.001 and p = 0.004, respectively). There was a significant shift of the irradiation effect towards the catheter entry site compared with the

  8. Assessment of doses and risk due to natural radionuclides in edible biota of Domiasiat, Meghalaya.

    Kumar, N; Chaturvedi, S S; Jha, S K

    2012-07-01

    A radiation dose assessment exercise was carried out for the edible biota Solanum nigrum, Carica papaya, Raphnus sativum and Phaseolus domesticus due to naturally available radionuclides (40)K, (238)U and (232)Th in the Domiasiat area in Meghalaya, India. The concentration of radionuclides in biota and corresponding soil was measured by the NaI(Tl) detector having a minimum detection limit (efficiency, 32.4%) and machine counting time of 3000 s. The obtained transfer factor for (40)K was 0.3061, 0.7163, 0.1988 and 0.1279, for (232)Th 0.0003, 2.22E-05, 2.71E-05 and 3.45E-05 and for (238)U 1.46E-05, 9.73E-05, 1.46E-05 and 3.11E-05 (ratio) in each biota, respectively. The detailed physiological and morphological study of the biota was carried out. The point source dose distribution (source↔target) hypothesis was applied for the radiation absorbed fraction. The generated data were modelled using FASSET and obtained un-weighted total dose was 1.78E-04, 6.84E-03, 8.46E-03 and 1.73E-04 μGy h(-1), respectively, finally compared with the IAEA and UNSCEAR data set for screening level dose risk assessment. PMID:22155750

  9. ARN Training on Advance Methods for Internal Dose Assessment: Application of Ideas Guidelines

    Dose assessment in case of internal exposure involves the estimation of committed effective dose based on the interpretation of bioassay measurement, and the assumptions of hypotheses on the characteristics of the radioactive material and the time pattern and the pathway of intake. The IDEAS Guidelines provide a method to harmonize dose evaluations using criteria and flow chart procedures to be followed step by step. The EURADOS Working Group 7 'Internal Dosimetry', in collaboration with IAEA and Czech Technical University (CTU) in Prague, promoted the 'EURADOS/IAEA Regional Training Course on Advanced Methods for Internal Dose Assessment: Application of IDEAS Guidelines' to broaden and encourage the use of IDEAS Guidelines, which took place in Prague (Czech Republic) from 2-6 February 2009. The ARN identified the relevance of this training and asked for a place for participating on this activity. After that, the first training course in Argentina took place from 24-28 August for training local internal dosimetry experts. This paper resumes the main characteristics of this activity. (authors)

  10. Dose assessment, radioecology, and community interaction at former nuclear test sites

    The US conducted a nuclear testing program at Bikini and Enewetak Atolls in the Marshall Islands from 1946 through 1958. A total of 66 nuclear devices were tested--23 at Bikini Atoll (total yield of 77 megatons) and 43 at Enewetak Atoll (total yield of 33 megatons). This resulted in contamination of many of the islands at each atoll. The BRAVO test (yield 15 megatons) on March 1, 1954 contaminated several atolls to the east of Bikini Atoll some of which were inhabited. The author has conducted an experimental, monitoring, and dose assessment program at atolls in the northern Marshall Islands for the past 20 years. The goals have been to: (1) determine the radiological conditions at the atolls; (2) provide dose assessments for resettlement options and alternate living patterns; (3) develop and evaluate remedial measures to reduce the dose to people reinhabiting the atolls; and (4) discuss the results with each of the communities and the Republic of the Marshall Islands government officials to help them understand the data as a basis for resettlement decisions. The remaining radionuclides at the atolls that contribute any significant dose are 137Cs, 90Sr, 239+240Pu, and 241Am

  11. Development of a dose assessment computer code for the NPP severe accident

    A real-time emergency dose assessment computer code called KEDA (KAIST NPP Emergency Dose Assessment) has been developed for the NPP severe accident. A new mathematical model which can calculate cloud shine has been developed and implemented in the code. KEDA considers the specific Korean situations(complex topography, orientals' thyroid metabolism, continuous washout, etc.), and provides functions of dose-monitoring and automatic decision-making. To verify the code results, KEDA has been compared with an NRC officially certified code, RASCAL, for eight hypertical accident scenarios. Through the comparison, KEDA has been proved to provide reasonable results. Qualitative sensitivity analysis also the been performed for potentially important six input parameters, and the trends of the dose v.s. down-wind distance curve have been analyzed comparing with the physical phenomena occurred in the real atmosphere. The source term and meteorological conditions are turned out to be the most important input parameters. KEDA also has been applied to simulate Kori site and a hyperthetical accident with semi-real meteorological data has been simulated and analyzed

  12. MCNP Code in Assessment of Variations of Effective Dose with Torso Adipose Tissue Thickness

    The effective dose is the unite used in the field of radiation protection. It is a well defined doubly weighted uantity involving both physical and biological variables. Several factors may induce variation in the effective dose in different individuals of similar exposure data. One of these factors is the variation of adipose tissue thickness in different exposed individuals. This study essentially concenrs the assessment of the possible variation in the effective dose due to variation in the thickness of adipose tissue. The study was done using MCNP4b code to perform mathematical model of the human body depending on that given to the reference man developed by International Commission of Radiological Protection (ICRP), and calculate the effective dose with different thicknessess of adipose tissues. The study includes a comprehensive appraisal of the Monte Cario simulation, the Medical Internal Radiation Dose (MIRD) model for the human body, and the various mathematical considerations involved in the radiation dose calculations for the various pertinent parts of the human body. The radiation energies considered were 80 KeV, 300 KeV and I MeV, applying two exposure positions; anteroposterior (AP), postero-anterior (PA) with different adipose tissue thickness. This study is a theoretical approach based on detailed mathematical calculations of great precision that deals with all considerations involved in the mechanisms of radiation energy absorption in biological system depending on the variation in the densities of the particular in biological system depending on the variation in the densities of the particular tissues. The results obtained indicate that maximum decrease in effective dose occures with the lowest energy at 5cm adipose tissues thickeness for both AP and PA exposure positions. The results obtained were compared to similar work previsouly done using MCNP4 b showing very good agreement

  13. Assessment of neutron dose in Indus accelerator complex using CR-39 SSNTD

    Indus accelerator complex (IAC) consists of two synchrotron radiation sources namely Indus-1 and Indus-2. The radiation environment here is mainly due to Bremsstrahlung and photo-neutrons. Major problems faced in neutron detection in IAC are the severely pulsed nature and gamma (Bremsstrahlung) interference. Thus, to assess the neutron dose rates in the accessible and inaccessible areas of IAC, passive integrating type neutron detectors CR-39 and bubble detectors are used. The dose rates observed at microtron body; booster injection and extraction septum are significant (few mSv/h) when compared to other locations in IAC. From bubble detector data, it can be seen that the dose rate during injection is high (maximum 112 μSv/h) compared with storage mode (maximum 2.6 μSv/h) indicating high beam loss during injection. During the injection, the personnel are not allowed in these areas due to high radiation doses on account of the beam loss. The neutron dose rates observed for accessible areas are three orders of magnitude less than the inaccessible areas in the complex. (author)

  14. Evaluation of the dose assessment models for routine radioactive releases to the environment

    The aim of the work was to evaluate the needs of development concerning the dose calculation models for routine releases and application of the models for exceptional release situations at the NPP plants operated by Imatran Voima Ltd. and Teollisuuden Voima Ltd. in Finland. First, the differences of the calculation models concerning input data, models themselves and output are considered. Subsequently some single features like importance of nuclides in exposure pathways due to change of the release composition, dose calculation for children and importance of time period of particle releases are considered. The existing dose calculation model used by the radiation safety authorities is aimed at a tool for checking the results from calculations of doses arising from routine releases by the power companies. Characteristics of an independent, foreign model and its suitability for safety authorities for dose calculations of releases in normal operation is also assessed. The needs of improvements in the existing calculation models and characteristics of a comprehensive model for safety authorities are discussed as well

  15. Radiological characterization of tap waters in Croatia and the age dependent dose assessment.

    Rožmarić, Martina; Rogić, Matea; Benedik, Ljudmila; Barišić, Delko; Planinšek, Petra

    2014-09-01

    Activity concentrations of (234)U, (238)U, (226)Ra, (228)Ra, (210)Po and (210)Pb in tap waters, originating from various geological regions of Croatia, were determined. Activity concentrations of measured radionuclides are in general decreasing in this order: (238)U≈(234)U>(228)Ra≈(210)Pb>(226)Ra≈(210)Po. Based on the radionuclide activity concentrations average total annual internal doses for infants, children and adults, as well as contribution of each particular radionuclide to total dose, were assessed and discussed. The highest doses were calculated for infants, which makes them the most critical group of population. All values for each population group were well below the recommended reference dose level (RDL) of 0.1mSv from one year's consumption of drinking water according to European Commission recommendations from 1998. Contribution of each particular radionuclide to total doses varied among different age groups but for each group the lowest contribution was found for (226)Ra and the highest for (228)Ra. PMID:24997928

  16. Adult medical x-ray dose assessments for computed tomography procedures in Ghana: a review

    Adult Computed Tomography (CT) examinations and dose assessments for head, chest, abdomen, lumbar spine and pelvis at six CT Facilities in Ghana were undertaken (with approval from management of the participating hospitals). The dosimetric parameters estimated were volume computerized tomography dose index (CTDIvol), dose length product (DLP), and effective dose (E) for the stochastic radiation risk of a non-uniform exposure in terms of whole body exposure. For the 39429 examinations, routine head and chest accounted for 50.6 % and 17.0 % frequency, while abdomen, lumbar spine and pelvis accounted for 11.3 %, 10.9 %, and 10.6 % respectively. Among the Facilities, CTDIvol, DLP and E values varied respectively by a factor of 2.7 for chest and abdomen, 3.5 for chest and 3.4 for chest. The mean CTDIvol for all the examinations and mean DLP values for head, abdomen and lumbar spine were below the European Commission diagnostic reference levels, while mean DLP of chest and pelvis exceeded the reference levels by 2 and 6 % respectively. With increase in frequency of CT examinations in Ghana, National Reference Levels should be established for patient dose management system. (au)

  17. Internal dose assessment data management system for a large population of Pu workers.

    Bertelli, L; Miller, G; Little, T; Guilmette, R A; Glasser, S M

    2007-01-01

    This paper describes the design and implementation of the Los Alamos National Laboratory (LANL) dose assessment (DA) data system. Dose calculations for the most important radionuclides at LANL, namely plutonium, americium, uranium and tritium, are performed through the Microsoft Access DA database. DA includes specially developed forms and macros that perform a variety of tasks, such as retrieving bioassay data, launching the FORTRAN internal dosimetry applications and displaying dose results in the form of text summaries and plots. The DA software involves the following major processes: (1) downloading of bioassay data from a remote data source, (2) editing local and remote databases, (3) setting up and carrying out internal dose calculations using the UF code or the ID code, (3) importing results of the dose calculations into local results databases, (4) producing a secondary database of 'official results' and (5) automatically creating and e-mailing reports. The software also provides summary status and reports of the pending DAs, which are useful for managing the cases in process. PMID:17925307

  18. Applying the PCXMCR software for dose assessment in patients submitted to chest and skull X-ray examinations

    The International Commission of radiation and Units (ICRU) has recommended the use of Monte Carlo calculation software to assess the organ doses in patient undergoing x-ray examinations. The PCXMCR is a largely used computational program for assessing organ doses in chest and skull diagnostic radiology. The aim of this work was assess doses in critical and relevant organs of several patients in a hospital in Belo Horizonte, Minas Gerais. The work was done by recording the patient and geometrical data during several exams in the xray sectors of the hospital. Patients were classified according to their biotype as A, B and C and they were chosen for dose assessment s. Patients A, B and C have the smallest, the medium and the largest dimensions, respectively. Simulation was dose using the PCXMCR and organ doses were assessed. Analyses were carried out only for the highest exposed organs in terms of their contribution to the effective dose; doses due to the posteroanterior followed by lateral projections were added. During the chest examinations, the lungs got the highest doses. The lung doses were 23.5, 33.6, 45.4 μSv in patients A, B and C, respectively. During the skull examinations, the thyroid was the critical organ that gave the highest contribution to the effective dose. The thyroid doses were 30.5, 27.6 and 22.3 μSv, in patient A, B and C, respectively. Doses variations suggested that there is space for standardization of the radiological techniques and for optimizing the radiographic procedures to reduce patient doses. (author)

  19. A method for assessing the annual dose to the most exposed individual from tritium and 14C reactor discharges to atmosphere

    A method is described for assessing the annual dose to the most exposed individual from routine releases of tritium and 14C to the atmosphere during normal reactor operations. A detailed assessment has been made of the resulting equilibrium contamination levels in a range of foodstuffs typical of an average UK diet and of the annual doses resulting from a chronic intake of tritium and 14C via inhalation, ingestion and, additionally, in the case of tritium, via skin absorption. Equilibrium annual doses from the global circulation of tritium and 14C have also been calculated. Upper limits to the effective annual dose-equivalents to the most exposed individual were found to be 0.6 rem.yr-1 and 100 rem.yr-1 per Ci.yr-1 release of tritium and 14C respectively, with the ingestion pathway contributing significantly to the overall exposure. The most exposed individual was found to be a Reference 10 year old child. The methods outlined for calculating the ingestion dose from tritium and 14C releases hav been incorporated into the more generally applicable code FOODDOSE. The code may be used to make more realistic dose calculations to the individuals based on site-specific surveys of variables such as local meteorology, local diet and local land use for agriculture, which may lead to doses smaller than the upper limit values quoted by factors of 20 and 200 for tritium and 14C respectively. (author)

  20. Radiation-induced biomarkers for the detection and assessment of absorbed radiation doses

    Sudha Rana

    2010-01-01

    Full Text Available Radiation incident involving living organisms is an uncommon but a very serious situation. The first step in medical management including triage is high-throughput assessment of the radiation dose received. Radiation exposure levels can be assessed from viability of cells, cellular organelles such as chromosome and different intermediate metabolites. Oxidative damages by ionizing radiation result in carcinogenesis, lowering of the immune response and, ultimately, damage to the hematopoietic system, gastrointestinal system and central nervous system. Biodosimetry is based on the measurement of the radiation-induced changes, which can correlate them with the absorbed dose. Radiation biomarkers such as chromosome aberration are most widely used. Serum enzymes such as serum amylase and diamine oxidase are the most promising biodosimeters. The level of gene expression and protein are also good biomarkers of radiation.

  1. Monitoring and assessment of individual doses of occupationally exposed workers due to external radiation

    Exposure to external radiation occurs in many occupations. Any exposure to ionizing radiation has the tendency to change the biochemical make-up of the human body which may result in biological health effects of ionizing radiation. This study reviews the monitoring and assessment of external radiation doses in industrial radiography using thermoluminescence and direct reading dosimeters. Poor handling procedures such as inadequate engineering control of equipment, safety culture, management, and inadequate assessment and monitoring of doses are the causes of most of the reported cases of exposure to external radiation in industrial radiography. Occupational exposure data in industrial radiography taken from UNSCEAR report 2008 was discussed and recommendations were made to regulatory authorities, operating organizations and radiographers. (au)

  2. Monitoring and assessment of individual doses of occupationally exposed workers due to external radiation

    Exposure to external radiation occurs in many occupations. Any exposure to ionizing radiation has the tendency to change the biochemical make-up of the human body which may result in biological health effects of ionizing radiation. This study reviews the monitoring and assessment of external radiation doses in industrial radiography using thermoluminescence and direct reading dosimeters. Poor handling procedures such as inadequate engineering control of equipment, safety culture, management, and inadequate assessment and monitoring of doses are the causes of most of the reported cases of exposure to external radiation in industrial radiography. Occupational exposure data in industrial radiography from UNSCEAR report 2008 was discussed and recommendations were made to regulatory authorities, operating organizations and radiographers. (au)

  3. Assessment of individual dose equivalents Hp(0.07 of medical staff occupationally exposed to ionizing radiation in 2012

    Sylwia Papierz

    2014-04-01

    Full Text Available Background: The paper presents the Nofer Institutes of Occupational Medicine in Łódź's results of the assessment of individual dose equivalents Hp(0.07 of medical staff exposed to X-rays in Poland in 2012. In addition, the collected data was analysed in terms of types of medical units performing medical procedures and the categorization of personnel. Material and Methods: Dosimetric service was provided for medical staff of interventional radiology departments occupationally exposed to ionizing radiation in terms of individual dose equivalents Hp(0.07. In 2012, personal dosimetry Hp(0.07 determinations were performed by the Nofer Institute of Occupational Medicine in Łódź and covered 2044 employees from 174 health facilities. The determinations were performed using thermoluminescence dosimetry according to the procedure accredited by the Polish Centre for Accreditation (document number AB 327. The measurements were performed using ring-dosimeters in the periods of 1 or 2 months. Results: Mean annual individual dose equivalent Hp(0.07 in 2012 was equal to 3.3 mSv (annual limit for Hp(0.07 is 500 mSv. The average value of annual individual dose equivalent Hp(0.07 decreased comparing to the previous year. In 2012, no single case of exceeding the annual limit for Hp(0.07 was reported. Data stored in the file indicates that more than 96% of all of the annual doses did not exceed the level of 10 mSv. Conclusions: The analysis of data on occupational exposure to ionizing radiation confirms a stable level of exposure and satisfactory radiological protection in interventional radiology facilities monitored by the Nofer Institute of Occupational Medicine in Łódź in Poland in 2012. Med Pr 2014;65(2:167–171

  4. Naturally occurring radioactivity in some Swedish concretes and their constituents - Assessment by using I-index and dose-model.

    Döse, M; Silfwerbrand, J; Jelinek, C; Trägårdh, J; Isaksson, M

    2016-05-01

    The reference level for effective dose due to gamma radiation from building materials and construction products used for dwellings is set to 1 mSv per year (EC, 1996, 1999), (CE, 2014). Given the specific conditions presented by the EC in report 112 (1999) considering building and construction materials, an I-index of 1 may generate an effective dose of 1 mSv per year. This paper presents a comparison of the activity concentrations of (4)(0)K, (226)Ra and (232)Th of aggregates and when these aggregates constitute a part of concrete. The activity concentration assessment tool for building and construction materials, the I-index, introduced by the EC in 1996, is used in the comparison. A comparison of the I-indices values are also made with a recently presented dose model by Hoffman (2014), where density variations of the construction material and thickness of the construction walls within the building are considered. There was a ∼16-19% lower activity index in concretes than in the corresponding aggregates. The model by Hoffman further implies that the differences between the I-indices of aggregates and the concretes' final effective doses are even larger. The difference is due, mainly to a dilution effect of the added cement with low levels of natural radioisotopes, but also to a different and slightly higher subtracted background value (terrestrial value) used in the modeled calculation of the revised I-index by Hoffman (2014). Only very minimal contributions to the annual dose could be related to the water and additives used, due to their very low content of radionuclides reported. PMID:26942843

  5. Sensitivity Analysis of Input Parameters for the Dose Assessment from Gaseous Effluents due to the Normal Operation of Jordan Research and Training Reactor

    In this study, therefore, the sensitivity analysis of input variables for the dose assessment was performed for reviewing the effect of each parameter on the result after determining the type and range of parameters that could affect the exposure dose of the public. (Since JRTR will be operated by the concept of 'no liquid discharge,' the input parameters used for calculation of dose due to liquid effluents are not considered in the sensitivity analysis.) In this paper, the sensitivity analysis of input parameters for the dose assessment in the vicinity of the site boundary due to gaseous effluents was performed for a total of thirty-five (35) cases. And, detailed results for the input variables that have an significant effect are shown in Figures 1 through 7, respectively. For preparing a R-ER for the operating license of the JRTR, these results will be updated by the additional information and could be applied to predicting the variation trend of the exposure dose in the process of updating the input parameters for the dose assessment reflecting the characteristics of the JRTR site

  6. Sensitivity Analysis of Input Parameters for the Dose Assessment from Gaseous Effluents due to the Normal Operation of Jordan Research and Training Reactor

    Kim, Sukhoon; Lee, Seunghee; Kim, Juyoul; Kim, Juyub [FNC Technology Co., Ltd., Yongin (Korea, Republic of); Han, Moonhee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    In this study, therefore, the sensitivity analysis of input variables for the dose assessment was performed for reviewing the effect of each parameter on the result after determining the type and range of parameters that could affect the exposure dose of the public. (Since JRTR will be operated by the concept of 'no liquid discharge,' the input parameters used for calculation of dose due to liquid effluents are not considered in the sensitivity analysis.) In this paper, the sensitivity analysis of input parameters for the dose assessment in the vicinity of the site boundary due to gaseous effluents was performed for a total of thirty-five (35) cases. And, detailed results for the input variables that have an significant effect are shown in Figures 1 through 7, respectively. For preparing a R-ER for the operating license of the JRTR, these results will be updated by the additional information and could be applied to predicting the variation trend of the exposure dose in the process of updating the input parameters for the dose assessment reflecting the characteristics of the JRTR site.

  7. Environmental dose rate assessment of ITER using the Monte Carlo method

    Karimian Alireza; Beheshti Amir; Abdi Mohammadreza; Jabbari Iraj

    2014-01-01

    Exposure to radiation is one of the main sources of risk to staff employed in reactor facilities. The staff of a tokamak is exposed to a wide range of neutrons and photons around the tokamak hall. The International Thermonuclear Experimental Reactor (ITER) is a nuclear fusion engineering project and the most advanced experimental tokamak in the world. From the radiobiological point of view, ITER dose rates assessment is particularly important. The aim of th...

  8. Assessment of radiation protection awareness and knowledge about radiological examination doses among Italian radiographers

    Paolicchi, F.; Miniati, F.; Bastiani, L; Faggioni, L; Ciaramella, A.; Creonti, I.; Sottocornola, C.; Dionisi, C.; Caramella, D.

    2015-01-01

    Objectives To evaluate radiation protection basic knowledge and dose assessment for radiological procedures among Italian radiographers Methods A validated questionnaire was distributed to 780 participants with balanced demographic characteristics and geographic distribution. Results Only 12.1 % of participants attended radiation protection courses on a regular basis. Despite 90 % of radiographers stating to have sufficient awareness of radiation protection issues, most of them underestimated...

  9. Introduction: Endocrine disruptors-exposure assessment, novel end points, and low-dose and mixture effects

    Kortenkamp, A

    2007-01-01

    With the aim of discussing new research findings about chemicals able to interfere with the endocrine system, so-called endocrine disruptors, an international workshop was held in Prague, Czech Republic, 10–12 May 2005. The workshop was organized jointly by the EDEN project (Endocrine Disrupters: Exploring Novel Endpoints, Exposure, Low-Dose and Mixture-Effects in Humans, Aquatic Wildlife and Laboratory Animals; http://www.edenresearch.info) and the FIRE project (Risk Assessment of Bromina...

  10. Summary of comparative assessment of US and foreign Nuclear Power Plant dose experience

    Data gathered at the 1984 BNL Workshop on Historical Dose Experience and Dose Reduction (ALARA) at Nuclear Power Plants and from recently published literature were reviewed and analyzed. Large differences were noted, between countries and between similar plants, for collective dose (man-rem) per plant and per unit of electricity generated (MWe-yr). During the period 1978-1982, for PWRs, the US ranked highest in terms of collective dose per MWe-yr (1.2), and France, Sweden, and Finland were lowest (0.27 to 0.37). For BWRs, Japan, the US, and the Federal Republic of Germany ranked highest (2.2 to 1.9), and Finland and Sweden were lowest (0.08 to 0.32). Only a small portion of the differences could be attributed to average plant age, vintage, or rated capacity. Fifteen factors were identified (in addition to age) which contribute to differences. In estimated order of importance, these were plant chemistry, water purification, materials selection for low cobalt and nickel, special tools, decontamination of primary systems, required multi-plant actions, worker motivation and commitment, permanent work force, management commitment to dose control, three or more reactors per site, design for reliability, passivation of primary systems, quality assurance, standardized plant design, and shielding. 49 refs

  11. VARSKIN MOD 2 and SADDE MOD2: Computer codes for assessing skin dose from skin contamination

    The computer code VARSKIN has been modified to calculate dose to skin from three-dimensional sources, sources separated from the skin by layers of protective clothing, and gamma dose from certain radionuclides correction for backscatter has also been incorporated for certain geometries. This document describes the new code, VARSKIN Mod 2, including installation and operation instructions, provides detailed descriptions of the models used, and suggests methods for avoiding misuse of the code. The input data file for VARSKIN Mod 2 has been modified to reflect current physical data, to include the contribution to dose from internal conversion and Auger electrons, and to reflect a correction for low-energy electrons. In addition, the computer code SADDE: Scaled Absorbed Dose Distribution Evaluator has been modified to allow the generation of scaled absorbed dose distributions for mixtures of radionuclides and intereat conversion and Auger electrons. This new code, SADDE Mod 2, is also described in this document. Instructions for installation and operation of the code and detailed descriptions of the models used in the code are provided

  12. Emergency preparedness in Finland: improvement of the measurement equipment used in the assessment of internal doses

    The need for assessing internal radiation doses in emergency situations is evident. Internal exposure can be assessed using direct measurement results or by using information on activity concentrations in inhaled air and in foodstuffs combined with inhalation and consumption data. As a part of the continuous improving of emergency preparedness in Finland, S.T.U.K. - Radiation and Nuclear Safety Authority has obtained 35 monitors for thyroid measurements in field conditions and initiated a project to revise the radiation measurement equipment in local food and environmental laboratories. (authors)

  13. Additional safety assessment of common means or support of the Marcoule centre

    This report first presents some characteristics of the Marcoule centre: location and environment, base nuclear installations and other installations, technical installations and installations classified for protection of the environment which could affect the safety of nearby installations, demographic and industrial environment and risks generated for the site's installations, general description of crisis management means. The second part addresses situations to be considered, functional needs related to additional safety assessments, needs in terms of support functions, and critical structures and equipment. The next parts address the seismic risk (structure and equipment sizing, margin assessment, flooding due to an earthquake, loss of electric supply due to an earthquake), the flooding risk (flooding sources, main alarm measures, structure and equipment sizing and availability for crisis management during a flooding from different origins), other extreme phenomena (lightning, hail, wind, external fire), the loss of electric supplies and the loss of cooling systems, the organisation of accident management, and subcontracting practices

  14. Modelling PK/QT relationships from Phase I dose-escalation trials for drug combinations and developing quantitative risk assessments of clinically relevant QT prolongations.

    Sinclair, Karen; Kinable, Els; Grosch, Kai; Wang, Jixian

    2016-05-01

    In current industry practice, it is difficult to assess QT effects at potential therapeutic doses based on Phase I dose-escalation trials in oncology due to data scarcity, particularly in combinations trials. In this paper, we propose to use dose-concentration and concentration-QT models jointly to model the exposures and effects of multiple drugs in combination. The fitted models then can be used to make early predictions for QT prolongation to aid choosing recommended dose combinations for further investigation. The models consider potential correlation between concentrations of test drugs and potential drug-drug interactions at PK and QT levels. In addition, this approach allows for the assessment of the probability of QT prolongation exceeding given thresholds of clinical significance. The performance of this approach was examined via simulation under practical scenarios for dose-escalation trials for a combination of two drugs. The simulation results show that invaluable information of QT effects at therapeutic dose combinations can be gained by the proposed approaches. Early detection of dose combinations with substantial QT prolongation is evaluated effectively through the CIs of the predicted peak QT prolongation at each dose combination. Furthermore, the probability of QT prolongation exceeding a certain threshold is also computed to support early detection of safety signals while accounting for uncertainty associated with data from Phase I studies. While the prediction of QT effects is sensitive to the dose escalation process, the sensitivity and limited sample size should be considered when providing support to the decision-making process for further developing certain dose combinations. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26991506

  15. Expected dose for the seismic scenario classes in the 2008 performance assessment for the proposed high-level radioactive waste repository at Yucca Mountain, Nevada

    Extensive work has been carried out by the U.S. Department of Energy (DOE) in the development of a proposed geologic repository at Yucca Mountain (YM), Nevada, for the disposal of high-level radioactive waste. In support of this development and an associated license application to the U.S. Nuclear Regulatory Commission (NRC), the DOE completed an extensive performance assessment (PA) for the proposed YM repository in 2008. This presentation describes the determination of expected dose to the reasonably maximally exposed individual (RMEI) specified in the NRC regulations for the YM repository for the seismic ground motion scenario class and the seismic fault displacement scenario class in the 2008 YM PA. The following topics are addressed: (i) definition of the seismic scenario classes and the determination of dose and expected dose to the RMEI, (ii) properties of the seismic ground motion scenario class, (iii) expected dose and uncertainty in expected dose to the RMEI for the seismic ground motion scenario class from 0 to 20,000 yr, (iv) expected dose and uncertainty in expected dose to the RMEI for the seismic ground motion scenario class from 0 to 106 yr, (v) properties of the seismic fault displacement scenario class including expected dose and uncertainty in expected dose to the RMEI from 0 to 20,000 yr and 0 to 106 yr, (vi) expected dose and uncertainty in expected dose to the RMEI for the combined ground motion and seismic fault displacement scenario class, and (vii) probabilities associated with seismic scenario classes. The present article is part of a special issue of Reliability Engineering and System Safety devoted to the 2008 YM PA; additional articles in the issue describe other aspects of the 2008 YM PA. - Highlights: • Properties of the seismic ground motion and seismic fault displacement scenario classes are described. • Determination of dose, expected dose and expected (mean) dose to the reasonably maximally exposed individual (RMEI) is

  16. Occupational radiation dose of staff and workplace assessment at service des radioimmunodosages in Benin

    Occupational radiation dose of staff handling 125 I and workplace assessment in nuclear medicine unit at Service des Radioimmunodosages (SeRiD) in Benin have been undertaken to determine levels of radiation safety. Firstly, three permanent workers and two students were provided with finger ring thermoluminescent dosimeters (TLD) to wear at index finger base of both hands. Ring dosimeters were used for four month in two sequences of two months and were evaluated with HARSHAW 4500. Secondly, three permanent workers and three students were provided with TLD badge to wear at the chest level for skin and deep dose measurement. TLD badges were used for six months in six sequences of one month. The exposed TLDs were evaluated with HARSHAW 6600. Ambient equivalent dose rate (μSv/h) was measured using microsieverts model dose rate meter. Sixteen control points closed to the source or situated where staff are exposed to ionizing radiation were chosen. Fixed and removable contamination were surveyed at six and three controlled points respectively. Results from the study showed that permanent workers highest index finger base average equivalent dose was 142.75± 89.54μSv/2months, while that of students was 34.69 ± 29.23 µSv/2months. The maximum annual skin dose of Permanent workers represent 0.46% of dose limit (500mSv/yr), while that of the student represent 0.37%of dose limit (150mSv/yr). Average ambient equivalent dose rate from radiation survey was lower than 20μSv/h. It was noted that the freezer door plays an inportant role in shielding. The result in waste disposal room confirm the decay in storage of radioactive waste principle. Data on removable and fixed contamination value was below the limits of 0.33 dps/100cm2 and 8.33dps/100cm2 respectively. The study indicated that SeRiD staff are not exposed to ionizing radiation at work in safe working environment. (au)

  17. Radiation dose assessment in nuclear plants through virtual simulations using a game engine

    Full text: This paper reports an R and D which has the purpose of performing dose assessment of workers in nuclear plants, through virtual simulations using a game engine. The main objective of this R and D is to support the planning of operational and maintenance routines in nuclear plants, aiming to reduce the dose received by workers. Game engine is the core of a computer game, that is usually made independent of both the scenarios and the original applications, and thus can be adapted for any other purposes, including scientific or technological ones. Computer games have experienced a great development in the last years, regarding computer graphics, 3D image rendering and the representation of the physics needed for the virtual simulations, such as gravity effect and collision among virtual components within the games. Thus, researchers do not need to develop an entire platform for virtual simulations, what would be a hard work itself, but they can rather take advantage of such well developed platforms, adapting them for their own applications. The game engine used in this R and D is part of a computer game widely used, Unreal, that has its source code partially open, and can be pursued for low cost. A nuclear plant in our Institution, Argonauta research reactor, has been virtually modeled in 3D, and trainees can navigate virtually through it, with realistic walking velocity, and experiencing collision. The modified game engine computes and displays in real-time the dose received by a virtual person, the avatar, as it walks through the plant, from the radiation dose rate distribution assigned to the virtual environment. In the beginning of this R and D, radiation dose rate measurements were previously collected by the radiological protection service, and input off-line to the game engine. Currently, on-line measurements can be also input to it, by taking advantage of the game's networking capabilities. A real radiation monitor has been used to collect real

  18. Pilot website to support international collaboration for dose assessments in a radiation emergency

    Livingston, G.K., E-mail: Gordon.Livingston@orise.orau.gov [Oak Ridge Associated Universities, REAC/TS, Radiation Emergency Medicine (REM), P.O. Box 117, Oak Ridge, TN 37831 (United States); Wilkins, R.C., E-mail: Ruth.Wilkins@hc-sc.gc.ca [Health Canada, Consumer and Clinical Radiation Protection Bureau, Ottawa, ON K1A 1C1 (Canada); Ainsbury, E.A., E-mail: liz.ainsbury@hpa.org.uk [Health Protection Agency, Radiation Protection Division, Chilton, Didcot, Oxfordshire OX11 0RQ (United Kingdom)

    2011-09-15

    Nuclear terrorism has emerged as a significant threat which could require timely medical interventions to reduce potential radiation casualties. Early dose assessments are critical since optimal care depends on knowing a victim's radiation dose. The dicentric chromosome aberration assay is considered the 'gold standard' to estimate the radiation dose because the yield of dicentrics correlates positively with the absorbed dose. Dicentrics have a low background frequency, are independent of age and gender and are relatively easy to identify. This diagnostic test for radiation exposure, however, is labor intensive and any single or small group of laboratories could easily be overwhelmed by a mass casualty event. One solution to this potential problem is to link the global WHO BioDoseNet members via the Internet so multiple laboratories could work cooperatively to screen specimens for dicentric chromosomes and generate timely dose estimates. Inter-laboratory comparison studies have shown that analysis of electronic chromosome images viewed on the computer monitor produces scoring accuracy equivalent to viewing live images in the microscope. This functional equivalence was demonstrated during a comparative study involving five laboratories constructing {sup 60}Co gamma ray calibration curves and was further confirmed when comparing results of blind dose estimates submitted by each laboratory. It has been further validated in two recent WHO BioDoseNet trial exercises where 20 metaphase images were shared by e-mail and 50 images were shared on a test website created for this purpose. The Internet-based exercise demonstrated a high level of concordance among 20 expert scorers who evaluated the same 50 metaphase spreads selected to exhibit no, low, moderate and severe radiation damage. Nineteen of 20 scorers produced dicentric equivalent counts within the 95% confidence limits of the mean. The Chi-squared test showed strong evidence of homogeneity in the data

  19. On use of the multistage dose-response model for assessing laboratory animal carcinogenicity

    Nitcheva, Daniella; Piegorsch, Walter W.; West, R. Webster

    2007-01-01

    We explore how well a statistical multistage model describes dose-response patterns in laboratory animal carcinogenicity experiments from a large database of quantal response data. The data are collected from the U.S. EPA’s publicly available IRIS data warehouse and examined statistically to determine how often higher-order values in the multistage predictor yield significant improvements in explanatory power over lower-order values. Our results suggest that the addition of a second-order par...

  20. Development of Dose Assessment Procedures and a Computer Code for Control of Skin Exposure due to Radioactive Contamination

    High doses to skin lead to harmful effects to the exposed skin, such as skin erythema, severe deep ulceration of the dermis, and cancer induction. Skin exposure due to contamination, on skin or clothing is highly localized and the skin dose equivalent cannot be adequately measured by a personal dosimeter, which calls for detection and quantification of personal contamination and appropriate assessment of skin doses from the results. In this study, new and pragmatic procedures and a computational tool are developed for skin exposure control at a nuclear facilities involving unsealed radioactive material. As a trigger for initiation of skin dose assessment, a screening level of 600 ccpm (corrected counts per minute) measured with a standard frisker having a pancake GM detector is derived based on the dose limit to skin, potential frequency of contamination, and correlations between beta count rates and estimated dose rates to skin. A quick dose assessment model directly relating count rates to skin dose rates was provided for use at lower level contamination. For initiation of detailed dose assessment, which requires considerable efforts such as sampling of contaminant, gamma spectroscopy and computation of skin doses, a screening level of 12000 ccpm is proposed. With respect to the hot particle issue, a screening level of 25000 ccpm is recommended for initiation of actions to search hot particles. For use in the detailed skin dose assessment, a new compute code, K-SKIN, has been developed. The K-SKIN code calculates dose distribution over the area under contamination using point kernels of monoenergetic electrons. These kernels are averaged over the beta spectra of contaminated radionuclides to get the dose distributions. Then beta dose rates to the skin are calculated by numerical integration of point kernel data over contaminated area. Photon dose rates, if involved, are calculated using the specific gamma-ray dose constant for the radionuclides. K-SKIN also has

  1. Assessment of doses to non-human biota: Review of developments and demonstration assessment for Olkiluoto repository

    Smith, K. [Carol Robinson Enviros Consulting Ltd, Edinburgh (United Kingdom)

    2006-12-15

    This report provides a summary of work commissioned by Posiva Oy and undertaken by Enviros Consulting Ltd to support the development of a strategy for the assessment of environmental impacts from ionising radiation associated with the Olkiluoto waste repository, Finland, as part of the development of the Posiva Safety Case Portfolio. This project included a review of the development of international policies and standards related to protection of biota from the effects of ionizing radiation and of biota assessment methodologies, paying particular attention to those that have been applied to waste repository performance assessments. On the basis of this review, recommendations were developed on the most appropriate methodology to apply in order to assess the impact of radioactive releases from the planned spent fuel repository in Olkiluoto. A test-case was developed, in collaboration with staff from Posiva and Facilia AB, and an assessment was performed. The results and experience of which were analysed and summarised to develop recommendations for a future strategy. The test case highlighted some significant data gaps related to the assessment of impacts to both generic biota types and to interest species. In particular, concentration ratios for generic carnivorous mammals and migratory species such as moose that may consume food from multiple ecosystems and dose conversion factors for large burrowing (i.e. hibernating) mammals. However, in general terms, the dose rates predicted for all organism types were several orders of magnitude below those at which population effects would be expected to be observed and those at which effects on the individual may be anticipated. There would therefore be scope for simplifying the approach applied, although there would be value in performing a sensitivity analysis to ensure that the simplification is applied appropriately. There would also be value in ensuring consistency of the developing approach for non-human biota with

  2. Assessment of doses to non-human biota: Review of developments and demonstration assessment for Olkiluoto repository

    This report provides a summary of work commissioned by Posiva Oy and undertaken by Enviros Consulting Ltd to support the development of a strategy for the assessment of environmental impacts from ionising radiation associated with the Olkiluoto waste repository, Finland, as part of the development of the Posiva Safety Case Portfolio. This project included a review of the development of international policies and standards related to protection of biota from the effects of ionizing radiation and of biota assessment methodologies, paying particular attention to those that have been applied to waste repository performance assessments. On the basis of this review, recommendations were developed on the most appropriate methodology to apply in order to assess the impact of radioactive releases from the planned spent fuel repository in Olkiluoto. A test-case was developed, in collaboration with staff from Posiva and Facilia AB, and an assessment was performed. The results and experience of which were analysed and summarised to develop recommendations for a future strategy. The test case highlighted some significant data gaps related to the assessment of impacts to both generic biota types and to interest species. In particular, concentration ratios for generic carnivorous mammals and migratory species such as moose that may consume food from multiple ecosystems and dose conversion factors for large burrowing (i.e. hibernating) mammals. However, in general terms, the dose rates predicted for all organism types were several orders of magnitude below those at which population effects would be expected to be observed and those at which effects on the individual may be anticipated. There would therefore be scope for simplifying the approach applied, although there would be value in performing a sensitivity analysis to ensure that the simplification is applied appropriately. There would also be value in ensuring consistency of the developing approach for non-human biota with

  3. Dosimetric characterization and organ dose assessment in digital breast tomosynthesis: Measurements and Monte Carlo simulations using voxel phantoms

    . Regarding the BSF, the results achieved may lead to a MGD correction of about 6%, contributing to the improvement of the current guidelines used in these applications. Finally, considering the MC results obtained for the organ dose study, the radiation doses found for the tissues of the body other than the breast were in the range of tens of μSv, and are in part comparable to the ones obtained in standard DM. Nevertheless, in a single DBT examination, some organs (such as lung and thyroid) receive higher doses (of about 9% and 21%, respectively) with respect to the CC DM acquisition. Conclusions: Taking into account an average breast with a thickness of 4.5 cm, the MGDs for DM and DBT acquisitions were below the achievable value (2.0 mGy) defined by the European protocol. Additionally, in the case of a fusion imaging study (DM + DBT), the MGD for a 4.5 cm thick breast is of the order of 1.88 ± 0.36 mGy. Finally, organ dose evaluations underline the need to improve awareness concerning dose estimation of DBT exams for some organs, especially when radiation risk is assessed by using the effective dose

  4. Dosimetric characterization and organ dose assessment in digital breast tomosynthesis: Measurements and Monte Carlo simulations using voxel phantoms

    Baptista, Mariana, E-mail: marianabaptista@ctn.ist.utl.pt; Di Maria, Salvatore; Barros, Sílvia; Vaz, Pedro [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela LRS 2695-066 (Portugal); Figueira, Catarina [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University, Belfast BT7 1NN (United Kingdom); Sarmento, Marta; Orvalho, Lurdes [Serviço de Imagiologia, Hospital da Luz, Avenida Lusíada, 100, Lisboa 1500-650 (Portugal)

    2015-07-15

    . Regarding the BSF, the results achieved may lead to a MGD correction of about 6%, contributing to the improvement of the current guidelines used in these applications. Finally, considering the MC results obtained for the organ dose study, the radiation doses found for the tissues of the body other than the breast were in the range of tens of μSv, and are in part comparable to the ones obtained in standard DM. Nevertheless, in a single DBT examination, some organs (such as lung and thyroid) receive higher doses (of about 9% and 21%, respectively) with respect to the CC DM acquisition. Conclusions: Taking into account an average breast with a thickness of 4.5 cm, the MGDs for DM and DBT acquisitions were below the achievable value (2.0 mGy) defined by the European protocol. Additionally, in the case of a fusion imaging study (DM + DBT), the MGD for a 4.5 cm thick breast is of the order of 1.88 ± 0.36 mGy. Finally, organ dose evaluations underline the need to improve awareness concerning dose estimation of DBT exams for some organs, especially when radiation risk is assessed by using the effective dose.

  5. Standards in biological dosimetry: A requirement to perform an appropriate dose assessment.

    Voisin, Philippe

    2015-11-01

    Every year, many countries perform a significant number of investigations based on biological radiation dose assessment to check suspected or true overexposure by irradiation of radiation workers and individuals of the general population. The scoring of dicentrics in peripheral blood lymphocytes has gradually become the "gold standard" for the biodosimetry-based assessment of accidental situations. Nevertheless, other "classical" biodosimetric methods such as micronuclei, prematurely condensed chromosomes (PCC) and FISH translocations are relevant in some exposure situations, also for surveillance of groups of populations at risk. Historical international intercomparison studies have shown discrepancies among dose-effect curves used to estimate doses from blood samples irradiated between 0 and 4Gy. Recent experimental work performed by the biological dosimetry laboratory of the French Institute for Radiation Protection and Nuclear Safety (IRSN) has shown the impact of some blood harvesting parameters on the mitotic index, and consequently on the quality of dose assessment. Therefore, it was relevant to define the best Quality Assurance (QA) and Quality Control (QC) criteria to harmonize protocols among biodosimetry laboratories. Complementary with several editions of an IAEA technical manual, ISO standards were written with the view of considering the most used chromosome aberrations assays: dicentrics and micronuclei. An important feature of these standards is to address the organization of population triage and laboratories networking that would be required in case of a large nuclear event or malicious act involving radioactive material. These ISO standards are relevant and helpful to implement a coordinated response of several biodosimetry networks in Europe, Japan, Canada, and to support European programs such as MULTIBIODOSE and RENEB. A new important ISO standard on the use of FISH translocations in retrospective dosimetry is now being drafted. PMID:26520381

  6. Personnel neutron dose assessment upgrade: Volume 2, Field neutron spectrometer for health physics applications

    Both the (ICRP) and the (NCPR) have recommended an increase in neutron quality factors and the adoption of effective dose equivalent methods. The series of reports entitled Personnel Neutron Dose Assessment Upgrade (PNL-6620) addresses these changes. Volume 1 in this series of reports (Personnel Neutron Dosimetry Assessment) provided guidance on the characteristics, use, and calibration of personnel neutron dosimeters in order to meet the new recommendations. This report, Volume 2: Field Neutron Spectrometer for Health Physics Applications describes the development of a portable field spectrometer which can be set up for use in a few minutes by a single person. The field spectrometer described herein represents a significant advance in improving the accuracy of neutron dose assessment. It permits an immediate analysis of the energy spectral distribution associated with the radiation from which neutron quality factor can be determined. It is now possible to depart from the use of maximum Q by determining and realistically applying a lower Q based on spectral data. The field spectrometer is made up of two modules: a detector module with built-in electronics and an analysis module with a IBM PC/reg sign/-compatible computer to control the data acquisition and analysis of data in the field. The unit is simple enough to allow the operator to perform spectral measurements with minimal training. The instrument is intended for use in steady-state radiation fields with neutrons energies covering the fission spectrum range. The prototype field spectrometer has been field tested in plutonium processing facilities, and has been proven to operate satisfactorily. The prototype field spectrometer uses a 3He proportional counter to measure the neutron energy spectrum between 50 keV and 5 MeV and a tissue equivalent proportional counter (TEPC) to measure absorbed neutron dose

  7. Assessment of phase based dose modulation for improved dose efficiency in cardiac CT on an anthropomorphic motion phantom

    Budde, Adam; Nilsen, Roy; Nett, Brian

    2014-03-01

    State of the art automatic exposure control modulates the tube current across view angle and Z based on patient anatomy for use in axial full scan reconstructions. Cardiac CT, however, uses a fundamentally different image reconstruction that applies a temporal weighting to reduce motion artifacts. This paper describes a phase based mA modulation that goes beyond axial and ECG modulation; it uses knowledge of the temporal view weighting applied within the reconstruction algorithm to improve dose efficiency in cardiac CT scanning. Using physical phantoms and synthetic noise emulation, we measure how knowledge of sinogram temporal weighting and the prescribed cardiac phase can be used to improve dose efficiency. First, we validated that a synthetic CT noise emulation method produced realistic image noise. Next, we used the CT noise emulation method to simulate mA modulation on scans of a physical anthropomorphic phantom where a motion profile corresponding to a heart rate of 60 beats per minute was used. The CT noise emulation method matched noise to lower dose scans across the image within 1.5% relative error. Using this noise emulation method to simulate modulating the mA while keeping the total dose constant, the image variance was reduced by an average of 11.9% on a scan with 50 msec padding, demonstrating improved dose efficiency. Radiation dose reduction in cardiac CT can be achieved while maintaining the same level of image noise through phase based dose modulation that incorporates knowledge of the cardiac reconstruction algorithm.

  8. Computed isotopic inventory and dose assessment for SRS fuel and target assemblies

    Past studies have identified and evaluated important radionuclide contributors to dose from reprocessed spent fuel sent to waste for Mark 16B and 22 fuel assemblies and for Mark 31 A and 31B target assemblies. Fission-product distributions after a 5- and 15-year decay time were calculated for a ''representative'' set of irradiation conditions (i.e., reactor power, irradiation time, and exposure) for each type of assembly. The numerical calculations were performed using the SHIELD/GLASS system of codes. The sludge and supernate source terms for dose were studied separately with the significant radionuclide contributors for each identified and evaluated. Dose analysis considered both inhalation and ingestion pathways: The inhalation pathway was analyzed for both evaporative and volatile releases. Analysis of evaporative releases utilized release fractions for the individual radionuclides as defined in the ICRP-30 by DOE guidance. A release fraction of unity was assumed for each radionuclide under volatile-type releases, which would encompass internally initiated events (e.g., fires, explosions), process-initiated events, and externally initiated events. Radionuclides which contributed at least 1% to the overall dose were designated as significant contributors. The present analysis extends and complements the past analyses through considering a broader spectrum of fuel types and a wider range of irradiation conditions. The results provide for a more thorough understanding of the influences of fuel composition and irradiation parameters on fission product distributions (at 2 years or more). Additionally, the present work allows for a more comprehensive evaluation of radionuclide contributions to dose and an estimation of the variability in the radionuclide composition of the dose source term that results from the spent fuel sent to waste encompassing a broad spectrum of fuel compositions and irradiation conditions

  9. The ecosystem models used for dose assessments in SR-Can

    Avila, Rodolfo [Facilia AB, Bromma (Sweden)

    2006-11-15

    chronic contamination. From the simulations for the different release cases, activity concentrations in water and soil are obtained and then multiplied with the aggregated transfer factors to obtain concentrations in food products. For terrestrial ecosystems, the aggregated transfer factors in Becquerel per Kilogram of edible carbon in the food are used to calculate the activity intake and from this the effective dose rate per unit release to an adult individual. For aquatic ecosystems, only doses from the ingestion of water (for lakes) and food (for sea and lakes) are considered, as previous assessments have shown that in these types of ecosystems other exposure pathways give a very low contribution to the total doses. A sensitivity analysis of the ecosystem models is presented in the report, identifying which parameters have the largest effect on the simulation endpoints of interest. The endpoints considered are the fraction of the release that is retained in the ecosystem, the activity concentrations in soil, water and sediments, and the total dose rates from external exposure, inhalation, and ingestion of water and food. These endpoints are evaluated at different times within the simulation and a sensitivity analysis using the Morris method is carried out. For some of the scenarios considered in SR-Can, the LDF concept is not applicable. One of these scenarios comprises the contamination of ground caused by inadvertent drilling into the repository. Doses which would arise for a family using this contaminated ground for housing and food production are estimated. The other scenario which is assessed separately is the release of C-14 and Rn-222 from the repository in gaseous form, entering the biosphere via soil as a diffuse source. Pathways considered are doses from ingestion of C-14 and from inhalation of C-14 and Rn-222 outdoors as well as indoors. For these scenarios, specific dose calculations were carried out. The methods applied for these calculations and the

  10. The ecosystem models used for dose assessments in SR-Can

    chronic contamination. From the simulations for the different release cases, activity concentrations in water and soil are obtained and then multiplied with the aggregated transfer factors to obtain concentrations in food products. For terrestrial ecosystems, the aggregated transfer factors in Becquerel per Kilogram of edible carbon in the food are used to calculate the activity intake and from this the effective dose rate per unit release to an adult individual. For aquatic ecosystems, only doses from the ingestion of water (for lakes) and food (for sea and lakes) are considered, as previous assessments have shown that in these types of ecosystems other exposure pathways give a very low contribution to the total doses. A sensitivity analysis of the ecosystem models is presented in the report, identifying which parameters have the largest effect on the simulation endpoints of interest. The endpoints considered are the fraction of the release that is retained in the ecosystem, the activity concentrations in soil, water and sediments, and the total dose rates from external exposure, inhalation, and ingestion of water and food. These endpoints are evaluated at different times within the simulation and a sensitivity analysis using the Morris method is carried out. For some of the scenarios considered in SR-Can, the LDF concept is not applicable. One of these scenarios comprises the contamination of ground caused by inadvertent drilling into the repository. Doses which would arise for a family using this contaminated ground for housing and food production are estimated. The other scenario which is assessed separately is the release of C-14 and Rn-222 from the repository in gaseous form, entering the biosphere via soil as a diffuse source. Pathways considered are doses from ingestion of C-14 and from inhalation of C-14 and Rn-222 outdoors as well as indoors. For these scenarios, specific dose calculations were carried out. The methods applied for these calculations and the

  11. Monitoring and assessment of individual doses of occupationally exposed workers due to intake of radionuclides

    Monitoring and estimation of individual intakes of radionuclides can be complex. Doses of intakes cannot be measured directly, however must be assessed from the monitoring data of the individual. The individual monitoring data includes whole body counting, excretion analysis (urine or faecal). In the estimation of these data requires that the assessor makes assumptions about the exposure scenario, including the pattern and mode of radionuclide intake. Also physicochemical characteristics of the material involved and the period of time between exposure and measurement. This project report seeks to provide some underlying guidance on monitoring programmes and data interpretation using case study. In this present study the committed effective dose (CED) 1.20mSv exceeded the recording level (i.e. 1mSv) however it was below the investigation level (i.e. 2mSv). The present study recommends that as an essential part in internal dosimetry, specialists be capable of recognizing conditions warranting follow-up bioassay and dose evaluation. Personnel should be familiar with the relevant internal dosimetry literature and the recommendations of national and international scientific organizations with regard to internal dose. (au)

  12. Personal dose monitoring in hospitals: Global assessment, critical applications and future needs

    It is known that medical applications using ionising radiation are wide spread and still increasing. Physicians, technicians, nurses and others constitute the largest group of workers occupationally exposed to man-made sources of radiation. Many hospital workers are consequently subjected to routine monitoring of professional radiation exposures. in the university hospital, UZ Brussel, 600 out of 4000 staff members are daily monitored for external radiation exposures. The most obvious applications of ionising radiation are diagnostic radiology, diagnostic or therapeutic use of radionuclides in nuclear medicine and external radiation therapy or brachytherapy in radiotherapy departments. Other important applications also include various procedures in interventional radiology (IR), in vitro biomedical research and radiopharmaceutical production around cyclotrons. Besides the fact that many of the staff members, involved in these applications, are not measurably exposed, detailed studies were carried out at workplaces where routine dose monitoring encounters difficulties and for some applications where relatively high occupational exposures can be found. most of the studies are concentrated around nuclear medicine applications and IR. They contain assessments of both effective dose and doses at different parts of the body. The results contribute to better characterisation of the different workplaces in a way that critical applications can be identified. Moreover, conclusions point out future needs for practical routine dose monitoring and optimisation of radiation protection. (authors)

  13. Assessment of body doses from photon exposures using human voxel models

    For the scope of risk assessment in protection against ionising radiation (occupational, environmental and medical) it is necessary to determine the radiation dose to specific body organs and tissues. For this purpose, a series of models of the human body were designed in the past, together with computer codes simulating the radiation transport and energy deposition in the body. Most of the computational body models in use are so-called mathematical models; the most famous is the MIRD-5 phantom developed at Oak Ridge National Laboratory. In the 1980s, a new generation of human body models was introduced at GSF, constructed from whole body CT data. Due to being constructed from image data of real persons, these 'voxel models' offer an improved realism of external and internal shape of the body and its organs, compared to MIRD-type models. Comparison of dose calculations involving voxel models with respective dose calculations for MIRD-type models revealed that the deviation of the individual anatomy from that described in the MIRD-type models indeed introduces significant deviations of the calculated organ doses. Specific absorbed fractions of energy released in a source organ due to incorporated activity which are absorbed in target organs may differ by more than an order of magnitude between different body models; for external photon irradiation, the discrepancies are more moderate. (author)

  14. Three years of seasonal dose assessment from outdoors gamma exposure in Sao Paulo city, Brazil

    Carneiro, Janete C.G.G.; Sanches, Matias P.; Betti, Flavio; Pecequilo, Brigitte R.S., E-mail: janetegc@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Measurements of external (outdoors) gamma exposure from natural background radiation have been used to estimate the average annual doses in Sao Paulo city. Twelve monitoring stations were placed in different regions of the town including both urban (where building materials are present) and outskirts areas. Seasonally surveys observing the four seasons from 2008 to 2010 have been carried out. The data were drawn from a 3-month sampling using the thermoluminescent dosimetry. The effective doses values are quite similar (slightly higher during the winter), so it can be considered that these results are not under significant influence (or variability) of seasonal environmental conditions like temperature, wind or rain. Dose values over the three years period, from Vila Carrao district, exclusively an urban location with mostly no green areas, present the highest values, while the lower values were always obtained for Tucuruvi district, near the biggest urban forest, Parque Estadual da Cantareira. Over the assessed period, the mean of the average annual effective doses was 1.3 {+-} 0.1 mSv.y{sup -1}. For the same period, the average annual background from nuclear and radioactive facility at IPEN was 0.75 {+-} 0.12 mSv.y{sup -1}. (author)

  15. Three years of seasonal dose assessment from outdoors gamma exposure in Sao Paulo city, Brazil

    Measurements of external (outdoors) gamma exposure from natural background radiation have been used to estimate the average annual doses in Sao Paulo city. Twelve monitoring stations were placed in different regions of the town including both urban (where building materials are present) and outskirts areas. Seasonally surveys observing the four seasons from 2008 to 2010 have been carried out. The data were drawn from a 3-month sampling using the thermoluminescent dosimetry. The effective doses values are quite similar (slightly higher during the winter), so it can be considered that these results are not under significant influence (or variability) of seasonal environmental conditions like temperature, wind or rain. Dose values over the three years period, from Vila Carrao district, exclusively an urban location with mostly no green areas, present the highest values, while the lower values were always obtained for Tucuruvi district, near the biggest urban forest, Parque Estadual da Cantareira. Over the assessed period, the mean of the average annual effective doses was 1.3 ± 0.1 mSv.y-1. For the same period, the average annual background from nuclear and radioactive facility at IPEN was 0.75 ± 0.12 mSv.y-1. (author)

  16. Screening level dose assessment of aquatic biota downstream of the Marcoule nuclear complex in southern France

    Aquatic biota in the Rhone River downstream of the Marcoule nuclear complex in France are exposed to natural sources of radiation and to radioactivity released from the Marcoule complex. A simple conservative screening level model was used to estimate the range of concentrations in aquatic media of both artificial and natural radionuclides and the consequent absorbed dose rates for aquatic organisms. Five categories of aquatic organisms were studied, namely, submerged aquatic plants (phanerogam), non-bottom-feeding fish, bottom-feeding fish, mollusca, and fish-eating birds. The analysis was based on the radionuclide concentrations reported in four consecutive annual radioecological monitoring reports published by French agencies with nuclear regulatory responsibilities. The results of this assessment were used to determine, qualitatively, the magnitude of any potential health impacts on each of the five categories of aquatic organisms studied. The range of dose rate estimates ranged over three orders of magnitude, with maximum dose rates estimated to be in the order of 1 to 10 microGy h-1. These maximum dose rates are a factor 40 or more below the international guideline intended to ensure the protection of aquatic populations, and a factor ten or more below the level which may trigger the need for a more detailed evaluation of potential ecological consequences to the exposed populations

  17. [Requirements for drug approval and additional benefits assessment: Regulatory aspects and experiences].

    Broich, K; Löbker, W; Schulte, A; Beinlich, P; Müller, T

    2016-04-01

    The early assessment of benefits of newly approved drugs with novel active substances or new applications, which came into force on 1 January 2011 still represents a challenge to all parties involved. This article highlights the definitions, regulatory requirements and interaction between drug marketing approval and early assessment of benefits in Germany. The constellation of an extensively harmonized European and even international drug authorization process with a predominantly national regulation of drug reimbursement situation inevitably causes friction, which could be markedly reduced through early joint advisory discussions during the planning phase for pivotal clinical trials. During the year 2015 the Federal Institute for Drugs and Medical Devices (BfArM) carried out 300 scientific advice procedures of which 34 were concerned with applications in the field of indications for the central nervous system (CNS). In comparison 98 advisory meetings were held by the Federal Joint Committee (G-BA) of which the BfArM provided advice in 12 instances and in 2 cases on CNS indications. Study design, endpoints and appropriate comparative therapies are the key issues in exchanges and discussions between the BfArM, the G‑BA and applicants. Under these aspects the BfArM and G‑BA promote an early and consistent involvement in early advice procedures regarding the prerequisites for drug approval and assessment of additional benefits. PMID:27003322

  18. Image quality evaluation and patient dose assessment of medical fluoroscopic X-ray systems: a national study.

    Economides, S; Hourdakis, C J; Kalivas, N; Kalathaki, M; Simantirakis, G; Tritakis, P; Manousaridis, G; Vogiatzi, S; Kipouros, P; Boziari, A; Kamenopoulou, V

    2008-01-01

    This study presents the results from a survey conducted by the Greek Atomic Energy Commission (GAEC), during the period 1998-2003, in 530 public and private owned fluoroscopic X-ray systems in Greece. Certain operational parameters for conventional and remote control systems were assessed, according to a quality control protocol developed by GAEC on the basis of the current literature. Public (91.5%) and private (81.5%) owned fluoroscopic units exhibit high-contrast resolution values over 1 lp mm(-1). Moreover, 88.5 and 87.1% of the fluoroscopic units installed in the public and private sector, respectively, present Maximum Patient Entrance Kerma Rate values lower than 100 mGy min(-1). Additionally, 68.3% of the units assessed were found to perform within the acceptance limits. Finally, the third quartile of the Entrance Surface Dose Rate distribution was estimated according to the Dose Reference Level definition and found equal to 35 mGy min(-1). PMID:17971345

  19. Image quality evaluation and patient dose assessment of medical fluoroscopic X-ray systems: A national study

    This study presents the results from a survey conducted by the Greek Atomic Energy Commission (GAEC), during the period 1998-2003, in 530 public and private owned fluoroscopic X-ray systems in Greece. Certain operational parameters for conventional and remote control systems were assessed, according to a quality control protocol developed by GAEC on the basis of the current literature. Public (91.5%) and private (81.5%) owned fluoroscopic units exhibit high-contrast resolution values over 1 lp mm-1. Moreover, 88.5 and 87.1% of the fluoroscopic units installed in the public and private sector, respectively, present Maximum Patient Entrance Kerma Rate values lower than 100 mGy min-1. Additionally, 68.3% of the units assessed were found to perform within the acceptance limits. Finally, the third quartile of the Entrance Surface Dose Rate distribution was estimated according to the Dose Reference Level definition and found equal to 35 mGy min-1. (authors)

  20. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons

    The evaluation of absorbed dose in the case of external and internal contamination due to radionuclides is sometimes hard, because of the difficulties in the assessment of the absorbed dose caused by electrons with energy less than 100 KeV in mucous membrane. In this work, a methodology for assessment of absorbed dose and stopping power in VYNS (co-polymer of polivinyl chloride - acetate) absorbers, for the 62.5 KeV and 84-88 KeV energy 109 Cd conversion electrons, working with a 4 π proportional pressurized detector, is presented. In order to assure the reproducibility of measurement conditions, one of the detector halves has been used to obtain a spectrum of a thin 109 Cd source, without absorber. The other half of the detector was used in concomitance to obtain spectra with different thicknesses if absorber. The absorbed energy was obtained subtracting each spectrum with absorber from the spectrum without absorber, which were stored in a microcomputer connected to signal processing systems by ACE type interface. The VYNS weight and thickness were evaluated using common radionuclide metrology procedures. As VYNS has characteristics similar to a tissue equivalent material, the results obtained are consistent with dosimetric concepts and have a good agreement with those of the literature. (author)

  1. General guidelines for the assessment of internal dose from monitoring data: Progress of the IDEAS project

    In recent major international intercomparison exercises on intake and internal dose assessments from monitoring data, the results calculated by different participants varied significantly. Based on this experience the need for harmonisation of the procedures has been formulated within an EU 5. Framework Programme research project. The aim of the project, IDEAS, is to develop general guidelines for standardising assessments of intakes and internal doses. The IDEAS project started in October 2001 and ended in June 2005. The project is closely related to some goals of the work of Committee 2 of the ICRP and since 2003 there has been close cooperation between the two groups. To ensure that the guidelines are applicable to a wide range of practical situations, the first step was to compile a database of well-documented cases of internal contamination. In parallel, an improved version of an existing software package was developed and distributed to the partners for further use. A large number of cases from the database was evaluated independently by the partners and the results reviewed. Based on these evaluations, guidelines were drafted and discussed with dosimetry professionals from around the world by means of a virtual workshop on the Internet early in 2004. The guidelines have been revised and refined on the basis of the experiences and discussions in this virtual workshop. The general philosophy of the Guidelines is presented here, focusing on the principles of harmonisation, optimisation and proportionality. Finally, the proposed Levels of Task to structure the approach of internal dose evaluation are reported. (authors)

  2. Evolving Adjustments to External (Gamma) Slope Factors for CERCLA Risk and Dose Assessments - 12290

    To model the external exposure pathway in risk and dose assessments of radioactive contamination at Superfund sites, the U.S. Environmental Protection Agency (EPA) uses slope factors (SFs), also known as risk coefficients, and dose conversion factors (DCFs). Without any adjustment these external radiation exposure pathways effectively assumes that an individual is exposed to a source geometry that is effectively an infinite slab. The concept of an 'infinite slab' means that the thickness of the contaminated zone and its aerial extent are so large that it behaves as if it were infinite in its physical dimensions. EPA has been making increasingly complex adjustments to account for the extent of the contamination and its corresponding radiation field to provide more accurate risk and dose assessment modeling when using its calculators. In most instances, the more accurate modeling results derived from these gamma adjustments are less conservative. The notable exception are for some radionuclides in rooms with contaminated walls, ceiling, and floors, and the receptor is in location of the room with the highest amount of radiation exposure, usually the corner of small rooms and the center of large conference rooms. (authors)

  3. Dose assessment of the patient and the helper in emergency head computed tomography

    Computed Tomography (CT) becomes more and more important and is frequently used in modern diagnostic techniques. CT offers an effective diagnosis on lesion and pathology; however, it also delivers a radiation dose to patients. Besides, in some special emergency cases, the patient may require someone to help him in the examination room to perform the head CT, due to the patient lost intellectual and operational capacity. This study evaluated the delivered radiation dose and the risk of radiation-induced cancer for the patient and for the helper after carrying out the emergent head CT examination. A Rando phantom with thermoluminescent dosimeter (TLD) chips inside relevant organs was used to simulate the patient during head CT examination. An effective dose of 2.06 ± 0.16 mSv and 1.46 ± 0.07 mSv without and with wearing the lead apron were found respectively, considering ICRP 60 recommendation. ICRP 103 recommendations the readings would have been 1.29 ± 0.15 mSv and 0.71 ± 0.04 mSv. The effective dose determined from the dose-length product (DLP) method (2.19 mSv) was similar to the value (2.06 ± 0.16 mSv) estimated by TLD method considering the ICRP 60 recommendation (without lead apron). Assuming a 5% total risk for fatal cancer per Sv in the general population, risk of radiation-induced cancer for patients were 1.03 × 10−2% (without lead apron) and 7.80 × 10−3% (with lead apron) for ICRP 60, and were 6.45 × 10−3% (without lead apron) and 3.55 × 10−3% (with lead apron) for ICRP 103. The dose received by the helper was assessed by wearing a personal badge. The helper during emergent head CT examination may receive a personal dose equivalent (Hp(10)) of 19.36 ± 5.89 μSv and 138.81 ± 101.28 μSv with and without lead apron, respectively, at distance of 0.3–1 m from the center of CT scanner. Based on the observed dose reduction of a factor of 7.17 we recommend that helpers wear lead apron in the CT examination room.

  4. Application of a simple phantom in assessing the effects of dose reduction on image quality in chest radiography

    Purpose: Firstly, to evaluate a commercial chest phantom incorporating a quasi anthropomorphic insert by comparing exposure measurements on the phantom with those of actual patients and, secondly, to assess the value of the phantom for image quality and dose optimisation. Methods: In the first part of the study entrance surface doses (ESD), Beam transmission (BT), and optical density (OD) were obtained for 77 chest radiography patients and compared with measurements made from exposures of the phantom using the respective patient exposure factors from chest examination. Differences were assessed with a student t-test, while the Pearson's linear correlation coefficient was used to test for any linear relationship. The second part assessed the applicability of the phantom to image quality studies by investigating the effect, on the clarity and detectability of lung lesions made from gelatine, of reducing patient dose below current dose levels. Clarity of linear objects of different dimensions was also studied. Lesion detectability and clarity was assessed by four observers. The possibility of extending dose reduction below current dose levels (Dref) was assessed from comparison of doses that produced statistically significant differences in image quality from Dref. Results: Results show that, with the exception of entrance doses and beam transmission through the diaphragm (P > 0.05), differences in OD and beam transmission between patients and phantom were statistically significant (P ref produced significant changes in both clarity and detectability. Conclusion: Within limits posed by the observed differences, the phantom can be applied to image quality studies in diagnostic radiology.

  5. Determination of 210Po concentration in commercially available infant formulae and assessment of daily ingestion dose

    Ravi K. Prabhath

    2015-07-01

    Full Text Available A study has been conducted to estimate the concentration of natural radioactive polonium in commercially available packaged infant food formulae available in Mumbai, India and the corresponding daily dose normalized based on its shelf life. Eleven most popular international brands of infant formulae were sourced from market and three aliquots from each sample were analysed for concordant results. Autodeposition method onto a silver planchet from hot dilute acid solution followed by alpha spectrometry was performed for estimation of polonium. Radiochemical recovery was ascertained by the addition of 209Po tracer. Radiochemical recovery of 209Po tracer was ranged from 14.7 to 98.1 %. The 210Po concentration in the samples was in the range of 0.08–0.23 Bq kg−1 on measured date and the corresponding daily dose, calculated on normalized date which is at mid-point of the shelf life of the sample, was ranged from 0.04 to 0.89 μSv d−1 as per the recommended daily consumption. The annual committed effective dose estimated based on the average of daily dose was found to be 150 μSv.

  6. A video analysis technique for organ dose assessment in pediatric fluoroscopy: Applications to voiding cystourethrograms (VCUG)

    The time-sequence videotape-analysis methodology, originally developed by Sulieman et al. [Radiol. 178, 653-658 (1991)] for use in tissue dose estimation in adult fluoroscopy exams, has been adapted to the study of the newborn voiding cystourethrogram (VCUG). Individual frames of fluoroscopic and radiographic video were analyzed with respect to unique combinations of field size, field center, projection, tube potential, and mA or mAs, respectively. A modified version of the stylized ORNL newborn model was coupled to the MCNP4C radiation transport code to report organ doses per unit entrance air kerma (free-in-air) for each identified x-ray field. A series of urinary bladder models was additionally developed representing the organ at differing stages of contrast filling. The technique was subsequently applied to two patients, a 3-month male and a 1-month female, examined via a conventional fluoroscopy system used just prior to departmental conversion to digital systems. The effective dose to these patients was estimated as 0.47 mSv and 1.36 mSv, respectively (ratio of 2.9). Corresponding ratios of cumulative fluoroscopy time and entrance air kerma were 2.2 and 1.6, respectively. For the male patient, the mean percent dose contribution from fluoroscopy for all irradiated organs was 71±12%, while that value for the female patient was 88±4%

  7. Dose-to-dose variations with single packages of counterfeit medicines and adulterated dietary supplements as a potential source of false negatives and inaccurate health risk assessments.

    Venhuis, B J; Zwaagstra, M E; Keizers, P H J; de Kaste, D

    2014-02-01

    In this report, we show three examples of how the variability in dose units in single packages of counterfeit medicines and adulterated dietary supplements may contribute to a false negative screening result and inaccurate health risk assessments. We describe a counterfeit Viagra 100mg blister pack and a box of an instant coffee both containing dose units with and without an active pharmaceutical ingredient (API). We also describe a purportedly herbal slimming product with capsules that mutually differed in API and impurities. The adulterated dietary supplements contained sibutramine, benzyl-sibutramine, N-desmethyl-sibutramine (DMS), N,N-didesmethyl-sibutramine (DDMS) and several other related impurities. Counterfeit medicines and adulterated dietary supplements are a health risk because their quality is unreliable. Health risks are even greater when such unreliability extends to fundamental differences between dose units in one package. Because dose-to-dose variability for these products is unpredictable, the confidence interval of a sample size is unknown. Consequently, the analyses of a selection of dose units may not be representative for the package. In the worst case, counterfeit or unauthorised medicines are not recognised as such or a health risk is not identified. In order to reduce erroneous results particular care should be taken when analysing a composite of dose units, when finding no API in a dietary supplement and when finding conformity in a suspect counterfeit medicine. PMID:24291553

  8. Assessment of natural radioactivity concentrations and gamma dose levels around Shorapur, Karnataka

    Rajesh, S.; Avinash, P.; Kerur, B. R.; Anilkumar, S.

    2015-08-01

    This study assesses the level of background radiation around Shorapur. The study region locates the western part of the Yadgir district of Karnataka. Shorapur and Shahapur talukas are mostly composed of clay, shale sandstone, granite rock and part of study area is black soil. Thirty sample locations were selected along the length and breadth of Shorapur and Shahapur taluka. Natural radionuclide activity concentrations in soil samples were determined using 4"X4" NaI (Tl) gamma spectroscopy. Outdoor gamma dose measurements in air at 1 m above ground level were determined using Rad Eye PRD survey meter. Estimated dose values are compared with the survey meter values and found to be good agreement between them and also with the data obtained from different other areas of Karnataka and India. The average values were found to be slightly higher in the present investigation.

  9. Assessment of natural radioactivity concentrations and gamma dose levels around Shorapur, Karnataka

    Rajesh, S.; Avinash, P.; Kerur, B. R., E-mail: kerurpbk@rediffmail.com.com [Department of Physics, Gulbarga University Kalaburagi – 585 106 India (India); Anilkumar, S. [Radiation Safety Systems Division, BARC, Mumbai - 400 085 (India)

    2015-08-28

    This study assesses the level of background radiation around Shorapur. The study region locates the western part of the Yadgir district of Karnataka. Shorapur and Shahapur talukas are mostly composed of clay, shale sandstone, granite rock and part of study area is black soil. Thirty sample locations were selected along the length and breadth of Shorapur and Shahapur taluka. Natural radionuclide activity concentrations in soil samples were determined using 4'X4' NaI (Tl) gamma spectroscopy. Outdoor gamma dose measurements in air at 1 m above ground level were determined using Rad Eye PRD survey meter. Estimated dose values are compared with the survey meter values and found to be good agreement between them and also with the data obtained from different other areas of Karnataka and India. The average values were found to be slightly higher in the present investigation.

  10. OEDIPE: a new numerical tool for the personalized internal dose assessment

    Within the framework of radiation protection or internal radiotherapy, one of the major stakes is to determine in the most realistic possible way the dose received by every patient. In this purpose, a tool called OEDIPE, French acronym for 'tool for personalized internal dose assessment', was developed at IRSN associating numerical voxelized phantoms, created with anatomical images, and Monte Carlo calculations. After a presentation of the principal functionalities of OEDIPE, two applications one for the determination of the internal contamination of workers and the other in the field of nuclear medicine, are detailed. These 2 applications demonstrate the interest and potential of the software OEDIPE in case of internal contamination and in internal radiotherapy. The slides of the presentation have been added at the end of the paper

  11. Assessment of natural radioactivity concentrations and gamma dose levels around Shorapur, Karnataka

    This study assesses the level of background radiation around Shorapur. The study region locates the western part of the Yadgir district of Karnataka. Shorapur and Shahapur talukas are mostly composed of clay, shale sandstone, granite rock and part of study area is black soil. Thirty sample locations were selected along the length and breadth of Shorapur and Shahapur taluka. Natural radionuclide activity concentrations in soil samples were determined using 4'X4' NaI (Tl) gamma spectroscopy. Outdoor gamma dose measurements in air at 1 m above ground level were determined using Rad Eye PRD survey meter. Estimated dose values are compared with the survey meter values and found to be good agreement between them and also with the data obtained from different other areas of Karnataka and India. The average values were found to be slightly higher in the present investigation

  12. Simple lake breeze front position technique for off-site dose assessment

    During a lake/sea breeze an airflow trajectory reversal generally occurs at the leading edge (lake/sea breeze front) of the landward advancing marine air and can significantly affect the use of an off-site dose assessment procedure. Knowledge of the location of the lake/sea breeze front in real time is vital in interpreting the results from a conventional straightline Gaussian off-site dose calculation methodology, which ignores this complex flow pattern. A simple, low-cost technique was developed to estimate the location of the lake/sea breeze front in real time from easily obtainable meteorological parameters recorded at National Weather Service stations. Although this technique was developed for lake breezes occurring near the Wisconsin Public Service Kewaunee nuclear plant, the concept is applicable after site-specific modifications for other lakeshore sites in approximating the location of the lake breeze front

  13. An assessment of methods for monitoring entrance surface dose in fluoroscopically guided interventional procedures

    In the light of a growing awareness of the risks of inducing skin injuries as a consequence of fluoroscopically guided interventional procedures (FGIPs), this paper compares three methods of monitoring entrance surface dose (ESD). It also reports measurements of ESDs made during the period August 1998 to June 1999 on 137 patients undergoing cardiac, neurological and general FGIPs. Although the sample is small, the results reinforce the need for routine assessments to be made of ESDs in FGIPs. At present, the most reliable and accurate form of ESD measurement would seem to be arrays of TLDs. However, transducer based methods, although likely to be less accurate, have considerable advantages in relation to a continuous monitoring programme. It is also suggested that there may be the potential locally for threshold dose area product (DAP) values to be set for specific procedures. These could be used to provide early warning of the potential for skin injuries. (author)

  14. Natural radioactivity measurements and dose assessments in sand samples collected from Zonguldak beaches in Turkey

    In this study, measurements of the gamma activity concentrations of 238U, 232Th and 40K natural radionuclides and associated dose assessments in sand samples collected from Zonguldak beaches (Turkey) were carried out. In order to measure the activity concentrations an Ortec GEM30 P4 model gamma spectrometer with HPGe detector was used. The activity concentrations for 238U, 232Th and 40K radionuclides were found to vary from 9.98 ± 0.82 to 56.81 ± 2.44, from 9.93 ± 1.46 to 48.87 ± 3.81 and from 103.00 ± 6.73 to 610.50 ± 24.24 Bq kg-1, respectively. The gamma dose rates were estimated to be from 16.67 ± 1.63 to 79.44 ± 4.37 nGy h-1. (author)

  15. Personnel neutron dose assessment upgrade: Volume 1, Personnel neutron dosimetry assessment: [Final report

    This report provides guidance on the characteristics, use, and calibration criteria for personnel neutron dosimeters. The report is applicable for neutrons with energies ranging from thermal to less than 20 MeV. Background for general neutron dosimetry requirements is provided, as is relevant federal regulations and other standards. The characteristics of personnel neutron dosimeters are discussed, with particular attention paid to passive neutron dosimetry systems. Two of the systems discussed are used at DOE and DOE-contractor facilities (nuclear track emulsion and thermoluminescent-albedo) and another (the combination TLD/TED) was recently developed. Topics discussed in the field applications of these dosimeters include their theory of operation, their processing, readout, and interpretation, and their advantages and disadvantages for field use. The procedures required for occupational neutron dosimetry are discussed, including radiation monitoring and the wearing of dosimeters, their exchange periods, dose equivalent evaluations, and the documenting of neutron exposures. The coverage of dosimeter testing, maintenance, and calibration includes guidance on the selection of calibration sources, the effects of irradiation geometries, lower limits of detectability, fading, frequency of calibration, spectrometry, and quality control. 49 refs., 6 figs., 8 tabs

  16. Dose assessment of deliberate actions involving the use of radioactive sources

    Recently at the Italian Institute of Health an interactive algorithm (RANA - Radiological Assessment of Nuclear Accidents) has been developed to evaluate the space and time structure of the radiological consequences of an accident at a nuclear plant in Europe. Individual or collective doses from several exposure paths are calculated, either starting from the source term or from air and ground contamination data. The algorithm, formulated in the language of Mathematica, can be run on a personal computer. After 11 September 2001, the risks associated with nuclear terrorism have been the subject of increasing attention. Three categories of risk have been identified: theft of nuclear material, physical attack or sabotage action onto a nuclear facility or use of one or more radioactive sources in a radiological dispersion device. The above mentioned algorithm has been therefore expanded to allow dealing with an arbitrary source term, as could be the case in a sabotage-induced accident, allowing for both somatic (short distance) and stochastic effects evaluation. Along with the previous functions of RANA, a new set of tools allows the user to evaluate also the areas where doses (from several pathways and to all age classes) exceed those at which onset of deterministic effects begin, a variable that plays a major role in emergency planning. In this paper the radiological risks related to the hypothetical use of radioactive sources in a dispersion device have been evaluated. By means of the improved version of the model, the doses as a function of the distance from the release point, for those sources that may be of concern for use in a dispersion device, are evaluated, taking into account the relevant exposure paths in the early emergency phase. For emergency planning purposes the distances within which the absorbed doses (to bone marrow) exceed the threshold values for deterministic effects have been assessed too. A radiological ranking of the most significant accidents

  17. Assessment Of Dose From External Exposure To A Plume Of Radioactive Material Using Mathematical Models

    Egypt is one of the growing lists of countries turning to nuclear energy to provide a dependable source of power. The public should be protected from the radiological hazards due to normal operation and accidental releases .This study focus on assessment of the dose due to routinely dispersion of gaseous radioactive plume from NPP in Inshas site, Egypt, which was calculated by using different models and WRPLOT computer code was used for determination of the wind rose. The analysis of the results showed that the value of the effective dose received by critical public (considering occupation factor 100% and the source of release is ground) due to immersion in radioactive gases plume was higher than the effective dose deposition of radioactive material on the ground surface for downwind sector. The results of the effective dose due to these pathways for different organs are: gonad (6.84E-1 µSv/y and 3.21E-7 µSv/y), breast (8.33E-1 µSv/y and 3.42E-7 µSv/y), lung (5.61E-1 µSv/y and 2.66E-7 µSv/y) and thyroid (6.42E-1 µSv/y and 2.56E-7 µSv/y). The results also show that annual effective dose received by critical group living next to NPP from different releases was less than the reference value for any organ according to ICRP (2007) and ICRP (1990). These results are very useful for the decision maker

  18. Radiological dose assessment of naturally occurring radioactive materials in concrete building materials

    Previous studies have shown that the natural radioactivity contained in building materials have significantly influenced the dose rates in dwelling. Exposure to natural radiation in building has been of concerned since almost 80 % of our daily live are spend indoor. Thus, the aim of the study is to assess the radiological risk associated by natural radioactivity in soil based building materials to dwellers. A total of 13 Portland cement, 46 sand and 43 gravel samples obtained from manufacturers or bought directly from local hardware stores in Peninsular of Malaysia were analysed for their radioactivity concentrations. The activity concentrations of 226Ra, 232Th and 40K in the studied building materials samples were found to be in the range of 3.7-359.3, 2.0-370.8 and 10.3-1,949.5 Bq kg-1 respectively. The annual radiation dose rates (μSv year-1) received by dwellers were evaluated for 1 to 50 years of exposure using Resrad-Build Computer Code based on the activity concentration of 226Ra, 232Th and 40K found in the studied building material samples. The rooms modelling were based on the changing parameters of concrete wall thickness and the room dimensions. The annual radiation dose rates to dwellers were found to increase annually over a period of 50 years. The concrete thicknesses were found to have significantly influenced the dose rates in building. The self-absorption occurred when the concrete thickness was thicker than 0.4 m. Results of this study shows that the dose rates received by the dwellers of the building are proportional to the size of the room. In general the study concludes that concrete building materials; Portland cements, sands, and gravels in Peninsular of Malaysia does not pose radiological hazard to the building dwellers. (author)

  19. Assessing the Risk of Birth Defects Associated with Exposure to Fixed-Dose Combined Antituberculous Agents during Pregnancy in Rats

    O Awodele; E. B. Patrick; Esther Oluwatoyin Agbaje; Oremosu, A. A.; Gbotolorun, S. C.

    2012-01-01

    Due to the risks of disease progression and transmission to the newborn, treatment of tuberculosis is often pursued during pregnancy and fixed-dose combined antituberculous agents have been found to be beneficial. Unfortunately, there is paucity of data on the safety of the fixed-dose combined antituberculous drugs during pregnancy. This study intends to assess the teratogenic effect of fixed-dose combined antituberculous drugs on the organogenesis stage of fetal development and also investig...

  20. RADIATION DOSE ASSESSMENT FOR THE BIOTA OF TERRESTRIAL ECOSYSTEMS IN THE SHORELINE ZONE OF THE CHERNOBYL NUCLEAR POWER PLANT COOLING POND

    Farfan, E.; Jannik, T.

    2011-10-01

    Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. The article addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from {sup 90}Sr and {sup 137}Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to drawdown naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.

  1. Radiation Dose Assessment For The Biota Of Terrestrial Ecosystems In The Shoreline Zone Of The Chernobyl Nuclear Power Plant Cooling Pond

    Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. The article addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from 90Sr and 137Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to drawdown naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.

  2. Assessing the effect of copper additions on the corrosion behaviour of grey cast iron

    Saliu Ojo SEIDU

    2015-05-01

    Full Text Available In this research work, the effect of copper additions on the corrosion behaviour of grey cast iron in 3.5 wt% NaCl, 0.3M H2SO4, and 0.1M NaOH respectively was investigated. Grey cast iron samples containing 3.0%, 2.5%, 2.0%, and 1.5% weight percent of copper were produced. The corrosion behaviour of the grey cast iron samples produced were assessed using mass loss and corrosion rate measurements according to America Society for Testing and Materials standard (ASTM procedures in salt water, basic, and acidic environments. The results reveal that the samples containing 2.0% and 1.5% weight percent of copper show an excellent corrosion resistance while samples containing 3.0% and 2.5% weight percent of copper show good corrosion behaviour all in salt water and basic environments but poorly in acidic environment.

  3. Performance assessment of the BEBIG MultiSource high dose rate brachytherapy treatment unit.

    Palmer, Antony; Mzenda, Bongile

    2009-12-21

    A comprehensive system characterisation was performed of the Eckert & Ziegler BEBIG GmbH MultiSource High Dose Rate (HDR) brachytherapy treatment unit with an (192)Ir source. The unit is relatively new to the UK market, with the first installation in the country having been made in the summer of 2009. A detailed commissioning programme was devised and is reported including checks of the fundamental parameters of source positioning, dwell timing, transit doses and absolute dosimetry of the source. Well chamber measurements, autoradiography and video camera analysis techniques were all employed. The absolute dosimetry was verified by the National Physical Laboratory, UK, and compared to a measurement based on a calibration from PTB, Germany, and the supplied source certificate, as well as an independent assessment by a visiting UK centre. The use of the 'Krieger' dosimetry phantom has also been evaluated. Users of the BEBIG HDR system should take care to avoid any significant bend in the transfer tube, as this will lead to positioning errors of the source, of up to 1.0 mm for slight bends, 2.0 mm for moderate bends and 5.0 mm for extreme curvature (depending on applicators and transfer tube used) for the situations reported in this study. The reason for these errors and the potential clinical impact are discussed. Users should also note the methodology employed by the system for correction of transit doses, and that no correction is made for the initial and final transit doses. The results of this investigation found that the uncorrected transit doses lead to small errors in the delivered dose at the first dwell position, of up to 2.5 cGy at 2 cm (5.6 cGy at 1 cm) from a 10 Ci source, but the transit dose correction for other dwells was accurate within 0.2 cGy. The unit has been mechanically reliable, and source positioning accuracy and dwell timing have been reproducible, with overall performance similar to other existing HDR equipment. The unit is capable of high

  4. Assessment of the Technologies for Molecular Biodosimetry for Human Low-Dose Radiation Exposure Symposium

    Matthew A. Coleman Ph.D.; Narayani Ramakrishnan, Ph.D.; Sally A. Amundson; James D. Tucker, Ph.D.; Stephen D. Dertinger, Ph.D.; Natalia I. Ossetrova, Ph.D.; Tao Chen

    2009-11-16

    Exposure to ionizing radiation produces few immediate outwardly-visible clinical signs, yet, depending on dose, can severely damage vital physiological functions within days to weeks and produce long-lasting health consequences among survivors. In the event of a radiological accident, the rapid evaluation of the individual absorbed dose is paramount to discriminate the worried but unharmed from those individuals who must receive medical attention. Physical, clinical and biological dosimetry are usually combined for the best dose assessment. However, because of the practical limits of physical and clinical dosimetry, many attempts have been made to develop a dosimetry system based on changes in biological parameters, including techniques for hematology, biochemistry, immunology, cytogenetics, etc. Lymphocyte counts and chromosome aberrations analyses are among the methods that have been routinely used for estimating radiation dose. However, these assays require several days to a week to be completed and therefore cannot be used to obtain a fast estimate of the dose during the first few days after exposure when the information would be most critical for identifying victims of radiation accidents who could benefit the most by medical intervention. The steadily increasing sophistication in our understanding of the early biochemical responses of irradiated cells and tissues provides the opportunity for developing mechanism-based biosignatures of exposure. Compelling breakthroughs have been made in the technologies for genome-scale analysis of cellular transcriptional and proteomic profiles. There have also been major strides in the mechanistic understanding of the early events in DNA damage and radiation damage products, as well as in the cellular pathways that lead to radiation injury. New research with genomic- and proteomic-wide tools is showing that within minutes to hours after exposure to ionizing radiation protein machines are modified and activated, and large

  5. A Review of Models for Dose Assessment Employed by SKB in the Renewed Safety Assessment for SFR 1

    This document provides a critical review, on behalf of SSI, of the models employed by the Swedish Nuclear Fuel and Waste Management Co (SKB) for dose assessment in the renewed safety assessment for the final repository for radioactive operational waste (SFR 1) in Forsmark, Sweden. The main objective of the review is to examine the models used by SKB for radiological dose assessment in a series of evolving biotopes in the vicinity of the Forsmark repository within a time frame beginning in 3000 AD and extending beyond 7500 AD. Five biosphere models (for coasts, lakes, agriculture, mires and wells) are described in Report TR-01-04. The principal consideration of the review is to determine whether these models are fit for the purpose of dose evaluation over the time frames involved and in the evolving sequence of biotopes specified. As well as providing general observations and comments on the modelling approach taken, six specific questions are addressed, as follows. Are the assumptions underlying the models justifiable? Are all reasonably foreseeable environmental processes considered? Has parameter uncertainty been sufficiently and reasonably addressed? Have sufficient models been used to address all reasonably foreseeable biotopes? Are the transitions between biotopes modelled adequately (specifically, are initial conditions for developing biotopes adequately specified by calculations for subsiding biotopes)? Have all critical radionuclides been identified? It is concluded that, in general, the assumptions underlying most of the models are justifiable. The exceptions are a) the rather simplistic approach taken in the Coastal Model and b) the lack of consideration of wild foods and age-dependence when calculating exposures of humans to radionuclides via dietary pathways. Most foreseeable processes appear to have been accounted for within the constraints of the models used, although it is recommended that attention be paid to future climate states when considering

  6. Results of comparative assessment of US and foreign nuclear power plant dose experience and dose reduction programs

    The objectives of this study were to determine how collective dose equivalents at US nuclear power plants compare to those of other technically advanced countries, and to evaluate factors that contribute to the differences. Fifty Health Physicists and nuclear engineers from 10 countries met at BNL May 29 - June 1, 1984 to exchange information and hold discussions on ''Historical Dose Experience and Dose Reduction (ALARA) at Nuclear Power Plants''. Results of evaluation of data from this meeting and other data from recent publications are summarized. Based on data evaluated to date it is clear that US plants have higher collective dose equivalents per reactor and per MW-yr generated than most other countries. Factors which contribute to low doses include: 1) minimization of cobalt in primary system components exposed to water, 2) careful control of primary system oxygen and pH, 3) good primary system water purity to minimize corrosion product formation, 4) careful plant design, layout and component segregation and shielding, 5) management interest and commitment, 6) minimum number of workers and in-depth worker training, 7) use of special tools, and 8) plant standardization

  7. Image quality assessment of ultra low-dose chest CT using sinogram-affirmed iterative reconstruction

    Lee, So Won; Shim, Sung Shine; Lee, Jeong Kyong [School of Medicine, Ewha Womans University, Department of Radiology, Seoul (Korea, Republic of); Kim, Yookyung [School of Medicine, Ewha Womans University, Department of Radiology, Seoul (Korea, Republic of); Ewha Womans University Mokdong Hospital, Department of Radiology, 1071, Anyangcheon-ro, Yangcheon-gu, Seoul (Korea, Republic of); Lee, Seok Jeong; Ryu, Yon Ju; Chang, Jung Hyun [School of Medicine, Ewha Womans University, Division of Pulmonology in the Department of Internal Medicine, Seoul (Korea, Republic of)

    2014-04-15

    To assess the image quality of ultra-low-dose computed tomography (ULDCT) using sinogram-affirmed iterative reconstruction (SAFIRE) compared to reduced dose CT (RDCT). Eighty-one consecutive patients underwent non-enhanced ULDCT using 80 kVp and 30 mAs and contrast-enhanced RDCT using automated tube potential selection and tube current modulation. CT images were reconstructed with SAFIRE. Image noise and subjective image quality of normal structures and various pulmonary lesions were assessed. The mean effective doses were 0.29 ± 0.03 and 2.88 ± 1.11 mSv for ULDCT and RDCT, respectively. ULDCT had significantly higher noise (p < 0.001). Image quality of five normal structures was diagnostic in 91.1 % of ULDCT and 100 % of RDCT. With ULDCT, the frequencies of non-diagnostic image quality were 2.0 (1/50), 4.6 (13/280), 25.5 (14/55), and 40.0 (8/20)% for BMIs of < 20, 20-25, 25-30, and >30. In the assessment of pulmonary lesions, non-diagnostic image quality was observed for 11.2 % of all lesions, 60.9 % of decreased attenuation (significantly more frequent for upper lung lesions), and 23.5 % of ground-glass nodules. ULDCT generates diagnostic images in patients with a BMI ≤25, but is of limited use for lesions with decreased attenuation, ground-glass nodules, or those located in the upper lobe. (orig.)

  8. Standard Procedure for Dose Assessment using the film holder NRPB/AERE and the film AGFA Monitoring 2/10

    This paper describes the calculation method to assess dose and energy using the film holder from NRPB/AERE and the film Agfa Monitoring 2/10. Also includes all the steps since preparing the standard curve, fitting of calibration curve, dose assesment, description of filtration of the film holder and the form of the calibration curve

  9. Doses Assessment to the Population in the Environment of a Nuclear Power Plant

    The main objective of the nuclear power plant safety is to ensure that its operation does not cause radiation hazards which could endanger safety of workers or population in the vicinity or could other wise harm the environment. The radiation exposure arising from the operation of a nuclear power plant shall be kept as low as reasonably achievable (ALARA principle). The aim of this paper is to summarize the principles to be followed for radiation doses assessment of the surrounding population of a nuclear power plant

  10. WELL-94: a stylized well scenario for indicative dose assessment of deep repositories

    WELL-94 is a stylized well scenario aimed to be used as an indicator in assessing the performance of the near-field and geosphere barriers of a deep repository for nuclear waste. It converts the release rates of radionuclides from the repository into the geosphere or from the geosphere into the biosphere into a dose rate. The scenario is based on an assumption that the annual releases from the repository into the biosphere are diluted in 100 000 m3 of water and an individual drinks 500 litres of contaminated water per year. Drinking of water is the only exposure pathway considered. (12 refs., 4 tabs.)

  11. DOSE ASSESSMENT OF THE FINAL INVENTORIES IN CENTER SLIT TRENCHES ONE THROUGH FIVE

    Collard, L.; Hamm, L.; Smith, F.

    2011-05-02

    In response to a request from Solid Waste Management (SWM), this study evaluates the performance of waste disposed in Slit Trenches 1-5 by calculating exposure doses and concentrations. As of 8/19/2010, Slit Trenches 1-5 have been filled and are closed to future waste disposal in support of an ARRA-funded interim operational cover project. Slit Trenches 6 and 7 are currently in operation and are not addressed within this analysis. Their current inventory limits are based on the 2008 SA and are not being impacted by this study. This analysis considers the location and the timing of waste disposal in Slit Trenches 1-5 throughout their operational life. In addition, the following improvements to the modeling approach have been incorporated into this analysis: (1) Final waste inventories from WITS are used for the base case analysis where variance in the reported final disposal inventories is addressed through a sensitivity analysis; (2) Updated K{sub d} values are used; (3) Area percentages of non-crushable containers are used in the analysis to determine expected infiltration flows for cases that consider collapse of these containers; (4) An updated representation of ETF carbon column vessels disposed in SLIT3-Unit F is used. Preliminary analyses indicated a problem meeting the groundwater beta-gamma dose limit because of high H-3 and I-129 release from the ETF vessels. The updated model uses results from a recent structural analysis of the ETF vessels indicating that water does not penetrate the vessels for about 130 years and that the vessels remain structurally intact throughout the 1130-year period of assessment; and (5) Operational covers are included with revised installation dates and sets of Slit Trenches that have a common cover. With the exception of the modeling enhancements noted above, the analysis follows the same methodology used in the 2008 PA (WSRC, 2008) and the 2008 SA (Collard and Hamm, 2008). Infiltration flows through the vadose zone are

  12. Development of low-dose protocols for thin-section CT assessment of cystic fibrosis in pediatric patients.

    O'Connor, Owen J

    2010-12-01

    To develop low-dose thin-section computed tomographic (CT) protocols for assessment of cystic fibrosis (CF) in pediatric patients and determine the clinical usefulness thereof compared with chest radiography.

  13. Understanding Non-Completion of the Human Papillomavirus Vaccine Series: Parent-Reported Reasons for Why Adolescents Might Not Receive Additional Doses, United States, 2012.

    Clark, Sarah J; Cowan, Anne E; Filipp, Stephanie L; Fisher, Allison M; Stokley, Shannon

    2016-01-01

    Completion rates of the human papillomavirus (HPV) vaccine series among U.S. adolescents are below public health targets. We explored parent-reported reasons for their children's non-completion of the HPV vaccine series using a nationally representative online survey of parents of children aged 9-17 years, fielded in October 2012. Among the 1,653 parents who responded, the proportion reporting that their child would definitely continue with the HPV vaccine series among those who had started the series ranged from 28% to 54%. The most common reason cited by parents for non-completion of the series was their child's fear of needles, followed by lack of awareness about additional doses and safety concerns. These findings demonstrate the need to encourage adoption of strategies addressing needle fears, utilize reminders for parents about subsequent doses, and emphasize recent HPV vaccine safety data in discussions with parents. PMID:27252558

  14. Radioactivity concentrations and dose assessment for soil samples around nuclear power plant IV in Taiwan.

    Tsai, Tsuey-Lin; Lin, Chun-Chih; Wang, Tzu-Wen; Chu, Tieh-Chi

    2008-09-01

    Activity concentrations and distributions of natural and man-made radionuclides in soil samples collected around nuclear power plant IV, Taiwan, were investigated for five years to assess the environmental radioactivity and characterisation of radiological hazard prior to commercial operation. The activity concentrations of radionuclides were determined via gamma-ray spectrometry using an HPGe detector. Data obtained show that the average concentrations of the (238)U and (232)Th series, and (40)K, were within world median ranges in the UNSCEAR report. The (137)Cs ranged from 2.46 +/- 0.55 to 12.13 +/- 1.31 Bq kg(-1). The terrestrial absorbed dose rate estimated by soil activity and directly measured with a thermoluminescence dosemeter (excluding cosmic rays), and the annual effective doses, were 45.63, 57.34 nGy h(-1) and 57.19 microSv, respectively. Experimental results were compared with international recommended values. Since the soil in this area is an important building material, the mean radium equivalent activity, external and inhalation hazard indices and the representative level index using various models given in the literature for the study area were 98.18 Bq kg(-1), 0.27, 0.34 and 0.73, respectively, which were below the recommended limits. Analytical results demonstrate that no radiological anomaly exists. The baseline data will prove useful and important in estimating the collective dose near the new nuclear power plant under construction in Taiwan. PMID:18714131

  15. Assessment of Dose to the Nursing Infant from Radionuclides in Breast Milk

    Leggett, Richard Wayne [ORNL; Eckerman, Keith F [ORNL

    2010-03-01

    A computer software package was developed to predict tissue doses to an infant due to intake of radionuclides in breast milk based on bioassay measurements and exposure data for the mother. The package is intended mainly to aid in decisions regarding the safety of breast feeding by a mother who has been acutely exposed to a radionuclide during lactation or pregnancy, but it may be applied to previous intakes during the mother s adult life. The package includes biokinetic and dosimetric information needed to address intake of Co-60, Sr-90, Cs-134, Cs-137, Ir-192, Pu-238, Pu-239, Am-241, or Cf-252 by the mother. It has been designed so that the library of biokinetic and dosimetric files can be expanded to address a more comprehensive set of radionuclides without modifying the basic computational module. The methods and models build on the approach used in Publication 95 of the International Commission on Radiological Protection (ICRP 2004), Doses to Infants from Ingestion of Radionuclides in Mothers Milk . The software package allows input of case-specific information or judgments such as chemical form or particle size of an inhaled aerosol. The package is expected to be more suitable than ICRP Publication 95 for dose assessment for real events or realistic planning scenarios in which measurements of the mother s excretion or body burden are available.

  16. Dose assessment of SiC nanoparticle dispersions during in vitro assays

    Here, we show that key physicochemical parameters of commercial Silicon Carbide nanoparticles, such as the primary particles of about 53 nm in size, the agglomerates size, and the surface composition, are considerably modified with respect to the pristine conditions, during in vitro assessment. The use of sample conditioning stages, such as the pre-dispersion in aqueous media and the subsequent dispersion in a culture medium specific to the in vitro assay, produce modifications as the absorption of N, C, and O, from the culture medium, in the nanoparticles surface. Our results show that the sedimented dose, fraction of sedimented NPs during incubation and consequently in contact with cells seeded at the bottom, of Silicon Carbide nanoparticles can be measured from the particle size distribution obtained using a centrifugal liquid sedimentation technique. It is underlined that the variations observed in the physicochemical properties are related to the in vitro assay conditions. Culture medium and incubation time are found to influence the most the sedimented dose and consequently the cells dose uptake

  17. Analysis of terrestrial natural radionuclides in soil samples and assessment of average effective dose

    Radionuclides that are present in soil significantly affect terrestrial gamma radiation levels which in turn can be used for the assessment of terrestrial gamma dose rates. Natural radioactivity analysis has been done for the soil samples collected from different villages/towns of Hoshiarpur district of Punjab, India. The measurements have been carried out using HPGe detector based on high-resolution gamma spectrometry system. The calculated activity concentration values for terrestrial gamma viz. 238U, 232Th and 40K have been found to vary from 8.89 to 56.71 Bq kg-1, from 137.32 to 334.47 Bq kg-1 and from 823.62 to 1064.97 Bq kg-1, respectively. The total average absorbed dose rate in the study areas is 185.32 nGyh-1. The calculated value of average radium equivalent activity (401.13 Bq kg-1) exceeds the permissible limit (370 Bqkg-1) recommended by Organization for Economic Corporation and Development (OECD). The calculated average value of external hazard index (Hex) is 1.097. The calculated values of Indoor and Outdoor annual effective doses vary from 0.61 to 1.28 mSv and from 0.15 to 0.32 mSv, respectively. A positive correlation (R2 = 0.71) has also been observed for concentration of 232Th and 40K. (author)

  18. Equivalent dose, effective dose and risk assessment from panoramic radiography to the critical organs of head and neck region

    The purpose of this study was to evaluate the equivalent and effective dose, and estimate radiation risk to the critical organs of head and neck region from the use of adult and child mode in panoramic radiography. The results were as follows. 1. The salivary glands showed the highest equivalent and effective dose in adult and child mode. The equivalent and effective dose in adult mode were 837 μSv and 20.93 μSv, those in child mode were 462 μSv and 11.54 μSv, respectively. 2. Total effective doses to the critical head and neck organs were estimated 34.2l μSv in adult mode, 20.14 μSv in child mode. From these data, the probabilities of stochastic effect from adult and child mode were 2.50xl0-6 and 1.47x10-6 3. The other remainder showed the greatest risk of fatal cancer. The risk estimate were 4.5 and 2.7 fatal malignancies in adult and child mode from million examinations. The bone marrow and thyroid gland showed about 0.1 fatal cancer in adult. and child mode from these examinations.

  19. Equivalent dose, effective dose and risk assessment from panoramic radiography to the critical organs of head and neck region

    Cho, Bong Hae; Nah, Kyung Soo [Dept. of Dental Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of); Lee, Ae Ryeon [Dept. of Pediatric Dentistry, College of Dentistry, Pusan National University, Pusan (Korea, Republic of)

    1995-08-15

    The purpose of this study was to evaluate the equivalent and effective dose, and estimate radiation risk to the critical organs of head and neck region from the use of adult and child mode in panoramic radiography. The results were as follows. 1. The salivary glands showed the highest equivalent and effective dose in adult and child mode. The equivalent and effective dose in adult mode were 837 {mu}Sv and 20.93 {mu}Sv, those in child mode were 462 {mu}Sv and 11.54 {mu}Sv, respectively. 2. Total effective doses to the critical head and neck organs were estimated 34.2l {mu}Sv in adult mode, 20.14 {mu}Sv in child mode. From these data, the probabilities of stochastic effect from adult and child mode were 2.50xl0{sup -6} and 1.47x10{sup -6} 3. The other remainder showed the greatest risk of fatal cancer. The risk estimate were 4.5 and 2.7 fatal malignancies in adult and child mode from million examinations. The bone marrow and thyroid gland showed about 0.1 fatal cancer in adult. and child mode from these examinations.

  20. Assessment of the x-ray dose to the patient in angiography and catheterization procedures in Israel

    Angiography and catheterization are medical procedures that involve high X-ray doses to the patient. This X-ray dose arises from the fluoroscopy, Cine and Digital Subtraction Angiography procedures used for interventional radiography. The main goal of the present work was to assess the average patient dose delivered by these procedures. For this purpose we carried out a survey m two major Israeli hospitals, using the integrated Dose Area Product meter which was part of the X-ray imaging equipment.We calibrated these Digital Subtraction Angiography instruments with our Digital Subtraction Angiography dosemeter. (authors)

  1. Characterization of uranium and its progenies in drinking water and assessment of dose to public around a NHBRA, Odisha, India

    Present work deals with the distribution study of naturally occurring radioactive materials in drinking water samples around Orissa sands complex, Odisha, India and assessment of the comprehensive ingestion dose to members of the public. The mean total effective dose to member of public is found to be 67.1 µSv/y with a range of 13.2-198.5 µSv/y. The average effective dose is below the reference level of 100 µSv/y and also comparable with the range of global annual ingestion dose value reported worldwide. The activity concentration in drinking water reported here is due to natural distribution of radionuclides. (author)

  2. Valdose program: methodologies for dose assessment in internal contamination, 1997 census; Programma valdose: metodologie di valutazione della dose da contaminazione interna, censimento 1997

    Castellani, C.M.; Battisti, P.; Tarroni, G. [ENEA, Centro Ricerche `Ezio Clementel`, Bologna (Italy). Dip. Ambiente

    1998-12-31

    Dose assessment in internal dosimetry needs computational and interpretative tools that allow carrying out, as a first step, an evaluation of intake on the base of bioassay measurements or WBC measurements, and as a second step, dose evaluation on the base of estimated intake. In the frame of the MIDIA Co-ordination (WBC operating in Italy), in the first months of 1997 a census on methodologies for dose evaluation in internal contamination has been proposed. A technical form has been sent to all the WBC Centres allowing an accurate description of modalities used in each centre. 9 out of 17 centres sent the answers to the technical form in time. In this paper all the forms filled in are reported. A careful comparative evaluation of the answers has been made both for routine monitoring and for special monitoring. The various radionuclides present in the Italian reality, calculation methodologies both for intake and dose, hypotheses adopted for date, path and modalities of contaminations are also presented. Proposals for conforming to the methodology in Italy after the introduction of the models following ICRP 60 publication that are the base of the Euratom 96/29 Directive are also discussed. [Italiano] La valutazione di dose in contaminazione interna necessita di strumenti interpretativi che permettano di effettuare in una prima la valutazione dell`intake sulla base delle misure dei campioni biologici o del corpo intero (WBC), ed in una seconda fase la valutazione della dose sulla base dell`intake. All`interno del coordinamento MIDIA dei WBC operanti in Italia e` stato proposto, nel primo trimestre del 1997, un censimento sulle metodologie di valutazione di dose da contaminazione interna. Ai diversi centri e` stato inviato una scheda tecnica che, mediante un particolareggiato schema di domande, aiutava i diversi centri nella esposizione delle modalita` di valutazione di dose che ogni centro segue. 9 au 17 centri WBC operanti al momemnto in Italia hanno inviato la

  3. Quantitative assessment of inhalation exposure and deposited dose of aerosol from nanotechnology-based consumer sprays†

    Nazarenko, Yevgen; Lioy, Paul J.; Mainelis, Gediminas

    2015-01-01

    This study provides a quantitative assessment of inhalation exposure and deposited aerosol dose in the 14 nm to 20 μm particle size range based on the aerosol measurements conducted during realistic usage simulation of five nanotechnology-based and five regular spray products matching the nano-products by purpose of application. The products were also examined using transmission electron microscopy. In seven out of ten sprays, the highest inhalation exposure was observed for the coarse (2.5–10 μm) particles while being minimal or below the detection limit for the remaining three sprays. Nanosized aerosol particles (14–100 nm) were released, which resulted in low but measurable inhalation exposures from all of the investigated consumer sprays. Eight out of ten products produced high total deposited aerosol doses on the order of 101–103 ng kg−1 bw per application, ~85–88% of which were in the head airways, only <10% in the alveolar region and <8% in the tracheobronchial region. One nano and one regular spray produced substantially lower total deposited doses (by 2–4 orders of magnitude less), only ~52–64% of which were in the head while ~29–40% in the alveolar region. The electron microscopy data showed nanosized objects in some products not labeled as nanotechnology-based and conversely did not find nano-objects in some nano-sprays. We found no correlation between nano-object presence and abundance as per the electron microscopy data and the determined inhalation exposures and deposited doses. The findings of this study and the reported quantitative exposure data will be valuable for the manufacturers of nanotechnology-based consumer sprays to minimize inhalation exposure from their products, as well as for the regulators focusing on protecting the public health. PMID:25621175

  4. Assessment of entrance surface dose and health risk from common radiology examinations in Iran

    Medical X-ray exposures are the largest man-made source of population exposure to ionising radiation in many countries. Although information on medical exposure is already incorporated into national legislative documents, in Isfahan there is no data on the assessment of patient's entrance surface dose (ESD) and the health risk from conventional radiography in daily clinical practice. The aim of this study was to investigate ESDs and the consequent health risk for the patients undergoing routine X-ray procedures in hospitals under the control of Isfahan University of Medical Sciences, Iran, in year 2011. The values of ESDs were measured for common radiographical examinations with the highest absorbed dose to the patient in seven hospitals (Alzahra, Ashrafi-Khomeini-shahr, Feyz, Isabne-Maryam, Kashani, Nour-Aliasghar and Seyed-Al Shohada) and six stationary X-ray machines (General Electric, USA; Phillips, The Netherlands; Siemens, Germany; Shimadzu (Japan)); Toshiba (Japan)) and Varian, USA). The results of the ESD measurements as well as the calculated effective dose values between different X-ray examinations showed values significantly greater than those recorded in some other countries especially for the high tube potential technique (such as the skull) by factors of 2.5-5.0. Based on the fatality risk of 5 % per sievert, it was estimated that, for chest and skull examinations approximately two (40.18 person-Sv x 5 % per sievert) and one (2.53 person-Sv x 5 % per sievert) cases of health risk, respectively, may in the future be attributable to diagnostic X rays done in year 2011 in Isfahan. Efforts should be taken to further lower patient doses while securing image quality. The need to provide relevant education and training to staff in the radiology sections is of utmost importance. (authors)

  5. Organ Dose Assessment and Evaluation of Cancer Risk on Mars Surface

    Kim, Myung-Hee; Cucinotta, Francis A.

    2011-01-01

    Organ specific fluence spectra and doses for large solar particle events (SPE) and galactic cosmic rays (GCR) at various levels of solar activity are simulated on the surface of Mars using the HZETRN/QMSFRG computer code and the 2010 version of the Badhwar and O Neill GCR model. The NASA JSC propensity model of SPE fluence and occurrence is used to consider upper bounds on SPE fluence for increasing mission lengths. To account for the radiation transmission through the Mars atmosphere, a vertical distribution of Mars atmospheric thickness is calculated from the temperature and pressure data of Mars Global Surveyor. To describe the spherically distributed atmospheric distance on the Mars surface at each elevation, the directional cosine distribution is implemented. The resultant directional shielding by Mars atmosphere at each elevation is then coupled with vehicle and body shielding for organ dose estimates. Finally, cancer risks for astronauts exploring Mars can be assessed by applying the NASA Space Radiation Cancer Risk 2010 model with the resultant organ dose estimates. Variations of organ doses and cancer risk quantities on the surface of Mars, which are due to a 16-km elevation range between the Tharsis Montes and the Hellas impact basin, are visualized on the global topography of Mars measured by the Mars Orbiter Laser Altimeter. It is found that cancer incidence risks are about 2-fold higher than mortality risks with a disproportionate increase in skin and thyroid cancers for male and female astronauts and in breast cancer for female astronauts. The number of safe days, defined by the upper 95% percent confidence level to be below cancer limits, on Mars is analyzed for several Mars mission design scenarios.

  6. Natural radioactivity and external dose assessment of surface soils in Vietnam

    In this study, natural radioactivity in surface soils of Vietnam and external dose assessment to human population, deduced from activities of 226Ra, 232Th and 40K nuclides, were determined. From 528 soil samples collected in 63 provinces of Vietnam, including five centrally governed cities, the average activities were obtained and equal to 42.77 ± 18.15 Bq kg-1 for 226Ra, 59.84 ± 19.81 Bq kg-1 for 232Th and 411.93 ± 230.69 Bq kg-1 for 40K. The outdoor absorbed dose rates (OADRs) in air at 1 m above the ground level for 63 provinces were calculated, and their average value was 71.72 ± 24.72 nGy h-1, with a range from 17.45 to 149.40 nGy h-1. The population-weighted OADR of Vietnam was 66.70 nGy h-1, which lies in the range of 18-93 nGy h-1 found in the World. From the OADRs obtained, it was estimated that the outdoor annual effective dose and indoor annual effective dose to the population were 0.082 and 0.458 mSv, which are higher than the corresponding values 0.07 and 0.41 mSv, respectively, of the World. The radium equivalent activity Ra eq and the external hazard index H ex of surface soils of Vietnam are lower than the corresponding permissible limits of 370 Bq kg-1 and 1, respectively. Therefore, soil from Vietnam is safe for the human population when it is used as a building material. (authors)

  7. Radon dispersion modeling and dose assessment for uranium mine ventilation shaft exhausts under neutral atmospheric stability

    In the present study, the roles of atmospheric wind profiles in the neutral atmosphere and surface roughness parameters in a complex terrain were examined to determine their impacts on radon (222Rn) dispersion from an actual uranium mine ventilation shaft. Simulations were completed on 222Rn dispersion extending from the shaft to a vulnerable distance, near the location of an occupied farmhouse. The eight dispersion scenarios for the ventilation shaft source included four downwind velocities (0.5, 1.0, 2.0 and 4.0 m s−1) and two underlying surface roughness characteristics (0.1 m and 1.0 m). 222Rn distributions and elevated pollution regions were identified. Effective dose estimation methods involving a historical weighting of wind speeds in the direction of interest coupled to the complex dispersion model were proposed. Using this approach, the radiation effects on the residents assumed to be outside at the location of the farm house 250 m downwind from the ventilation shaft outlet were computed. The maximum effective dose rate calculated for the residents at the outside of the farm house was 2.2 mSv y−1, which is less than the low limit action level of 3–10 mSv y−1 recommended by the International Commission on Radiological Protection (ICRP) occupational exposure action level for radon. - Highlights: • Modeling of radon dispersion from uranium mine shafts. • Rn modeling methods include complex meteorology and geography. • Dose computation methods involving historical wind speeds weighting are proposed. • Rn dose rate for the residents near uranium mine shafts are calculated and assessed

  8. Does the use of additional X-ray beam filtration during cine acquisition reduce clinical image quality and effective dose in cardiac interventional imaging?

    The impact of spectral filtration in digital ('cine') acquisition was investigated using a flat panel cardiac interventional X-ray imaging system. A 0.1-mm copper (Cu) and 1.0-mm aluminium (Al) filter added to the standard acquisition mode created the filtered mode for comparison. Image sequences of 35 patients were acquired, a double-blind subjective image quality assessment was completed and dose-area product (DAP) rates were calculated. Entrance surface dose (ESD) and effective dose (E) rates were determined for 20- and 30-cm phantoms. Phantom ESD fell by 28 and 41 % and E by 1 and 0.7 %, for the 20- and 30-cm phantoms, respectively, when using the filtration. Patient DAP rates fell by 43 % with no statistically significant difference in clinical image quality. Adding 0.1-mm Cu and 1.0-mm Al filtration in acquisition substantially reduces patient ESD and DAP, with no significant change in E or clinical image quality. (authors)

  9. The Radiobiological Basis for Improvements in Radiotherapy and Low Dose Risk Assessment

    Hei, Tom K

    2009-12-09

    Overall Goal: This conference grant was proposed to organize and host an international conference at Columbia University in New York to critically assess the cellular and molecular signaling events and tissue response following radiation damage. The conference would also serve as a venue to play tribute to the more than forty years contributions made by Professor Eric J. Hall to the radiation biology field. The goals of the meeting were to examine tumor hypoxia and sensitizer development; recent advances made in clinical radiotherapy; addressed several low dose phenomena, including genomic instability and bystander effects that are important in radiation risk assessment. Study and Results: The symposium was held on October 13th and 14th, 2008 at the Alfred Lerner Hall in the Morningside campus of Columbia University. The symposium, entitled “From Beans to Genes: A Forty Year Odyssey in Radiation Biology” was attended by more than 120 faculty, scientists, clinicians, fellows and students. The symposium, spanned over a day and a half, covered four scientific themes. These included tumor hypoxia and radiosensitizers; low dose radiation response; radiation biology in the practice of radiotherapy, and radiation hazard in space and genetic predisposition to cancer. The program of the symposium is as follow:

  10. Computer program for assessing the human dose due to stationary release of tritium

    The computer program TriStat (Tritium dose assessment for stationary release) has been developed to assess the dose to humans assuming a stationary release of tritium as HTO and/or HT from nuclear facilities. A Gaussian dispersion model describes the behavior of HT gas and HTO vapor in the atmosphere. Tritium concentrations in soil, vegetables and forage were estimated on the basis of specific tritium concentrations in the free water component and the organic component. The uptake of contamination via food by humans was modeled by assuming a forage compartment, a vegetable component, and an animal compartment. A standardized vegetable and a standardized animal with the relative content of major nutrients, i.e. proteins, lipids and carbohydrates, representing a standard Japanese diet, were included. A standardized forage was defined in a similar manner by using the forage composition for typical farm animals. These standard feed- and foodstuffs are useful to simplify the tritium dosimetry and the food chain related to the tritium transfer to the human body. (author)

  11. Energy-dependency correction factors for the digital dosimeters using in NMD environment dose assessment

    Full text: Short-term environment dose-rate assessments using real-time digital dosimeters within a Nuclear Medicine Department (NMD) are gaining more world-wide uses recently. In the past, conventional ion chamber-type survey-meters are used dominantly in environmental dose rates evaluation. Although it has suffered less gamma energy-dependency, but it is less sensitive in comparison with other digital dosimeters and more bulky in design that can hardly make it into a pocket size application. With modern electronic advancement and its shrinking in physical size, real-time personal dosimeter nowadays has gaining more popular to use a miniature G-M counter or a solid-state diode sensor, or even a NaI(Tl) scintillation device for ambient radiation monitoring. Radiation sensor operated in pulse-mode can never been used in doses or dose rates determination since each digital pulse has carried no energy information of the impinging gamma ray being interactive with, especially in the G-M counter or the diode sensor case. The raw count rates measured from a pulse-mode device are heavily dependent on the packaging of the sensor to make it less energy-sensitive. The doses or dose rates are then calculated by using a built-in conversion factor, based on a Cs-137 beam source calibration data conducted by various manufacturing vendors, to convert its raw counts into a so-called dose or dose-rate unit. In this study, we have focused our interests in the low energy response of the digital dosimeters from several brands currently for our in-house uses. Mainly, Tc-99m and I-131 in point sources and water phantoms detection configurations have been deployed to simulate our NMD outpatients for environment radiation monitoring purpose. The energy-dependent correction factors of the digital dosimeters will be evaluated by using calibrated Tc-99m or I-131 standard sources directly that has much lower gamma energy than the Cs-137 beam source of 661 keV. In the near future, we would

  12. Critical review of the safety assessment of nano-structured silica additives in food.

    Winkler, Hans Christian; Suter, Mark; Naegeli, Hanspeter

    2016-01-01

    The development of nano-materials is viewed as one of the most important technological advances of the 21st century and new applications of nano-sized particles in the production, processing, packaging or storage of food are expected to emerge soon. This trend of growing commercialization of engineered nano-particles as part of modern diet will substantially increase oral exposure. Contrary to the proven benefits of nano-materials, however, possible adverse health effects have generally received less attention. This problem is very well illustrated by nano-structured synthetic amorphous silica (SAS), which is a common food additive since several decades although the relevant risk assessment has never been satisfactorily completed. A no observed adverse effect level of 2500 mg SAS particles/kg body weight per day was derived from the only available long-term administration study in rodents. However, extrapolation to a safe daily intake for humans is problematic due to limitations of this chronic animal study and knowledge gaps as to possible local intestinal effects of SAS particles, primarily on the gut-associated lymphoid system. This uncertainty is aggravated by digestion experiments indicating that dietary SAS particles preserve their nano-sized structure when reaching the intestinal lumen. An important aspect is whether food-borne particles like SAS alter the function of dendritic cells that, embedded in the intestinal mucosa, act as first-line sentinels of foreign materials. We conclude that nano-particles do not represent a completely new threat and that most potential risks can be assessed following procedures established for conventional chemical hazards. However, specific properties of food-borne nano-particles should be further examined and, for that purpose, in vitro tests with decision-making cells of the immune system are needed to complement existing in vivo studies. PMID:27287345

  13. Determination of (210)Po in calcium supplements and the possible related dose assessment to the consumers.

    Strumińska-Parulska, Dagmara I

    2015-12-01

    The aim of this pioneer study was to investigate the most popular calcium supplements as a potential additional source of polonium (210)Po in human diet. The analyzed calcium pharmaceutics contained organic or inorganic calcium compounds; some from natural sources as mussels' shells, fish extracts, or sedimentary rocks. The objectives of this research were to investigate the naturally occurring (210)Po activity concentrations in calcium supplements, find the correlations between (210)Po concentration in medicament and calcium chemical form, and calculate the effective radiation dose connected to analyzed calcium supplement consumption. As results showed, (210)Po concentrations in natural origin calcium supplements (especially sedimentary rocks) were higher than the other analyzed. Also the results of (210)Po analysis obtained for inorganic forms of calcium supplements were higher. The highest (210)Po activity concentrations were determined in mineral tablets made from sedimentary rocks: dolomite and chalk - 3.88 ± 0.22 and 3.36 ± 0.10 mBq g(-1) respectively; while the lowest in organic calcium compounds: calcium lactate and calcium gluconate - 0.07 ± 0.02 and 0.17 ± 0.01 mBq g(-1). The annual effective radiation doses from supplements intake were estimated as well. The highest annual radiation dose from (210)Po taken with 1 tablet of calcium supplement per day was connected to sample made from chalk - 2.5 ± 0.07 μSv year(-1), while the highest annual radiation dose from (210)Po taken with 1 g of pure calcium per day was connected to dolomite - 12.7 ± 0.70 μSv year(-1). PMID:26318774

  14. Genetic assessment of additional endophenotypes from the Consortium on the Genetics of Schizophrenia Family Study.

    Greenwood, Tiffany A; Lazzeroni, Laura C; Calkins, Monica E; Freedman, Robert; Green, Michael F; Gur, Raquel E; Gur, Ruben C; Light, Gregory A; Nuechterlein, Keith H; Olincy, Ann; Radant, Allen D; Seidman, Larry J; Siever, Larry J; Silverman, Jeremy M; Stone, William S; Sugar, Catherine A; Swerdlow, Neal R; Tsuang, Debby W; Tsuang, Ming T; Turetsky, Bruce I; Braff, David L

    2016-01-01

    The Consortium on the Genetics of Schizophrenia Family Study (COGS-1) has previously reported our efforts to characterize the genetic architecture of 12 primary endophenotypes for schizophrenia. We now report the characterization of 13 additional measures derived from the same endophenotype test paradigms in the COGS-1 families. Nine of the measures were found to discriminate between schizophrenia patients and controls, were significantly heritable (31 to 62%), and were sufficiently independent of previously assessed endophenotypes, demonstrating utility as additional endophenotypes. Genotyping via a custom array of 1536 SNPs from 94 candidate genes identified associations for CTNNA2, ERBB4, GRID1, GRID2, GRIK3, GRIK4, GRIN2B, NOS1AP, NRG1, and RELN across multiple endophenotypes. An experiment-wide p value of 0.003 suggested that the associations across all SNPs and endophenotypes collectively exceeded chance. Linkage analyses performed using a genome-wide SNP array further identified significant or suggestive linkage for six of the candidate endophenotypes, with several genes of interest located beneath the linkage peaks (e.g., CSMD1, DISC1, DLGAP2, GRIK2, GRIN3A, and SLC6A3). While the partial convergence of the association and linkage likely reflects differences in density of gene coverage provided by the distinct genotyping platforms, it is also likely an indication of the differential contribution of rare and common variants for some genes and methodological differences in detection ability. Still, many of the genes implicated by COGS through endophenotypes have been identified by independent studies of common, rare, and de novo variation in schizophrenia, all converging on a functional genetic network related to glutamatergic neurotransmission that warrants further investigation. PMID:26597662

  15. Neuraxial opioids in geriatrics: A dose reduction study of local anesthetic with addition of sufentanil in lower limb surgery for elderly patients

    Sumit Kumar

    2011-01-01

    Full Text Available Background and Objectives: Neuraxial anesthesia in the elderly is associated with exaggerated responses to conventional doses of local anesthetics, thereby increasing the incidence of hemodynamic complications. A double-blind prospective study was carried out in our institute with an aim to compare the hemodynamic stability and quality of the conventional dose of hyperbaric bupivacaine (LA with low dose of LA and sufentanil in elderly patients scheduled for lower limb surgery, randomized to receive combined spinal epidural anesthesia. Methods: A total of 50 elderly patients of ASA grade I and II, divided randomly into groups I and II, of either sex undergoing lower limb surgery under combined spinal epidural anesthesia at our institute attached to a Government Medical College were enrolled for study. Group I received 2.5 ml of intrathecal hyperbaric bupivacaine (LA, while group II received 1.5 ml of intrathecal LA+0.1 ml sufentanil (5 μg. Both initial and postoperative subarachnoid block characteristics, hemodynamic and respiratory parameters, duration of analgesia, and side effects were observed and recorded. Statistical analysis was carried out using Chi-square and paired t test. Results: Demographic profile was comparable in both groups. Group I had a greater incidence of hypotension and, consequently, higher use of vasopressors (P<0.05. Onset of sensory analgesia, time to achieve peak sensory level, and recovery from motor blockade were significantly earlier in group II (P<0.05. Postoperative consumption of LA through epidural route was significantly higher in group I (P<0.05. The side effect profile was similar, except for a significantly higher incidence of shivering in group I (P<0.05. Conclusions: The study established that the dose of a local anesthetic can be safely and significantly lowered by 40%, with addition of low-dose sufentanil, thereby avoiding the hemodynamic fluctuation and providing a stable perioperative and postoperative

  16. Operational difficulties experienced in the assignment of respiratory protection factors for use in the assessment of internal doses

    UK legislation requires employers to make assessments of all significant components of dose received by classified persons (category A workers). In this context ''significant'' is taken to be components (such as internal dose) which might exceed one-tenth of a relevant annual limit. It is common practice in industry for employers to provide respiratory protective equipment to reduce the consequences of radioactivity in air. In some cases (for example, half face dust masks) a ''protection factor'' is assigned by the Approved Dosimetry Service (ADS) on the advice of the employer in making internal dose assessments. Respiratory protection factors are used to modify internal doses assessed on the basis of air monitoring to take account of reductions in radionuclide in air concentrations as a result of wearing respiratory protective equipment (RPE). The Health and Safety Executive (HSE) requires adequate justification to support the use of numerical protection factors in making internal dose assessments. Sometimes too much reliance is placed upon standardised laboratory trials to determine mask in-leakage properties for dosimetry purposes. This has resulted in less consideration being given to operational factors such as the period for which the mask is worn, discomfort, adequacy of fit, training and supervision which are important in terms of the overall adequacy of the employer's arrangements for ensuring compliance with IRR 85. This paper gives a practical example to show that caution must be exerci