WorldWideScience

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. 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

  1. 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 ...

  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. 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)

  9. 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

  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. 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)

  15. 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)

  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. 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

  5. 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.)

  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

    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

    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.

  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. 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

  6. 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

  7. 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.)

  8. 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.)

  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. 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)

  11. 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)

  12. 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)

  13. 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)

  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. 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

  18. 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.

  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

    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.

  2. 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

  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. 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.

  19. 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)

  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. 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)

  5. 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

  6. 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....

  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. 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)

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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

  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. 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

  15. 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.

  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

    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

  3. 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

  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. 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)

  7. 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

  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

    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)

  16. 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.

  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. 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

  2. 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)

  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. 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.

  8. 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)

  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. 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)

  13. 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)

  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 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

  17. 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

  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

    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

  1. 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

  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. 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....

  8. 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.)

  9. 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

  10. 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.