WorldWideScience

Sample records for dose assessment method

  1. Epidemiological methods for assessing dose-response and dose-effect relationships

    DEFF Research Database (Denmark)

    Kjellström, Tord; Grandjean, Philippe

    2007-01-01

    Selected Molecular Mechanisms of Metal Toxicity and Carcinogenicity General Considerations of Dose-Effect and Dose-Response Relationships Interactions in Metal Toxicology Epidemiological Methods for Assessing Dose-Response and Dose-Effect Relationships Essential Metals: Assessing Risks from Deficiency......Description Handbook of the Toxicology of Metals is the standard reference work for physicians, toxicologists and engineers in the field of environmental and occupational health. This new edition is a comprehensive review of the effects on biological systems from metallic elements...... access to a broad range of basic toxicological data and also gives a general introduction to the toxicology of metallic compounds. Audience Toxicologists, physicians, and engineers in the fields of environmental and occupational health as well as libraries in these disciplines. Will also be a useful...

  2. Methods of assessing total doses integrated across pathways

    International Nuclear Information System (INIS)

    Grzechnik, M.; Camplin, W.; Clyne, F.; Allott, R.; Webbe-Wood, D.

    2006-01-01

    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

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

    International Nuclear Information System (INIS)

    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

  4. Radiological environmental dose assessment methods and compliance dose results for 2015 operations at the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Jannik, G. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Dixon, K. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-09-01

    This report presents the environmental dose assessment methods and the estimated potential doses to the offsite public from 2015 Savannah River Site (SRS) atmospheric and liquid radioactive releases. Also documented are potential doses from special-case exposure scenarios - such as the consumption of deer meat, fish, and goat milk.

  5. Radiological environmental dose assessment methods and compliance dose results for 2015 operations at the Savannah River Site

    International Nuclear Information System (INIS)

    Jannik, G. T.; Dixon, K. L.

    2016-01-01

    This report presents the environmental dose assessment methods and the estimated potential doses to the offsite public from 2015 Savannah River Site (SRS) atmospheric and liquid radioactive releases. Also documented are potential doses from special-case exposure scenarios - such as the consumption of deer meat, fish, and goat milk.

  6. Multiple methods for assessing the dose to skin exposed to radioactive contamination

    International Nuclear Information System (INIS)

    Dubeau, J.; Heinmiller, B.E.; Corrigan, M.

    2017-01-01

    There is the possibility for a worker at a nuclear installation, such as a nuclear power reactor, a fuel production facility or a medical facility, to come in contact with radioactive contaminants. When such an event occurs, the first order of business is to care for the worker by promptly initiating a decontamination process. Usually, the radiation protection personnel performs a G-M pancake probe measurement of the contamination in situ and collects part or all of the radioactive contamination for further laboratory analysis. The health physicist on duty must then perform, using the available information, a skin dose assessment that will go into the worker's permanent dose record. The contamination situations are often complex and the dose assessment can be laborious. This article compares five dose assessment methods that involve analysis, new technologies and new software. The five methods are applied to 13 actual contamination incidents consisting of direct skin contact, contamination on clothing and contamination on clothing in the presence of an air gap between the clothing and the skin. This work shows that, for the cases studied, the methods provided dose estimates that were usually within 12% (1σ) of each other, for those cases where absolute activity information for every radionuclide was available. One method, which relies simply on a G-M pancake probe measurement, appeared to be particularly useful in situations where a contamination sample could not be recovered for laboratory analysis. (authors)

  7. A METHOD TO IMPROVE DOSE ASSESSMENT BY RECONSTRUCTION OF THE COMPLETE ISOTOPES INVENTORY.

    Science.gov (United States)

    Bonin, Alice; Tsilanizara, Aimé

    2017-06-01

    Radiation shielding assessments may underestimate the expected dose if some isotopes at trace level are not considered in the isotopes inventory of the shielded radioactive materials. Indeed, information about traces is not often available. Nevertheless, the activation of some minor isotopic traces may significantly contribute to the dose build-up. This paper presents a new method (Isotopes Inventory Reconstruction-IIR) estimating the concentration of the minor isotopes in the irradiated material at the beginning of the cooling period. The method requires the solution of the inverse problem describing the irradiated material's decay. In a mixture of an irradiated uranium-plutonium oxide shielded by a set-up made of stainless-steel, porous polyethylene plaster and lead methyl methacrylate, the comparison between different methods proves that the IIR-method allows better assessment of the dose than other approximate methods. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    Directory of Open Access Journals (Sweden)

    Karimian Alireza

    2014-01-01

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

  9. Risk and dose assessment methods in gamma knife QA

    International Nuclear Information System (INIS)

    Banks, W.W.; Jones, E.D.; Rathbun, P.

    1992-10-01

    Traditional methods used in assessing risk in nuclear power plants may be inappropriate to use in assessing medical radiation risks. The typical philosophy used in assessing nuclear reactor risks is machine dominated with only secondary attention paid to the human component, and only after critical machine failure events have been identified. In assessing the risk of a misadministrative radiation dose to patients, the primary source of failures seems to stem overwhelmingly, from the actions of people and only secondarily from machine mode failures. In essence, certain medical misadministrations are dominated by human events not machine failures. Radiological medical devices such as the Leksell Gamma Knife are very simple in design, have few moving parts, and are relatively free from the risks of wear when compared with a nuclear power plant. Since there are major technical differences between a gamma knife and a nuclear power plant, one must select a particular risk assessment method which is sensitive to these system differences and tailored to the unique medical aspects of the phenomena under study. These differences also generate major shifts in the philosophy and assumptions which drive the risk assessment (Machine-centered vs Person-centered) method. We were prompted by these basic differences to develop a person-centered approach to risk assessment which would reflect these basic philosophical and technological differences, have the necessary resolution in its metrics, and be highly reliable (repeatable). The risk approach chosen by the Livermore investigative team has been called the ''Relative Risk Profile Method'' and has been described in detail by Banks and Paramore, (1983)

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

    International Nuclear Information System (INIS)

    Rojo, A.M.; Gomez Parada, I.; Puerta Yepes, N.; Gossio, S.

    2010-01-01

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

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

    International Nuclear Information System (INIS)

    Rojo, A.M.; Gomez Parada, I.; Puerta Yepes, N.; Gossio, S.

    2010-01-01

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

  12. Consultative exercise on dose assessments.

    Science.gov (United States)

    Bridges, B A; Parker, T; Simmonds, J R; Sumner, D

    2001-06-01

    A summary is given of a meeting held at Sussex University, UK, in October 2000, which allowed the exchange of ideas on methods of assessment of dose to the public arising from potential authorised radioactive discharges from nuclear sites in the UK. Representatives of groups with an interest in dose assessments were invited, and hence the meeting was called the Consultative Exercise on Dose Assessments (CEDA). Although initiated and funded by the Food Standards Agency, its organisation, and the writing of the report, were overseen by an independent Chairman and Steering Group. The report contains recommendations for improvement in co-ordination between different agencies involved in assessments, on method development and on the presentation of data on assessments. These have been prepared by the Steering Group, and will be taken forward by the Food Standards Agency and other agencies in the UK. The recommendations are included in this memorandum.

  13. Enjebi Island dose assessment

    International Nuclear Information System (INIS)

    Robison, W.L.; Conrado, C.L.; Phillips, W.A.

    1987-07-01

    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 137 Cs 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

  14. Occupational dose assessment in interventional cardiology in Serbia

    International Nuclear Information System (INIS)

    Kaljevic, J.; Ciraj-Bjelac, O.; Stankovic, J.; Arandjic, D.; Bozovic, P.; Antic, V.

    2016-01-01

    The objective of this work is to assess the occupational dose in interventional cardiology in a large hospital in Belgrade, Serbia. A double-dosimetry method was applied for the estimation of whole-body dose, using thermoluminescent dosemeters, calibrated in terms of the personal dose equivalent H p (10). Besides the double-dosimetry method, eye dose was also estimated by means of measuring ambient dose equivalent, H*(10), and doses per procedure were reported. Doses were assessed for 13 physicians, 6 nurses and 10 radiographers, for 2 consequent years. The maximum annual effective dose assessed was 4.3, 2.1 and 1.3 mSv for physicians, nurses and radiographers, respectively. The maximum doses recorded by the dosemeter worn at the collar level (over the apron) were 16.8, 11.9 and 4.5 mSv, respectively. This value was used for the eye lens dose assessment. Estimated doses are in accordance with or higher than annual dose limits for the occupational exposure. (authors)

  15. A dose assessment method for arbitrary geometries with virtual reality in the nuclear facilities decommissioning

    Science.gov (United States)

    Chao, Nan; Liu, Yong-kuo; Xia, Hong; Ayodeji, Abiodun; Bai, Lu

    2018-03-01

    During the decommissioning of nuclear facilities, a large number of cutting and demolition activities are performed, which results in a frequent change in the structure and produce many irregular objects. In order to assess dose rates during the cutting and demolition process, a flexible dose assessment method for arbitrary geometries and radiation sources was proposed based on virtual reality technology and Point-Kernel method. The initial geometry is designed with the three-dimensional computer-aided design tools. An approximate model is built automatically in the process of geometric modeling via three procedures namely: space division, rough modeling of the body and fine modeling of the surface, all in combination with collision detection of virtual reality technology. Then point kernels are generated by sampling within the approximate model, and when the material and radiometric attributes are inputted, dose rates can be calculated with the Point-Kernel method. To account for radiation scattering effects, buildup factors are calculated with the Geometric-Progression formula in the fitting function. The effectiveness and accuracy of the proposed method was verified by means of simulations using different geometries and the dose rate results were compared with that derived from CIDEC code, MCNP code and experimental measurements.

  16. A new method to assess the gonadal doses in women during radiation treatment

    International Nuclear Information System (INIS)

    Agrawal, M.S.; Pant, G.C.

    1977-01-01

    The relative inaccessibility of the ovaries renders direct measurement of the gonadal doses difficult. A relatively simple method is described to tackle this problem - using the upper margin of the public symphysis as a reference point. Measurement of Radiation doses were done in a Masonite human phantom using T.L.D. and a Co-60 teletherapy unit. The accompanying figures document the observations made. The distance between the lower edge of the treatment port and the reference point is denoted by 'd'. First figure relates observed ratios of the radiation doses at the ovary and the reference point to 'd' for various port sizes and the second figure shows the relationship between the area of the port and the dose ratio (ovary: reference-point) for various values of 'd'. The advantage of this documentation is that it serves as a 'Ready Reckoner' to assess the ovarian doses under different treatment situations-once the doses at the reference point is measured

  17. A real-time internal dose assessment exercise

    International Nuclear Information System (INIS)

    Bingham, D.; Bull, R. K.

    2013-01-01

    A real-time internal dose assessment exercise has been conducted in which participants were required to make decisions about sampling requirements, seek relevant information about the 'incident' and make various interim dose assessments. At the end of the exercise, each participant was requested to make a formal assessment, providing statements of the methods, models and assumptions used in that assessment. In this paper we describe how the hypothetical assessment case was set up and the exercise was conducted, the responses of the participants and the assessments of dose that they made. Finally we discuss the lessons learnt from the exercise and suggest how the exercise may be adapted to a wider range of participants. (authors)

  18. Virtual reality based adaptive dose assessment method for arbitrary geometries in nuclear facility decommissioning.

    Science.gov (United States)

    Liu, Yong-Kuo; Chao, Nan; Xia, Hong; Peng, Min-Jun; Ayodeji, Abiodun

    2018-05-17

    This paper presents an improved and efficient virtual reality-based adaptive dose assessment method (VRBAM) applicable to the cutting and dismantling tasks in nuclear facility decommissioning. The method combines the modeling strength of virtual reality with the flexibility of adaptive technology. The initial geometry is designed with the three-dimensional computer-aided design tools, and a hybrid model composed of cuboids and a point-cloud is generated automatically according to the virtual model of the object. In order to improve the efficiency of dose calculation while retaining accuracy, the hybrid model is converted to a weighted point-cloud model, and the point kernels are generated by adaptively simplifying the weighted point-cloud model according to the detector position, an approach that is suitable for arbitrary geometries. The dose rates are calculated with the Point-Kernel method. To account for radiation scattering effects, buildup factors are calculated with the Geometric-Progression formula in the fitting function. The geometric modeling capability of VRBAM was verified by simulating basic geometries, which included a convex surface, a concave surface, a flat surface and their combination. The simulation results show that the VRBAM is more flexible and superior to other approaches in modeling complex geometries. In this paper, the computation time and dose rate results obtained from the proposed method were also compared with those obtained using the MCNP code and an earlier virtual reality-based method (VRBM) developed by the same authors. © 2018 IOP Publishing Ltd.

  19. Determination of environmental radioactivity for dose assessment

    International Nuclear Information System (INIS)

    Nakoaka, A.; Fukushima, M.; Takagi, S.

    1980-01-01

    A method was devised to determine detection limits for radioactivity in environmental samples. The method is based on the 5 mrem/yr whole-body dose objective established by the Japan Atomic Enerty Commission and is valid for assessing the internal dose from radionuclides in the environment around a nuclear facility. Eleven samples and 15 radionuclides were considered. Internal dose was assumed to be one-half of the total dose (5 mrem/yr) and was assessed using the critical pathway method. Needed detection limits (NDLs) were established to confirm the dose of 5 mrem/yr when there was more than one radionuclide per sample. The NDLs for γ-emitters were 10 -5 pCi/l. for air; 10 -3 pCi/l. for seawater; 10 -1 pCi/l. for drinking water; 10 0 pCi/kg for vegetables and fish; 10 0 pCi/l. for milk; and 10 1 pCi/kg for molluscs, crustaceans, seaweeds, soil and submarine sediments. The NDLs for β-emitters were 1-1/100 of those for γ-emitters. (author)

  20. Environmental dose-assessment methods for normal operations at DOE nuclear sites

    International Nuclear Information System (INIS)

    Strenge, D.L.; Kennedy, W.E. Jr.; Corley, J.P.

    1982-09-01

    Methods for assessing public exposure to radiation from normal operations at DOE facilities are reviewed in this report. The report includes a discussion of environmental doses to be calculated, a review of currently available environmental pathway models and a set of recommended models for use when environmental pathway modeling is necessary. Currently available models reviewed include those used by DOE contractors, the Environmental Protection Agency (EPA), the Nuclear Regulatory Commission (NRC), and other organizations involved in environmental assessments. General modeling areas considered for routine releases are atmospheric transport, airborne pathways, waterborne pathways, direct exposure to penetrating radiation, and internal dosimetry. The pathway models discussed in this report are applicable to long-term (annual) uniform releases to the environment: they do not apply to acute releases resulting from accidents or emergency situations

  1. An updated dose assessment for Rongelap Island

    Energy Technology Data Exchange (ETDEWEB)

    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).

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

    International Nuclear Information System (INIS)

    Ould-Dada, Z.; Tucker, S.; Webbe-Wood, D.; Mondon, K.; Hunt, J.

    2002-01-01

    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

  3. Methods of assessment of individual and collective doses to transport workers and members of the public during the transport of radioactive material

    International Nuclear Information System (INIS)

    Vohra, K.G.; Subrahmanian, G.; Nandakumar, A.N.; Kher, R.K.; Iyer, S.R.K.

    1986-01-01

    Transport workers handling radioactive cargoes are generally exposed to the highest dose rates of any population group. Methods of assessment of dose received by transport workers are studied to arrive at a useful method. An empirical model based on a detailed work study of individuals handling radioactive cargoes and the exposure rates at various distances from specific individual packages is developed. The personnel doses thus calculated compared reasonably well with the doses recorded on personnel monitoring badges. The personnel doses were also evaluated with reference to the total transport index handled by the workers, yielding results consistent with those reported elsewhere by earlier researchers. For assessing the collective dose to the public due to urban transport of radioactive material, the space around the vehicle transporting cargo was divided into a number of cells of dimensions 1mx1m. The radiation level in each cell was measured and the pedestrian density along the route was obtained. Using the pedestrian occupancy in the cells and the measured radiation levels, the total dose to the public was assessed. A similar assessment was made with respect to the passengers in the neighbouring vehicles. The suggested method of calculation may aid determination of the route and time of transport and the preferable traffic configuration for the vehicle carrying the radioactive consignments for optimizing the dose to the urban public

  4. Assessment of exposure dose to workers in virtual decommissioning environments

    International Nuclear Information System (INIS)

    Jeong, KwanSeong; Moon, JeiKwon; Choi, ByungSeon; Hyun, Dongjun; Lee, Jonghwan; Kim, Ikjune; Kim, GeunHo; Seo, JaeSeok

    2014-01-01

    This paper is intended to suggest the method analyze and assess the exposure dose to workers in virtual decommissioning environments. To simulate a lot of decommissioning scenarios, decommissioning environments were designed in virtual reality. To simulate and assess the exposure dose to workers, human model also was designed in virtual environments. These virtual decommissioning environments made it possible to real-time simulate and assess the exposure dose to workers. This work was to be able to simulate scenarios of decommissioning so that exposure dose to workers could be measured and assessed. To establish the plan of exposure dose to workers during decommissioning of nuclear facilities before decommissioning activities are accomplished, the method of simulation assessment was developed in virtual radiological environments. But this work was developed as a tool of simulation for single subject mode. Afterwards, the simulation environment for multi-subjects mode will be upgraded by simultaneous modules with networking environments. Then the much more practical method will be developed by changing number of workers and duration of time under any circumstances of decommissioning

  5. Assessment of exposure dose to workers in virtual decommissioning environments

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, KwanSeong; Moon, JeiKwon; Choi, ByungSeon; Hyun, Dongjun; Lee, Jonghwan; Kim, Ikjune; Kim, GeunHo; Seo, JaeSeok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    This paper is intended to suggest the method analyze and assess the exposure dose to workers in virtual decommissioning environments. To simulate a lot of decommissioning scenarios, decommissioning environments were designed in virtual reality. To simulate and assess the exposure dose to workers, human model also was designed in virtual environments. These virtual decommissioning environments made it possible to real-time simulate and assess the exposure dose to workers. This work was to be able to simulate scenarios of decommissioning so that exposure dose to workers could be measured and assessed. To establish the plan of exposure dose to workers during decommissioning of nuclear facilities before decommissioning activities are accomplished, the method of simulation assessment was developed in virtual radiological environments. But this work was developed as a tool of simulation for single subject mode. Afterwards, the simulation environment for multi-subjects mode will be upgraded by simultaneous modules with networking environments. Then the much more practical method will be developed by changing number of workers and duration of time under any circumstances of decommissioning.

  6. Interactive Rapid Dose Assessment Model (IRDAM): user's guide

    International Nuclear Information System (INIS)

    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 User's Guide provides instruction in the setup and operation of the equipment necessary to run IRDAM. Instructions are also given on how to load the magnetic disks and access the interactive part of the program. Two other companion volumes to this one provide additional information on IRDAM. Reactor Accident Assessment Methods (NUREG/CR-3012, Volume 2) describes the technical bases for IRDAM including methods, models and assumptions used in calculations. 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

  7. Dose assessment in radiological accidents

    International Nuclear Information System (INIS)

    Donkor, S.

    2013-04-01

    The applications of ionizing radiation bring many benefits to humankind, ranging from power generation to uses in medicine, industry and agriculture. Facilities that use radiation source require special care in the design and operation of equipment to prevent radiation injury to workers or to the public. Despite considerable development of radiation safety, radiation accidents do happen. The purpose of this study is therefore to discuss how to assess doses to people who will be exposed to a range of internal and external radiation sources in the event of radiological accidents. This will go a long way to complement their medical assessment thereby helping to plan their treatment. Three radiological accidents were reviewed to learn about the causes of those accidents and the recommendations that were put in place to prevent recurrence of such accidents. Various types of dose assessment methods were discussed.(au)

  8. Non-monotonic dose-response relationships and endocrine disruptors: a qualitative method of assessment

    OpenAIRE

    Lagarde, Fabien; Beausoleil, Claire; Belcher, Scott M; Belzunces, Luc P; Emond, Claude; Guerbet, Michel; Rousselle, Christophe

    2015-01-01

    International audience; Experimental studies investigating the effects of endocrine disruptors frequently identify potential unconventional dose-response relationships called non-monotonic dose-response (NMDR) relationships. Standardized approaches for investigating NMDR relationships in a risk assessment context are missing. The aim of this work was to develop criteria for assessing the strength of NMDR relationships. A literature search was conducted to identify published studies that repor...

  9. An assessment of methods for monitoring entrance surface dose in fluoroscopically guided interventional procedures

    International Nuclear Information System (INIS)

    Waite, J.C.; Fitzgerald, M.

    2001-01-01

    In the light of a growing awareness of the risks of inducing skin injuries as a consequence of fluoroscopically guided interventional procedures (FGIPs), this paper compares three methods of monitoring entrance surface dose (ESD). It also reports measurements of ESDs made during the period August 1998 to June 1999 on 137 patients undergoing cardiac, neurological and general FGIPs. Although the sample is small, the results reinforce the need for routine assessments to be made of ESDs in FGIPs. At present, the most reliable and accurate form of ESD measurement would seem to be arrays of TLDs. However, transducer based methods, although likely to be less accurate, have considerable advantages in relation to a continuous monitoring programme. It is also suggested that there may be the potential locally for threshold dose area product (DAP) values to be set for specific procedures. These could be used to provide early warning of the potential for skin injuries. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-15

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

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

    International Nuclear Information System (INIS)

    Vaishnav, J. Y.; Jung, W. C.; Popescu, L. M.; Zeng, R.; Myers, K. J.

    2014-01-01

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

  12. Internal dose assessment in radiation accidents

    International Nuclear Information System (INIS)

    Toohey, R.E.

    2003-01-01

    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 241 Am accident. (author)

  13. Uncertainty of fast biological radiation dose assessment for emergency response scenarios.

    Science.gov (United States)

    Ainsbury, Elizabeth A; Higueras, Manuel; Puig, Pedro; Einbeck, Jochen; Samaga, Daniel; Barquinero, Joan Francesc; Barrios, Lleonard; Brzozowska, Beata; Fattibene, Paola; Gregoire, Eric; Jaworska, Alicja; Lloyd, David; Oestreicher, Ursula; Romm, Horst; Rothkamm, Kai; Roy, Laurence; Sommer, Sylwester; Terzoudi, Georgia; Thierens, Hubert; Trompier, Francois; Vral, Anne; Woda, Clemens

    2017-01-01

    Reliable dose estimation is an important factor in appropriate dosimetric triage categorization of exposed individuals to support radiation emergency response. Following work done under the EU FP7 MULTIBIODOSE and RENEB projects, formal methods for defining uncertainties on biological dose estimates are compared using simulated and real data from recent exercises. The results demonstrate that a Bayesian method of uncertainty assessment is the most appropriate, even in the absence of detailed prior information. The relative accuracy and relevance of techniques for calculating uncertainty and combining assay results to produce single dose and uncertainty estimates is further discussed. Finally, it is demonstrated that whatever uncertainty estimation method is employed, ignoring the uncertainty on fast dose assessments can have an important impact on rapid biodosimetric categorization.

  14. Occupational dose assessment and national dose registry system in Iran

    International Nuclear Information System (INIS)

    Jafari-Zadeh, M.; Nazeri, F.; Hosseini-Pooya, S. M.; Taheri, M.; Gheshlaghi, F.; Kardan, M. R.; Babakhani, A.; Rastkhah, N.; Yousefi-Nejad, F.; Darabi, M.; Oruji, T.; Gholamali-Zadeh, Z.; Karimi-Diba, J.; Kazemi-Movahed, A. A.; Dashti-Pour, M. R.; Enferadi, A.; Jahanbakhshian, M. H.; Sadegh-Khani, M. R.

    2011-01-01

    This report presents status of external and internal dose assessment of workers and introducing the structure of National Dose Registry System of Iran (NDRSI). As well as types of individual dosemeters in use, techniques for internal dose assessment are presented. Results obtained from the International Atomic Energy Agency intercomparison programme on measurement of personal dose equivalent H p (10) and consistency of the measured doses with the delivered doses are shown. Also, implementation of dosimetry standards, establishment of quality management system, authorisation and approval procedure of dosimetry service providers are discussed. (authors)

  15. Estimation of absorbed doses on the basis of cytogenetic methods

    International Nuclear Information System (INIS)

    Shevchenko, V.A.; Rubanovich, A.V.; Snigiryova, G.P.

    1998-01-01

    Long-term studies in the field of radiation cytogenetics have resulted in the discovery of relationship between induction of chromosome aberrations and the type of ionizing radiation, their intensity and dose. This has served as a basis of biological dosimetry as an area of application of the revealed relationship, and has been used in the practice to estimate absorbed doses in people exposed to emergency irradiation. The necessity of using the methods of biological dosimetry became most pressing in connection with the Chernobyl accident in 1986, as well as in connection with other radiation situations that occurred in nuclear industry of the former USSR. The materials presented in our works demonstrate the possibility of applying cytogenetic methods for assessing absorbed doses in populations of different regions exposed to radiation as a result of accidents at nuclear facilities (Chernobyl, the village Muslymovo on the Techa river, the Three Mile Island nuclear power station in the USA where an accident occurred in 1979). Fundamentally, new possibilities for retrospective dose assessment are provided by the FISH-method that permits the assessment of absorbed doses after several decades since the exposure occurred. In addition, the application of this method makes it possible to restore the dynamics of unstable chromosome aberrations (dicentrics and centric rings), which is important for further improvement of the method of biological dosimetry based on the analysis of unstable chromosome aberrations. The purpose of our presentation is a brief description of the cytogenetic methods used in biological dosimetry, consideration of statistical methods of data analysis and a description of concrete examples of their application. (J.P.N.)

  16. Skin dose assessment in routine personnel beta/gamma dosimetry

    International Nuclear Information System (INIS)

    Christensen, P.

    1980-01-01

    Three alternative methods are outlined by which substantial improvements of the capabilities of existing routine monitoring systems for skin dose assessment can be obtained. The introduction of a supplementary skin dosemeter may be an attractive method for systems with badges that have a capability for an additional dosemeter already built-in. The two-side reading method has limited possibilities because of reduced accuracy for mixed radiation and technical difficulties in using it for TLD systems with planchet heating. The use of a boron diffused LiF layer for skin dose assessment seems to be most attractive method since the only modification needed here is replacement of a dosemeter. However the study of this method is so far only in a preliminary stage and further investigations are needed. (U.K.)

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

    International Nuclear Information System (INIS)

    Wu, K.; Guo, L.; Cong, J.B.; Sun, C.P.; Hu, J.M.; Zhou, Z.S.; Wang, S.; Zhang, Y.; Zhang, X.; Shi, Y.M.

    1998-01-01

    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)

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

    International Nuclear Information System (INIS)

    Jeong, KwanSeong; Choi, ByungSeon; Moon, JeiKwon; Hyun, Dongjun; Lee, Jonghwan; Kim, IkJune; Kim, GeunHo; Seo, JaeSeok; Jeong, SeongYoung; Lee, JungJun; Song, HaeSang; Lee, SangWha; Son, BongKi

    2014-01-01

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

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

    International Nuclear Information System (INIS)

    Pfingston, M.; Arnish, J.; LePoire, D.; Chen, S.-Y.

    1998-01-01

    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

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

    International Nuclear Information System (INIS)

    Nair, S.

    1979-10-01

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

  1. Maximum skin dose assessment in interventional cardiology: large area detectors and calculation methods

    International Nuclear Information System (INIS)

    Quail, E.; Petersol, A.

    2002-01-01

    Advances in imaging technology have facilitated the development of increasingly complex radiological procedures for interventional radiology. Such interventional procedures can involve significant patient exposure, although often represent alternatives to more hazardous surgery or are the sole method for treatment. Interventional radiology is already an established part of mainstream medicine and is likely to expand further with the continuing development and adoption of new procedures. Between all medical exposures, interventional radiology is first of the list of the more expansive radiological practice in terms of effective dose per examination with a mean value of 20 mSv. Currently interventional radiology contribute 4% to the annual collective dose, in spite of contributing to total annual frequency only 0.3% but considering the perspectives of this method can be expected a large expansion of this value. In IR procedures the potential for deterministic effects on the skin is a risk to be taken into account together with stochastic long term risk. Indeed, the International Commission on Radiological Protection (ICRP) in its publication No 85, affirms that the patient dose of priority concern is the absorbed dose in the area of skin that receives the maximum dose during an interventional procedure. For the mentioned reasons, in IR it is important to give to practitioners information on the dose received by the skin of the patient during the procedure. In this paper maximum local skin dose (MSD) is called the absorbed dose in the area of skin receiving the maximum dose during an interventional procedure

  2. Rectal dose assessment in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer

    International Nuclear Information System (INIS)

    Oliveira, Jetro Pereira de; Batista, Delano Valdivino Santos; Bardella, Lucia Helena; Carvalho, Arnaldo Rangel

    2009-01-01

    Objective: The present study was aimed at developing a thermoluminescent dosimetric system capable of assessing the doses delivered to the rectum of patients submitted to high-dose-rate brachytherapy for uterine cervix cancer. Materials and methods: LiF:Mg,Ti,Na powder was the thermoluminescent material utilized for evaluating the rectal dose. The powder was divided into small portions (34 mg) which were accommodated in a capillary tube. This tube was placed into a rectal probe that was introduced into the patient's rectum. Results: The doses delivered to the rectum of six patients submitted to high-dose-rate brachytherapy for uterine cervix cancer evaluated by means of thermoluminescent dosimeters presented a good agreement with the planned values based on two orthogonal (anteroposterior and lateral) radiographic images of the patients. Conclusion: The thermoluminescent dosimetric system developed in the present study is simple and easy to be utilized as compared to other rectal dosimetry methods. The system has shown to be effective in the evaluation of rectal doses in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer. (author)

  3. Skin dose assessment in routine personnel beta/gamma dosimetry

    International Nuclear Information System (INIS)

    Christensen, P.

    1980-01-01

    The International Commission on Radiological Protection (Publication 26) has recommended a tissue depth of 5 to 10 mg.cm -2 for skin dose assessments. This requirement is generally not fulfilled by routine monitoring procedures because of practical difficulties in using very thin dosemeters with low sensitivity and therefore a high minimum detectable dose. Especially for low-energy beta-ray exposures underestimations of the skin dose by a factor of more than ten may occur. Low-transparent graphite-mixed sintered LiF and Li 2 B 4 0 7 : Mn dosemeters were produced which show a skin-equivalent response to beta and gamma exposures over a wide range of energies. These have found wide-spread application for extremity dosimetry but have not yet been generally introduced in routine personnel beta/gamma monitoring. The following adaptations of existing routine monitoring systems for improved skin dose assessments have been investigated: 1) Placement of a supplementary, thin, skin-dose equivalent dosemeter in the TLD badge to give additional information on low-energy exposures. 2) Introduction of a second photomultiplier in the read-out chamber which enables a simultaneous determination of emitted TL from both sides of the dosemeter separately. This method makes use of the selfshielding of the dosemeter to give information on the low-energy dose contribution. 3) By diffusion of Li 2 B 4 0 7 into solid LiF-dosemeters it was possible to produce a surface layer with a new distinct glow-peak at about 340 deg C which is not present in the undiffused part of the LiF chip, and which can be utilized for the assessment of the skin-dose. Data on energy response and accuracy of dose measurement for beta/gamma exposures are given for the three methods and advantages and disadvantages are discussed (H.K.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Juyub; Kim, Juyoul; Shin, Kwangyoung [FNC Technology Co. Ltd., Yongin (Korea, Republic of); You, Songjae; Moon, Jongyi [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2014-05-15

    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.

  5. Variability in dose-equivalent assessments for inhaled U3O8 concentrations

    International Nuclear Information System (INIS)

    Hewson, G.; Blyth, D.I.

    1985-01-01

    A potentially significant radiological hazard exists in the packaging area of uranium mills through the inhalation of airborne uranium octoxide (U 3 O 8 ). The Radiation Protection (Mining and Milling Code (1980) requires the measurement and assessment of quarterly, annual and cumulative dose equivalents for employees working in these areas. Arising through differences which exist between the abovementioned Code and ICRP 30, and assumptions of particle size and dust concentration distributions, confusion exists within Australia regarding the methods which can be used to make the required assessments. Exposure data were collected during routine monitoring at an operating mill facility and were interpreted using different methods and a range of assumptions. Results indicated the dust at this facility is characterised by an AMAD greater than 10 μ, and dust concentrations were distributed lognormally. Assumptions of a normal distribution may result in an overestimate of the dose equivalent. The importance of particle size in dose assessments using ICRP 30 techniques was highlighted. Information was masked when employee data was grouped to provide work category dose assessments. The use of ICRP 30 methods were recommended to provide uniformity throughout Australia

  6. Retrospective methods of dose assessment of the Chernobyl 'liquidators'. A comparison

    International Nuclear Information System (INIS)

    Schmidt, M.; Ziggel, H.; Schmitz-Feuerhaake, I.; Dannheim, B.; Schikalov, V.; Usatyj, A.; Shevchenko, V.; Snigireva, G.; Serezhenkov, V.; Klevezal, G.

    1998-01-01

    A database of biomedical and dosimetric data of participants in the liquidation work at Chernobyl was set up. Dose profiles were created by using suitable dose modelling. EPR spectrometric measurements of the tooth enamel was performed as a routine method of retrospective dosimetry for radiation workers at medium to low exposures. Chromosome analyses were carried out in peripheral blood lymphocytes of a cohort of the liquidation workers. Fluorescence in-situ hybridization was also used. The number of workers volunteering to take part in the research, however, was too small to allow statistically relevant results to be obtained. (P.A.)

  7. Optimizing CT radiation dose based on patient size and image quality: the size-specific dose estimate method

    Energy Technology Data Exchange (ETDEWEB)

    Larson, David B. [Stanford University School of Medicine, Department of Radiology, Stanford, CA (United States)

    2014-10-15

    The principle of ALARA (dose as low as reasonably achievable) calls for dose optimization rather than dose reduction, per se. Optimization of CT radiation dose is accomplished by producing images of acceptable diagnostic image quality using the lowest dose method available. Because it is image quality that constrains the dose, CT dose optimization is primarily a problem of image quality rather than radiation dose. Therefore, the primary focus in CT radiation dose optimization should be on image quality. However, no reliable direct measure of image quality has been developed for routine clinical practice. Until such measures become available, size-specific dose estimates (SSDE) can be used as a reasonable image-quality estimate. The SSDE method of radiation dose optimization for CT abdomen and pelvis consists of plotting SSDE for a sample of examinations as a function of patient size, establishing an SSDE threshold curve based on radiologists' assessment of image quality, and modifying protocols to consistently produce doses that are slightly above the threshold SSDE curve. Challenges in operationalizing CT radiation dose optimization include data gathering and monitoring, managing the complexities of the numerous protocols, scanners and operators, and understanding the relationship of the automated tube current modulation (ATCM) parameters to image quality. Because CT manufacturers currently maintain their ATCM algorithms as secret for proprietary reasons, prospective modeling of SSDE for patient populations is not possible without reverse engineering the ATCM algorithm and, hence, optimization by this method requires a trial-and-error approach. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Ryong; Ha, Wi Ho; Yoon, Seok Won; Han, Eun Ae; Lee, Seung Sook [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2011-10-15

    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

  9. Assessment and recording of radiation doses to workers

    International Nuclear Information System (INIS)

    1986-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    Scott, C.K.; Kennedy, E.R.; Hughs, R.

    1991-05-01

    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

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

    International Nuclear Information System (INIS)

    Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan

    2012-01-01

    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 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 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 adj that differed by up to 44% from effective dose estimates that were not

  13. Calculation methods for determining dose equivalent

    International Nuclear Information System (INIS)

    Endres, G.W.R.; Tanner, J.E.; Scherpelz, R.I.; Hadlock, D.E.

    1987-11-01

    A series of calculations of neutron fluence as a function of energy in an anthropomorphic phantom was performed to develop a system for determining effective dose equivalent for external radiation sources. Critical organ dose equivalents are calculated and effective dose equivalents are determined using ICRP-26 [1] methods. Quality factors based on both present definitions and ICRP-40 definitions are used in the analysis. The results of these calculations are presented and discussed. The effective dose equivalent determined using ICRP-26 methods is significantly smaller than the dose equivalent determined by traditional methods. No existing personnel dosimeter or health physics instrument can determine effective dose equivalent. At the present time, the conversion of dosimeter response to dose equivalent is based on calculations for maximal or ''cap'' values using homogeneous spherical or cylindrical phantoms. The evaluated dose equivalent is, therefore, a poor approximation of the effective dose equivalent as defined by ICRP Publication 26. 3 refs., 2 figs., 1 tab

  14. Assessing Doses to Interventional Radiologists Using a Personal Dosimeter Worn Over a Protective Apron

    Energy Technology Data Exchange (ETDEWEB)

    Stranden, E.; Widmark, A.; Sekse, T. (Buskerud Univ. College, Drammen (Norway))

    2008-05-15

    Background: Interventional radiologists receive significant radiation doses, and it is important to have simple methods for routine monitoring of their exposure. Purpose: To evaluate the usefulness of a dosimeter worn outside the protective apron for assessments of dose to interventional radiologists. Material and Methods: Assessments of effective dose versus dose to dosimeters worn outside the protective apron were achieved by phantom measurements. Doses outside and under the apron were assessed by phantom measurements and measurements on eight radiologists wearing two routine dosimeters for a 2-month period during ordinary working conditions. Finger doses for the same radiologists were recorded using thermoluminescent dosimeters (TLD; DXT-RAD Extremity dosimeters). Results: Typical values for the ratio between effective dose and dosimeter dose were found to be about 0.02 when the radiologist used a thyroid shield and about 0.03 without. The ratio between the dose to the dosimeter under and outside a protective apron was found to be less than 0.04. There was very good correlation between finger dose and dosimeter dose. Conclusion: A personal dosimeter worn outside a protective apron is a good screening device for dose to the eyes and fingers as well as for effective dose, even though the effective dose is grossly overestimated. Relatively high dose to the fingers and eyes remains undetected by a dosimeter worn under the apron

  15. Assessing Doses to Interventional Radiologists Using a Personal Dosimeter Worn Over a Protective Apron

    International Nuclear Information System (INIS)

    Stranden, E.; Widmark, A.; Sekse, T.

    2008-01-01

    Background: Interventional radiologists receive significant radiation doses, and it is important to have simple methods for routine monitoring of their exposure. Purpose: To evaluate the usefulness of a dosimeter worn outside the protective apron for assessments of dose to interventional radiologists. Material and Methods: Assessments of effective dose versus dose to dosimeters worn outside the protective apron were achieved by phantom measurements. Doses outside and under the apron were assessed by phantom measurements and measurements on eight radiologists wearing two routine dosimeters for a 2-month period during ordinary working conditions. Finger doses for the same radiologists were recorded using thermoluminescent dosimeters (TLD; DXT-RAD Extremity dosimeters). Results: Typical values for the ratio between effective dose and dosimeter dose were found to be about 0.02 when the radiologist used a thyroid shield and about 0.03 without. The ratio between the dose to the dosimeter under and outside a protective apron was found to be less than 0.04. There was very good correlation between finger dose and dosimeter dose. Conclusion: A personal dosimeter worn outside a protective apron is a good screening device for dose to the eyes and fingers as well as for effective dose, even though the effective dose is grossly overestimated. Relatively high dose to the fingers and eyes remains undetected by a dosimeter worn under the apron

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

    International Nuclear Information System (INIS)

    Allott, Rob

    2003-01-01

    Dear Sir: I read with interest the paper by W C Camplin, G P Brownless, G D Round, K Winpenny and G J Hunt from the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) on 'Radioactivity in food and the environment: calculations of UK radiation doses using integrated methods' in the December 2002 issue of this journal (J. Radiol. Prot. 22 371-88). The Environment Agency has a keen interest in the development of a robust methodology for assessing total doses which have been received by members of the public from authorised discharges of radioactive substances to the environment. Total dose in this context means the dose received from all authorised discharges and all exposure pathways (e.g. inhalation, external irradiation from radionuclides in sediment/soil, direct radiation from operations on a nuclear site, consumption of food etc). I chair a 'total retrospective dose assessment' working group with representatives from the Scottish Environment Protection Agency (SEPA), Food Standards Agency (FSA), National Radiological Protection Board, CEFAS and BNFL which began discussing precisely this issue during 2002. This group is a sub-group of the National Dose Assessment Working Group which was set up in April 2002 (J. Radiol. Prot. 22 318-9). The Environment Agency, Food Standards Agency and the Nuclear Installations Inspectorate previously undertook joint research into the most appropriate methodology to use for total dose assessment (J J Hancox, S J Stansby and M C Thorne 2002 The Development of a Methodology to Assess Population Doses from Multiple Source and Exposure Pathways of Radioactivity (Environment Agency R and D Technical Report P3-070/TR). This work came to broadly the same conclusion as the work by CEFAS, that an individual dose method is probably the most appropriate method to use. This research and that undertaken by CEFAS will help the total retrospective dose assessment working group refine a set of principles and a methodology for the

  17. Methods of bone marrow dose calculation

    International Nuclear Information System (INIS)

    Taboaco, R.C.

    1982-02-01

    Several methods of bone marrow dose calculation for photon irradiation were analised. After a critical analysis, the author proposes the adoption, by the Instituto de Radioprotecao e Dosimetria/CNEN, of Rosenstein's method for dose calculations in Radiodiagnostic examinations and Kramer's method in case of occupational irradiation. It was verified by Eckerman and Simpson that for monoenergetic gamma emitters uniformly distributed within the bone mineral of the skeleton the dose in the bone surface can be several times higher than dose in skeleton. In this way, is also proposed the Calculation of tissue-air ratios for bone surfaces in some irradiation geometries and photon energies to be included in the Rosenstein's method for organ dose calculation in Radiodiagnostic examinations. (Author) [pt

  18. Nonparametric estimation of benchmark doses in environmental risk assessment

    Science.gov (United States)

    Piegorsch, Walter W.; Xiong, Hui; Bhattacharya, Rabi N.; Lin, Lizhen

    2013-01-01

    Summary An important statistical objective in environmental risk analysis is estimation of minimum exposure levels, called benchmark doses (BMDs), that induce a pre-specified benchmark response in a dose-response experiment. In such settings, representations of the risk are traditionally based on a parametric dose-response model. It is a well-known concern, however, that if the chosen parametric form is misspecified, inaccurate and possibly unsafe low-dose inferences can result. We apply a nonparametric approach for calculating benchmark doses, based on an isotonic regression method for dose-response estimation with quantal-response data (Bhattacharya and Kong, 2007). We determine the large-sample properties of the estimator, develop bootstrap-based confidence limits on the BMDs, and explore the confidence limits’ small-sample properties via a short simulation study. An example from cancer risk assessment illustrates the calculations. PMID:23914133

  19. Assessment of internal doses

    CERN Document Server

    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...

  20. Introduction to benchmark dose methods and U.S. EPA's benchmark dose software (BMDS) version 2.1.1

    International Nuclear Information System (INIS)

    Davis, J. Allen; Gift, Jeffrey S.; Zhao, Q. Jay

    2011-01-01

    Traditionally, the No-Observed-Adverse-Effect-Level (NOAEL) approach has been used to determine the point of departure (POD) from animal toxicology data for use in human health risk assessments. However, this approach is subject to substantial limitations that have been well defined, such as strict dependence on the dose selection, dose spacing, and sample size of the study from which the critical effect has been identified. Also, the NOAEL approach fails to take into consideration the shape of the dose-response curve and other related information. The benchmark dose (BMD) method, originally proposed as an alternative to the NOAEL methodology in the 1980s, addresses many of the limitations of the NOAEL method. It is less dependent on dose selection and spacing, and it takes into account the shape of the dose-response curve. In addition, the estimation of a BMD 95% lower bound confidence limit (BMDL) results in a POD that appropriately accounts for study quality (i.e., sample size). With the recent advent of user-friendly BMD software programs, including the U.S. Environmental Protection Agency's (U.S. EPA) Benchmark Dose Software (BMDS), BMD has become the method of choice for many health organizations world-wide. This paper discusses the BMD methods and corresponding software (i.e., BMDS version 2.1.1) that have been developed by the U.S. EPA, and includes a comparison with recently released European Food Safety Authority (EFSA) BMD guidance.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  2. Technical basis for using nose swab bioassay data for early internal dose assessment

    International Nuclear Information System (INIS)

    Guilmette, Raymond A.; Bertelli, Luiz; Miller, Guthrie; Little, Tom T.

    2007-01-01

    One of the challenges to the dose assessment team in response to an inhalation incident in the workplace is to provide the occupational physicians, operational radiation protection personnel and line managers with early estimates of radionuclide intakes so that appropriate consequence management and mitigation can be done. For radionuclides such as Pu, where in vivo counting is not adequately sensitive, other techniques such as the measurement of removable radionuclide from the nasal airway passages can be used. At Los Alamos National Laboratory (LANL), nose swabs of the ET 1 region have been used routinely as a first response to airborne Pu releases in the workplace, as well as for other radionuclides. This paper presents the results of analysing over 15 years of nose swab data, comparing these with dose assessments performed using the Bayesian methods developed at LANL. The results provide empirical support for using nose swab data for early dose assessments. For Pu, a rule of thumb is a dose factor of 0.8 mSv Bq -1 , assuming a linear relationship between nasal swab activity and committed effective dose equivalent. However, this value is specific to the methods and models used at LANL, and should not be applied directly without considering possible differences in measurement and calculation methods. (authors)

  3. Characteristics of environmental gamma-rays and dose assessment

    International Nuclear Information System (INIS)

    Saito, Kimiaki; Moriuchi, Shigeru

    1986-01-01

    Environmental radioactivity has attracted much attention in terms of exposure to the population, although its exposure doses are minimal. This paper presents problems encountered in the assessment of exposure doses using model and monitoring systems, focusing on the characteristics, such as energy distribution, direction distribution, and site, of environmental gamma-rays. The assessment of outdoor and indoor exposure doses of natural gamma-rays is discussed in relation to the shielding effect of the human body. In the assessment of artificial gamma-rays, calculation of exposure doses using build-up factor, the shielding effect of the human body, and energy dependency of the measuring instrument are covered. A continuing elucidation about uncertainties in dose assessment is emphasized. (Namekawa, K.)

  4. Assessments for high dose radionuclide therapy treatment planning

    International Nuclear Information System (INIS)

    Fisher, D.R.

    2003-01-01

    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)

  5. Bootstrap resampling: a powerful method of assessing confidence intervals for doses from experimental data

    International Nuclear Information System (INIS)

    Iwi, G.; Millard, R.K.; Palmer, A.M.; Preece, A.W.; Saunders, M.

    1999-01-01

    Bootstrap resampling provides a versatile and reliable statistical method for estimating the accuracy of quantities which are calculated from experimental data. It is an empirically based method, in which large numbers of simulated datasets are generated by computer from existing measurements, so that approximate confidence intervals of the derived quantities may be obtained by direct numerical evaluation. A simple introduction to the method is given via a detailed example of estimating 95% confidence intervals for cumulated activity in the thyroid following injection of 99m Tc-sodium pertechnetate using activity-time data from 23 subjects. The application of the approach to estimating confidence limits for the self-dose to the kidney following injection of 99m Tc-DTPA organ imaging agent based on uptake data from 19 subjects is also illustrated. Results are then given for estimates of doses to the foetus following administration of 99m Tc-sodium pertechnetate for clinical reasons during pregnancy, averaged over 25 subjects. The bootstrap method is well suited for applications in radiation dosimetry including uncertainty, reliability and sensitivity analysis of dose coefficients in biokinetic models, but it can also be applied in a wide range of other biomedical situations. (author)

  6. A review of occupational dose assessment uncertainties and approaches

    International Nuclear Information System (INIS)

    Anderson, R. W.

    2004-01-01

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Optimization of radiation therapy, III: a method of assessing complication probabilities from dose-volume histograms

    International Nuclear Information System (INIS)

    Lyman, J.T.; Wolbarst, A.B.

    1987-01-01

    To predict the likelihood of success of a therapeutic strategy, one must be able to assess the effects of the treatment upon both diseased and healthy tissues. This paper proposes a method for determining the probability that a healthy organ that receives a non-uniform distribution of X-irradiation, heat, chemotherapy, or other agent will escape complications. Starting with any given dose distribution, a dose-cumulative-volume histogram for the organ is generated. This is then reduced by an interpolation scheme (involving the volume-weighting of complication probabilities) to a slightly different histogram that corresponds to the same overall likelihood of complications, but which contains one less step. The procedure is repeated, one step at a time, until there remains a final, single-step histogram, for which the complication probability can be determined. The formalism makes use of a complication response function C(D, V) which, for the given treatment schedule, represents the probability of complications arising when the fraction V of the organ receives dose D and the rest of the organ gets none. Although the data required to generate this function are sparse at present, it should be possible to obtain the necessary information from in vivo and clinical studies. Volume effects are taken explicitly into account in two ways: the precise shape of the patient's histogram is employed in the calculation, and the complication response function is a function of the volume

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

    International Nuclear Information System (INIS)

    Pfingston, M.

    1998-01-01

    In May 1991, the U.S. Department of Energy (DOE), Office of Waste Operations, issued a nationwide moratorium on shipping slightly radioactive mixed waste from DOE facilities to commercial treatment, storage, and disposal (TSD) facilities. Studies were subsequently conducted to evaluate the radiological impacts associated with DOE's prior shipments through DOE's authorized release process under DOE Order 5400.5. To support this endeavor, a radiological assessment computer code--TSD-DOSE (Version 1.1)--was developed and issued by DOE in 1997. The code was developed on the basis of detailed radiological assessments performed for eight commercial hazardous waste TSD facilities. It was designed to utilize 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 has since been released for use by DOE field offices and was recently used by DOE to evaluate the release of septic waste containing residual radioactive material to a TSD facility licensed under the Resource Conservation and Recovery Act. Revisions to the code were initiated in 1997 to incorporate comments received from users and to increase TSD-DOSE's capability, accuracy, and flexibility. These updates included incorporation of the method used to estimate external radiation doses from DOE's RESRAD model and expansion of the source term to include 85 radionuclides. In addition, a detailed verification and benchmarking analysis was performed

  10. Thermoluminescence dosemeter for personal dose equivalent assessment

    International Nuclear Information System (INIS)

    Silva, T.A. da; Rosa, L.A.R. da; Campos, L.L.

    1995-01-01

    The possibility was investigated of utilising a Brazilian thermoluminescence individual dosemeter, usually calibrated in terms of photon dose equivalent, for the assessment of the personal dose equivalent, H p (d), at depths of 0.07 and 10 mm. The dosemeter uses four CaSO 4 :Dy thermoluminescent detectors, between different filters, as the sensitive materials. It was calibrated in gamma and X radiation fields in the energy range from 17 to 1250 keV. Linear combinations of the responses of three detectors, in this energy range, allow the evaluation of H p (0.07) and H p (10), for radiation incidence angles varying from 0 to 60 degrees, with an accuracy better than 35%. The method is not applicable to mixed photon-beta fields. (author)

  11. An Internal Dose Assessment Associated with Personal Food Intake

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joeun; Jae, Moosung [Hanyang University, Seoul (Korea, Republic of); Hwang, Wontae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    ICRP (International Commission on Radiological Protection), Therefore, had recommended the concept of 'Critical Group'. Recently the ICRP has recommended the use of 'Representative Person' on the new basic recommendation 103. On the other hand the U.S. NRC (Nuclear Regulatory Commission) has adopted more conservative concept, 'Maximum Exposed Individuals (MEI)' of critical Group. The dose assessment in Korea is based on MEI. Although dose assessment based on MEI is easy to receive the permission of the regulatory authority, it is not efficient. Meanwhile, the internal dose by food consumption takes an important part. Therefore, in this study, the internal dose assessment was performed in accordance with ICRP's new recommendations. The internal dose assessment was performed in accordance with ICRP's new recommendations. It showed 13.2% decreased of the annual internal dose due to gaseous effluents by replacing MEI to the concept of representative person. Also, this calculation based on new ICRP's recommendation has to be extended to all areas of individual dose assessment. Then, more accurate and efficient values might be obtained for dose assessment.

  12. IAEA/IDEAS intercomparison exercise on internal dose assessment

    International Nuclear Information System (INIS)

    Doerfel, H.; Andrasi, A.; Cruz-Suarez, R.; Castellani, C. M.; Hurtgen, C.; Marsh, J.; Zeger, J.

    2007-01-01

    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)

  13. Local dose assessment for a contaminated wound

    International Nuclear Information System (INIS)

    Piechowski, J.; Chaptinel, Y.

    2004-01-01

    Contaminated wounds present a great variability concerning the type of lesion. Assessment of the local dose is one amongst other factors for a decision as to the surgical operation. A simple model has been used to calculate the doses in a representative volume, that of a phalanx for instance. The dose rates are given for current radionuclides. The method of calculation is enough simple in order to allow the practitioners to use it in situations involving other radionuclides. Committed dose depends on the biological half-life which can be estimated from the local measurements. Some examples of calculation of committed dose are given considering half-lives characteristic of the compound. Transposition of the dose to the local risk is easy for the non-stochastic risk. Conversely, this is not the case for the risk of chronic inflammation or cancer. The latter question could only be solved by a feedback based on the analysis of real till now observed cases, nevertheless taking into account the fact that the available data are generally not so easy to make use for establishing an unquestionable dose - effect relation. A critical issue remains open as to the use of these doses for their comparison to the regulatory limits and for the subsequent decisions in case of exceeding the limits. The actual impact of an irradiation, especially by alpha particles, is not linked to the calculated dose in a simple and direct way. This question needs further consideration and perhaps a practical guide concerning this topic would be useful. The anatomical (surgical side effects), psychological and professional consequences should have a large weight relatively to the doses, obviously except for the cases, involving actually large contamination. (authors)

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

    International Nuclear Information System (INIS)

    Takahashi, Fumiaki

    2006-09-01

    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 24 Na 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 24 Na. 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 24 Na 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 24 Na 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)

  15. Assessment of dose received by organ in lumbosacral examination

    International Nuclear Information System (INIS)

    Eltyeib, Nashwa Kheirallah

    2014-11-01

    The biological damage produced by radiation is closely related to the amount of energy absorbed in the case x- rays. Measurement of produced ionizing provides a useful assessment of the total energy absorbed. This study was performed in Khartoum Teaching Hospital in period of January to June 2014. This study was performed to assess the effective dose (ED) received in lumbosacral radiography examination and to analyze effective dose distributions among radiological department under study. The study was performed in Khartoum Teaching Hospital, covering two x-ray units and a sample of 50 patients. The following parameters were recorded: age weight, height, body mass index (BMI) derived from mass (kg) and (height. (m)) and exposure factors. The dose was measured for lumbosacral x- rays examination. For effective dose calculation, the entrance surface dose (ESD) values were estimated from the x-ray tube output parameters for lumbosacral spine A P and lateral examinations. The ED values were then calculated from the obtained ESD values using IAEA calculation methods. Effective doses were than calculated from energy imported using ED conversion factors by IAEA. The results of ED values calculated showed that patient exposures were within the normal range of exposure. The mean ED values calculated were (2.49 ±0.03) mGy and (5.5.60 ± 0.0.22) mGy for Lumbosacral spine A P and lateral examinations, respectively. Further studies are recommended with more number of patients and using more modalities for comparison.(Author)

  16. TU-H-CAMPUS-JeP3-02: Automated Dose Accumulation and Dose Accuracy Assessment for Online Or Offline Adaptive Replanning

    International Nuclear Information System (INIS)

    Chen, G; Ahunbay, E; Li, X

    2016-01-01

    Purpose: With introduction of high-quality treatment imaging during radiation therapy (RT) delivery, e.g., MR-Linac, adaptive replanning of either online or offline becomes appealing. Dose accumulation of delivered fractions, a prerequisite for the adaptive replanning, can be cumbersome and inaccurate. The purpose of this work is to develop an automated process to accumulate daily doses and to assess the dose accumulation accuracy voxel-by-voxel for adaptive replanning. Methods: The process includes the following main steps: 1) reconstructing daily dose for each delivered fraction with a treatment planning system (Monaco, Elekta) based on the daily images using machine delivery log file and considering patient repositioning if applicable, 2) overlaying the daily dose to the planning image based on deformable image registering (DIR) (ADMIRE, Elekta), 3) assessing voxel dose deformation accuracy based on deformation field using predetermined criteria, and 4) outputting accumulated dose and dose-accuracy volume histograms and parameters. Daily CTs acquired using a CT-on-rails during routine CT-guided RT for sample patients with head and neck and prostate cancers were used to test the process. Results: Daily and accumulated doses (dose-volume histograms, etc) along with their accuracies (dose-accuracy volume histogram) can be robustly generated using the proposed process. The test data for a head and neck cancer case shows that the gross tumor volume decreased by 20% towards the end of treatment course, and the parotid gland mean dose increased by 10%. Such information would trigger adaptive replanning for the subsequent fractions. The voxel-based accuracy in the accumulated dose showed that errors in accumulated dose near rigid structures were small. Conclusion: A procedure as well as necessary tools to automatically accumulate daily dose and assess dose accumulation accuracy is developed and is useful for adaptive replanning. Partially supported by Elekta, Inc.

  17. A radiological dose assessment for the Port Hope conversion facility

    International Nuclear Information System (INIS)

    Garisto, N.C.; Cooper, F.; Janes, A.; Stager, R.; Peters, R.

    2011-01-01

    The Port Hope Conversion Facility (PHCF) receives uranium trioxide for conversion to uranium hexafluoride (UF 6 ) or uranium dioxide (UO 2 ). The PHCF Site has a long history of industrial use. A Radiological Dose Assessment was undertaken as part of a Site Wide Risk Assessment. This assessment took into account all possible human receptors, both workers and members of the public. This paper focuses on a radiological assessment of dose to members of the public. The doses to members of the public from terrestrial pathways were added to the doses from aquatic pathways to obtain overall dose to receptors. The benchmark used in the assessment is 1 mSv/y. The estimated doses related to PHCF operations are much lower than the dose limit. (author)

  18. Dose assessment for Greifswald and Cadarache

    International Nuclear Information System (INIS)

    Raskob, W.

    1996-07-01

    Probabilistic dose assessments for accidental atmospheric releases of tritium and activation products as well as releases under normal operation conditions were performed for the sites of Greifswald, Germany, and Cadarache, France. Additionally, aquatic releases were considered for both sites. No country specific rules were applied and the input parameters were adapted as far as possible to those used within former ITER studies to have a better comparison to site independent dose assessments performed in the frame of ITER. The main goal was to complete the generic data base with site specific values. The agreement between the results from the ITER study on atmospheric releases and the two sites are rather good for tritium, whereas the ITER reference dose values for the activation product releases are often lower, than the maximum doses for Greifswald and Cadarache. However, the percentile values fit better to the deterministic approach of ITER. Within all scenarios, the consequences of aquatic releases are in nearly all cases smaller than those from comparable releases to the atmosphere (HTO and steel). This rule is only broken once in case of accidental releases of activated steel from Cadarache. However, the uncertainties associated with the aquatic assessments are rather high and a better data base is needed to obtain more realistic and thus more reliable dose values. (orig.) [de

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

    International Nuclear Information System (INIS)

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

    2000-01-01

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

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

    International Nuclear Information System (INIS)

    Smith, K.; Robinson, C.; Jackson, D.; La Cruz, I. de; Zinger, I.; Avila, R.

    2010-10-01

    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.)

  1. Accurate assessment of the distortions produced by the transit dose in HDR brachytherapy

    International Nuclear Information System (INIS)

    Nani, E.K.; Kyere, A.W.K.; Tetteh, K.

    2001-01-01

    Current polynomial methods used in the modelling of the dose distributions in HDR brachytherapy have been reformulated to improve accuracy. An example is provided to show the effects of the transit dose on the output. The transit dose, which is neglected by current computer software for calculating doses, can result in significant dosimetric errors. These additional unrecognised doses imply over-dosing and distortions in the dose distributions within the irradiated volume. Assessment of dose to critical and radiosensitive organs is therefore inaccurate. These could increase late tissue complications as predicted by the Linear Quadratic Model. Our model works very well for straight catheters and is highly recommended for the evaluation of the transit dose around such catheters. (author)

  2. Cytogenetic analysis for radiation dose assessment. A manual

    International Nuclear Information System (INIS)

    2001-01-01

    Chromosome aberration analysis is recognized as a valuable dose assessment method which fills a gap in dosimetric technology, particularly when there are difficulties in interpreting the data, in cases where there is reason to believe that persons not wearing dosimeters have been exposed to radiation, in cases of claims for compensation for radiation injuries that are not supported by unequivocal dosimetric evidence, or in cases of exposure over an individual's working lifetime. The IAEA has maintained a long standing involvement in biological dosimetry commencing in 1978. This has been via a sequence of Co-ordinated Research Programmes (CRPs), the running of Regional Training Courses, the sponsorship of individual training fellowships and the provision of necessary equipment to laboratories in developing Member States. The CRP on the 'Use of Chromosome Aberration Analysis in Radiation Protection' was initiated by IAEA in 1982. It ended with the publication of the IAEA Technical Report Series No. 260, titled 'Biological Dosimetry: Chromosomal Aberration Analysis for Dose Assessment' in 1986. The overall objective of the CRP (1998-2000) on 'Radiation Dosimetry through Biological Indicators' is to review and standardize the available methods and amend the above mentioned previous IAEA publication with current techniques on cytogenetic bioindicators which may be of practical use in biological dosimetry worldwide. An additional objective is to identify promising cytogenetic techniques to provide Member States with up to date and generally agreed advice regarding the best focus for research and suggestions for the most suitable techniques for near future practice in biodosimetry. This activity is in accordance with the International Basic Safety Standards (BSS) published in 1996. To pursue this task the IAEA has conducted a Research Co-ordination Meeting (Budapest, Hungary, June 1998) with the participation of senior scientists of 24 biodosimetry laboratories to discuss

  3. Howard Hughes Medical Institute dose assessment survey

    International Nuclear Information System (INIS)

    O'Brien, S.L.; McDougall, M.M.; Barkley, W.E.

    1996-01-01

    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

  4. Summary of the dose assessment tool for diagnostic X-ray CT, WAZA-ARIv2

    International Nuclear Information System (INIS)

    Koba, Yosuke

    2016-01-01

    WAZA-ARIv2 is the web-based open system for the dose assessment for diagnostic X-ray CT. Amid growing interest about the dose assessment for medical exposure, WAZA-ARIv2 is opened to the public from January 2015 and attracts rising attention. Using WAZA-ARIv2 system, users can calculate exposure dose to consider patient's age and body shape, and can register the calculation results on WAZA-ARIv2 server for checking as histogram statistics. This paper reviews the background of development of WAZA-ARI system, the comparison of characteristics between WAZA-ARIv2 and other tools, and the calculation method of organ dose in WAZA-ARIv2. (author)

  5. Dose assessment method for control room habitability in accident condition in nuclear power plants

    International Nuclear Information System (INIS)

    Yang Dong; Tang Shaohua; Wang Jianhua

    2012-01-01

    Based on the NRC. technical requirements on NPP control room habitability assessment, and considering the characteristics of the improved second generation NPPs in China, this paper developed a complete dose assessment model for control room habitability. Contrasting to the existing model in China, this model is applicable for DBA and sever accident, and the short term atmospheric diffusion factor can be calculated using the combined wake mode. By considering the zoning of habitable area and the design characteristics of the ventilation system, the effects of un-filtrated air leakage from the building and the ventilation system on the assessment calculation can be considered. (authors)

  6. Dose assessment in the Marshall Islands

    International Nuclear Information System (INIS)

    Robison, William L.

    1978-01-01

    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)

  7. Inhalation dose assessment for Maralinga and Emu

    International Nuclear Information System (INIS)

    Johnston, P.N.; Lokan, K.H.; Williams, G.A.

    1990-01-01

    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/m 3 for adults and 1.5 mg/m 3 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 239 Pu is the largest contributor. Therefore, considering the long half lives of the radionuclides concerned, it appears that the inhalation problems highlighted by this dose assessment will not diminish significantly within any reasonable period of time and hence management strategies must be developed to deal with such problems. 32 refs., 5 tabs., 1 fig

  8. The MIRD method of estimating absorbed dose

    International Nuclear Information System (INIS)

    Weber, D.A.

    1991-01-01

    The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to combining the biologic distribution data and clearance data of radiopharmaceuticals and the physical properties of radionuclides to obtain dose estimates. This tutorial presents a review of the MIRD schema, the derivation of the equations used to calculate absorbed dose, and shows how the MIRD schema can be applied to estimate dose from radiopharmaceuticals used in nuclear medicine

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

    Science.gov (United States)

    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

  10. Assessment of dose inhomogeneity at target level by in vivo dosimetry

    International Nuclear Information System (INIS)

    Leunens, G.; Verstraete, J.; Dutreix, A.; Schueren, E. van der

    1992-01-01

    Inhomogeneity of dose delivered to the target volume due to irregular body surface and tissue densities remains in many cases unknown, since dose distribution is calculated for most radiation treatments in only one transverse section and assuming the patient to be water equivalent. In this study transmission and target absorbed dose homogeneity is assessed for 11 head-and-neck cancer treatments by in vivo measurements with silicon diodes. Besides the dose to specification point, the dose delivered to 2-4 off-axis points in midline sagittal plane is estimated from entrance and exit dose measurements. Simultaneously made portal films allow to identify anatomical structures passed by the beam before reaching exit diode. Mean deviation from expected transmission is -6.8% for bone, +6% for air cavities and -2.5% for soft tissue. At midplane, mean deviations from expected target dose are respectively -3.5%, +2.3% and -1.9%. Deviations from prescribed dose are larger than 5% in 12/39 target points. Accuracy requirements in target dose delivery of plus or minus 5%, as proposed by ICRU, cannot be fulfilled in 7/11 patients and is mostly due to irregular body contour and tissue densities. as only a limited number of points are considered, inhomogeneity in dose delivered throughout whole irradiated volume is underestimated, as is illustrated from exit dose profiles obtained from portal image. Besides its tremendous value as a quality assurance procedure, in vivo dose measurements are shown to be a valid method for assessing dose delivered to irradiated tissues when dose computations are assumed to be inaccurate or even impossible in current practice. (author). 21 refs., 8 figs., 1 tab

  11. REIDAC. A software package for retrospective dose assessment in internal contamination with radionuclides

    International Nuclear Information System (INIS)

    Kurihara, Osamu; Kanai, Katsuta; Takada, Chie; Takasaki, Koji; Ito, Kimio; Momose, Takumaro; Hato, Shinji; Ikeda, Hiroshi; Oeda, Mikihiro; Kurosawa, Naohiro; Fukutsu, Kumiko; Yamada, Yuji; Akashi, Makoto

    2007-01-01

    For cases of internal contamination with radionuclides, it is necessary to perform an internal dose assessment to facilitate radiation protection. For this purpose, the ICRP has supplied the dose coefficients and the retention and excretion rates for various radionuclides. However, these dosimetric quantities are calculated under typical conditions and are not necessarily detailed enough for dose assessment situations in which specific information on the incident or/and individual biokinetic characteristics could or should be taken into account retrospectively. This paper describes a newly developed PC-based software package called Retrospective Internal Dose Assessment Code (REIDAC) that meets the needs of retrospective dose assessment. REIDAC is made up of a series of calculation programs and a package of software. The former calculates the dosimetric quantities for any radionuclide being assessed and the latter provides a user with the graphical user interface (GUI) for executing the programs, editing parameter values and displaying results. The accuracy of REIDAC was verified by comparisons with dosimetric quantities given in the ICRP publications. This paper presents the basic structure of REIDAC and its calculation methods. Sensitivity analysis of the aerosol size for 239 Pu compounds and provisional calculations for wound contamination with 241 Am were performed as examples of the practical application of REIDAC. (author)

  12. 4D cone beam CT-based dose assessment for SBRT lung cancer treatment

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  13. Bio-indicators for radiation dose assessment

    International Nuclear Information System (INIS)

    Trivedi, A.

    1990-12-01

    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

  14. Assessment of physician and patient (child and adult) equivalent doses during renal angiography by Monte Carlo method

    International Nuclear Information System (INIS)

    Karimian, A.; Nikparvar, B.; Jabbari, I.

    2014-01-01

    Renal angiography is one of the medical imaging methods in which patient and physician receive high equivalent doses due to long duration of fluoroscopy. In this research, equivalent doses of some radiosensitive tissues of patient (adult and child) and physician during renal angiography have been calculated by using adult and child Oak Ridge National Laboratory phantoms and Monte Carlo method (MCNPX). The results showed, in angiography of right kidney in a child and adult patient, that gall bladder with the amounts of 2.32 and 0.35 mSv, respectively, has received the most equivalent dose. About the physician, left hand, left eye and thymus absorbed the most amounts of doses, means 0.020 mSv. In addition, equivalent doses of the physician's lens eye, thyroid and knees were 0.023, 0.007 and 7.9 - 4 mSv, respectively. Although these values are less than the reported thresholds by ICRP 103, it should be noted that these amounts are related to one examination. (authors)

  15. Dose assessments for SFR 1

    International Nuclear Information System (INIS)

    Bergstroem, Ulla; Avila, Rodolfo; Ekstroem, Per-Anders; Cruz, Idalmis de la

    2008-05-01

    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

  16. Dose assessments for SFR 1

    Energy Technology Data Exchange (ETDEWEB)

    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

  17. Dose assessment for brachytherapy with Henschke applicator

    International Nuclear Information System (INIS)

    Yu, Pei-Chieh; Chao, Tsi-Chian; Tung, Chuan-Jong; Wu, Ching-Jung; Lee, Chung-Chi

    2011-01-01

    Dose perturbation caused by the Henschke applicator is a major concern for the brachytherapy planning system (BPS) in recent years. To investigate dose impact owing to neglect of the metal shielding effect, Monte Carlo (MC) simulation, BPS calculation, and film measurement have been performed for dose assessment in a water phantom. Additionally, a cylindrical air cavity representing the rectum was added into the MC simulation to study its effect on dose distribution. Monte Carlo N-Particle Transport Code (MCNP) was used in this study to simulate the dose distribution using a mesh tally. This Monte Carlo simulation has been validated using the TG-43 data in a previous report. For the measurement, the Henschke applicator was placed in a specially-designed phantom, and Gafchromic films were inserted in the center plane for 2D dose assessment. Isodose distributions with and without the Henschke applicator by the MC simulation show significant deviation from those by the BPS. For MC simulation, the isodose curves shrank more significantly when the metal applicator was applied. For the impact of the added air cavity, the results indicate that it is hard to distinguish between with and without the cavity. Thus, the rectum cavity has little impact on the dose distribution around the Henschke applicator.

  18. Indoor aerosol modeling for assessment of exposure and respiratory tract deposited dose

    Science.gov (United States)

    Hussein, Tareq; Wierzbicka, Aneta; Löndahl, Jakob; Lazaridis, Mihalis; Hänninen, Otto

    2015-04-01

    Air pollution is one of the major environmental problems that influence people's health. Exposure to harmful particulate matter (PM) occurs both outdoors and indoors, but while people spend most of their time indoors, the indoor exposures tend to dominate. Moreover, higher PM concentrations due to indoor sources and tightness of indoor environments may substantially add to the outdoor originating exposures. Empirical and real-time assessment of human exposure is often impossible; therefore, indoor aerosol modeling (IAM) can be used as a superior method in exposure and health effects studies. This paper presents a simple approach in combining available aerosol-based modeling techniques to evaluate the real-time exposure and respiratory tract deposited dose based on particle size. Our simple approach consists of outdoor aerosol data base, IAM simulations, time-activity pattern data-base, physical-chemical properties of inhaled aerosols, and semi-empirical deposition fraction of aerosols in the respiratory tract. These modeling techniques allow the characterization of regional deposited dose in any metric: particle mass, particle number, and surface area. The first part of this presentation reviews recent advances in simple mass-balance based modeling methods that are needed in analyzing the health relevance of indoor exposures. The second part illustrates the use of IAM in the calculations of exposure and deposited dose. Contrary to previous methods, the approach presented is a real-time approach and it goes beyond the exposure assessment to provide the required information for the health risk assessment, which is the respiratory tract deposited dose. This simplified approach is foreseen to support epidemiological studies focusing on exposures originating from both indoor and outdoor sources.

  19. Dose assessment for public by packages shipping radioactive materials hypothetically sunk on the continental shelf. Annex 3

    International Nuclear Information System (INIS)

    Tsumune, Daisuke; Suzuki, Hiroshi; Saegusa, Toshiari; Watabe, Naohito; Asano, Hiroyuki; Maruyama, Koki; Kinehara, Yoshiki

    2001-01-01

    Radioactive materials such as spent fuel (SF), PuO 2 powder, high level wastes (HLW) and fresh mixed oxide (MOX) fuel have been transported by sea between Europe and Japan. Dose assessments for public have been performed in the past when the packages shipping radioactive materials were hypothetically sunk on the continental shelf. These studies employed various conditions and methods in their assessments and the results were not always the same. In this study, the dose assessment for these packages was performed under the same conditions and by the same methods. The effective dose equivalents of radiation exposure to the public for all materials become smaller than the previous evaluations due to more realistic assumption in this study. These evaluated results are far less than the effective dose equivalent limit (1 mSv year -1 ) by the ICRP recommendation. (author)

  20. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, So Ra; Min, Byung Il; Park, Kihyun; Yang, Byung Mo; Suh, Kyung Suk [Nuclear Environmental Safety Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-12-15

    The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment.

  1. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR

    International Nuclear Information System (INIS)

    Kim, So Ra; Min, Byung Il; Park, Kihyun; Yang, Byung Mo; Suh, Kyung Suk

    2016-01-01

    The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment

  2. Development of internal dose assessment procedure for workers in industries using raw materials containing naturally occurring radioactive materials

    International Nuclear Information System (INIS)

    Choi, Cheol Kyu; KIm, Yong Geon; Ji, Seung Woo; Kim, Kwang Pyo; Koo, Bon Cheol; Chang, Byung Uck

    2016-01-01

    It is necessary to assess radiation dose to workers due to inhalation of airborne particulates containing naturally occurring radioactive materials (NORM) to ensure radiological safety required by the Natural Radiation Safety Management Act. The objective of this study is to develop an internal dose assessment procedure for workers at industries using raw materials containing natural radionuclides. The dose assessment procedure was developed based on harmonization, accuracy, and proportionality. The procedure includes determination of dose assessment necessity, preliminary dose estimation, airborne particulate sampling and characterization, and detailed assessment of radiation dose. The developed dose assessment procedure is as follows. Radioactivity concentration criteria to determine dose assessment necessity are 10 Bq·g-1 for 40K and 1 Bq·g-1 for the other natural radionuclides. The preliminary dose estimation is performed using annual limit on intake (ALI). The estimated doses are classified into 3 groups (<0.1 mSv, 0.1-0.3 mSv, and >0.3 mSv). Air sampling methods are determined based on the dose estimates. Detailed dose assessment is performed using air sampling and particulate characterization. The final dose results are classified into 4 different levels (<0.1 mSv, 0.1-0.3 mSv, 0.3-1 mSv, and >1 mSv). Proper radiation protection measures are suggested according to the dose level. The developed dose assessment procedure was applied for NORM industries in Korea, including coal combustion, phosphate processing, and monazite handing facilities. The developed procedure provides consistent dose assessment results and contributes to the establishment of optimization of radiological protection in NORM industries

  3. Development of internal dose assessment procedure for workers in industries using raw materials containing naturally occurring radioactive materials

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Cheol Kyu; KIm, Yong Geon; Ji, Seung Woo; Kim, Kwang Pyo [College of Engineering, Kyung Hee University, Yongin (Korea, Republic of); Koo, Bon Cheol; Chang, Byung Uck [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2016-09-15

    It is necessary to assess radiation dose to workers due to inhalation of airborne particulates containing naturally occurring radioactive materials (NORM) to ensure radiological safety required by the Natural Radiation Safety Management Act. The objective of this study is to develop an internal dose assessment procedure for workers at industries using raw materials containing natural radionuclides. The dose assessment procedure was developed based on harmonization, accuracy, and proportionality. The procedure includes determination of dose assessment necessity, preliminary dose estimation, airborne particulate sampling and characterization, and detailed assessment of radiation dose. The developed dose assessment procedure is as follows. Radioactivity concentration criteria to determine dose assessment necessity are 10 Bq·g-1 for 40K and 1 Bq·g-1 for the other natural radionuclides. The preliminary dose estimation is performed using annual limit on intake (ALI). The estimated doses are classified into 3 groups (<0.1 mSv, 0.1-0.3 mSv, and >0.3 mSv). Air sampling methods are determined based on the dose estimates. Detailed dose assessment is performed using air sampling and particulate characterization. The final dose results are classified into 4 different levels (<0.1 mSv, 0.1-0.3 mSv, 0.3-1 mSv, and >1 mSv). Proper radiation protection measures are suggested according to the dose level. The developed dose assessment procedure was applied for NORM industries in Korea, including coal combustion, phosphate processing, and monazite handing facilities. The developed procedure provides consistent dose assessment results and contributes to the establishment of optimization of radiological protection in NORM industries.

  4. Occupational radiation dose assessment for a non site specific spent fuel storage facility

    International Nuclear Information System (INIS)

    Hadley, J.; Eble, R.G. Jr.

    1997-01-01

    To expedite the licensing process of the non site specific Centralized Interim Storage Facility (CISF) the Department of Energy has completed a phase I CISF Topical Safety Analysis Report (TSAR). The TSAR will be used in licensing the phase I CISF if a site is designated. An occupational radiation does assessment of the facility operations is performed as part of the phase I CISF design. The first phase of the CISF has the capability to receive, transfer, and store SNF in dual-purpose cask/canister systems (DPC's). Currently there are five vendor technologies under consideration. The preliminary dose assessment is based on estimated occupational exposures using traditional power plant ISFSI and transport cask handling processes. The second step in the process is to recommend ALARA techniques to reduce potential exposures. A final dose assessment is completed implementing the ALARA techniques and a review is performed to ensure that the design is in compliance with regulatory criteria. The dose assessment and ALARA evaluation are determined using the following input information: Dose estimates from vendor SAR's; ISFSI experience with similar systems; Traditional methods of operations; Expected CISF cask receipt rates; and feasible ALARA techniques. 5 refs., 1 tab

  5. Comparison of passive and active radon measurement methods for personal occupational dose assessment

    Directory of Open Access Journals (Sweden)

    Hasanzadeh Elham

    2016-01-01

    Full Text Available To compare the performance of the active short-term and passive long-term radon measurement methods, a study was carried out in several closed spaces, including a uranium mine in Iran. For the passive method, solid-state nuclear track detectors based on Lexan polycarbonate were utilized, for the active method, AlphaGUARD. The study focused on the correlation between the results obtained for estimating the average indoor radon concentrations and consequent personal occupational doses in various working places. The repeatability of each method was investigated, too. In addition, it was shown that the radon concentrations in different stations of the continually ventilated uranium mine were comparable to the ground floor laboratories or storage rooms (without continual ventilation and lower than underground laboratories.

  6. Uncertainty on faecal analysis on dose assessment

    Energy Technology Data Exchange (ETDEWEB)

    Juliao, Ligia M.Q.C.; Melo, Dunstana R.; Sousa, Wanderson de O.; Santos, Maristela S.; Fernandes, Paulo Cesar P. [Instituto de Radioprotecao e Dosimetria, Comissao Nacional de Energia Nuclear, Av. Salvador Allende s/n. Via 9, Recreio, CEP 22780-160, Rio de Janeiro, RJ (Brazil)

    2007-07-01

    Monitoring programmes for internal dose assessment may need to have a combination of bioassay techniques, e.g. urine and faecal analysis, especially in workplaces where compounds of different solubilities are handled and also in cases of accidental intakes. Faecal analysis may be an important data for assessment of committed effective dose due to exposure to insoluble compounds, since the activity excreted by urine may not be detectable, unless a very sensitive measurement system is available. This paper discusses the variability of the daily faecal excretion based on data from just one daily collection; collection during three consecutive days: samples analysed individually and samples analysed as a pool. The results suggest that just 1 d collection is not appropriate for dose assessment, since the 24 h uranium excretion may vary by a factor of 40. On the basis of this analysis, the recommendation should be faecal collection during three consecutive days, and samples analysed as a pool, it is more economic and faster. (authors)

  7. Assessment of low absorbed dose with a MOSFET detector

    International Nuclear Information System (INIS)

    Butson, M.J.; Cancer Services, Wollongong, NSW; Cheung, T.; Yu, P.K.N.

    2004-01-01

    Full text: The ability of a MOSFET dosimetry system to measure low therapeutic doses has been evaluated for accuracy for high energy x-ray radiotherapy applications. The MOSFET system in high sensitivity mode produces a dose measurement reproducibility of within 10%, 4% and 2.5% for 2 cGy, 5 cGy and 10cGy dose assessment respectively. This is compared to 7%, 4% and 2% for an Attix parallel plate ionisation chamber and 20%, 7% and 3.5% for a Wellhofer IC4 small volume ionisation chamber. Results for our dose standard thimble ionisation chamber and low noise farmer dosemeter were 2%, 0.5% and 0.25% respectively for these measurements. The quoted accuracy of the MOSFET dosimetry system is partially due to the slight non linear dose response (reduced response) with age of the detector but mainly due to the intrinsic variations in measured voltage differential per applied dose. Results have shown that the MOSFET dosimetry system provides an adequate measure of dose at low dose levels and is comparable in accuracy to the Attix parallel plate ionisation chambers for relative dose assessment at levels of 2cGy to 10cGy. The use of the MOSFET dosimeter at low doses can extend the life expectancy of the device and may provide useful information for areas where low dose assessment is required. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  8. Method of simulating dose reduction for digital radiographic systems

    International Nuclear Information System (INIS)

    Baath, M.; Haakansson, M.; Tingberg, A.; Maansson, L. G.

    2005-01-01

    The optimisation of image quality vs. radiation dose is an important task in medical imaging. To obtain maximum validity of the optimisation, it must be based on clinical images. Images at different dose levels can then either be obtained by collecting patient images at the different dose levels sought to investigate - including additional exposures and permission from an ethical committee - or by manipulating images to simulate different dose levels. The aim of the present work was to develop a method of simulating dose reduction for digital radiographic systems. The method uses information about the detective quantum efficiency and noise power spectrum at the original and simulated dose levels to create an image containing filtered noise. When added to the original image this results in an image with noise which, in terms of frequency content, agrees with the noise present in an image collected at the simulated dose level. To increase the validity, the method takes local dose variations in the original image into account. The method was tested on a computed radiography system and was shown to produce images with noise behaviour similar to that of images actually collected at the simulated dose levels. The method can, therefore, be used to modify an image collected at one dose level so that it simulates an image of the same object collected at any lower dose level. (authors)

  9. Calculation methods for determining dose equivalent

    International Nuclear Information System (INIS)

    Endres, G.W.R.; Tanner, J.E.; Scherpelz, R.I.; Hadlock, D.E.

    1988-01-01

    A series of calculations of neutron fluence as a function of energy in an anthropomorphic phantom was performed to develop a system for determining effective dose equivalent for external radiation sources. critical organ dose equivalents are calculated and effective dose equivalents are determined using ICRP-26 methods. Quality factors based on both present definitions and ICRP-40 definitions are used in the analysis. The results of these calculations are presented and discussed

  10. SU-F-I-38: Patient Organ Specific Dose Assessment in Coronary CT Angiograph Using Voxellaized Volume Dose Index in Monte Carlo Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Fallal, Mohammadi Gh.; Riyahi, Alam N.; Graily, Gh. [Tehran University of Medical Scienced(TUMS), School of Medicine, Department of Nedical Physics and Biomedical Engineering, Tehran (Iran, Islamic Republic of); Paydar, R. [Iran University of Medical Sciences(IUMS), Allied Medicine Faculty, Department of radiation Sciences, Tehran (Iran, Islamic Republic of)

    2016-06-15

    Purpose: Clinical use of multi detector computed tomography(MDCT) in diagnosis of diseases due to high speed in data acquisition and high spatial resolution is significantly increased. Regarding to the high radiation dose in CT and necessity of patient specific radiation risk assessment, the adoption of new method in the calculation of organ dose is completely required and necessary. In this study by introducing a conversion factor, patient organ dose in thorax region based on CT image data using MC system was calculated. Methods: The geometry of x-ray tube, inherent filter, bow tie filter and collimator were designed using EGSnrc/BEAMnrc MC-system component modules according to GE-Light-speed 64-slices CT-scanner geometry. CT-scan image of patient thorax as a specific phantom was voxellised with 6.25mm3 in voxel and 64×64×20 matrix size. Dose to thorax organ include esophagus, lung, heart, breast, ribs, muscle, spine, spinal cord with imaging technical condition of prospectively-gated-coronary CT-Angiography(PGT) as a step and shoot method, were calculated. Irradiation of patient specific phantom was performed using a dedicated MC-code as DOSXYZnrc with PGT-irradiation model. The ratio of organ dose value calculated in MC-method to the volume CT dose index(CTDIvol) reported by CT-scanner machine according to PGT radiation technique has been introduced as conversion factor. Results: In PGT method, CTDIvol was 10.6mGy and Organ Dose/CTDIvol conversion factor for esophagus, lung, heart, breast, ribs, muscle, spine and spinal cord were obtained as; 0.96, 1.46, 1.2, 3.28. 6.68. 1.35, 3.41 and 0.93 respectively. Conclusion: The results showed while, underestimation of patient dose was found in dose calculation based on CTDIvol, also dose to breast is higher than the other studies. Therefore, the method in this study can be used to provide the actual patient organ dose in CT imaging based on CTDIvol in order to calculation of real effective dose(ED) based on organ dose

  11. Dose measurement, its distribution and individual external dose assessments of inhabitants on high background radiation area in China

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Taeko; Morishima, Hiroshige [Kinki Univ., Atomic Energy Research Institute, Osaka (Japan); Tatsumi, Kusuo [Kinki Univ., Life Science Research Institute, Osaka (Japan); Nakai, Sayaka; Sugahara, Tsutomu [Health Research Foundation, Kyoto (Japan); Yuan Yongling [Labor Hygiene Institute of Hunan Prov. (China); Wei Luxin [Laboratory of Industorial Hygiene, Ministry of Health (China)

    2001-01-01

    As a part of the China-Japan cooperative research on the natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external to natural radiation in the high background radiation area (HBRA) of Yangjiang in Guangdong province and in the control area (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by the personal dosimeters, an indirect method was applied to estimate the exposed dose rates from the environmental radiation dose rates measured by survey meters and the occupancy factors of each hamlet. An individual radiation dose roughly correlates with the environmental radiation dose and the life style of the inhabitant. We have analyzed the environmental radiation doses in the hamlets and the variation of the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and the several hamlets of the different level doses in HBRA and Hampizai hamlet in CA. With these parameters, we made estimations of individual dose rates and compared them with those obtained from the direct measurement using dosimeters carried by selected individuals. The results obtained are as follows: (1) The environmental radiation dose rates are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiation. The indoor radiation dose rates were due to the exposure from the natural radioactive nuclides in the building materials and they were about twice higher than the outdoor radiation dose rates. This difference was not observed in CA. (2) The occupancy factor was affected by the age of individuals and the seasons of a year. Indoor occupancy factors were higher for infants and aged individuals than for other age groups. This lead to higher

  12. Dose measurement, its distribution and individual external dose assessments of inhabitants on high background radiation area in China

    International Nuclear Information System (INIS)

    Koga, Taeko; Morishima, Hiroshige; Tatsumi, Kusuo; Nakai, Sayaka; Sugahara, Tsutomu; Yuan Yongling; Wei Luxin

    2001-01-01

    As a part of the China-Japan cooperative research on the natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external to natural radiation in the high background radiation area (HBRA) of Yangjiang in Guangdong province and in the control area (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by the personal dosimeters, an indirect method was applied to estimate the exposed dose rates from the environmental radiation dose rates measured by survey meters and the occupancy factors of each hamlet. An individual radiation dose roughly correlates with the environmental radiation dose and the life style of the inhabitant. We have analyzed the environmental radiation doses in the hamlets and the variation of the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and the several hamlets of the different level doses in HBRA and Hampizai hamlet in CA. With these parameters, we made estimations of individual dose rates and compared them with those obtained from the direct measurement using dosimeters carried by selected individuals. The results obtained are as follows: 1) The environmental radiation dose rates are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiation. The indoor radiation dose rates were due to the exposure from the natural radioactive nuclides in the building materials and they were about twice higher than the outdoor radiation dose rates. This difference was not observed in CA. 2) The occupancy factor was affected by the age of individuals and the seasons of a year. Indoor occupancy factors were higher for infants and aged individuals than for other age groups. This lead to higher

  13. Real time source term and dose assessment

    International Nuclear Information System (INIS)

    Breznik, B.; Kovac, A.; Mlakar, P.

    2001-01-01

    The Dose Projection Programme is a tool for decision making in case of nuclear emergency. The essential input data for quick emergency evaluation in the case of hypothetical pressurised water reactor accident are following: source term, core damage assessment, fission product radioactivity, release source term and critical exposure pathways for an early phase of the release. A reduced number of radio-nuclides and simplified calculations can be used in dose calculation algorithm. Simple expert system personal computer programme has been developed for the Krsko Nuclear Power Plant for dose projection within the radius of few kilometers from the pressurised water reactor in early phase of an accident. The input data are instantaneous data of core activity, core damage indicators, release fractions, reduction factor of the release pathways, spray operation, release timing, and dispersion coefficient. Main dose projection steps are: accurate in-core radioactivity determination using reactor power input; core damage and in-containment source term assessment based on quick indications of instrumentation or on activity analysis data; user defines release pathway for typical PWR accident scenarius; dose calculation is performed only for exposure pathway critical for decision about evacuation or sheltering in early phase of an accident.(author)

  14. Assessment of dose load of personnel in intratissue gamma beam therapy

    International Nuclear Information System (INIS)

    Stavitskij, R.V.; Zamyatin, O.A.; Varennikov, O.I.; Astakhova, I.V.

    1995-01-01

    Suggest a method for retrospective assessment of levels of irradiation of small groups of personnel exposed to radiation sources. Presents estimated values of cumulative and local doses obtained by personnel during intratissue gamma beam therapy carried out by manual consecutive injections of intrastats and irradiation sources. 3 refs.; 5 tabs

  15. Assessment of dose in cervical vertebrae radiographic examinations

    International Nuclear Information System (INIS)

    Owrnasir, Wafa Fadol Orsud

    2014-12-01

    Reference dose levels provide a framework to reduce doses variability and aid in the optimization of radiation protection.This study was performed in Khartoum Teaching Hospital in period of January to June 2014. This study performed to assess the entrance surface dose ( ESD) received in Cervical Vertebrae radiographic examination and to analyze effective dose distributions among radiological departments under study. The study was performed in Khartoum Teaching Hospital, covering two x-ray units and a sample of 64 patients. The following parameter were recorded; age, weight, height, body mass index (BMI) derived from weight (kg) and height (m) and exposure factors. The dose was measured for Cervical Vertebrae x-ray examinations, the entrance surface dose (ESD) values were estimated from the x-ray tube output parameters for Cervical Vertebrae AP and lateral examinations. The ESD values were then calculated using IAEA calculation methods. The results of ESD values calculated showed than patient exposure were within the normal range of exposure. The mean ED values calculated were ( 3.85 ±0.04) and (4.02 ±0.05) mGy for Cervical Vertebrae AP and lateral examinations, respectively in department Na1 and (3.99± 0.15) and (4.23± 0.34) mGy, for Cervical Vertebrae Ap and lateral examinations respectively in department Na2, the IAEA standard value of ESD for cervical equal (7), (20) mGy AP and LAT, Further studies are recommended with more number of patients and using more than two modalities for comparison. (Author)

  16. Dose measurement, its distribution and individual external dose assessments of inhabitants in the high background radiation areas in China

    International Nuclear Information System (INIS)

    Morishima, Hiroshige; Koga, Taeko; Tatsumi, Kusuo; Nakai, Sayaka; Sugahara, Tsutomu; Yuan Yongling; Wei Luxin

    2000-01-01

    As a part of the China-Japan cooperative research on natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external exposure to natural radiation in the high background radiation areas (HBRA) of Yangjiang in Guangdong province and in the control areas (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by personal dosimeters, an indirect method was applied in which the exposed individual doses were estimated from the environmental radiation doses measured by survey meters and the occupancy factors of each hamlet. We analyzed the dose in the hamlets and the variation in the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and several hamlets of different dose levels in HBRA and Hampizai hamlet in CA. With these parameters, we estimated individual dose rates and compared them with those obtained from direct measurement using dosimeters carried by selected individuals. The results obtained are as follows. The environmental radiation doses are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiations. The indoor radiation doses were due to exposure from the natural radioactive nuclides in the building materials and were about two times as large as the outdoor radiation doses. The difference between indoor and outdoor doses was not observed in CA. The occupancy factor was influenced by the age of individuals and by the season of the year. The occupancy factor was higher for infants and aged individuals than for other age groups. This lead to higher dose rates of exposure to those age groups. A good correlation was observed between the dose assessed indirectly and that measured directly and the

  17. Dose measurement, its distribution and individual external dose assessments of inhabitants in the high background radiation areas in China

    Energy Technology Data Exchange (ETDEWEB)

    Morishima, Hiroshige; Koga, Taeko [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.; Tatsumi, Kusuo; Nakai, Sayaka; Sugahara, Tsutomu; Yuan Yongling; Wei Luxin

    2000-10-01

    As a part of the China-Japan cooperative research on natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external exposure to natural radiation in the high background radiation areas (HBRA) of Yangjiang in Guangdong province and in the control areas (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by personal dosimeters, an indirect method was applied in which the exposed individual doses were estimated from the environmental radiation doses measured by survey meters and the occupancy factors of each hamlet. We analyzed the dose in the hamlets and the variation in the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and several hamlets of different dose levels in HBRA and Hampizai hamlet in CA. With these parameters, we estimated individual dose rates and compared them with those obtained from direct measurement using dosimeters carried by selected individuals. The results obtained are as follows. The environmental radiation doses are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiations. The indoor radiation doses were due to exposure from the natural radioactive nuclides in the building materials and were about two times as large as the outdoor radiation doses. The difference between indoor and outdoor doses was not observed in CA. The occupancy factor was influenced by the age of individuals and by the season of the year. The occupancy factor was higher for infants and aged individuals than for other age groups. This lead to higher dose rates of exposure to those age groups. A good correlation was observed between the dose assessed indirectly and that measured directly and the

  18. Digital radiography of scoliosis with a scanning method: radiation dose optimization

    Energy Technology Data Exchange (ETDEWEB)

    Geijer, Haakan; Andersson, Torbjoern [Department of Radiology, Oerebro University Hospital, 701 85 Oerebro (Sweden); Verdonck, Bert [Philips Medical Systems, P.O. Box 10,000, 5680 Best (Netherlands); Beckman, Karl-Wilhelm; Persliden, Jan [Department of Medical Physics, Oerebro University Hospital, 701 85 Oerebro (Sweden)

    2003-03-01

    The aim of this study was optimization of the radiation dose-image quality relationship for a digital scanning method of scoliosis radiography. The examination is performed as a digital multi-image translation scan that is reconstructed to a single image in a workstation. Entrance dose was recorded with thermoluminescent dosimeters placed dorsally on an Alderson phantom. At the same time, kerma area product (KAP) values were recorded. A Monte Carlo calculation of effective dose was also made. Image quality was evaluated with a contrast-detail phantom and Visual Grading. The radiation dose was reduced by lowering the image intensifier entrance dose request, adjusting pulse frequency and scan speed, and by raising tube voltage. The calculated effective dose was reduced from 0.15 to 0.05 mSv with reduction of KAP from 1.07 to 0.25 Gy cm{sup 2} and entrance dose from 0.90 to 0.21 mGy. The image quality was reduced with the Image Quality Figure going from 52 to 62 and a corresponding reduction in image quality as assessed with Visual Grading. The optimization resulted in a dose reduction to 31% of the original effective dose with an acceptable reduction in image quality considering the intended use of the images for angle measurements. (orig.)

  19. The MESORAD dose assessment model: Computer code

    International Nuclear Information System (INIS)

    Ramsdell, J.V.; Athey, G.F.; Bander, T.J.; Scherpelz, R.I.

    1988-10-01

    MESORAD is a dose equivalent model for emergency response applications that is designed to be run on minicomputers. It has been developed by the Pacific Northwest Laboratory for use as part of the Intermediate Dose Assessment System in the US Nuclear Regulatory Commission Operations Center in Washington, DC, and the Emergency Management System in the US Department of Energy Unified Dose Assessment Center in Richland, Washington. This volume describes the MESORAD computer code and contains a listing of the code. The technical basis for MESORAD is described in the first volume of this report (Scherpelz et al. 1986). A third volume of the documentation planned. That volume will contain utility programs and input and output files that can be used to check the implementation of MESORAD. 18 figs., 4 tabs

  20. Assessment of external dose indoors in Lithuania

    International Nuclear Information System (INIS)

    Pilkyte, L.; Butkus, D.; Morkunas, G.

    2006-01-01

    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)

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

    International Nuclear Information System (INIS)

    Vettese, F.; Donichak, C.; Bourgeault, P.

    1995-01-01

    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.)

  2. The experimental method for neutron dose-equivalent detection

    International Nuclear Information System (INIS)

    Ji Changsong

    1992-01-01

    A new method, for getting neutron dose-equivalent Cd rode absorption method is described. The method adopts Cd-rode-swarm buck absorption, which greatly improved the neutron sensitivity and simplified the adjustment method. By this method, the author has developed BH3105 model neutron dose equivalent meter, the sensitivity of this instrument reach 10 cps/μSvh -1 . γ-ray depression rate reaches 4000:1, the measurement range is 0.1 μSv/h-10 6 μSv/h. The energy response is good (from thermal neutron-14 MeV neutron), this instrument can be used to measure the dose equivalent of the neutron areas

  3. Going beyond the most exposed people in a dose assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hjerpe, Thomas; Broed, Robert [Facilia AB, Gustavslundsvaegen 151C, SE-167 51 Bromma (Sweden); Ikonen, Ari T.K. [Environmental Research and Assessment, EnviroCase, Ltd., Hallituskatu 1 D 4, FI-28 100 Pori (Finland)

    2014-07-01

    The dose assessment in a long-term radiation safety assessment often focus on assessing dose of a representative person to be used for determining compliance with a radiation dose constraint. This representative person is often assumed to receive a dose that is representative of the most exposed people, i.e., the more highly exposed individuals in the population. This is not always sufficient, the Finnish regulations for disposal of nuclear waste has radiation dose constraint to the most exposed people as well as for larger groups of exposed people. This work presents the methodology to assessing dose of a representative person for a larger group of exposed people as applied by Posiva in the TURVA-2012 safety case for the spent nuclear fuel disposal at Olkiluoto. In addition, annual doses from the set of biosphere calculation cases analysed in TURVA-2012 are presented and discussed. Special focus is given on explaining the differences in exposure levels and exposure routes between the estimated annual doses to representative persons for most exposed people and a larger exposed group. The results show that the annual doses to a larger group of people ranges from one to three orders of magnitude below the annual doses to the most exposed people. Furthermore, the exposure route related to food ingestion is less significant for the larger group of people compared to the most exposed people and that the exposure route related to water ingestion shows the opposite behaviour. (authors)

  4. Development of a method to estimate organ doses for pediatric CT examinations

    Energy Technology Data Exchange (ETDEWEB)

    Papadakis, Antonios E., E-mail: apapadak@pagni.gr; Perisinakis, Kostas; Damilakis, John [Department of Medical Physics, University Hospital of Heraklion, Faculty of Medicine, University of Crete, P.O. Box 1352, Iraklion, Crete 71110 (Greece)

    2016-05-15

    Purpose: To develop a method for estimating doses to primarily exposed organs in pediatric CT by taking into account patient size and automatic tube current modulation (ATCM). Methods: A Monte Carlo CT dosimetry software package, which creates patient-specific voxelized phantoms, accurately simulates CT exposures, and generates dose images depicting the energy imparted on the exposed volume, was used. Routine head, thorax, and abdomen/pelvis CT examinations in 92 pediatric patients, ranging from 1-month to 14-yr-old (49 boys and 43 girls), were simulated on a 64-slice CT scanner. Two sets of simulations were performed in each patient using (i) a fixed tube current (FTC) value over the entire examination length and (ii) the ATCM profile extracted from the DICOM header of the reconstructed images. Normalized to CTDI{sub vol} organ dose was derived for all primary irradiated radiosensitive organs. Normalized dose data were correlated to patient’s water equivalent diameter using log-transformed linear regression analysis. Results: The maximum percent difference in normalized organ dose between FTC and ATCM acquisitions was 10% for eyes in head, 26% for thymus in thorax, and 76% for kidneys in abdomen/pelvis. In most of the organs, the correlation between dose and water equivalent diameter was significantly improved in ATCM compared to FTC acquisitions (P < 0.001). Conclusions: The proposed method employs size specific CTDI{sub vol}-normalized organ dose coefficients for ATCM-activated and FTC acquisitions in pediatric CT. These coefficients are substantially different between ATCM and FTC modes of operation and enable a more accurate assessment of patient-specific organ dose in the clinical setting.

  5. Application of Monte Carlo method for dose calculation in thyroid follicle

    International Nuclear Information System (INIS)

    Silva, Frank Sinatra Gomes da

    2008-02-01

    The Monte Carlo method is an important tool to simulate radioactive particles interaction with biologic medium. The principal advantage of the method when compared with deterministic methods is the ability to simulate a complex geometry. Several computational codes use the Monte Carlo method to simulate the particles transport and they have the capacity to simulate energy deposition in models of organs and/or tissues, as well models of cells of human body. Thus, the calculation of the absorbed dose to thyroid's follicles (compound of colloid and follicles' cells) have a fundamental importance to dosimetry, because these cells are radiosensitive due to ionizing radiation exposition, in particular, exposition due to radioisotopes of iodine, because a great amount of radioiodine may be released into the environment in case of a nuclear accidents. In this case, the goal of this work was use the code of particles transport MNCP4C to calculate absorbed doses in models of thyroid's follicles, for Auger electrons, internal conversion electrons and beta particles, by iodine-131 and short-lived iodines (131, 132, 133, 134 e 135), with diameters varying from 30 to 500 μm. The results obtained from simulation with the MCNP4C code shown an average percentage of the 25% of total absorbed dose by colloid to iodine- 131 and 75% to short-lived iodine's. For follicular cells, this percentage was of 13% to iodine-131 and 87% to short-lived iodine's. The contributions from particles with low energies, like Auger and internal conversion electrons should not be neglected, to assessment the absorbed dose in cellular level. Agglomerative hierarchical clustering was used to compare doses obtained by codes MCNP4C, EPOTRAN, EGS4 and by deterministic methods. (author)

  6. Rectal dose assessment in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer; Avaliacao da dose no reto em pacientes submetidas a braquiterapia de alta taxa de dose para o tratamento do cancer do colo uterino

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Jetro Pereira de [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Faculdade de Medicina; Rosa, Luiz Antonio Ribeiro da [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], e-mail: lrosa@ird.gov.br; Batista, Delano Valdivino Santos; Bardella, Lucia Helena [Instituto Nacional de Cancer (INCA), Rio de Janeiro, RJ (Brazil). Unit of Medical Physics; Carvalho, Arnaldo Rangel [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. of Thermoluminescent Dosimetry

    2009-03-15

    Objective: The present study was aimed at developing a thermoluminescent dosimetric system capable of assessing the doses delivered to the rectum of patients submitted to high-dose-rate brachytherapy for uterine cervix cancer. Materials and methods: LiF:Mg,Ti,Na powder was the thermoluminescent material utilized for evaluating the rectal dose. The powder was divided into small portions (34 mg) which were accommodated in a capillary tube. This tube was placed into a rectal probe that was introduced into the patient's rectum. Results: The doses delivered to the rectum of six patients submitted to high-dose-rate brachytherapy for uterine cervix cancer evaluated by means of thermoluminescent dosimeters presented a good agreement with the planned values based on two orthogonal (anteroposterior and lateral) radiographic images of the patients. Conclusion: The thermoluminescent dosimetric system developed in the present study is simple and easy to be utilized as compared to other rectal dosimetry methods. The system has shown to be effective in the evaluation of rectal doses in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer. (author)

  7. Dose. Detriment. Limit assessment

    International Nuclear Information System (INIS)

    Breckow, J.

    2015-01-01

    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.

  8. Assessment of concomitant testicular dose with radiochromic film

    International Nuclear Information System (INIS)

    Fricker, Katherine; Thompson, Christine; Meyer, Juergen

    2013-01-01

    To assess the suitability of EBT2 and XRQA2 Gafchromic film for measuring low doses in the periphery of treatment fields, and to measure the accumulative concomitant dose to the contralateral testis resulting from CT imaging, pre-treatment imaging (CBCT) and seminoma radiotherapy with and without gonadal shielding. Superficial peripheral dose measurements made using EBT2 Gafchromic film on the surface of water equivalent material were compared to measurements made with an ionisation chamber in a water phantom to evaluate the suitability and accuracy of the film dosimeter for such measurements. Similarly, XRQA2 was used to measure surface doses within a kilovoltage beam and compared with ionisation chamber measurements. Gafchromic film was used to measure CT, CBCT and seminoma treatment related testicular doses on an anthropomorphic phantom. Doses were assessed for two clinical plans, both with and without gonadal shielding. Testicular doses resulting from the treatment of up to 0.83 ± 0.17 Gy were measured per treatment. Additional doses of up to 0.49 ± 0.01 and 2.35 ± 0.05 cGy were measured per CBCT and CT image, respectively. Reductions in the testicular dose in the order of 10, 36 and 78 % were observed when gonadal shielding was fitted for treatment, CT and CBCT imaging, respectively. Gafchromic film was found to be suitable for measuring dose in the periphery of treatment fields. The dose to the testis should be limited to minimise the risk of radiation related side effects. This can be achieved by using appropriate gonadal shielding, irrespective of the treatment fields employed.

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

    International Nuclear Information System (INIS)

    Yoo, Do Hyeon; Lee, Hyun Cheol; Shin, Wook-Geun; Min, Chul Hee; Ha, Wi-Ho; Yoo, Jae Ryong; Yoon, Seok-Won; Lee, Jiyon; Choi, Won-Chul

    2015-01-01

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

  10. Thermoluminescent dosimetry and assessment of personal dose

    International Nuclear Information System (INIS)

    Boas, J.F.; Martin, L.J.; Young, J.G.

    1982-01-01

    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 CaSO 4 :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

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

    International Nuclear Information System (INIS)

    Andrasi, A.; Bailey, M.; Puncher, M.; Berkovski, V.; Eric Blanchardon, E.; Jourdain, J.-R.; Carlo-Maria Castellani, C.-M.; Doerfel, H.; Christian Hurtgen, Ch.; Le Guen, B.

    2003-01-01

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

  12. Iodine-129 Dose in LLW Disposal Facility Performance Assessments

    International Nuclear Information System (INIS)

    Wilhite, E.L.

    1999-01-01

    Iodine-129 has the lowest Performance Assessment derived inventory limit in SRS disposal facilities. Because iodine is concentrated in the body to one organ, the thyroid, it has been thought that dilution with stable iodine would reduce the dose effects of 129I.Examination of the dose model used to establish the Dose conversion factor for 129I shows that, at the levels considered in performance assessments of low-level waste disposal facilities, the calculated 129I dose already accounts for ingestion of stable iodine. At higher than normal iodine ingestion rates, the uptake of iodine by the thyroid itself decrease, which effectively cancels out the isotopic dilution effect

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

    International Nuclear Information System (INIS)

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

    2005-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  15. Radiation dose assessment in a 320-detector-row CT scanner used in cardiac imaging

    International Nuclear Information System (INIS)

    Goma, Carles; Ruiz, Agustin; Jornet, Nuria; Latorre, Artur; Pallerol, Rosa M.; Carrasco, Pablo; Eudaldo, Teresa; Ribas, Montserrat

    2011-01-01

    Purpose: In the present era of cone-beam CT scanners, the use of the standardized CTDI 100 as a surrogate of the idealized CTDI is strongly discouraged and, consequently, so should be the use of the dose-length product (DLP) as an estimate of the total energy imparted to the patient. However, the DLP is still widely used as a reference quantity to normalize the effective dose for a given scan protocol mainly because the CTDI 100 is an easy-to-measure quantity. The aim of this article is therefore to describe a method for radiation dose assessment in large cone-beam single axial scans, which leads to a straightforward estimation of the total energy imparted to the patient. The authors developed a method accessible to all medical physicists and easy to implement in clinical practice in an attempt to update the bridge between CT dosimetry and the estimation of the effective dose. Methods: The authors used commercially available material and a simple mathematical model. The method described herein is based on the dosimetry paradigm introduced by the AAPM Task Group 111. It consists of measuring the dose profiles at the center and the periphery of a long body phantom with a commercial solid-state detector. A weighted dose profile is then calculated from these measurements. To calculate the CT dosimetric quantities analytically, a Gaussian function was fitted to the dose profile data. Furthermore, the Gaussian model has the power to condense the z-axis information of the dose profile in two parameters: The single-scan central dose, f(0), and the width of the profile, σ. To check the energy dependence of the solid-state detector, the authors compared the dose profiles to measurements made with a small volume ion chamber. To validate the overall method, the authors compared the CTDI 100 calculated analytically to the measurement made with a 100 mm pencil ion chamber. Results: For the central and weighted dose profiles, the authors found a good agreement between the

  16. Radiation dose assessment in a 320-detector-row CT scanner used in cardiac imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goma, Carles; Ruiz, Agustin; Jornet, Nuria; Latorre, Artur; Pallerol, Rosa M.; Carrasco, Pablo; Eudaldo, Teresa; Ribas, Montserrat [Servei de Radiofisica i Radioproteccio, Hospital de la Santa Creu i Sant Pau, Sant Antoni Maria Claret 167, 08025 Barcelona (Spain)

    2011-03-15

    Purpose: In the present era of cone-beam CT scanners, the use of the standardized CTDI{sub 100} as a surrogate of the idealized CTDI is strongly discouraged and, consequently, so should be the use of the dose-length product (DLP) as an estimate of the total energy imparted to the patient. However, the DLP is still widely used as a reference quantity to normalize the effective dose for a given scan protocol mainly because the CTDI{sub 100} is an easy-to-measure quantity. The aim of this article is therefore to describe a method for radiation dose assessment in large cone-beam single axial scans, which leads to a straightforward estimation of the total energy imparted to the patient. The authors developed a method accessible to all medical physicists and easy to implement in clinical practice in an attempt to update the bridge between CT dosimetry and the estimation of the effective dose. Methods: The authors used commercially available material and a simple mathematical model. The method described herein is based on the dosimetry paradigm introduced by the AAPM Task Group 111. It consists of measuring the dose profiles at the center and the periphery of a long body phantom with a commercial solid-state detector. A weighted dose profile is then calculated from these measurements. To calculate the CT dosimetric quantities analytically, a Gaussian function was fitted to the dose profile data. Furthermore, the Gaussian model has the power to condense the z-axis information of the dose profile in two parameters: The single-scan central dose, f(0), and the width of the profile, {sigma}. To check the energy dependence of the solid-state detector, the authors compared the dose profiles to measurements made with a small volume ion chamber. To validate the overall method, the authors compared the CTDI{sub 100} calculated analytically to the measurement made with a 100 mm pencil ion chamber. Results: For the central and weighted dose profiles, the authors found a good

  17. Dose escalation methods in phase I cancer clinical trials.

    Science.gov (United States)

    Le Tourneau, Christophe; Lee, J Jack; Siu, Lillian L

    2009-05-20

    Phase I clinical trials are an essential step in the development of anticancer drugs. The main goal of these studies is to establish the recommended dose and/or schedule of new drugs or drug combinations for phase II trials. The guiding principle for dose escalation in phase I trials is to avoid exposing too many patients to subtherapeutic doses while preserving safety and maintaining rapid accrual. Here we review dose escalation methods for phase I trials, including the rule-based and model-based dose escalation methods that have been developed to evaluate new anticancer agents. Toxicity has traditionally been the primary endpoint for phase I trials involving cytotoxic agents. However, with the emergence of molecularly targeted anticancer agents, potential alternative endpoints to delineate optimal biological activity, such as plasma drug concentration and target inhibition in tumor or surrogate tissues, have been proposed along with new trial designs. We also describe specific methods for drug combinations as well as methods that use a time-to-event endpoint or both toxicity and efficacy as endpoints. Finally, we present the advantages and drawbacks of the various dose escalation methods and discuss specific applications of the methods in developmental oncotherapeutics.

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

    International Nuclear Information System (INIS)

    Sullivan, T.J.

    1990-01-01

    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

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

    International Nuclear Information System (INIS)

    Hjerpe, T.; Broed, R.

    2010-11-01

    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.)

  20. Dose volume assessment of high dose rate 192IR endobronchial implants

    International Nuclear Information System (INIS)

    Cheng, B. Saw; Korb, Leroy J.; Pawlicki, Todd; Wu, Andrew

    1996-01-01

    Purpose: To study the dose distributions of high dose rate (HDR) endobronchial implants using the dose nonuniformity ratio (DNR) and three volumetric irradiation indices. Methods and Materials: Multiple implants were configured by allowing a single HDR 192 Ir source to step through a length of 6 cm along an endobronchial catheter. Dwell times were computed to deliver a dose of 5 Gy to points 1 cm away from the catheter axis. Five sets of source configurations, each with different dwell position spacings from 0.5 to 3.0 cm, were evaluated. Three-dimensional (3D) dose distributions were then generated for each source configuration. Differential and cumulative dose-volume curves were generated to quantify the degree of target volume coverage, dose nonuniformity within the target volume, and irradiation of tissues outside the target volume. Evaluation of the implants were made using the DNR and three volumetric irradiation indices. Results: The observed isodose distributions were not able to satisfy all the dose constraints. The ability to optimally satisfy the dose constraints depended on the choice of dwell position spacing and the specification of the dose constraint points. The DNR and irradiation indices suggest that small dwell position spacing does not result in a more homogeneous dose distribution for the implant. This study supports the existence of a relationship between the dwell position spacing and the distance from the catheter axis to the reference dose or dose constraint points. Better dose homogeneity for an implant can be obtained if the spacing of the dwell positions are about twice the distance from the catheter axis to the reference dose or dose constraint points

  1. Dosing method of physical activity in aerobics classes for students

    Directory of Open Access Journals (Sweden)

    Yu.I. Beliak

    2014-10-01

    Full Text Available Purpose : reasons for the method of dosing of physical activity in aerobics classes for students. The basis of the method is the evaluation of the metabolic cost of funds used in them. Material : experiment involved the assessment of the pulse response of students to load complexes classical and step aerobics (n = 47, age 20-23 years. In complexes used various factors regulating the intensity: perform combinations of basic steps, involvement of movements with his hands, holding in hands dumbbells weighing 1kg increase in the rate of musical accompaniment, varying heights step platform. Results . on the basis of the relationship between heart rate and oxygen consumption was determined by the energy cost of each admission control load intensity. This indicator has been used to justify the intensity and duration of multiplicity aerobics. Figure correspond to the level of physical condition and motor activity deficits students. Conclusions : the estimated component of this method of dosing load makes it convenient for use in automated computer programs. Also it can be easily modified to dispense load other types of recreational fitness.

  2. Determination of the delivered hemodialysis dose using standard methods and on-line clearance monitoring

    Directory of Open Access Journals (Sweden)

    Vlatković Vlastimir

    2006-01-01

    Full Text Available Background/aim: Delivered dialysis dose has a cumulative effect and significant influence upon the adequacy of dialysis, quality of life and development of co-morbidity at patients on dialysis. Thus, a great attention is given to the optimization of dialysis treatment. On-line Clearance Monitoring (OCM allows a precise and continuous measurement of the delivered dialysis dose. Kt/V index (K = dialyzer clearance of urea; t = dialysis time; V = patient's total body water, measured in real time is used as a unit for expressing the dialysis dose. The aim of this research was to perform a comparative assessment of the delivered dialysis dose by the application of the standard measurement methods and a module for continuous clearance monitoring. Methods. The study encompassed 105 patients who had been on the chronic hemodialysis program for more than three months, three times a week. By random choice, one treatment per each controlled patient was taken. All the treatments understood bicarbonate dialysis. The delivered dialysis dose was determined by the calculation of mathematical models: Urea Reduction Ratio (URR singlepool index Kt/V (spKt/V and by the application of OCM. Results. Urea Reduction Ratio was the most sensitive parameter for the assessment and, at the same time, it was in the strongest correlation with the other two, spKt/V indexes and OCM. The values pointed out an adequate dialysis dose. The URR values were significantly higher in women than in men, p < 0.05. The other applied model for the delivered dialysis dose measurement was Kt/V index. The obtained values showed that the dialysis dose was adequate, and that, according to this parameter, the women had significantly better dialysis, then the men p < 0.05. According to the OCM, the average value was slightly lower than the adequate one. The women had a satisfactory dialysis according to this index as well, while the delivered dialysis dose was insufficient in men. The difference

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

    International Nuclear Information System (INIS)

    Tubiana, M.; Aurengo, A.

    2005-01-01

    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

  4. Efficacy of reduced doses of bentazone assessed by instruments based on measurement of chlorophyll fluorescence

    Directory of Open Access Journals (Sweden)

    Vojtěch Kocurek

    2011-01-01

    Full Text Available Chlorophyll fluorescence is a type of radiation emitted by plants as unused part of energy absorbed from sunlight. Its intensity depends on many stress factors, nutrition, weather conditions etc. Methods based on chlorophyll fluorescence measurement have potential to be perspective for the assessment of herbicide efficacy, phytotoxicity or stress influence. Two fluorometers (FluorCam and handy FluorPen were used for measurements in laboratory experiments in 2007–2009. Herbicide Basagran super with active ingredient bentazone (480 g.l−1 was tested using a parameter called ‚Quantum yield of fluorescence‘ (QY in three different doses: the registered dose 2.0 l.ha−1 (100% and lower doses 1.5 l.ha−1 (75% and 1.0 l.ha−1 (50%. Treated experimental plants of redroot pigweed (Amaranthus retroflexus L. were measured in 0, 1, 2, 3, 6, 9 and 15 days after treatment and the results were compared with subjective assessment (estimation and growth parameters. The obtained results showed that the effect of bentazone measured by both devices was statistically significantly different from untreated control. We can also detect herbicide effect earlier by QY measurement than by other methods. Different doses showed significant differences 15 days after treatment for dose 2.0 l.ha−1 in comparison with both reduced doses. The subjective assessment showed significant differences in all terms of measurement (1–15 days after application except of the day of application. Regeneration of plants for which the youngest leaves were not treated by herbicide was observed for all doses. Difference of QY values between used devices was on average 0.119 (higher for FluorCam but statistically insignificant.

  5. Establishment and validation of a method for multi-dose irradiation of cells in 96-well microplates

    International Nuclear Information System (INIS)

    Abatzoglou, Ioannis; Zois, Christos E.; Pouliliou, Stamatia; Koukourakis, Michael I.

    2013-01-01

    Highlights: ► We established a method for multi-dose irradiation of cell cultures within a 96-well plate. ► Equations to adjust to preferable dose levels are produced and provided. ► Up to eight different dose levels can be tested in one microplate. ► This method results in fast and reliable estimation of radiation dose–response curves. -- Abstract: Microplates are useful tools in chemistry, biotechnology and molecular biology. In radiobiology research, these can be also applied to assess the effect of a certain radiation dose delivered to the whole microplate, to test radio-sensitivity, radio-sensitization or radio-protection. Whether different radiation doses can be accurately applied to a single 96-well plate to further facilitate and accelerated research by one hand and spare funds on the other, is a question dealt in the current paper. Following repeated ion-chamber, TLD and radiotherapy planning dosimetry we established a method for multi-dose irradiation of cell cultures within a 96-well plate, which allows an accurate delivery of desired doses in sequential columns of the microplate. Up to eight different dose levels can be tested in one microplate. This method results in fast and reliable estimation of radiation dose–response curves

  6. Exposure dose assessment using bioassay

    International Nuclear Information System (INIS)

    Suga, Shinichi

    1994-01-01

    Bioassay involves following steps: sampling, pre-treatment, chemical separation and counting of radioactivity. As bioassay samples, urines are usually used, although faecal analysis may be required in some occasions for example to assess intake of non-transferable radioactive materials. Nasal smear is a useful indicator of an inhalation case. Exhalation air is used to estimate the intake of tritiated water. Sample pre-treatment includes evaporation for concentration, wet ashing, dry ashing and co-precipitation. After adding small amount of nitric acid, the sample can be concentrated by 1/10 of initial volume, which may be used to identify γ-emitters. As the pre-treatment of urine, wet ashing is used for example for analysis of Pu, and co-precipitation is used for example for analysis of Sr. Dry ashing by electric furnace is usually adopted for faecal samples. Methods of chemical separation depend on the radionuclide(s) to be analysed. The detection limit depends also on radionuclide, and for example typical detection limits are 0.4Bq / l (volume of urine sample) for 89 Sr or 90 Sr, and 0.01 Bq / l with urine and 0.01 Bq per sample with faeces for 238 Pu, 239 Pu or 241 Am. Simpler methods can be used for some radionuclides: For example, radioactivity concentration of tritium can be determined by liquid scintillation counting of urine or condensed water from exhaled air, and natural uranium in urine can be quantified by using fluorometric method. In some circumstances, gross-α or gross-β analyses are useful for quick estimation. To estimate intakes by inhalation or by ingestion from bioassay results and to assess the committed dose equivalent, commonly available bases are the relevant publications by the ICRP and domestic guides and manuals that conform to the radiation protection regulations. (author)

  7. Simplified dose calculation method for mantle technique

    International Nuclear Information System (INIS)

    Scaff, L.A.M.

    1984-01-01

    A simplified dose calculation method for mantle technique is described. In the routine treatment of lymphom as using this technique, the daily doses at the midpoints at five anatomical regions are different because the thicknesses are not equal. (Author) [pt

  8. Effect of Low-Dose MDCT and Iterative Reconstruction on Trabecular Bone Microstructure Assessment.

    Science.gov (United States)

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

    2016-01-01

    We investigated the effects of low-dose multi detector computed tomography (MDCT) in combination with statistical iterative reconstruction algorithms on trabecular bone microstructure parameters. Twelve donated vertebrae were scanned with the routine radiation exposure used in our department (standard-dose) and a low-dose protocol. Reconstructions were performed with filtered backprojection (FBP) and maximum-likelihood based statistical iterative reconstruction (SIR). Trabecular bone microstructure parameters were assessed and statistically compared for each reconstruction. Moreover, fracture loads of the vertebrae were biomechanically determined and correlated to the assessed microstructure parameters. Trabecular bone microstructure parameters based on low-dose MDCT and SIR significantly correlated with vertebral bone strength. There was no significant difference between microstructure parameters calculated on low-dose SIR and standard-dose FBP images. However, the results revealed a strong dependency on the regularization strength applied during SIR. It was observed that stronger regularization might corrupt the microstructure analysis, because the trabecular structure is a very small detail that might get lost during the regularization process. As a consequence, the introduction of SIR for trabecular bone microstructure analysis requires a specific optimization of the regularization parameters. Moreover, in comparison to other approaches, superior noise-resolution trade-offs can be found with the proposed methods.

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

    International Nuclear Information System (INIS)

    Swindon, T.N.; Morris, N.D.

    1981-12-01

    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

  10. Repeated dose titration versus age-based method in electroconvulsive therapy: a pilot study.

    Science.gov (United States)

    Aten, Jan Jaap; Oudega, Mardien; van Exel, Eric; Stek, Max L; van Waarde, Jeroen A

    2015-06-01

    In electroconvulsive therapy (ECT), a dose titration method (DTM) was suggested to be more individualized and therefore more accurate than formula-based dosing methods. A repeated DTM (every sixth session and dose adjustment accordingly) was compared to an age-based method (ABM) regarding treatment characteristics, clinical outcome, and cognitive functioning after ECT. Thirty-nine unipolar depressed patients dosed using repeated DTM and 40 matched patients treated with ABM were compared. Montgomery-Åsberg Depression Rating Scale (MADRS) and Mini-Mental State Examination (MMSE) were assessed at baseline and at the end of the index course, as well as the total number of ECT sessions. Both groups were similar regarding age, sex, psychotic features, mean baseline MADRS, and median baseline MMSE. At the end of the index course, the two methods showed equal outcome (mean end MADRS, 11.6 ± 8.3 in DTM and 9.5 ± 7.6 in ABM (P = 0.26); median end MMSE, 28 (25-29) and 28 (25-29.8), respectively (P = 0.81). However, the median number of all ECT sessions differed 16 (11-22) in DTM versus 12 (10-14.8) in ABM; P = 0.02]. Using regression analysis, dosing method and age were independently associated with the total number of ECT sessions, with less sessions needed in ABM (P = 0.02) and in older patients (P = 0.001). In this comparative cohort study, ABM and DTM showed equal outcome for depression and cognition. However, the median ECT course duration in repeated DTM appeared longer. Additionally, higher age was associated with shorter ECT courses regardless of the dosing method. Further prospective studies are needed to confirm these findings.

  11. ALARA ASSESSMENT OF SETTLER SLUDGE SAMPLING METHODS

    International Nuclear Information System (INIS)

    Nelsen, L.A.

    2009-01-01

    The purpose of this assessment is to compare underwater and above water settler sludge sampling methods to determine if the added cost for underwater sampling for the sole purpose of worker dose reductions is justified. Initial planning for sludge sampling included container, settler and knock-out-pot (KOP) sampling. Due to the significantly higher dose consequence of KOP sludge, a decision was made to sample KOP underwater to achieve worker dose reductions. Additionally, initial plans were to utilize the underwater sampling apparatus for settler sludge. Since there are no longer plans to sample KOP sludge, the decision for underwater sampling for settler sludge needs to be revisited. The present sampling plan calls for spending an estimated $2,500,000 to design and construct a new underwater sampling system (per A21 C-PL-001 RevOE). This evaluation will compare and contrast the present method of above water sampling to the underwater method that is planned by the Sludge Treatment Project (STP) and determine if settler samples can be taken using the existing sampling cart (with potentially minor modifications) while maintaining doses to workers As Low As Reasonably Achievable (ALARA) and eliminate the need for costly redesigns, testing and personnel retraining

  12. ALARA ASSESSMENT OF SETTLER SLUDGE SAMPLING METHODS

    Energy Technology Data Exchange (ETDEWEB)

    NELSEN LA

    2009-01-30

    The purpose of this assessment is to compare underwater and above water settler sludge sampling methods to determine if the added cost for underwater sampling for the sole purpose of worker dose reductions is justified. Initial planning for sludge sampling included container, settler and knock-out-pot (KOP) sampling. Due to the significantly higher dose consequence of KOP sludge, a decision was made to sample KOP underwater to achieve worker dose reductions. Additionally, initial plans were to utilize the underwater sampling apparatus for settler sludge. Since there are no longer plans to sample KOP sludge, the decision for underwater sampling for settler sludge needs to be revisited. The present sampling plan calls for spending an estimated $2,500,000 to design and construct a new underwater sampling system (per A21 C-PL-001 RevOE). This evaluation will compare and contrast the present method of above water sampling to the underwater method that is planned by the Sludge Treatment Project (STP) and determine if settler samples can be taken using the existing sampling cart (with potentially minor modifications) while maintaining doses to workers As Low As Reasonably Achievable (ALARA) and eliminate the need for costly redesigns, testing and personnel retraining.

  13. Reevaluation of nasal swab method for dose estimation at nuclear emergency accident

    International Nuclear Information System (INIS)

    Yamada, Yuji; Fukutsu, Kumiko; Kurihara, Osamu; Akashi, Makoto

    2008-01-01

    ICRP Publication 66 human respiratory tract model has been used extensively over in exposure dose assessment. It is well known that respiratory deposition efficiency of inhaled aerosol and its deposition region strongly depend on the particle size. In most of exposure accidents, however, nobody knows a size of inhaled aerosol. And thus two default aerosol sizes of 5μ in AMAD for the workers and 1μ in AMAD for the public are given as being representative in the ICRP model, but both sizes are not linked directly to the maximum dose. In this study, the most hazardous size to our health effects and how to estimate an intake activity was discussed from a viewpoint of emergency medicine. In exposure accident of alpha emitter such as Pu-239, lung monitor and bioassay measurements are not the best methods for rapid estimation with high sensitivity, so that an applicability of nasal swab method has been investigated. A computer software, LUDEP, was used in the calculation of respiratory deposition. It showed that the effective dose per unit intake activity strongly depended on the inhaled aerosol size. In case of Pu-239 dioxide aerosols, it was confirmed that the maximum of dose conversion factor was observed around 0.01μ. It means that this 0.01μ is the most hazardous size at exposure accident of Pu-239. From analysis of the relationship between AI and ET l deposition, it was found that the dose conversion factor from the activity deposited in ET l region also was affected by the aerosol size. The usage of the ICRP's default size in nasal swab method might cause obvious underestimation of the intake activity. Dose estimation based on nasal swab method is possible from safety side at nuclear emergency, and the availability in quantity should be reevaluated for emergency medicine considering of chelating agent administration. (author)

  14. Probabilistic Dose Assessment from SB-LOCA Accident in Ujung Lemahabang Using TMI-2 Source Term

    Directory of Open Access Journals (Sweden)

    Sunarko

    2017-01-01

    Full Text Available Probabilistic dose assessment and mapping for nuclear accident condition are performed for Ujung Lemahabang site in Muria Peninsula region in Indonesia. Source term is obtained from Three-Mile Island unit 2 (TMI-2 PWR-type SB-LOCA reactor accident inverse modeling. Effluent consisted of Xe-133, Kr-88, I-131, and Cs-137 released from a 50 m stack. Lagrangian Particle Dispersion Method (LPDM and 3-dimensional mass-consistent wind field are employed to obtain surface-level time-integrated air concentration and spatial distribution of ground-level total dose in dry condition. Site-specific meteorological data is obtained from hourly records obtained during the Site Feasibility Study period in Ujung Lemahabang. Effluent is released from a height of 50 meters in uniform rate during a 6-hour period and the dose is integrated during this period in a neutrally stable atmospheric condition. Maximum dose noted is below regulatory limit of 1 mSv and radioactive plume is spread mostly to the W-SW inland and to N-NE from the proposed plant to Java Sea. This paper has demonstrated for the first time a probabilistic analysis method for assessing possible spatial dose distribution, a hypothetical release, and a set of meteorological data for Ujung Lemahabang region.

  15. Manual method for dose calculation in gynecologic brachytherapy

    International Nuclear Information System (INIS)

    Vianello, Elizabeth A.; Almeida, Carlos E. de; Biaggio, Maria F. de

    1998-01-01

    This paper describes a manual method for dose calculation in brachytherapy of gynecological tumors, which allows the calculation of the doses at any plane or point of clinical interest. This method uses basic principles of vectorial algebra and the simulating orthogonal films taken from the patient with the applicators and dummy sources in place. The results obtained with method were compared with the values calculated with the values calculated with the treatment planning system model Theraplan and the agreement was better than 5% in most cases. The critical points associated with the final accuracy of the proposed method is related to the quality of the image and the appropriate selection of the magnification factors. This method is strongly recommended to the radiation oncology centers where are no treatment planning systems available and the dose calculations are manually done. (author)

  16. METHODS OF ASSESSMENT OF THE RELATIVE BIOLOGICAL EFFECTIVENESS OF NEUTRONS IN NEUTRON THERAPY

    Directory of Open Access Journals (Sweden)

    V. A. Lisin

    2017-01-01

    Full Text Available The relative biological effectiveness (RBE of fast neutrons is an important factor influencing the quality of neutron therapy therefore, the assessment of RBE is of great importance. Experimental and clinical studies as well as different mathematical and radiobiological models are used for assessing RBE. Research is conducted for neutron sources differing in the method of producing particles, energy and energy spectrum. Purpose: to find and analyze the dose-dependence of fast neutron RBE in neutron therapy using the U-120 cyclotron and NG-12I generator. Material and methods: The optimal method for assessing the relative biological effectiveness of neutrons for neutron therapy was described. To analyze the dependence of the RBE on neutron dose, the multi-target model of cell survival was applied. Results: The dependence of the RBE of neutrons produced from the U-120 cyclotron and NG-120 generator on the dose level was found for a single irradiation of biological objects. It was shown that the function of neutron dose was consistent with similar dependencies found by other authors in the experimental and clinical studies.

  17. Evaluation of various approaches for assessing dose indicators and patient organ doses resulting from radiotherapy cone-beam CT

    International Nuclear Information System (INIS)

    Rampado, Osvaldo; Giglioli, Francesca Romana; Rossetti, Veronica; Ropolo, Roberto; Fiandra, Christian; Ragona, Riccardo

    2016-01-01

    Purpose: The aim of this study was to evaluate various approaches for assessing patient organ doses resulting from radiotherapy cone-beam CT (CBCT), by the use of thermoluminescent dosimeter (TLD) measurements in anthropomorphic phantoms, a Monte Carlo based dose calculation software, and different dose indicators as presently defined. Methods: Dose evaluations were performed on a CBCT Elekta XVI (Elekta, Crawley, UK) for different protocols and anatomical regions. The first part of the study focuses on using PCXMC software (PCXMC 2.0, STUK, Helsinki, Finland) for calculating organ doses, adapting the input parameters to simulate the exposure geometry, and beam dose distribution in an appropriate way. The calculated doses were compared to readouts of TLDs placed in an anthropomorphic Rando phantom. After this validation, the software was used for analyzing organ dose variability associated with patients’ differences in size and gender. At the same time, various dose indicators were evaluated: kerma area product (KAP), cumulative air-kerma at the isocenter (K_a_i_r), cone-beam dose index, and central cumulative dose. The latter was evaluated in a single phantom and in a stack of three adjacent computed tomography dose index phantoms. Based on the different dose indicators, a set of coefficients was calculated to estimate organ doses for a range of patient morphologies, using their equivalent diameters. Results: Maximum organ doses were about 1 mGy for head and neck and 25 mGy for chest and pelvis protocols. The differences between PCXMC and TLDs doses were generally below 10% for organs within the field of view and approximately 15% for organs at the boundaries of the radiation beam. When considering patient size and gender variability, differences in organ doses up to 40% were observed especially in the pelvic region; for the organs in the thorax, the maximum differences ranged between 20% and 30%. Phantom dose indexes provided better correlation with organ doses

  18. An efficient dose-compensation method for proximity effect correction

    International Nuclear Information System (INIS)

    Wang Ying; Han Weihua; Yang Xiang; Zhang Yang; Yang Fuhua; Zhang Renping

    2010-01-01

    A novel simple dose-compensation method is developed for proximity effect correction in electron-beam lithography. The sizes of exposed patterns depend on dose factors while other exposure parameters (including accelerate voltage, resist thickness, exposing step size, substrate material, and so on) remain constant. This method is based on two reasonable assumptions in the evaluation of the compensated dose factor: one is that the relation between dose factors and circle-diameters is linear in the range under consideration; the other is that the compensated dose factor is only affected by the nearest neighbors for simplicity. Four-layer-hexagon photonic crystal structures were fabricated as test patterns to demonstrate this method. Compared to the uncorrected structures, the homogeneity of the corrected hole-size in photonic crystal structures was clearly improved. (semiconductor technology)

  19. A model for radiological dose assessment in an urban environment

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Jeong, Hyo Joon; Suh, Kyung Suk; Han, Moon Hee

    2007-01-01

    A model for radiological dose assessment in an urban environment, METRO-K has been developed. Characteristics of the model are as follows ; 1) mathematical structures are simple (i.e. simplified input parameters) and easy to understand due to get the results by analytical methods using experimental and empirical data, 2) complex urban environment can easily be made up using only 5 types of basic surfaces, 3) various remediation measures can be applied to different surfaces by evaluating the exposure doses contributing from each contamination surface. Exposure doses contributing from each contamination surface at a particular location of a receptor were evaluated using the data library of kerma values as a function of gamma energy and contamination surface. A kerma data library was prepared for 7 representative types of Korean urban building by extending those data given for 4 representative types of European urban buildings. Initial input data are daily radionuclide concentration in air and precipitation, and fraction of chemical type. Final outputs are absorbed dose rate in air contributing from the basic surfaces as a function of time following a radionuclide deposition, and exposure dose rate contributing from various surfaces constituting the urban environment at a particular location of a receptor. As the result of a contaminative scenario for an apartment built-up area, exposure dose rates show a distinct difference for surrounding environment as well as locations of a receptor

  20. Radiological assessment. A textbook on environmental dose analysis

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Radiological assessment. A textbook on environmental dose analysis

    International Nuclear Information System (INIS)

    Till, J.E.; Meyer, H.R.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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. (authors)

  3. Dose assessment activities in the Republic of the Marshall Islands

    International Nuclear Information System (INIS)

    Simon, S.L.; Graham, J.C.

    1996-01-01

    Dose assessments, both retrospective and prospective, comprise one important function of a radiological study commissioned by the Republic of the Marshall Islands (RMI) government in late 1989. Estimating past or future exposure requires the synthesis of information from historical data, results from a recently completed field monitoring program, laboratory measurements, and some experimental studies. Most of the activities in the RMI to date have emphasized a pragmatic rather than theoretical approach. In particular, most of the recent effort has been expended on conducting an independent radiological monitoring program to determine the degree of deposition and the geographical extent of weapons test fallout over the nation. Contamination levels on 70% of the land mass of the Marshall Islands were unknown prior to 1994. The environmental radioactivity data play an integral role in both retrospective and prospective assessments. One recent use of dose assessment has been to interpret environmental measurements of radioactivity into annual doses that might be expected at every atoll. A second use for dose assessment has been to determine compliance with dose action level for the rehabitation of Rongelap Island. Careful examination of exposure pathways relevant to the island lifestyle has been necessary to accommodate these purposes. Finally, an examination is underway of gummed film, fixed-instrument, and aerial survey data accumulated during the 1950's by the Health and Safety Laboratory of the U.S. AEC. This article gives an overview of these many different activities and a summary of recent dose assessments

  4. Radiation dose assessment in nuclear medicine

    International Nuclear Information System (INIS)

    Stabin, M.G.

    2002-01-01

    In any application involving the use of ionizing radiation in humans, risks and benefits must be properly evaluated and balanced. 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, particularly in the treatment of hematologic and non-hematologic malignancies. This has heightened interest in the need for radiation dose calculations and challenged the scientific community to develop more patient-specific and relevant dose models. Consideration of radiation dose in such studies is central to efforts to maximize dose to tumor while sparing normal tissues. In many applications, a significant absorbed dose may be received by some radiosensitive organs, particularly the active marrow. This talk will review the methods and models used in internal dosimetry in nuclear medicine, and discuss some current trends and challenges in this field

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

    International Nuclear Information System (INIS)

    Pujol, M.; Puig, R.; Caballin, M. R.; Barrios, L.; Barquinero, J. F.

    2012-01-01

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

  6. Advancing Dose-Response Assessment Methods for Environmental Regulatory Impact Analysis: A Bayesian Belief Network Approach Applied to Inorganic Arsenic.

    Science.gov (United States)

    Zabinski, Joseph W; Garcia-Vargas, Gonzalo; Rubio-Andrade, Marisela; Fry, Rebecca C; Gibson, Jacqueline MacDonald

    2016-05-10

    Dose-response functions used in regulatory risk assessment are based on studies of whole organisms and fail to incorporate genetic and metabolomic data. Bayesian belief networks (BBNs) could provide a powerful framework for incorporating such data, but no prior research has examined this possibility. To address this gap, we develop a BBN-based model predicting birthweight at gestational age from arsenic exposure via drinking water and maternal metabolic indicators using a cohort of 200 pregnant women from an arsenic-endemic region of Mexico. We compare BBN predictions to those of prevailing slope-factor and reference-dose approaches. The BBN outperforms prevailing approaches in balancing false-positive and false-negative rates. Whereas the slope-factor approach had 2% sensitivity and 99% specificity and the reference-dose approach had 100% sensitivity and 0% specificity, the BBN's sensitivity and specificity were 71% and 30%, respectively. BBNs offer a promising opportunity to advance health risk assessment by incorporating modern genetic and metabolomic data.

  7. Outline of manual on measurement and assessment of doses from external radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizawa, Michio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tsujimura, Norio

    2001-03-01

    The external exposure part in the manual for measurement and assessment of doses from external radiation is described since the part is changed in accordance with the revision of the Law Concerning Prevention from Radiation Hazard due to Radioisotopes, Etc. The manual contains general remarks, control of external exposure and its methods, person monitoring, site monitoring, correction of instruments and storage of records. The 2nd and 3rd chapters are described in details, because which are considerably changed together with appendices concerning the operational quantity for measuring external dose, conversion coefficients, and correlations of 3 mm, 1 cm and 70 {mu}m dose equivalents. Making manuals unique to the individual offices, etc. is recommended in compliance with the above manual.(K.H.)

  8. Development of dose assessment code for accidental releases of activation products

    International Nuclear Information System (INIS)

    Noguchi, H.; Yokoyama, S.

    2000-01-01

    It is expected that activation products will be important radionuclides as well as tritium in the assessment of the public doses necessary for licensing of a future fusion reactor. In order to calculate the public doses due to the activation products released in cases of accidents, a code named ACUTAP (dose assessment code for ACUTe Activation Product releases) has been developed. Major characteristics of the code are as follows: (1) the transfer model reflects specific behavior of the activation products in the environment, (2) the doses are assessed based on ICRP dose models, (3) it is possible to calculate individual doses using annual meteorological data statistically according to the guide of the Nuclear Safety Commission of Japan, and (4) the code can calculate collective doses as well as individual doses. Individual doses are calculated for the following pathways: internal exposure by inhalation of activation products in a plume and those resuspended from the ground, external exposure from a plume (cloudshine), and external exposure from activation products deposited on the ground (groundshine). The inhalation in a plume and cloudshine pathways are included in the model for calculating collective doses. In addition to parent nuclides released from the facilities, progeny nuclides produced during the atmospheric dispersion are considered in calculating inhalation doses, and those during the deposition period in calculating groundshine doses. External doses from the cloudshine are calculated for 18 energy groups instead of individual energy of emitted gamma rays in order to save the computation time. Atmospheric concentrations are calculated using a Gaussian plume model with atmospheric dispersion parameters prescribed in the guide of the Nuclear Safety Commission of Japan. Data sets of parameters necessary for the dose assessment, such as internal dos coefficients, external dose rate conversion factors and half lives, are prepared for about 100 radionuclides

  9. Mixed species radioiodine air sampling readout and dose assessment system

    International Nuclear Information System (INIS)

    Distenfeld, C.H.; Klemish, J.R. Jr.

    1978-01-01

    This invention provides a simple, reliable, inexpensive and portable means and method for determining the thyroid dose rate of mixed airborne species of solid and gaseous radioiodine without requiring highly skilled personnel, such as health physicists or electronics technicians. To this end, this invention provides a means and method for sampling a gas from a source of a mixed species of solid and gaseous radioiodine for collection of the mixed species and readout and assessment of the emissions therefrom by cylindrically, concentrically and annularly molding the respective species around a cylindrical passage for receiving a conventional probe-type Geiger-Mueller radiation detector

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

    International Nuclear Information System (INIS)

    Scherpelz, R.I.; Bander, T.J.; Athey, G.F.; Ramsdell, J.V.

    1986-03-01

    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

  11. Revue of some dosimetry and dose assessment European projects

    International Nuclear Information System (INIS)

    Bolognese-Milsztajn, T.; Frank, D.; Lacoste, V.; Pihet, P.

    2006-01-01

    Full text of publication follows: Within the 5. Framework Programme of the European Commission several project dealing with dosimetry and dose assessment for internal and external exposure have been supported. A revue of the results of some of them is presented in this paper. The EURADOS network which involved 50 dosimetry institutes in EUROPE has coordinated the project DOSIMETRY NETWORK: the main results achieved within this action are the following: - The release on the World Wide Web of the EURADOS Database of Dosimetry Research Facilities; - The realisation of the report 'Harmonization of Individual Monitoring (IM) in Europe'; - The continuation of the intercomparisons programme of environmental radiation monitoring systems; - The realisation of the report Cosmic radiation exposure of aircraft crew. The EVIDOS project aimed at evaluating state of the art dosimetry techniques in representative workplaces of the nuclear industry with complex mixed neutron-photon radiation fields. This paper summarises the main findings from a practical point of view. Conclusions and recommendations will be given concerning characterisation of radiation fields, methods to derive radiation protection quantities and dosimeters results. The IDEA project aimed to improve the assessment of incorporated radionuclides through developments of advanced in-vivo and bioassay monitoring techniques and making use of such enhancements for improvements in routine monitoring. The primary goal was to categorize those new developments regarding their potential and eligibility for the routine monitoring community. The costs of monitoring for internal exposures in the workplace are usually significantly greater than the equivalent costs for external exposures. There is therefore a need to ensure that resources are employed with maximum effectiveness. The EC-funded OMINEX (Optimisation of Monitoring for Internal Exposure) project has developed methods for optimising the design and implementation of

  12. Design, implementation and verification of software code for radiation dose assessment based on simple generic environmental model

    International Nuclear Information System (INIS)

    I Putu Susila; Arif Yuniarto

    2017-01-01

    Radiation dose assessment to determine the potential of radiological impacts of various installations within nuclear facility complex is necessary to ensure environmental and public safety. A simple generic model-based method for calculating radiation doses caused by the release of radioactive substances into the environment has been published by the International Atomic Energy Agency (IAEA) as the Safety Report Series No. 19 (SRS-19). In order to assist the application of the assessment method and a basis for the development of more complex assessment methods, an open-source based software code has been designed and implemented. The software comes with maps and is very easy to be used because assessment scenarios can be done through diagrams. Software verification was performed by comparing its result to SRS-19 and CROM software calculation results. Dose estimated by SRS-19 are higher compared to the result of developed software. However, these are still acceptable since dose estimation in SRS-19 is based on conservative approach. On the other hand, compared to CROM software, the same results for three scenarios and a non-significant difference of 2.25 % in another scenario were obtained. These results indicate the correctness of our implementation and implies that the developed software is ready for use in real scenario. In the future, the addition of various features and development of new model need to be done to improve the capability of software that has been developed. (author)

  13. Potential radionuclide emissions from stacks on the Hanford Site. Part 1: Dose assessment

    International Nuclear Information System (INIS)

    Davis, W.E.; Barnett, J.M.

    1994-06-01

    On February 3, 1993, the US Department of Energy, Richland Operations Office (RL) received a Compliance Order and Information Request from the Director of the Air and Toxics Division of the US Environmental Protection Agency (EPA), Region 10. The Compliance Plan specified that a dose assessment would be performed for 84 Westinghouse Hanford Company (WHC) stacks registered with the Washington State Department of Health (WAC 246-247) on the Hanford Site. Stacks that have the potential emissions to cause an effective dose equivalent (EDE) to a maximum exposed individual (MEI) greater than 0.1 mrem y -1 must be monitored continuously for radionuclide emissions. Five methods were approved by EPA, Region 10 for performing the assessments: Release Fractions from Appendix D of 40 CFR 61, Back Calculations Using A HEPA Filtration Factor, Nondestructive Assay of HEPA Filters, A Spill Release Fraction, and Upstream of HEPA Filter Air Concentrations. The first two methods were extremely conservative for estimating releases. The third method which used a state-of-the-art portable gamma spectrometer, yielded surprising results from the distribution of radionuclides on the HEPA filters. All five methods are described

  14. Assessing the effect of electron density in photon dose calculations

    International Nuclear Information System (INIS)

    Seco, J.; Evans, P. M.

    2006-01-01

    Photon dose calculation algorithms (such as the pencil beam and collapsed cone, CC) model the attenuation of a primary photon beam in media other than water, by using pathlength scaling based on the relative mass density of the media to water. In this study, we assess if differences in the electron density between the water and media, with different atomic composition, can influence the accuracy of conventional photon dose calculations algorithms. A comparison is performed between an electron-density scaling method and the standard mass-density scaling method for (i) tissues present in the human body (such as bone, muscle, etc.), and for (ii) water-equivalent plastics, used in radiotherapy dosimetry and quality assurance. We demonstrate that the important material property that should be taken into account by photon dose algorithms is the electron density, and not the mass density. The mass-density scaling method is shown to overestimate, relative to electron-density predictions, the primary photon fluence for tissues in the human body and water-equivalent plastics, where 6%-7% and 10% differences were observed respectively for bone and air. However, in the case of patients, differences are expected to be smaller due to the large complexity of a treatment plan and of the patient anatomy and atomic composition and of the smaller thickness of bone/air that incident photon beams of a treatment plan may have to traverse. Differences have also been observed for conventional dose algorithms, such as CC, where an overestimate of the lung dose occurs, when irradiating lung tumors. The incorrect lung dose can be attributed to the incorrect modeling of the photon beam attenuation through the rib cage (thickness of 2-3 cm in bone upstream of the lung tumor) and through the lung and the oversimplified modeling of electron transport in convolution algorithms. In the present study, the overestimation of the primary photon fluence, using the mass-density scaling method, was shown

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

    International Nuclear Information System (INIS)

    Snyder, S.F.; Hwang, S.T.

    1994-03-01

    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

  16. Method to stimulate dose gradient in liquid media

    International Nuclear Information System (INIS)

    Scarlat, F.

    1993-01-01

    The depth absorbed dose from electrons with energy higher than 10 MeV shows a distribution with a big-percentage absorbed dose at the entrance surface and a small dose gradient. This is due to the big distance between the virtual focus and irradiated liquid medium. In order to stimulate dose gradient and decrease the surface dose, this paper presents a method for obtaining the second focus by means of a magnetostatic planar wiggler. Preliminary calculations indicated that the absorbed dose rate increases two-three times at the reference plane in the irradiated liquid medium. (Author)

  17. High efficiency mixed species radioiodine air sampling, readout, and dose assessment system

    International Nuclear Information System (INIS)

    Distenfeld, C.; Klemish, J.

    1976-05-01

    Reactor accidents require monitoring to assess the impact to persons in the environment. This implies methods and apparatus to accurately and economically sample and evaluate possible released activity. The development of a prototype iodine air sampling system that can differentiate against noble gas activity and be evaluated by standard Civil Defense instrumentation is reported. The apparatus can efficiently (95 percent) collect organic or inorganic, particulate or gaseous radioiodine in concentrations below stable atmospheric iodine, and under severe ambient conditions. Response to noble fission gases was reduced to less than 4 x 10 -4 of an equal iodine airborne activity by heating the collector to approximately 100 0 C. Reliable sample size, +-5 percent, was achieved by using a simple air flow regulator. Thyroid dose commitment was mathematically and graphically related to the iodine isotope distribution expected in the environment and to the response of the Civil Defense CDV-700 instrument used to evaluate the sample. Sensitivity of the method allows dose assessment of 1 to 2 rads to a child's thyroid

  18. Improvement on the KFOOD code for more realistic assessment of the annual food chain radiation dose due to operating nuclear facilities

    International Nuclear Information System (INIS)

    Choi, Yong Ho; Lee, Chang Woo; Kim, Jin Kyu; Lee, Myung Ho; Lee, Jeong Ho

    1993-01-01

    More realistic calculation models for evaluating man's annual intakes of radionuclides released from operating nuclear facilities were established. For the application of these models, the harvest years of food and feed crops consumed in the year of dose assessment and every year's average concentrations of a radionuclide in air and in water for the whole period of real operation had to be taken into account. KFOOD, an existing equilibrium food chain computer code for the Korean dose assessment, was modified according to the models. Sample runs of the modified code on the assumption of a constant release during 10 years' operation were made with three kinds of the input data files enabling the dose assessment in the improved method, the KFOOD method and another existing method, respectively, and the results were compared. Annual committed effective doses to Korean adult by intakes of Mn-54, Co-60, Sr-90, I-131 and Cs-137 calculated in the improved method were about 11, 2, 5, 60 and 3 %, respectively, lower than the corresponding KFOOD dose. To the intakes of the radionuclides except Sr-90 evaluated in the improved method, foliar uptake contributed much more than root uptake did but, in the case of Sr-90, the result was opposite. (Author)

  19. Issues in weighting bioassay data for use in regressions for internal dose assessments

    International Nuclear Information System (INIS)

    Strom, D.J.

    1992-11-01

    For use of bioassay data in internal dose assessment, research should be done to clarify the goal desired, the choice of method to achieve the goal, the selection of adjustable parameters, and on the ensemble of information that is available. Understanding of these issues should determine choices of weighting factors for bioassay data used in regression models. This paper provides an assessment of the relative importance of the various factors

  20. Assessment of population external irradiation doses with consideration of Rospotrebnadzor bodies equipment for monitoring of photon radiation dose

    Directory of Open Access Journals (Sweden)

    I. P. Stamat

    2016-01-01

    Full Text Available This paper provides review of equipment and methodology for measurement of photon radiation dose; analysis of possible reasons for considerable deviation between the Russian Federation population annual effective external irradiation doses and the relevant average global value. Data on Rospotrebnadzor bodies dosimetry equipment used for measurement of gamma radiation dose are collected and systematized. Over 60 kinds of dosimeters are used for monitoring of population external irradiation doses. Most of dosimeters used in the country have gas-discharge detectors (Geiger-Mueller counters, minor biochemical annunciators, etc. which have higher total values of own background level and of space radiation response than the modern dosimeters with scintillation detectors. This feature of dosimeters is apparently one of most plausible reasons of a bit overstating assessment of population external irradiation doses. The options for specification of population external irradiation doses assessment are: correction of gamma radiation dose measurement results with consideration of dosimeters own background level and space radiation response, introduction of more up-to-date dosimeters with scintillation detectors, etc. The most promising direction of research in verification of population external irradiation doses assessment is account of dosimetry equipment.

  1. Research and assessment of national population dose

    International Nuclear Information System (INIS)

    Pan Ziqiang

    1984-01-01

    This article describes the necessity and probability of making researches on assessment of national population dose, and discusses some problems which might be noticeable in the research work. (author)

  2. Calculational Tool for Skin Contamination Dose Assessment

    CERN Document Server

    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.

  3. Microdosimetric approach for lung dose assessments

    International Nuclear Information System (INIS)

    Hofmann, W.; Steinhausler, F.; Pohl, E.; Bernroider, G.

    1980-01-01

    In the macroscopic region the term ''organ dose'' is related to an uniform energy deposition within a homogeneous biological target. Considering the lung, inhaled radioactive nuclides, however, show a significant non-uniform distribution pattern throughout the respiratory tract. For the calculation of deposition and clearance of inhaled alpha-emitting radionuclides within different regions of this organ, a detailed compartment model, based on the Weibel model A was developed. Since biological effects (e.g. lung cancer initiation) are primarily caused at the cellular level, the interaction of alpha particles with different types of cells of the lung tissue was studied. The basic approach is to superimpose alpha particle tracks on magnified images of randomly selected tissue slices, simulating alpha emitting sources. Particle tracks are generated by means of a specially developed computer program and used as input data for an on-line electronic image analyzer (Quantimet-720). Using adaptive pattern recognition methods the different cells in the lung tissue can be identified and their distribution within the whole organ determined. This microdosimetric method is applied to soluble radon decay products as well as to insoluble, highly localized, plutonium particles. For a defined microdistribution of alpha emitters, the resulting dose, integrated over all cellular dose values, is compared to the compartmental doses of the ICRP lung model. Furthermore this methodology is also applicable to other organs and tissues of the human body for dose calculations in practical health physics. (author)

  4. ASSESSMENT OF THE AVERAGE ANNUAL EFFECTIVE DOSES FOR THE INHABITANTS OF THE SETTLEMENTS LOCATED IN THE TERRITORIES CONTAMINATED DUE TO THE CHERNOBYL ACCIDENT

    Directory of Open Access Journals (Sweden)

    N. G. Vlasova

    2012-01-01

    Full Text Available Catalogue of the average annual effective exposure doses of the inhabitants of the territories contaminated due to the Chernobul accident had been developed according to the method of the assessment of the average annual effective exposure doses of the settlements inhabitants. The cost-efficacy of the use of the average annual effective dose assessment method was 250 000 USD for the current 5 years. Average annual effective dose exceeded 1 mSv/year for 191 Belarus settlements from 2613. About 50 000 persons are living in these settlements.

  5. Dose assessment under incidental and accidental conditions

    International Nuclear Information System (INIS)

    Huebschmann, W.G.

    1988-01-01

    Dose assessment for the licesing process of a nuclear power plant covers the routine release of radioactive substances into the atmosphere as well as releases due to incidents. Source terms for these incidents are evaluated by the detailed incident analysis of the plant. The types of incidents to be covered are determined in the FRG by the ''Stoerfall-Leitlinien'' of the Ministry of the Interior. The calculation of dose equivalents in the environment of the plant differs from the calculation of doses due to routine releases, as incidents are single events occuring at undeterminate time, and the results must be conservative. Some details are being described. During the operation of the plant it is essential to measure not only the radioactivity release rates but also the necessary meteorological parameters for the instantaneous determination of the atmospheric dispersion in case of incidental or accidental releases of radioactivity. This instantaneous assessment assists in taking measurements of ground contamination and in deciding about countermeasures for the protection of plant personnell and population. (author) [pt

  6. BAYESIAN DATA AUGMENTATION DOSE FINDING WITH CONTINUAL REASSESSMENT METHOD AND DELAYED TOXICITY

    Science.gov (United States)

    Liu, Suyu; Yin, Guosheng; Yuan, Ying

    2014-01-01

    A major practical impediment when implementing adaptive dose-finding designs is that the toxicity outcome used by the decision rules may not be observed shortly after the initiation of the treatment. To address this issue, we propose the data augmentation continual re-assessment method (DA-CRM) for dose finding. By naturally treating the unobserved toxicities as missing data, we show that such missing data are nonignorable in the sense that the missingness depends on the unobserved outcomes. The Bayesian data augmentation approach is used to sample both the missing data and model parameters from their posterior full conditional distributions. We evaluate the performance of the DA-CRM through extensive simulation studies, and also compare it with other existing methods. The results show that the proposed design satisfactorily resolves the issues related to late-onset toxicities and possesses desirable operating characteristics: treating patients more safely, and also selecting the maximum tolerated dose with a higher probability. The new DA-CRM is illustrated with two phase I cancer clinical trials. PMID:24707327

  7. Internal Dose Conversion Coefficients of Domestic Reference Animal and Plants for Dose Assessment of Non-human Species

    International Nuclear Information System (INIS)

    Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Choi, Yong Ho

    2009-01-01

    Traditionally, radiation protection has been focused on a radiation exposure of human beings. In the international radiation protection community, one of the recent key issues is to establish the methodology for assessing the radiological impact of an ionizing radiation on non-human species for an environmental protection. To assess the radiological impact to non-human species dose conversion coefficients are essential. This paper describes the methodology to calculate the internal dose conversion coefficient for non-human species and presents calculated internal dose conversion coefficients of 25 radionuclides for 8 domestic reference animal and plants

  8. Application of Whole Body Counter to Neutron Dose Assessment in Criticality Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Kurihara, O.; Tsujimura, N.; Takasaki, K.; Momose, T.; Maruo, Y. [Japan Nuclear Cycle Development Institute, Tokai (Japan)

    2001-09-15

    Neutron dose assessment in criticality accidents using Whole Body Counter (WBC) was proved to be an effective method as rapid neutron dose estimation at the JCO criticality accident in Tokai-mura. The 1.36MeV gamma-ray of {sup 24}Na in a body can be detected easily by a germanium detector. The Minimum Detectable Activity (MDA) of {sup 24}Na is approximately 50Bq for 10minute measurement by the germanium-type whole body counter at JNC Tokai Works. Neutron energy spectra at the typical shielding conditions in criticality accidents were calculated and the conversion factor, whole body activity-to-organ mass weighted neutron absorbed dose, corresponding to each condition were determined. The conversion factor for uncollied fission spectrum is 7.7 [(Bq{sup 24}Na/g{sup 23}Na)/mGy].

  9. Radiation dose reduction in paediatric coronary computed tomography: assessment of effective dose and image quality

    International Nuclear Information System (INIS)

    Habib Geryes, Bouchra; Calmon, Raphael; Boddaert, Nathalie; Khraiche, Diala; Bonnet, Damien; Raimondi, Francesca

    2016-01-01

    To assess the impact of different protocols on radiation dose and image quality for paediatric coronary computed tomography (cCT). From January-2012 to June-2014, 140 children who underwent cCT on a 64-slice scanner were included. Two consecutive changes in imaging protocols were performed: 1) the use of adaptive statistical iterative reconstruction (ASIR); 2) the optimization of acquisition parameters. Effective dose (ED) was calculated by conversion of the dose-length product. Image quality was assessed as excellent, good or with significant artefacts. Patients were divided in three age groups: 0-4, 5-7 and 8-18 years. The use of ASIR combined to the adjustment of scan settings allowed a reduction in the median ED of 58 %, 82 % and 85 % in 0-4, 5-7 and 8-18 years group, respectively (7.3 ± 1.4 vs 3.1 ± 0.7 mSv, 5.5 ± 1.6 vs 1 ± 1.9 mSv and 5.3 ± 5.0 vs 0.8 ± 2.0 mSv, all p < 0,05). Prospective protocol was used in 51 % of children. The reduction in radiation dose was not associated with reduction in diagnostic image quality as assessed by the frequency of coronary segments with excellent or good image quality (88 %). cCT can be obtained at very low radiation doses in children using ASIR, and prospective acquisition with optimized imaging parameters. (orig.)

  10. Use of electron paramagnetic resonance dosimetry with tooth enamel for retrospective dose assessment. Report of a co-ordinated research project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-12-01

    Electron paramagnetic resonance (EPR) dosimetry is a physical method for the assessment of absorbed dose from ionising radiation. It is based on the measurement of stable radiation induced radicals in human calcified tissues (primarily in tooth enamel). EPR dosimetry with teeth is now firmly established in retrospective dosimetry. It is a powerful method for providing information on exposure to ionising radiation many years after the event, since the 'signal' is 'stored' in the tooth or the bone. This technique is of particular relevance to relatively low dose exposures or when the results of conventional dosimetry are not available (e.g. in accidental circumstances). The use of EPR dosimetry, as an essential tool for retrospective assessment of radiation exposure is an important part of radioepidemiological studies and also provides data to select appropriate countermeasures based on retrospective evaluation of individual doses. Despite well established regulations and protocols for maintaining radiation protection dose limits, the assurance that these limits will not be exceeded cannot be guaranteed, thus providing new challenges for development of accurate methods of individual dose assessment. To meet some of these challenges, in 1998 the IAEA initiated a co-ordinated research project (CRP) with the objective to review the available methods, current research and development in EPR biodosimetry technology, which may be of practical use. The major goal of this CRP was to investigate the use of EPR biodosimetry for reconstruction of absorbed dose in tooth enamel with the aim of providing Member States with up-to-date, and generally agreed upon advice regarding the most suitable procedures and the best focus for their research. The co-ordinated research project was conducted over four years and this publication presents the results and findings by a group of investigators from different countries. The available cytogenetic methods for radiation dose assessment were

  11. Use of electron paramagnetic resonance dosimetry with tooth enamel for retrospective dose assessment. Report of a co-ordinated research project

    International Nuclear Information System (INIS)

    2002-12-01

    Electron paramagnetic resonance (EPR) dosimetry is a physical method for the assessment of absorbed dose from ionising radiation. It is based on the measurement of stable radiation induced radicals in human calcified tissues (primarily in tooth enamel). EPR dosimetry with teeth is now firmly established in retrospective dosimetry. It is a powerful method for providing information on exposure to ionising radiation many years after the event, since the 'signal' is 'stored' in the tooth or the bone. This technique is of particular relevance to relatively low dose exposures or when the results of conventional dosimetry are not available (e.g. in accidental circumstances). The use of EPR dosimetry, as an essential tool for retrospective assessment of radiation exposure is an important part of radioepidemiological studies and also provides data to select appropriate countermeasures based on retrospective evaluation of individual doses. Despite well established regulations and protocols for maintaining radiation protection dose limits, the assurance that these limits will not be exceeded cannot be guaranteed, thus providing new challenges for development of accurate methods of individual dose assessment. To meet some of these challenges, in 1998 the IAEA initiated a co-ordinated research project (CRP) with the objective to review the available methods, current research and development in EPR biodosimetry technology, which may be of practical use. The major goal of this CRP was to investigate the use of EPR biodosimetry for reconstruction of absorbed dose in tooth enamel with the aim of providing Member States with up-to-date, and generally agreed upon advice regarding the most suitable procedures and the best focus for their research. The co-ordinated research project was conducted over four years and this publication presents the results and findings by a group of investigators from different countries. The available cytogenetic methods for radiation dose assessment were

  12. Technical Note: SCUDA: A software platform for cumulative dose assessment

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seyoun; McNutt, Todd; Quon, Harry; Wong, John; Lee, Junghoon, E-mail: rshekhar@childrensnational.org, E-mail: junghoon@jhu.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland 21231 (United States); Plishker, William [IGI Technologies, Inc., College Park, Maryland 20742 (United States); Shekhar, Raj, E-mail: rshekhar@childrensnational.org, E-mail: junghoon@jhu.edu [IGI Technologies, Inc., College Park, Maryland 20742 and Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Health System, Washington, DC 20010 (United States)

    2016-10-15

    Purpose: Accurate tracking of anatomical changes and computation of actually delivered dose to the patient are critical for successful adaptive radiation therapy (ART). Additionally, efficient data management and fast processing are practically important for the adoption in clinic as ART involves a large amount of image and treatment data. The purpose of this study was to develop an accurate and efficient Software platform for CUmulative Dose Assessment (SCUDA) that can be seamlessly integrated into the clinical workflow. Methods: SCUDA consists of deformable image registration (DIR), segmentation, dose computation modules, and a graphical user interface. It is connected to our image PACS and radiotherapy informatics databases from which it automatically queries/retrieves patient images, radiotherapy plan, beam data, and daily treatment information, thus providing an efficient and unified workflow. For accurate registration of the planning CT and daily CBCTs, the authors iteratively correct CBCT intensities by matching local intensity histograms during the DIR process. Contours of the target tumor and critical structures are then propagated from the planning CT to daily CBCTs using the computed deformations. The actual delivered daily dose is computed using the registered CT and patient setup information by a superposition/convolution algorithm, and accumulated using the computed deformation fields. Both DIR and dose computation modules are accelerated by a graphics processing unit. Results: The cumulative dose computation process has been validated on 30 head and neck (HN) cancer cases, showing 3.5 ± 5.0 Gy (mean±STD) absolute mean dose differences between the planned and the actually delivered doses in the parotid glands. On average, DIR, dose computation, and segmentation take 20 s/fraction and 17 min for a 35-fraction treatment including additional computation for dose accumulation. Conclusions: The authors developed a unified software platform that provides

  13. Problems Concerning Dose Assessments in Epidemiology of High Background Radiation Areas of Yangjiang, China (invited paper)

    International Nuclear Information System (INIS)

    Wei, L.X.; Yuan, Y.L.

    1998-01-01

    The purpose of this study on radiation levels and dose assessments in the epidemiology of a high background radiation area (HBRA) and the control area (CA) is to respond to the needs of epidemiology in these areas, where the inhabitants are continuously exposed to low dose, low dose rate ionising radiation. A brief description is given of how the research group evaluated the feasibility of the investigation by analysing the population size and the radiation levels, how simple reliable methods were used to get the individual annual dose for every cohort member, and how the cohort members were classified into various dose groups for dose-effect relationship analysis. Finally, the use of dose group classification for cancer mortality studies is described. (author)

  14. Point kernels and superposition methods for scatter dose calculations in brachytherapy

    International Nuclear Information System (INIS)

    Carlsson, A.K.

    2000-01-01

    Point kernels have been generated and applied for calculation of scatter dose distributions around monoenergetic point sources for photon energies ranging from 28 to 662 keV. Three different approaches for dose calculations have been compared: a single-kernel superposition method, a single-kernel superposition method where the point kernels are approximated as isotropic and a novel 'successive-scattering' superposition method for improved modelling of the dose from multiply scattered photons. An extended version of the EGS4 Monte Carlo code was used for generating the kernels and for benchmarking the absorbed dose distributions calculated with the superposition methods. It is shown that dose calculation by superposition at and below 100 keV can be simplified by using isotropic point kernels. Compared to the assumption of full in-scattering made by algorithms currently in clinical use, the single-kernel superposition method improves dose calculations in a half-phantom consisting of air and water. Further improvements are obtained using the successive-scattering superposition method, which reduces the overestimates of dose close to the phantom surface usually associated with kernel superposition methods at brachytherapy photon energies. It is also shown that scatter dose point kernels can be parametrized to biexponential functions, making them suitable for use with an effective implementation of the collapsed cone superposition algorithm. (author)

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

    CERN Document Server

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

    2002-01-01

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

  16. Assessment of peak skin dose in interventional cardiology: A comparison between Gafchromic film and dosimetric software em.dose.

    Science.gov (United States)

    Greffier, J; Van Ngoc Ty, C; Bonniaud, G; Moliner, G; Ledermann, B; Schmutz, L; Cornillet, L; Cayla, G; Beregi, J P; Pereira, F

    2017-06-01

    To compare the use of a dose mapping software to Gafchromic film measurement for a simplified peak skin dose (PSD) estimation in interventional cardiology procedure. The study was conducted on a total of 40 cardiac procedures (20 complex coronary angioplasty of chronic total occlusion (CTO) and 20 coronary angiography and coronary angioplasty (CA-PTCA)) conducted between January 2014 to December 2015. PSD measurement (PSD Film ) was obtained by placing XR-RV3 Gafchromic under the patient's back for each procedure. PSD (PSD em.dose ) was computed with the software em.dose©. The calculation was performed on the dose metrics collected from the private dose report of each procedure. Two calculation methods (method A: fluoroscopic kerma equally spread on cine acquisition and B: fluoroscopic kerma is added to one air Kerma cine acquisition that contributes to the PSD) were used to calculate the fluoroscopic dose contribution as fluoroscopic data were not recorded in our interventional room. Statistical analyses were carried out to compare PSD Film and PSD em.dose . The PSD Film median (1st quartile; 3rd quartile) was 0.251(0.190;0.336)Gy for CA-PTCA and 1.453(0.767;2.011)Gy for CTO. For method-A, the PSD em.dose was 0.248(0.182;0.369)Gy for CA-PTCA and 1.601(0.892;2.178)Gy for CTO, and 0.267(0.223;0.446)Gy and 1.75 (0.912;2.584)Gy for method-B, respectively. For the two methods, the correlation between PSD Film and PSD em.dose was strong. For all cardiology procedures investigated, the mean deviation between PSD Film and PSD em.dose was 3.4±21.1% for method-A and 17.3%±23.9% for method-B. The dose mapping software is convenient to calculate peak skin dose in interventional cardiology. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Maldonado, Delis

    2012-01-01

    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

  18. Combination TLD/TED dose assessment

    International Nuclear Information System (INIS)

    Parkhurst, M.A.

    1992-11-01

    During the early 1980s, an appraisal of dosimetry programs at US Department of Energy (DOE) facilities identified a significant weakness in dose assessment in fast neutron environments. Basing neutron dose equivalent on thermoluminescence dosimeters (TLDS) was not entirely satisfactory for environments that had not been well characterized. In most operational situations, the dosimeters overrespond to neutrons, and this overresponse could be further exaggerated with changes in the neutron quality factor (Q). Because TLDs are energy dependent with an excellent response to thermal and low-energy neutrons but a weak response to fast neutrons, calibrating the dosimetry system to account for mixed and moderated neutron energy fields is a difficult and seldom satisfactory exercise. To increase the detection of fast neutrons and help improve the accuracy of dose equivalent determinations, a combination dosimeter was developed using TLDs to detect thermal and low-energy neutrons and a track-etch detector (TED) to detect fast neutrons. By combining the albedo energy response function of the TLDs with the track detector elements, the dosimeter can nearly match the fluence-to-dose equivalent conversion curve. The polymer CR-39 has neutron detection characteristics superior to other materials tested. The CR-39 track detector is beta and gamma insensitive and does not require backscatter (albedo) from the body to detect the exposure. As part of DOE's Personnel Neutron and Upgrade Program, we have been developing a R-39 track detector over the past decade to address detection and measurement of fast neutrons. Using CR-39 TEDs in combination with TLDs will now allow us to detect the wide spectrum of occupational neutron energies and assign dose equivalents much more confidently

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

    International Nuclear Information System (INIS)

    Hoffman, F.O.; Simon, S.L.; Thiessen. K.M.

    1996-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. The D1 method: career dose estimation from a combination of historical monitoring data and a single year's dose data

    International Nuclear Information System (INIS)

    Sont, W.N.

    1995-01-01

    A method is introduced to estimate career doses from a combination of historical monitoring data and a single year's dose data. This method, called D1 eliminates the bias arising from incorporating historical dose data from times when occupational doses were generally much higher than they are today. Doses calculated by this method are still conditional on the preservation of the status quo in the effectiveness of radiation protection. The method takes into account the variation of the annual dose, and of the probability of being monitored, with the time elapsed since the start of a career. It also allows for the calculation of a standard error of the projected career dose. Results from recent Canadian dose data are presented. (author)

  2. Issues of assessment of doses from natural sources in working conditions: implications for the unified state system of individual dose monitoring

    Directory of Open Access Journals (Sweden)

    T. A. Kormanovskaya

    2017-01-01

    Full Text Available The aims of the work are: 1 an analysis of information on radiation doses from natural sources of ionizing radiation of employees of enterprises in some industries of the Russian Federation and 2 an assessment of the state of registration of doses from natural sources in working conditions in the Unified System of Individual Dose Control. Materials and methods. The analysis was performed on the results of the operation of the Federal database of radiation doses of the population due to natural and artificial radiation background in 2013–2015 on the basis of the forms of the Federal statistical observation No. 4-DOZ in terms of collecting information on the radiation doses of workers in some non-nuclear industries due to natural sources of ionizing radiation. Results. Analysis of enterprises in 17 industries in 23 regions of Russia connected with the specificity of production processes showed cases of natural exposure of workers at the dose level exceeding 5 mSv/year. We have identified those branches of industry, for which the doses were close to 5 mSv/year.Examples of reducing the radiation doses by reducing the time spent by workers in workplaces with high levels of radiation are given. The problems of insufficient representativeness of the sample data are due to the lack of interaction of the management of industrial enterprises with the bodies of the Rospotrebnadzor. The obtained data allow speaking about the problem of assessing the quality of radiation control in the organizations where additional exposure of workers from natural radiation sources is expected. It is necessary to create a system of regulatory and procedural documents to solve the problem at the national level.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-03-01

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

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

    International Nuclear Information System (INIS)

    Andrasi, A.

    1997-01-01

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

  5. The ecosystem models used for dose assessments in SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Rodolfo [Facilia AB, Bromma (Sweden)

    2006-11-15

    chronic contamination. From the simulations for the different release cases, activity concentrations in water and soil are obtained and then multiplied with the aggregated transfer factors to obtain concentrations in food products. For terrestrial ecosystems, the aggregated transfer factors in Becquerel per Kilogram of edible carbon in the food are used to calculate the activity intake and from this the effective dose rate per unit release to an adult individual. For aquatic ecosystems, only doses from the ingestion of water (for lakes) and food (for sea and lakes) are considered, as previous assessments have shown that in these types of ecosystems other exposure pathways give a very low contribution to the total doses. A sensitivity analysis of the ecosystem models is presented in the report, identifying which parameters have the largest effect on the simulation endpoints of interest. The endpoints considered are the fraction of the release that is retained in the ecosystem, the activity concentrations in soil, water and sediments, and the total dose rates from external exposure, inhalation, and ingestion of water and food. These endpoints are evaluated at different times within the simulation and a sensitivity analysis using the Morris method is carried out. For some of the scenarios considered in SR-Can, the LDF concept is not applicable. One of these scenarios comprises the contamination of ground caused by inadvertent drilling into the repository. Doses which would arise for a family using this contaminated ground for housing and food production are estimated. The other scenario which is assessed separately is the release of C-14 and Rn-222 from the repository in gaseous form, entering the biosphere via soil as a diffuse source. Pathways considered are doses from ingestion of C-14 and from inhalation of C-14 and Rn-222 outdoors as well as indoors. For these scenarios, specific dose calculations were carried out. The methods applied for these calculations and the

  6. The ecosystem models used for dose assessments in SR-Can

    International Nuclear Information System (INIS)

    Avila, Rodolfo

    2006-11-01

    chronic contamination. From the simulations for the different release cases, activity concentrations in water and soil are obtained and then multiplied with the aggregated transfer factors to obtain concentrations in food products. For terrestrial ecosystems, the aggregated transfer factors in Becquerel per Kilogram of edible carbon in the food are used to calculate the activity intake and from this the effective dose rate per unit release to an adult individual. For aquatic ecosystems, only doses from the ingestion of water (for lakes) and food (for sea and lakes) are considered, as previous assessments have shown that in these types of ecosystems other exposure pathways give a very low contribution to the total doses. A sensitivity analysis of the ecosystem models is presented in the report, identifying which parameters have the largest effect on the simulation endpoints of interest. The endpoints considered are the fraction of the release that is retained in the ecosystem, the activity concentrations in soil, water and sediments, and the total dose rates from external exposure, inhalation, and ingestion of water and food. These endpoints are evaluated at different times within the simulation and a sensitivity analysis using the Morris method is carried out. For some of the scenarios considered in SR-Can, the LDF concept is not applicable. One of these scenarios comprises the contamination of ground caused by inadvertent drilling into the repository. Doses which would arise for a family using this contaminated ground for housing and food production are estimated. The other scenario which is assessed separately is the release of C-14 and Rn-222 from the repository in gaseous form, entering the biosphere via soil as a diffuse source. Pathways considered are doses from ingestion of C-14 and from inhalation of C-14 and Rn-222 outdoors as well as indoors. For these scenarios, specific dose calculations were carried out. The methods applied for these calculations and the

  7. Development on Dose Assessment Model of Northeast Asia Nuclear Accident Simulator

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Yub; Kim, Ju Youl; Kim, Suk Hoon; Lee, Seung Hee; Yoon, Tae Bin [FNC Techology, Yongin (Korea, Republic of)

    2016-05-15

    In order to support the emergency response system, the simulator for overseas nuclear accident is under development including source-term estimation, atmospheric dispersion modeling and dose assessment. The simulator is named NANAS (Northeast Asia Nuclear Accident Simulator). For the source-term estimation, design characteristics of each reactor type should be reflected into the model. Since there are a lot of reactor types in neighboring countries, the representative reactors of China, Japan and Taiwan have been selected and the source-term estimation models for each reactor have been developed, respectively. For the atmospheric dispersion modeling, Lagrangian particle model will be integrated into the simulator for the long range dispersion modeling in Northeast Asia region. In this study, the dose assessment model has been developed considering external and internal exposure. The dose assessment model has been developed as a part of the overseas nuclear accidents simulator which is named NANAS. It addresses external and internal pathways including cloudshine, groundshine and inhalation. Also, it uses the output of atmospheric dispersion model (i.e. the average concentrations of radionuclides in air and ground) and various coefficients (e.g. dose conversion factor and breathing rate) as an input. Effective dose and thyroid dose for each grid in the Korean Peninsula region are printed out as a format of map projection and chart. Verification and validation on the dose assessment model will be conducted in further study by benchmarking with the measured data of Fukushima Daiichi Nuclear Accident.

  8. Application of the dose rate spectroscopy to the dose-to-curie conversion method using a NaI(Tl) detector

    International Nuclear Information System (INIS)

    JI, Young-Yong; Chung, Kun Ho; Kim, Chang-Jong; Kang, Mun Ja; Park, Sang Tae

    2015-01-01

    Dose rate spectroscopy is a very useful method to directly calculate the individual dose rate from the converted energy spectrum for the dose rate using the G-factor which is related to the used detector response function. A DTC conversion method for the estimation of the radioactivity based on the measured dose rate from the radioactive materials can then be modified into a simple equation using the dose rate spectroscopy. In order to make the method validation of the modified DTC conversion method, experimental verifications using a 3″φx3″ NaI(Tl) detector were conducted at the simple geometry of the point source located onto a detector and more complex geometries which mean the assay of the simulated radioactive material. In addition, the linearity about the results from the modified DTC conversion method was also estimated by increasing the distance between source positions and a detector to confirm the method validation in the energy, dose rate, and distance range of the gamma nuclides. - Highlights: • A modified DTC conversion method using the dose rate spectroscopy was established. • In-situ calibration factors were calculated from the MCNP simulation. • Radioactivities of the disk sources were accurately calculated using a modified DTC conversion method. • A modified DTC conversion method was applied to the assay of the radioactive material

  9. The embryogenesis of dose assessment at Hanford

    International Nuclear Information System (INIS)

    Foster, R.F.

    1990-01-01

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

    International Nuclear Information System (INIS)

    Takahashi, Fumiaki; Shigemori, Yuji; Seki, Akiyuki

    2009-07-01

    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

  11. Comparison of the dose evaluation methods for criticality accident

    International Nuclear Information System (INIS)

    Shimizu, Yoshio; Oka, Tsutomu

    2004-01-01

    The improvement of the dose evaluation method for criticality accidents is important to rationalize design of the nuclear fuel cycle facilities. The source spectrums of neutron and gamma ray of a criticality accident depend on the condition of the source, its materials, moderation, density and so on. The comparison of the dose evaluation methods for a criticality accident is made. Some methods, which are combination of criticality calculation and shielding calculation, are proposed. Prompt neutron and gamma ray doses from nuclear criticality of some uranium systems have been evaluated as the Nuclear Criticality Slide Rule. The uranium metal source (unmoderated system) and the uranyl nitrate solution source (moderated system) in the rule are evaluated by some calculation methods, which are combinations of code and cross section library, as follows: (a) SAS1X (ENDF/B-IV), (b) MCNP4C (ENDF/B-VI)-ANISN (DLC23E or JSD120), (c) MCNP4C-MCNP4C (ENDF/B-VI). They have consisted of criticality calculation and shielding calculation. These calculation methods are compared about the tissue absorbed dose and the spectrums at 2 m from the source. (author)

  12. Application of a simple phantom in assessing the effects of dose reduction on image quality in chest radiography

    International Nuclear Information System (INIS)

    Egbe, N.O.; Heaton, B.; Sharp, P.F.

    2010-01-01

    Purpose: Firstly, to evaluate a commercial chest phantom incorporating a quasi anthropomorphic insert by comparing exposure measurements on the phantom with those of actual patients and, secondly, to assess the value of the phantom for image quality and dose optimisation. Methods: In the first part of the study entrance surface doses (ESD), Beam transmission (BT), and optical density (OD) were obtained for 77 chest radiography patients and compared with measurements made from exposures of the phantom using the respective patient exposure factors from chest examination. Differences were assessed with a student t-test, while the Pearson's linear correlation coefficient was used to test for any linear relationship. The second part assessed the applicability of the phantom to image quality studies by investigating the effect, on the clarity and detectability of lung lesions made from gelatine, of reducing patient dose below current dose levels. Clarity of linear objects of different dimensions was also studied. Lesion detectability and clarity was assessed by four observers. The possibility of extending dose reduction below current dose levels (D ref ) was assessed from comparison of doses that produced statistically significant differences in image quality from D ref . Results: Results show that, with the exception of entrance doses and beam transmission through the diaphragm (P > 0.05), differences in OD and beam transmission between patients and phantom were statistically significant (P ref produced significant changes in both clarity and detectability. Conclusion: Within limits posed by the observed differences, the phantom can be applied to image quality studies in diagnostic radiology.

  13. Guidance on internal dose assessments from monitoring data (Project IDEAS)

    International Nuclear Information System (INIS)

    Doerfel, H.; Andrasi, A.; Bailey, M.; Berkovski, V.; Castellani, M.; Hurtgen, C.; Jourdain, R.; Le Guen, B.

    2003-01-01

    Several international intercomparison exercises on intake and internal dose assessments from monitoring data led to the conclusion that the results calculated by different participants varied significantly mainly to the broad variety of methods and assumptions applied in the assessment procedure. Based on these experiences the need of harmonisation of the procedures has been formulated as an EU research project under the 5th Framework Programme, with the aim of developing general guidelines for standardising assessments of intakes and internal doses. In the IDEAS project, eight institutions from seven European countries are participating, also using inputs from internal dosimetry professionals from across Europe to ensure broad consensus in the outcome of the project. To ensure that the guidelines are applicable to a wide range of practical situations, the first step will be to compile a database on well documented cases of internal contamination. In parallel, an improved version of existing software will be developed and distributed to the partners for further use. Many cases from the database will be evaluated independently by more partners using the same software and the results will be discussed and the draft guidelines prepared. The guidelines will then be revised and refined on the basis of the experiences and discussions of two workshops, and an inter-comparison exercise organised in the frame of the project which will be open to all internal dosimetry professionals. (author)

  14. OSL signal of IC chips from mobile phones for dose assessment in accidental dosimetry

    International Nuclear Information System (INIS)

    Mrozik, A.; Marczewska, B.; Bilski, P.; Książek, M.

    2017-01-01

    The rapid assessment of the radiation dose is very important for the prediction of biological effects after unintended exposition. The materials for use as dosimeters in accidental dosimetry should be everyday objects which are usually placed near the human body, for example mobile phones. IC (Integrated Circuit) chip is one of several electronic components of mobile phones which give a luminescent signal. The measurements of samples from different mobile phones and smartphones were conducted by optically stimulated luminescence (OSL) and thermoluminescence (TL) methods. The OSL measurement was performed in two ways: with readouts at room temperature and at 100 °C. This work is focused on determination of OSL dose response of IC chips, minimum detectable dose (MDD), OSL signal stability in the time after the exposition, its repeatability and sensitivity to light. Several tests of the assessment of unknown doses were also conducted. The readouts at 100 °C indicate the reducing of the fading of OSL signal in the first hours after irradiation in comparison with room temperature readouts. The obtained results showed relatively good dosimetric properties of IC chips: their high sensitivity to the ionizing radiation, linear dose response up to 10 Gy and a good reproducibility of OSL signal which can allow the dose recovery of doses less than 2 Gy in 14 days after an incident with the accuracy better than 25%. The fading is a drawback of IC chips and the fading factor should be considered when calculating the dose. - Highlights: • IC chips from smartphones demonstrated high potential for accidental dosimetry. • Minimum detectable dose was estimated as a value of 50 mGy. • Samples showed linear dose response for the dose range from 0.05 Gy up to 10 Gy.

  15. Antipsychotic dose equivalents and dose-years: a standardized method for comparing exposure to different drugs.

    Science.gov (United States)

    Andreasen, Nancy C; Pressler, Marcus; Nopoulos, Peg; Miller, Del; Ho, Beng-Choon

    2010-02-01

    A standardized quantitative method for comparing dosages of different drugs is a useful tool for designing clinical trials and for examining the effects of long-term medication side effects such as tardive dyskinesia. Such a method requires establishing dose equivalents. An expert consensus group has published charts of equivalent doses for various antipsychotic medications for first- and second-generation medications. These charts were used in this study. Regression was used to compare each drug in the experts' charts to chlorpromazine and haloperidol and to create formulas for each relationship. The formulas were solved for chlorpromazine 100 mg and haloperidol 2 mg to derive new chlorpromazine and haloperidol equivalents. The formulas were incorporated into our definition of dose-years such that 100 mg/day of chlorpromazine equivalent or 2 mg/day of haloperidol equivalent taken for 1 year is equal to one dose-year. All comparisons to chlorpromazine and haloperidol were highly linear with R(2) values greater than .9. A power transformation further improved linearity. By deriving a unique formula that converts doses to chlorpromazine or haloperidol equivalents, we can compare otherwise dissimilar drugs. These equivalents can be multiplied by the time an individual has been on a given dose to derive a cumulative value measured in dose-years in the form of (chlorpromazine equivalent in mg) x (time on dose measured in years). After each dose has been converted to dose-years, the results can be summed to provide a cumulative quantitative measure of lifetime exposure. Copyright 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  16. Two gamma dose evaluation methods for silicon semiconductor detector

    International Nuclear Information System (INIS)

    Chen Faguo; Jin Gen; Yang Yapeng; Xu Yuan

    2011-01-01

    Silicon PIN diodes have been widely used as personal and areal dosimeters because of their small volume, simplicity and real-time operation. However, because silicon is neither a tissue-equivalent nor an air-equivalent material, an intrinsic disadvantage for silicon dosimeters is that a significant over-response occurs at low-energy region, especially below 200 keV. Using a energy compensation filter to flatten the energy response is one method overcoming this disadvantage. But for dose compensation method, the estimated dose depends only on the number of the detector pulses. So a weight function method was introduced to evaluate gamma dose, which depends on pulse number as well as its amplitude. (authors)

  17. Dose assessment following an overexposure of a worker at a Swiss nuclear power plant.

    Science.gov (United States)

    Bailat, Claude J; Laedermann, Jean-Pascal; Baechler, Sébastien; Desorgher, Laurent; Aroua, Abbas; Bochud, François O

    2017-12-01

    The aim of this work was to assess the doses received by a diver exposed to a radiation source during maintenance work in the fuel transfer pool at a Swiss nuclear power plant, and to define whether the statutory limit was breached or not. Onsite measurements were carried out and different scenarios were simulated using the MicroShield Software and the MCNPX Monte Carlo radiation transport code to estimate the activity of the irradiating object as well as the doses to the limbs and the effective dose delivered to the operator. The activity of the object was estimated to 1.8 TBq. From the various dose estimations, a conservative value of 7.5 Sv was proposed for the equivalent dose to the skin on the hands and an effective dose of 28 mSv. The use of different experimental and calculation methods allowed us to accurately estimate the activity of the object and the dose delivered to the diver, useful information for making a decision on the most appropriate scheme of follow up for the patient.

  18. Validation of a computational method for assessing the impact of intra-fraction motion on helical tomotherapy plans

    Energy Technology Data Exchange (ETDEWEB)

    Ngwa, Wilfred; Meeks, Sanford L; Kupelian, Patrick A; Langen, Katja M [Department of Radiation Oncology, M D Anderson Cancer Center Orlando, 1400 South Orange Avenue, Orlando, FL 32806 (United States); Schnarr, Eric [TomoTherapy, Inc., 1240 Deming Way, Madison, WI 53717 (United States)], E-mail: wilfred.ngwa@orlandohealth.com

    2009-11-07

    In this work, a method for direct incorporation of patient motion into tomotherapy dose calculations is developed and validated. This computational method accounts for all treatment dynamics and can incorporate random as well as cyclical motion data. Hence, interplay effects between treatment dynamics and patient motion are taken into account during dose calculation. This allows for a realistic assessment of intra-fraction motion on the dose distribution. The specific approach entails modifying the position and velocity events in the tomotherapy delivery plan to accommodate any known motion. The computational method is verified through phantom and film measurements. Here, measured prostate motion and simulated respiratory motion tracks were incorporated in the dose calculation. The calculated motion-encoded dose profiles showed excellent agreement with the measurements. Gamma analysis using 3 mm and 3% tolerance criteria showed over 97% and 96% average of points passing for the prostate and breathing motion tracks, respectively. The profile and gamma analysis results validate the accuracy of this method for incorporating intra-fraction motion into the dose calculation engine for assessment of dosimetric effects on helical tomotherapy dose deliveries.

  19. Fast method for in-flight estimation of total dose from protons and electrons using RADE Minstrument on JUICE

    Science.gov (United States)

    Hajdas, Wojtek; Mrigakshi, Alankrita; Xiao, Hualin

    2017-04-01

    The primary concern of the ESA JUICE mission to Jupiter is the harsh particle radiation environment. Ionizing particles introduce radiation damage by total dose effects, displacement damages or single events effects. Therefore, both the total ionizing dose and the displacement damage equivalent fluence must be assessed to alert spacecraft and its payload as well as to quantify radiation levels for the entire mission lifetime. We present a concept and implementations steps for simplified method used to compute in flight a dose rate and total dose caused by protons. We also provide refinement of the method previously developed for electrons. The dose rates values are given for predefined active volumes located behind layers of materials with known thickness. Both methods are based on the electron and proton flux measurements provided by the Electron and Proton Detectors inside the Radiation Hard Electron Monitor (RADEM) located on-board of JUICE. The trade-off between method accuracy and programming limitations for in-flight computations are discussed. More comprehensive and precise dose rate computations based on detailed analysis of all stack detectors will be made during off-line data processing. It will utilize full spectral unfolding from all RADEM detector subsystems.

  20. Biological dosimetry: chromosomal aberration analysis for dose assessment

    International Nuclear Information System (INIS)

    1986-01-01

    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

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

    Directory of Open Access Journals (Sweden)

    Kropf Siegfried

    2011-09-01

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

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

    International Nuclear Information System (INIS)

    Park, Sang Hyun

    2003-02-01

    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

  3. Rapid radiological characterization method based on the use of dose coefficients

    International Nuclear Information System (INIS)

    Dulama, C.; Toma, Al.; Dobrin, R.; Valeca, M.

    2010-01-01

    Intervention actions in case of radiological emergencies and exploratory radiological surveys require rapid methods for the evaluation of the range and extent of contamination. When simple and homogeneous radionuclide composition characterize the radioactive contamination, surrogate measurements can be used to reduce the costs implied by laboratory analyses and to speed-up the process of decision support. A dose-rate measurement-based methodology can be used in conjunction with adequate dose coefficients to assess radionuclide inventories and to calculate dose projections for various intervention scenarios. The paper presents the results obtained for dose coefficients in some particular exposure geometries and the methodology used for deriving dose rate guidelines from activity concentration upper levels specified as contamination limits. All calculations were performed by using the commercial software MicroShield from Grove Software Inc. A test case was selected as to meet the conditions from EPA Federal Guidance Report no. 12 (FGR12) concerning the evaluation of dose coefficients for external exposure from contaminated soil and the obtained results were compared to values given in the referred document. The geometries considered as test cases are: contaminated ground surface; - infinite extended homogeneous surface contamination and soil contaminated to a depth of 15 cm. As shown by the results, the values agree within 50% relative difference for most of the cases. The greatest discrepancies were observed for depth contamination simulation and in the case of radionuclides with complicated gamma emission and this is due to the different approach from MicroShield and FGR12. A case study is presented for validation of the methodology, where both dose rate measurements and laboratory analyses were performed on an extended quasi-homogeneous NORM contamination. The dose rate estimations obtained by applying the dose coefficients to the radionuclide concentrations

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-05-01

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

  5. Development of a Method to Assess the Radiation Dose due to Internal Exposure to Short-lived Radioactive Materials

    International Nuclear Information System (INIS)

    Benmaman, D.; Koch, J.; Ribak, J.

    2014-01-01

    Work with radioactive materials requires monitoring of the employees' exposure to ionizing radiation. Employees may be exposed to radiation from internal and/or external exposure. Control of external exposure is mostly conducted through personal radiation dosimeters provided to employees. Control of internal exposure can be performed by measuring the concentration of radioactive substances excreted in urine or through whole-body counting in which the entire body or target organs are scanned with a sensitive detector system (1). According to the regulations in Israel an employee that may be internally exposed must undergo an exposure control at least once every three months. The idea lying behind the control of internal exposure by urine testing is that if radioactive material has penetrated into the employee body, it can be detected even if the test is performed once every three months. A model was fitted for each element describing its dispersion in the body and its excretion therefrom (2). By means of this model, one can estimate the activity that entered the body and calculate the resulting radiation dose to which the worker was exposed. There is a problem to implement this method when it comes to short-lived radioactive materials, for which it is very likely that the material that penetrated into the body has decayed and cannot be detected by testing once every three months. As a result, workers with short-lived radioactive materials are presently not monitored for internal exposure, in contradiction to the requirements of the Safety at Work Regulations. The purpose of the study is to develop an alternative method to assess the amount of radioactive material absorbed in the body and the resulting radiation dose due to internal exposure of workers to short-lived radioactive materials

  6. Simplified method for creating a density-absorbed dose calibration curve for the low dose range from Gafchromic EBT3 film

    Directory of Open Access Journals (Sweden)

    Tatsuhiro Gotanda

    2016-01-01

    Full Text Available Radiochromic film dosimeters have a disadvantage in comparison with an ionization chamber in that the dosimetry process is time-consuming for creating a density-absorbed dose calibration curve. The purpose of this study was the development of a simplified method of creating a density-absorbed dose calibration curve from radiochromic film within a short time. This simplified method was performed using Gafchromic EBT3 film with a low energy dependence and step-shaped Al filter. The simplified method was compared with the standard method. The density-absorbed dose calibration curves created using the simplified and standard methods exhibited approximately similar straight lines, and the gradients of the density-absorbed dose calibration curves were −32.336 and −33.746, respectively. The simplified method can obtain calibration curves within a much shorter time compared to the standard method. It is considered that the simplified method for EBT3 film offers a more time-efficient means of determining the density-absorbed dose calibration curve within a low absorbed dose range such as the diagnostic range.

  7. Outdoor solar UVA dose assessment with EBT2 radiochromic film using spectrophotometer and densitometer measurements

    International Nuclear Information System (INIS)

    Abukassem, I.; Bero, M.A.

    2015-01-01

    Direct measurements of solar ultraviolet radiations (UVRs) have an important role in the protection of humans against UVR hazard. This work presents simple technique based on the application of EBT2 GAFCHROMIC R film for direct solar UVA dose assessment. It demonstrates the effects of different parts of the solar spectrum (UVB, visible and infrared) on performed UVA field measurements and presents the measurement uncertainty budget. The gradient of sunlight exposure level permitted the authors to establish the mathematical relationships between the measured solar UVA dose and two measured quantities: the first was the changes in spectral absorbance at the wavelength 633 nm (A 633 ) and the second was the optical density (OD). The established standard relations were also applied to calculate the solar UVA dose variations during the whole day; 15 min of exposure each hour between 8:00 and 17:00 was recorded. Results show that both applied experimental methods, spectrophotometer absorbance and densitometer OD, deliver comparable figures for EBT2 solar UVA dose assessment with relative uncertainty of 11 % for spectral absorbance measurements and 15 % for OD measurements. (authors)

  8. Calculation method for gamma dose rates from Gaussian puffs

    Energy Technology Data Exchange (ETDEWEB)

    Thykier-Nielsen, S; Deme, S; Lang, E

    1995-06-01

    The Lagrangian puff models are widely used for calculation of the dispersion of releases to the atmosphere. Basic output from such models is concentration of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on the semi-infinite cloud model. This method is however only applicable for puffs with large dispersion parameters, i.e. for receptors far away from the release point. The exact calculation of the cloud dose using volume integral requires large computer time usually exceeding what is available for real time calculations. The volume integral for gamma doses could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor because only a few of the relevant parameters are considered. A multi-parameter method for calculation of gamma doses is described here. This method uses precalculated values of the gamma dose rates as a function of E{sub {gamma}}, {sigma}{sub y}, the asymmetry factor - {sigma}{sub y}/{sigma}{sub z}, the height of puff center - H and the distance from puff center R{sub xy}. To accelerate the calculations the release energy, for each significant radionuclide in each energy group, has been calculated and tabulated. Based on the precalculated values and suitable interpolation procedure the calculation of gamma doses needs only short computing time and it is almost independent of the number of radionuclides considered. (au) 2 tabs., 15 ills., 12 refs.

  9. Calculation method for gamma dose rates from Gaussian puffs

    International Nuclear Information System (INIS)

    Thykier-Nielsen, S.; Deme, S.; Lang, E.

    1995-06-01

    The Lagrangian puff models are widely used for calculation of the dispersion of releases to the atmosphere. Basic output from such models is concentration of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on the semi-infinite cloud model. This method is however only applicable for puffs with large dispersion parameters, i.e. for receptors far away from the release point. The exact calculation of the cloud dose using volume integral requires large computer time usually exceeding what is available for real time calculations. The volume integral for gamma doses could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor because only a few of the relevant parameters are considered. A multi-parameter method for calculation of gamma doses is described here. This method uses precalculated values of the gamma dose rates as a function of E γ , σ y , the asymmetry factor - σ y /σ z , the height of puff center - H and the distance from puff center R xy . To accelerate the calculations the release energy, for each significant radionuclide in each energy group, has been calculated and tabulated. Based on the precalculated values and suitable interpolation procedure the calculation of gamma doses needs only short computing time and it is almost independent of the number of radionuclides considered. (au) 2 tabs., 15 ills., 12 refs

  10. Standard Procedure for Dose Assessment using the film holder NRPB/AERE and the film AGFA Monitoring 2/10

    International Nuclear Information System (INIS)

    Guillen, J.A.

    1998-07-01

    This paper describes the calculation method to assess dose and energy using the film holder from NRPB/AERE and the film Agfa Monitoring 2/10. Also includes all the steps since preparing the standard curve, fitting of calibration curve, dose assesment, description of filtration of the film holder and the form of the calibration curve

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

    International Nuclear Information System (INIS)

    Avila, Rodolfo; Ekstroem, Per-Anders; Aastrand, Per-Gustav

    2010-12-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  13. Influence of high-dose lipid lowering treatment compared to low-dose lipid lowering treatment on plaque composition assessed by intravascular ultrasound virtual histology in patients with ST-segment elevation acute myocardial infarction

    DEFF Research Database (Denmark)

    Egede, Rasmus; Jensen, Lisette Okkels; Hansen, Henrik Steen

    2013-01-01

    Aims: The aim of this study was to evaluate the effect of low-dose versus high-dose rosuvastatin therapy on the necrotic core content in coronary plaques of angiographic non-significant lesions as assessed by intravascular ultrasound - virtual histology. Methods and results: Eighty-seven statin...

  14. Dose assessment from potential radionuclide emissions from stacks on the Hanford Site

    International Nuclear Information System (INIS)

    Davis, W.E.; Barnett, J.M.

    1995-04-01

    On February 3, 1993, the US Department of Energy, Richland Operations Office (RL), received a Compliance Order and Information Request from the Director of the Air and Toxics Division of the US Environmental Protection Agency (EPA), Region 10. The Compliance Order required RL to (1) evaluate all radionuclide emission points at the Hanford Site to determine which points are subject to the continuous emission sampling requirements of Title 40, Code of Federal Regulations, Part 61 (40 CFR 61), Subpart H, and (2) continuously sample radionuclide emissions in accordance with requirements in 40 CFR 61.93. The Information Request required RL to provide a written Compliance Plan to meet the requirements of the Compliance Order. A Compliance Plan was submitted to EPA, Region 10, on April 30, 1993. The Compliance Plan specified that a dose assessment would be performed for 84 Westinghouse Hanford Company (WHC) stacks registered with the Washington State Department of Health on the Hanford Site. Any stack identified in the assessment as having potential emissions to cause an effective dose equivalent (EDE) to a maximum exposed individual (MEI) greater than 0.1 mrem y -1 must have a compliant sampling system. In addition, a Federal Facility Compliance Agreement (FFCA) was signed on. February 7, 1994. The FFCA required that all unregistered stacks on the Hanford Site be assessed. This requirement increased the number of stacks to be assessed to 123 stacks. Six methods for performing the assessments are described. An initial assessment using only the HEPA filtration factor for back calculations identified 32 stacks that would have emissions which would cause an EDE to the MEI greater than 0.1 mrem y -1 . When the other methods were applied the number was reduced to 20 stacks. The paper discusses reasons for these overestimates

  15. Calculation method for gamma-dose rates from spherical puffs

    International Nuclear Information System (INIS)

    Thykier-Nielsen, S.; Deme, S.; Lang, E.

    1993-05-01

    The Lagrangian puff-models are widely used for calculation of the dispersion of atmospheric releases. Basic output from such models are concentrations of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on semi-infinite cloud model. This method is however only applicable for points far away from the release point. The exact calculation of the cloud dose using the volume integral requires significant computer time. The volume integral for the gamma dose could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor due to the fact that the same correction factors are used for all isotopes. The authors describe a more elaborate correction method. This method uses precalculated values of the gamma-dose rate as a function of the puff dispersion parameter (δ p ) and the distance from the puff centre for four energy groups. The release of energy for each radionuclide in each energy group has been calculated and tabulated. Based on these tables and a suitable interpolation procedure the calculation of gamma doses takes very short time and is almost independent of the number of radionuclides. (au) (7 tabs., 7 ills., 12 refs.)

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

    International Nuclear Information System (INIS)

    Castro, P.; Ardao, J.; Velarde, M.; Sedano, L.; Xiberta, J.

    2013-01-01

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

  17. Human data and internal dose assessment

    International Nuclear Information System (INIS)

    Kawamura, H.; Tanaka, G.; Shiraishi, K.; Yamamoto, M.

    1992-01-01

    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 226 Ra in bone of Japanese adult. (author)

  18. A unique manual method for emergency offsite dose calculations

    International Nuclear Information System (INIS)

    Wildner, T.E.; Carson, B.H.; Shank, K.E.

    1987-01-01

    This paper describes a manual method developed for performance of emergency offsite dose calculations for PP and L's Susquehanna Steam Electric Station. The method is based on a three-part carbonless form. The front page guides the user through selection of the appropriate accident case and inclusion of meteorological and effluent data data. By circling the applicable accident descriptors, the user circles the dose factors on pages 2 and 3 which are then simply multiplied to yield the whole body and thyroid dose rates at the plant boundary, two, five, and ten miles. The process used to generate the worksheet is discussed, including the method used to incorporate the observed terrain effects on airflow patterns caused by the Susquehanna River Valley topography

  19. Eye lens exposure to medical staff performing electrophysiology procedures: dose assessment and correlation to patient dose

    International Nuclear Information System (INIS)

    Ciraj-Bjelac, Olivera; Bozovic, Predrag; Arandjic, Danijela; Antic, Vojislav; Selakovic, Jovana; Pavlovic, Sinisa

    2016-01-01

    The purpose of this study was to assess the patient exposure and staff eye dose levels during implantation procedures for all types of pacemaker therapy devices performed under fluoroscopic guidance and to investigate potential correlation between patients and staff dose levels. The mean eye dose during pacemaker/defibrillator implementation was 12 μSv for the first operator, 8.7 μSv for the second operator/nurse and 0.50 μSv for radiographer. Corresponding values for cardiac re-synchronisation therapy procedures were 30, 26 and 2.0 μSv, respectively. Significant (p < 0.01) correlation between the eye dose and the kerma-area product was found for the first operator and radiographers, but not for other staff categories. The study revealed eye dose per procedure and eye dose normalised to patient dose indices for different staff categories and provided an input for radiation protection in electrophysiology procedures. (authors)

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

    International Nuclear Information System (INIS)

    Ulbak, K.

    2011-12-01

    Risoe DTU has carried out research on the terrestrial contamination in the Thule area after the radioactive contents of four nuclear weapons were dispersed following the crash of an American B-52 bomber in 1968. The results of Risoe DTU's studies are described in the report Thule-2007 - Investigation of radioactive pollution on land, which covers all measurements that were carried out on land in Thule in the years 2003, 2006, 2007 and 2008. The present report uses Risoe DTU's report as a basis for assessing radiation doses and consequently the risk for individuals as a result of terrestrial radioactive contamination in the Thule area. The assessment of radiation doses involves a number of conservative assumptions, estimates, and measurements, all of which are subject to considerable uncertainty. In some cases, models have been used based on experiences from other contaminated areas elsewhere in the world, which are subject to climatic and other conditions that diverge from those in the Thule area. The calculated doses are thus associated with considerable uncertainty, which must be taken into account when the results are used for comparison and when the risks of staying in the Thule area are assessed. It has therefore been chosen to provide the assessed radiation doses in the form of indicative orders of magnitude, which are applicable to everyone who might stay in the area, across various age groups. If the estimated doses in this report are combined with the National Institute of Radiation Protections recommended reference level for contamination as a result of the Thule Accident of 1 mSv/year, the assessed magnitudes of radiation doses for inhalation and ingestion as exposure pathways are many orders of magnitude below the reference level (10,00010 million times smaller). The wound contamination exposure pathway has a magnitude of radiation dose that is smaller than the reference level by a factor of 101000, and it should be recalled that the probability of this

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-15

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

  2. A method for calculation of dose per unit concentration values for aquatic biota

    International Nuclear Information System (INIS)

    Batlle, J Vives i; Jones, S R; Gomez-Ros, J M

    2004-01-01

    A dose per unit concentration database has been generated for application to ecosystem assessments within the FASSET framework. Organisms are represented by ellipsoids of appropriate dimensions, and the proportion of radiation absorbed within the organisms is calculated using a numerical method implemented in a series of spreadsheet-based programs. Energy-dependent absorbed fraction functions have been derived for calculating the total dose per unit concentration of radionuclides present in biota or in the media they inhabit. All radionuclides and reference organism dimensions defined within FASSET for marine and freshwater ecosystems are included. The methodology has been validated against more complex dosimetric models and compared with human dosimetry based on ICRP 72. Ecosystem assessments for aquatic biota within the FASSET framework can now be performed simply, once radionuclide concentrations in target organisms are known, either directly or indirectly by deduction from radionuclide concentrations in the surrounding medium

  3. Dose assessment activities in the Republic of the Marshall Islands.

    Science.gov (United States)

    Simon, S L; Graham, J C

    1996-10-01

    Dose assessments, both retrospective and prospective, comprise one important function of a radiological study commissioned by the Republic of the Marshall Islands (RMI) government in late 1989. Estimating past or future exposure requires the synthesis of information from historical data, results from a recently completed field monitoring program, laboratory measurements, and some experimental studies. Most of the activities in the RMI to date have emphasized a pragmatic rather than theoretical approach. In particular, most of the recent effort has been expended on conducting an independent radiological monitoring program to determine the degree of deposition and the geographical extent of weapons test fallout over the nation. Contamination levels on 70% of the land mass of the Marshall Islands were unknown prior to 1994. The environmental radioactivity data play an integral role in both retrospective and prospective assessments. One recent use of dose assessment has been to interpret environmental measurements of radioactivity into annual doses that might be expected at every atoll. A second use for dose assessment has been to determine compliance with a dose action level for the rehabilitation of Rongelap Island. Careful examination of exposure pathways relevant to the island lifestyle has been necessary to accommodate these purposes. Examples of specific issues studied include defining traditional island diets as well as current day variations, sources of drinking water, uses of tropical plants including those consumed for food and for medicinal purposes, the nature and microvariability of plutonium particles in the soil and unusual pathways of exposure, e.g., that which might be associated with cooking and washing outdoors and inadvertent soil ingestion. A study on the prevalence of thyroid disease is also being conducted and the geographic pattern of disease may be useful as a bioindicator of the geographic pattern of exposure to radioiodine. Finally, an

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

    International Nuclear Information System (INIS)

    Campos, Marcia Pires de

    1999-01-01

    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/m 3 at the nuclear materials storage site and from 0.9 to 249.8 Bq/m 3 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)

  5. The Dose Assessment in the Vault Test Case of Near-Surface Disposal Facility for Drinking Water Scenario

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Hyoung; Choi, Byung Seon; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Jae Woo [Jeju National University, Jeju (Korea, Republic of)

    2012-05-15

    It is generally accepted that the radionuclides contained in the radioactive wastes will be eventually released and these will be transported to the accessible environment (near-field, far-field, biosphere). Therefore, the long-term safety assessment of near-surface radioactive waste disposal should be required by modeling the expected release of radionuclides from the repository, far-field area, and biosphere. Finally, the effective dose rate should be estimated through the released radionuclides. In this study, the radiological dose was evaluated for the reference near-surface radioactive waste disposal facility in Vaalputs, South Africa, which has been selected as a part of IAEA coordinated research program on improvement of safety assessment methodologies(ISAM). The assessment of radiological dose was performed for drinking water scenario from a well. The release and transport of radionuclides in disposal system were simulated by GoldSim. This approach suggested the time variation of effective dose over long-term period. And the results from this approach were compared with another approach method for the same facility and scenario

  6. The Dose Assessment in the Vault Test Case of Near-Surface Disposal Facility for Drinking Water Scenario

    International Nuclear Information System (INIS)

    Kim, Tae Hyoung; Choi, Byung Seon; Moon, Jei Kwon; Park, Jae Woo

    2012-01-01

    It is generally accepted that the radionuclides contained in the radioactive wastes will be eventually released and these will be transported to the accessible environment (near-field, far-field, biosphere). Therefore, the long-term safety assessment of near-surface radioactive waste disposal should be required by modeling the expected release of radionuclides from the repository, far-field area, and biosphere. Finally, the effective dose rate should be estimated through the released radionuclides. In this study, the radiological dose was evaluated for the reference near-surface radioactive waste disposal facility in Vaalputs, South Africa, which has been selected as a part of IAEA coordinated research program on improvement of safety assessment methodologies(ISAM). The assessment of radiological dose was performed for drinking water scenario from a well. The release and transport of radionuclides in disposal system were simulated by GoldSim. This approach suggested the time variation of effective dose over long-term period. And the results from this approach were compared with another approach method for the same facility and scenario

  7. The assessment of personal dose due to external radiation

    International Nuclear Information System (INIS)

    Boas, J.F.; Young, J.G.

    1990-01-01

    The fundamental basis of thermoluminescent dosimetry (TLD) is discussed and a number of considerations in the measurement of thermoluminescence described, with particular reference to CaSO 4 :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

  8. 3D delivered dose assessment using a 4DCT-based motion model

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-15

    Purpose: The purpose of this work is to develop a clinically feasible method of calculating actual delivered dose distributions for patients who have significant respiratory motion during the course of stereotactic body radiation therapy (SBRT). Methods: A novel approach was proposed to calculate the actual delivered dose distribution for SBRT lung treatment. This approach can be specified in three steps. (1) At the treatment planning stage, a patient-specific motion model is created from planning 4DCT data. This model assumes that the displacement vector field (DVF) of any respiratory motion deformation can be described as a linear combination of some basis DVFs. (2) During the treatment procedure, 2D time-varying projection images (either kV or MV projections) are acquired, from which time-varying “fluoroscopic” 3D images of the patient are reconstructed using the motion model. The DVF of each timepoint in the time-varying reconstruction is an optimized linear combination of basis DVFs such that the 2D projection of the 3D volume at this timepoint matches the projection image. (3) 3D dose distribution is computed for each timepoint in the set of 3D reconstructed fluoroscopic images, from which the total effective 3D delivered dose is calculated by accumulating deformed dose distributions. This approach was first validated using two modified digital extended cardio-torso (XCAT) phantoms with lung tumors and different respiratory motions. The estimated doses were compared to the dose that would be calculated for routine 4DCT-based planning and to the actual delivered dose that was calculated using “ground truth” XCAT phantoms at all timepoints. The approach was also tested using one set of patient data, which demonstrated the application of our method in a clinical scenario. Results: For the first XCAT phantom that has a mostly regular breathing pattern, the errors in 95% volume dose (D95) are 0.11% and 0.83%, respectively for 3D fluoroscopic images

  9. 3D delivered dose assessment using a 4DCT-based motion model

    International Nuclear Information System (INIS)

    Cai, Weixing; Hurwitz, Martina H.; Williams, Christopher L.; Dhou, Salam; Berbeco, Ross I.; Mishra, Pankaj; Lewis, John H.; Seco, Joao

    2015-01-01

    Purpose: The purpose of this work is to develop a clinically feasible method of calculating actual delivered dose distributions for patients who have significant respiratory motion during the course of stereotactic body radiation therapy (SBRT). Methods: A novel approach was proposed to calculate the actual delivered dose distribution for SBRT lung treatment. This approach can be specified in three steps. (1) At the treatment planning stage, a patient-specific motion model is created from planning 4DCT data. This model assumes that the displacement vector field (DVF) of any respiratory motion deformation can be described as a linear combination of some basis DVFs. (2) During the treatment procedure, 2D time-varying projection images (either kV or MV projections) are acquired, from which time-varying “fluoroscopic” 3D images of the patient are reconstructed using the motion model. The DVF of each timepoint in the time-varying reconstruction is an optimized linear combination of basis DVFs such that the 2D projection of the 3D volume at this timepoint matches the projection image. (3) 3D dose distribution is computed for each timepoint in the set of 3D reconstructed fluoroscopic images, from which the total effective 3D delivered dose is calculated by accumulating deformed dose distributions. This approach was first validated using two modified digital extended cardio-torso (XCAT) phantoms with lung tumors and different respiratory motions. The estimated doses were compared to the dose that would be calculated for routine 4DCT-based planning and to the actual delivered dose that was calculated using “ground truth” XCAT phantoms at all timepoints. The approach was also tested using one set of patient data, which demonstrated the application of our method in a clinical scenario. Results: For the first XCAT phantom that has a mostly regular breathing pattern, the errors in 95% volume dose (D95) are 0.11% and 0.83%, respectively for 3D fluoroscopic images

  10. Dose rate reduction method for NMCA applied BWR plants

    International Nuclear Information System (INIS)

    Nagase, Makoto; Aizawa, Motohiro; Ito, Tsuyoshi; Hosokawa, Hideyuki; Varela, Juan; Caine, Thomas

    2012-09-01

    BRAC (BWR Radiation Assessment and Control) dose rate is used as an indicator of the incorporation of activated corrosion by products into BWR recirculation piping, which is known to be a significant contributor to dose rate received by workers during refueling outages. In order to reduce radiation exposure of the workers during the outage, it is desirable to keep BRAC dose rates as low as possible. After HWC was adopted to reduce IGSCC, a BRAC dose rate increase was observed in many plants. As a countermeasure to these rapid dose rate increases under HWC conditions, Zn injection was widely adopted in United States and Europe resulting in a reduction of BRAC dose rates. However, BRAC dose rates in several plants remain high, prompting the industry to continue to investigate methods to achieve further reductions. In recent years a large portion of the BWR fleet has adopted NMCA (NobleChem TM ) to enhance the hydrogen injection effect to suppress SCC. After NMCA, especially OLNC (On-Line NobleChem TM ), BRAC dose rates were observed to decrease. In some OLNC applied BWR plants this reduction was observed year after year to reach a new reduced equilibrium level. This dose rate reduction trends suggest the potential dose reduction might be obtained by the combination of Pt and Zn injection. So, laboratory experiments and in-plant tests were carried out to evaluate the effect of Pt and Zn on Co-60 deposition behaviour. Firstly, laboratory experiments were conducted to study the effect of noble metal deposition on Co deposition on stainless steel surfaces. Polished type 316 stainless steel coupons were prepared and some of them were OLNC treated in the test loop before the Co deposition test. Water chemistry conditions to simulate HWC were as follows: Dissolved oxygen, hydrogen and hydrogen peroxide were below 5 ppb, 100 ppb and 0 ppb (no addition), respectively. Zn was injected to target a concentration of 5 ppb. The test was conducted up to 1500 hours at 553 K. Test

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

    CERN Document Server

    Taki, M; Kobayashi, H; Yamaguchi, T

    2003-01-01

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

  12. Internal dosimetry hazard and risk assessments: methods and applications

    International Nuclear Information System (INIS)

    Roberts, G.A.

    2006-01-01

    Routine internal dose exposures are typically (in the UK nuclear industry) less than external dose exposures: however, the costs of internal dosimetry monitoring programmes can be significantly greater than those for external dosimetry. For this reason decisions on when to apply routine monitoring programmes, and the nature of these programmes, can be more critical than for external dosimetry programmes. This paper describes various methods for performing hazard and risk assessments which are being developed by RWE NUKEM Limited Approved Dosimetry Services to provide an indication when routine internal dosimetry monitoring should be considered. (author)

  13. Toward an organ based dose prescription method for the improved accuracy of murine dose in orthovoltage x-ray irradiators

    International Nuclear Information System (INIS)

    Belley, Matthew D.; Wang, Chu; Nguyen, Giao; Gunasingha, Rathnayaka; Chao, Nelson J.; Chen, Benny J.; Dewhirst, Mark W.; Yoshizumi, Terry T.

    2014-01-01

    Purpose: Accurate dosimetry is essential when irradiating mice to ensure that functional and molecular endpoints are well understood for the radiation dose delivered. Conventional methods of prescribing dose in mice involve the use of a single dose rate measurement and assume a uniform average dose throughout all organs of the entire mouse. Here, the authors report the individual average organ dose values for the irradiation of a 12, 23, and 33 g mouse on a 320 kVp x-ray irradiator and calculate the resulting error from using conventional dose prescription methods. Methods: Organ doses were simulated in the Geant4 application for tomographic emission toolkit using the MOBY mouse whole-body phantom. Dosimetry was performed for three beams utilizing filters A (1.65 mm Al), B (2.0 mm Al), and C (0.1 mm Cu + 2.5 mm Al), respectively. In addition, simulated x-ray spectra were validated with physical half-value layer measurements. Results: Average doses in soft-tissue organs were found to vary by as much as 23%–32% depending on the filter. Compared to filters A and B, filter C provided the hardest beam and had the lowest variation in soft-tissue average organ doses across all mouse sizes, with a difference of 23% for the median mouse size of 23 g. Conclusions: This work suggests a new dose prescription method in small animal dosimetry: it presents a departure from the conventional approach of assigninga single dose value for irradiation of mice to a more comprehensive approach of characterizing individual organ doses to minimize the error and uncertainty. In human radiation therapy, clinical treatment planning establishes the target dose as well as the dose distribution, however, this has generally not been done in small animal research. These results suggest that organ dose errors will be minimized by calibrating the dose rates for all filters, and using different dose rates for different organs

  14. Dose-stress synergism in cancer risk assessment

    International Nuclear Information System (INIS)

    Pop-Jordanova, N.; Pop-Jordanov, J.

    2001-01-01

    Our hypothesis is that the relatively low risk of cancer or leukaemia from depleted uranium, as predicted by the World Health Organization and the International Atomic Energy Agency, is a result of neglecting the synergism between physico-chemical agents and psychological stress agents (here shortly denoted as dose-stress synergism). We use the modified risk assessment model that comprises a psycho-somatic extension, originally developed by us for assessing the risks of energy sources. Our preliminary meta-analysis of animal and human studies on cancers confirmed the existence of stress effects, including the amplifying synergism. Consequently, the psychological stress can increase the probability of even small toxic chemical or ionizing radiation exposure to produce malignancy. Such dose-stress synergism might influence the health risks among military personnel and the residents in the highly stressful environment in the Balkans. Further investigation is needed to estimate the order of magnitude of these combined effects in particular circumstances. (Original)

  15. Dose Escalation Methods in Phase I Cancer Clinical Trials

    OpenAIRE

    Le Tourneau, Christophe; Lee, J. Jack; Siu, Lillian L.

    2009-01-01

    Phase I clinical trials are an essential step in the development of anticancer drugs. The main goal of these studies is to establish the recommended dose and/or schedule of new drugs or drug combinations for phase II trials. The guiding principle for dose escalation in phase I trials is to avoid exposing too many patients to subtherapeutic doses while preserving safety and maintaining rapid accrual. Here we review dose escalation methods for phase I trials, including the rule-based and model-...

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

    International Nuclear Information System (INIS)

    Urboniene, A.; Sadzeviciene, E.; Ziliukas, J.

    2015-01-01

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

  17. Re-assessment of dose from the Vinten extremity dosemeter

    International Nuclear Information System (INIS)

    O'Hagan, J.B.; Pearson, A.J.; Dutt, J.C.

    1989-01-01

    A procedure is described for re-assessing the dose from the Vinten extremity dosemeter using phototransferred thermoluminescence. The technique produces a linear response up to 50 Sv. The re-assessment efficiency is approximately 10% for the first re-assessment and 3-5% for the second re-assessment. The detection threshold values (at the 95% confidence level) are 3 mSv and 9 mSv respectively. (author)

  18. A Method for Correcting IMRT Optimizer Heterogeneity Dose Calculations

    International Nuclear Information System (INIS)

    Zacarias, Albert S.; Brown, Mellonie F.; Mills, Michael D.

    2010-01-01

    Radiation therapy treatment planning for volumes close to the patient's surface, in lung tissue and in the head and neck region, can be challenging for the planning system optimizer because of the complexity of the treatment and protected volumes, as well as striking heterogeneity corrections. Because it is often the goal of the planner to produce an isodose plan with uniform dose throughout the planning target volume (PTV), there is a need for improved planning optimization procedures for PTVs located in these anatomical regions. To illustrate such an improved procedure, we present a treatment planning case of a patient with a lung lesion located in the posterior right lung. The intensity-modulated radiation therapy (IMRT) plan generated using standard optimization procedures produced substantial dose nonuniformity across the tumor caused by the effect of lung tissue surrounding the tumor. We demonstrate a novel iterative method of dose correction performed on the initial IMRT plan to produce a more uniform dose distribution within the PTV. This optimization method corrected for the dose missing on the periphery of the PTV and reduced the maximum dose on the PTV to 106% from 120% on the representative IMRT plan.

  19. Pan-oral dose assessment: a comparative report of methodologies

    International Nuclear Information System (INIS)

    Shafford, J.; Pryor, M.; Hollaway, P.; Peet, D.; Oduko, J.

    2015-01-01

    National guidance from the Institute of Physics and Engineering in Medicine (IPEM Report 91) currently recommends that the patient dose for a pan-oral X-ray unit is measured as dose area product (DAP) replacing dose width product described in earlier guidance. An investigation identifying different methods available to carry out this measurement has been undertaken and errors in the methodologies analysed. It has been shown that there may be up to a 30 % variation in DAP measurement between methods. This paper recommends that where possible a DAP meter is used to measure the dose-area product from a pan-oral X-ray unit to give a direct DAP measurement. However, by using a solid-state dose measurement and film/ruler to calculate DAP the authors have established a conversion factor of 1.4. It is strongly recommended that wherever a DAP value is quoted the methodology used to obtain that value is also reported. (authors)

  20. A fast dose calculation method based on table lookup for IMRT optimization

    International Nuclear Information System (INIS)

    Wu Qiuwen; Djajaputra, David; Lauterbach, Marc; Wu Yan; Mohan, Radhe

    2003-01-01

    This note describes a fast dose calculation method that can be used to speed up the optimization process in intensity-modulated radiotherapy (IMRT). Most iterative optimization algorithms in IMRT require a large number of dose calculations to achieve convergence and therefore the total amount of time needed for the IMRT planning can be substantially reduced by using a faster dose calculation method. The method that is described in this note relies on an accurate dose calculation engine that is used to calculate an approximate dose kernel for each beam used in the treatment plan. Once the kernel is computed and saved, subsequent dose calculations can be done rapidly by looking up this kernel. Inaccuracies due to the approximate nature of the kernel in this method can be reduced by performing scheduled kernel updates. This fast dose calculation method can be performed more than two orders of magnitude faster than the typical superposition/convolution methods and therefore is suitable for applications in which speed is critical, e.g., in an IMRT optimization that requires a simulated annealing optimization algorithm or in a practical IMRT beam-angle optimization system. (note)

  1. In vivo assessment of the gastric mucosal tolerance dose after single fraction, small volume irradiation of liver malignancies by computed tomography-guided, high-dose-rate brachytherapy

    International Nuclear Information System (INIS)

    Streitparth, Florian; Pech, Maciej; Boehmig, Michael; Ruehl, Ricarda; Peters, Nils; Wieners, Gero; Steinberg, Johannes; Lopez-Haenninen, Enrique; Felix, Roland; Wust, Peter; Ricke, Jens

    2006-01-01

    Purpose: The aim of this study was to assess the tolerance dose of gastric mucosa for single-fraction computed tomography (CT)-guided, high-dose-rate (HDR) brachytherapy of liver malignancies. Methods and Materials: A total of 33 patients treated by CT-guided HDR brachytherapy of liver malignancies in segments II and/or III were included. Dose planning was performed upon a three-dimensional CT data set acquired after percutaneous applicator positioning. All patients received gastric protection post-treatment. For further analysis, the contours of the gastric wall were defined in every CT slice using Brachyvision Software. Dose-volume histograms were calculated for each treatment and correlated with clinical data derived from questionnaires assessing Common Toxicity Criteria (CTC). All patients presenting symptoms of upper GI toxicity were examined endoscopically. Results: Summarizing all patients the minimum dose applied to 1 ml of the gastric wall (D 1ml ) ranged from 6.3 to 34.2 Gy; median, 14.3 Gy. Toxicity was present in 18 patients (55%). We found nausea in 16 (69%), emesis in 9 (27%), cramping in 13 (39%), weight loss in 12 (36%), gastritis in 4 (12%), and ulceration in 5 patients (15%). We found a threshold dose D 1ml of 11 Gy for general gastric toxicity and 15.5 Gy for gastric ulceration verified by an univariate analysis (p = 0.01). Conclusions: For a single fraction, small volume irradiation we found in the upper abdomen a threshold dose D 1ml of 15.5 Gy for the clinical endpoint ulceration of the gastric mucosa. This in vivo assessment is in accordance with previously published tolerance data

  2. Method for simulating dose reduction in digital mammography using the Anscombe transformation

    OpenAIRE

    Borges, Lucas R.; de Oliveira, Helder C. R.; Nunes, Polyana F.; Bakic, Predrag R.; Maidment, Andrew D. A.; Vieira, Marcelo A. C.

    2016-01-01

    Purpose: This work proposes an accurate method for simulating dose reduction in digital mammography starting from a clinical image acquired with a standard dose. Methods: The method developed in this work consists of scaling a mammogram acquired at the standard radiation dose and adding signal-dependent noise. The algorithm accounts for specific issues relevant in digital mammography images, such as anisotropic noise, spatial variations in pixel gain, and the effect of dose reduction on the d...

  3. Objective method to report planner-independent skin/rib maximal dose in balloon-based high dose rate (HDR) brachytherapy for breast cancer

    International Nuclear Information System (INIS)

    Kim, Yongbok; Trombetta, Mark G.

    2011-01-01

    Purpose: An objective method was proposed and compared with a manual selection method to determine planner-independent skin and rib maximal dose in balloon-based high dose rate (HDR) brachytherapy planning. Methods: The maximal dose to skin and rib was objectively extracted from a dose volume histogram (DVH) of skin and rib volumes. A virtual skin volume was produced by expanding the skin surface in three dimensions (3D) external to the breast with a certain thickness in the planning computed tomography (CT) images. Therefore, the maximal dose to this volume occurs on the skin surface the same with a conventional manual selection method. The rib was also delineated in the planning CT images and its maximal dose was extracted from its DVH. The absolute (Abdiff=|D max Man -D max DVH |) and relative (Rediff[%]=100x(|D max Man -D max DVH |)/D max DVH ) maximal skin and rib dose differences between the manual selection method (D max Man ) and the objective method (D max DVH ) were measured for 50 balloon-based HDR (25 MammoSite and 25 Contura) patients. Results: The average±standard deviation of maximal dose difference was 1.67%±1.69% of the prescribed dose (PD). No statistical difference was observed between MammoSite and Contura patients for both Abdiff and Rediff[%] values. However, a statistically significant difference (p value max >90%) compared with lower dose range (D max <90%): 2.16%±1.93% vs 1.19%±1.25% with p value of 0.0049. However, the Rediff[%] analysis eliminated the inverse square factor and there was no statistically significant difference (p value=0.8931) between high and low dose ranges. Conclusions: The objective method using volumetric information of skin and rib can determine the planner-independent maximal dose compared with the manual selection method. However, the difference was <2% of PD, on average, if appropriate attention is paid to selecting a manual dose point in 3D planning CT images.

  4. Intravascular ultrasound based dose assessment in endovascular brachytherapy

    International Nuclear Information System (INIS)

    Catalano, Gianpiero; Tamburini, Vittorio; Colombo, Antonio; Nishida, Takahiro; Parisi, Giovanni; Mazzetta, Chiara; Orecchia, Roberto

    2003-01-01

    Background: the role of endovascular brachytherapy in restenosis prevention is well documented. Dose is usually prescribed at a fixed distance from the source axis by angiographic quantification of vessel diameter. Recently, intravascular ultrasound (IVUS) was introduced in dose prescription, allowing a better evaluation of the vessel anatomy. This study retrospectively explores the difference between prescription following angiographic vessel sizing and delivered dose calculated with IVUS. Methods and results: Seventeen lesions were studied with IVUS, identifying on irradiated segment, three sections on which measuring minimal and maximal distance from the centre of IVUS catheter to the adventitia; using dedicated software, corresponding doses were calculated. The dose ranged widely, with maximal and minimal values of 71.6 and 4.9 Gy; furthermore, heterogeneity in dose among different sections was observed. In the central section, the maximal dose was 206% of the one prescribed with the QCA model at 2 mm from the source axis, while the minimal dose was 96%. In proximal and distal sections, respective values were 182, 45, 243, and 122%. Conclusions: Our analysis confirmed the dose inhomogeneity delivered with an angiographic fixed-dose prescription strategy. A dose variation was found along the irradiated segment due to the differences in vessel thickness. IVUS emerged as an important tool in endovascular brachytherapy, especially for irregular-shaped vessels

  5. Late effects of low doses and dose rates

    International Nuclear Information System (INIS)

    Paretzke, H.G.

    1980-01-01

    This paper outlines the spectrum of problems and approaches used in work on the derivation of quantitative prognoses of late effects in man of low doses and dose rates. The origins of principal problems encountered in radiation risks assessments, definitions and explanations of useful quantities, methods of deriving risk factors from biological and epidemiological data, and concepts of risk evaluation and problems of acceptance are individually discussed

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

    International Nuclear Information System (INIS)

    Vasilev, G.; Khristova, M.

    1977-01-01

    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)

  7. Method for simulating dose reduction in digital mammography using the Anscombe transformation

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Lucas R., E-mail: lucas.rodrigues.borges@usp.br; Oliveira, Helder C. R. de; Nunes, Polyana F.; Vieira, Marcelo A. C. [Department of Electrical and Computer Engineering, São Carlos School of Engineering, University of São Paulo, 400 Trabalhador São-Carlense Avenue, São Carlos 13566-590 (Brazil); Bakic, Predrag R.; Maidment, Andrew D. A. [Department of Radiology, Hospital of the University of Pennsylvania, University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania 19104 (United States)

    2016-06-15

    Purpose: This work proposes an accurate method for simulating dose reduction in digital mammography starting from a clinical image acquired with a standard dose. Methods: The method developed in this work consists of scaling a mammogram acquired at the standard radiation dose and adding signal-dependent noise. The algorithm accounts for specific issues relevant in digital mammography images, such as anisotropic noise, spatial variations in pixel gain, and the effect of dose reduction on the detective quantum efficiency. The scaling process takes into account the linearity of the system and the offset of the detector elements. The inserted noise is obtained by acquiring images of a flat-field phantom at the standard radiation dose and at the simulated dose. Using the Anscombe transformation, a relationship is created between the calculated noise mask and the scaled image, resulting in a clinical mammogram with the same noise and gray level characteristics as an image acquired at the lower-radiation dose. Results: The performance of the proposed algorithm was validated using real images acquired with an anthropomorphic breast phantom at four different doses, with five exposures for each dose and 256 nonoverlapping ROIs extracted from each image and with uniform images. The authors simulated lower-dose images and compared these with the real images. The authors evaluated the similarity between the normalized noise power spectrum (NNPS) and power spectrum (PS) of simulated images and real images acquired with the same dose. The maximum relative error was less than 2.5% for every ROI. The added noise was also evaluated by measuring the local variance in the real and simulated images. The relative average error for the local variance was smaller than 1%. Conclusions: A new method is proposed for simulating dose reduction in clinical mammograms. In this method, the dependency between image noise and image signal is addressed using a novel application of the Anscombe

  8. Method for simulating dose reduction in digital mammography using the Anscombe transformation

    International Nuclear Information System (INIS)

    Borges, Lucas R.; Oliveira, Helder C. R. de; Nunes, Polyana F.; Vieira, Marcelo A. C.; Bakic, Predrag R.; Maidment, Andrew D. A.

    2016-01-01

    Purpose: This work proposes an accurate method for simulating dose reduction in digital mammography starting from a clinical image acquired with a standard dose. Methods: The method developed in this work consists of scaling a mammogram acquired at the standard radiation dose and adding signal-dependent noise. The algorithm accounts for specific issues relevant in digital mammography images, such as anisotropic noise, spatial variations in pixel gain, and the effect of dose reduction on the detective quantum efficiency. The scaling process takes into account the linearity of the system and the offset of the detector elements. The inserted noise is obtained by acquiring images of a flat-field phantom at the standard radiation dose and at the simulated dose. Using the Anscombe transformation, a relationship is created between the calculated noise mask and the scaled image, resulting in a clinical mammogram with the same noise and gray level characteristics as an image acquired at the lower-radiation dose. Results: The performance of the proposed algorithm was validated using real images acquired with an anthropomorphic breast phantom at four different doses, with five exposures for each dose and 256 nonoverlapping ROIs extracted from each image and with uniform images. The authors simulated lower-dose images and compared these with the real images. The authors evaluated the similarity between the normalized noise power spectrum (NNPS) and power spectrum (PS) of simulated images and real images acquired with the same dose. The maximum relative error was less than 2.5% for every ROI. The added noise was also evaluated by measuring the local variance in the real and simulated images. The relative average error for the local variance was smaller than 1%. Conclusions: A new method is proposed for simulating dose reduction in clinical mammograms. In this method, the dependency between image noise and image signal is addressed using a novel application of the Anscombe

  9. Improvement of the following accident dose assessment system

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. A Unified Probabilistic Framework for Dose-Response Assessment of Human Health Effects.

    Science.gov (United States)

    Chiu, Weihsueh A; Slob, Wout

    2015-12-01

    When chemical health hazards have been identified, probabilistic dose-response assessment ("hazard characterization") quantifies uncertainty and/or variability in toxicity as a function of human exposure. Existing probabilistic approaches differ for different types of endpoints or modes-of-action, lacking a unifying framework. We developed a unified framework for probabilistic dose-response assessment. We established a framework based on four principles: a) individual and population dose responses are distinct; b) dose-response relationships for all (including quantal) endpoints can be recast as relating to an underlying continuous measure of response at the individual level; c) for effects relevant to humans, "effect metrics" can be specified to define "toxicologically equivalent" sizes for this underlying individual response; and d) dose-response assessment requires making adjustments and accounting for uncertainty and variability. We then derived a step-by-step probabilistic approach for dose-response assessment of animal toxicology data similar to how nonprobabilistic reference doses are derived, illustrating the approach with example non-cancer and cancer datasets. Probabilistically derived exposure limits are based on estimating a "target human dose" (HDMI), which requires risk management-informed choices for the magnitude (M) of individual effect being protected against, the remaining incidence (I) of individuals with effects ≥ M in the population, and the percent confidence. In the example datasets, probabilistically derived 90% confidence intervals for HDMI values span a 40- to 60-fold range, where I = 1% of the population experiences ≥ M = 1%-10% effect sizes. Although some implementation challenges remain, this unified probabilistic framework can provide substantially more complete and transparent characterization of chemical hazards and support better-informed risk management decisions.

  11. Retrospective methods to estimate radiation dose at the site of breast cancer development after Hodgkin lymphoma radiotherapy

    Directory of Open Access Journals (Sweden)

    Nicola S. Russell

    2017-12-01

    Full Text Available Background: An increased risk of breast cancer following radiotherapy for Hodgkin lymphoma (HL has now been robustly established. In order to estimate the dose–response relationship more accurately, and to aid clinical decision making, a retrospective estimation of the radiation dose delivered to the site of the subsequent breast cancer is required. Methods: For 174 Dutch and 170 UK female patients with breast cancer following HL treatment, the 3-dimensional position of the breast cancer in the affected breast was determined and transferred onto a CT-based anthropomorphic phantom. Using a radiotherapy treatment planning system the dose distribution on the CT-based phantom was calculated for the 46 different radiation treatment field set-ups used in the study population. The estimated dose at the centre of the breast cancer, and a margin to reflect dose uncertainty were determined on the basis of the location of the tumour and the isodose lines from the treatment planning. We assessed inter-observer variation and for 47 patients we compared the results with a previously applied dosimetry method. Results: The estimated median point dose at the centre of the breast cancer location was 29.75 Gy (IQR 5.8–37.2, or about 75% of the prescribed radiotherapy dose. The median dose uncertainty range was 5.97 Gy. We observed an excellent inter-observer variation (ICC 0.89 (95% CI: 0.74–0.95. The absolute agreement intra-class correlation coefficient (ICC for inter-method variation was 0.59 (95% CI: 0.37–0.75, indicating (nearly good agreement. There were no systematic differences in the dose estimates between observers or methods. Conclusion: Estimates of the dose at the point of a subsequent breast cancer show good correlation between methods, but the retrospective nature of the estimates means that there is always some uncertainty to be accounted for. Keywords: Retrospective dosimetry, Hodgkin lymphoma, Breast carcinogenesis

  12. Methods for calculating dose conversion coefficients for terrestrial and aquatic biota

    International Nuclear Information System (INIS)

    Ulanovsky, A.; Proehl, G.; Gomez-Ros, J.M.

    2008-01-01

    Plants and animals may be exposed to ionizing radiation from radionuclides in the environment. This paper describes the underlying data and assumptions to assess doses to biota due to internal and external exposure for a wide range of masses and shapes living in various habitats. A dosimetric module is implemented which is a user-friendly and flexible possibility to assess dose conversion coefficients for aquatic and terrestrial biota. The dose conversion coefficients have been derived for internal and various external exposure scenarios. The dosimetric model is linked to radionuclide decay and emission database, compatible with the ICRP Publication 38, thus providing a capability to compute dose conversion coefficients for any nuclide from the database and its daughter nuclides. The dosimetric module has been integrated into the ERICA Tool, but it can also be used as a stand-alone version

  13. Monitoring of high-radiation areas for the assessment of operational and body doses

    International Nuclear Information System (INIS)

    Chen, T.J.; Tung, C.J.; Yeh, W.W.; Liao, R.Y.

    2004-01-01

    The International Commission on Radiological Protection (ICRP) recommended a system of dose limits for the protection of ionizing radiation. This system was established based on the effective dose, E, and the equivalent dose to an organ or tissue, H T , to assess stochastic and deterministic effects. In radiation protection monitoring for external radiation, operational doses such as the deep dose equivalent index, H I,d , shallow dose equivalent index, H I,s , ambient dose equivalent [1,4-6], H*, directional dose equivalent, H', individual dose equivalent-penetrating, H p , and individual dose equivalent-superficial, H s , are implemented. These quantities are defined in an International Commission on Radiation Units and Measurements (ICRU) sphere and in an anthropomorphic phantom under simplified irradiation conditions. They are useful when equivalent doses are below the corresponding limits. In the case of equivalent doses far below the limits, the exposure or air kerma is commonly applied. For workers exposed to high levels of radiation, accurate assessments of effective doses and equivalent doses may be needed in order to acquire legal and health information. In the general principles of monitoring for radiation protection of workers, ICRP recommended that: 'A graduated response is advocated for the monitoring of the workplace and for individual monitoring - graduated in the sense that a greater degree of monitoring is deemed to be necessary as doses increase of as unpredictability increases. Gradually more complex or realistic procedures should be adopted as doses become higher. Thus, at low dose equivalents (corresponding say to those within Working Condition B) dosimetric quantities might be used directly to assess exposure, since accuracy is not crucial. At intermediate dose equivalents (corresponding say to Working Condition A and slight overexposures) somewhat greater accuracy is warranted, and the conversion coefficients from dosimetric to radiation

  14. Methods of determining the effective dose in dental radiology

    International Nuclear Information System (INIS)

    Thilander-Klang, A.; Helmrot, E.

    2010-01-01

    A wide variety of X-ray equipment is used today in dental radiology, including intra-oral, ortho-pan-tomographic, cephalo-metric, cone-beam computed tomography (CBCT) and computed tomography (CT). This raises the question of how the radiation risks resulting from different kinds of examinations should be compared. The risk to the patient is usually expressed in terms of effective dose. However, it is difficult to determine its reliability, and it is difficult to make comparisons, especially when different modalities are used. The classification of the new CBCT units is also problematic as they are sometimes classified as CT units. This will lead to problems in choosing the best dosimetric method, especially when the examination geometry resembles more on an ordinary ortho-pan-tomographic examination, as the axis of rotation is not at the centre of the patient, and small radiation field sizes are used. The purpose of this study was to present different methods for the estimation of the effective dose from the equipment currently used in dental radiology, and to discuss their limitations. The methods are compared based on commonly used measurable and computable dose quantities, and their reliability in the estimation of the effective dose. (authors)

  15. Robust EM Continual Reassessment Method in Oncology Dose Finding

    Science.gov (United States)

    Yuan, Ying; Yin, Guosheng

    2012-01-01

    The continual reassessment method (CRM) is a commonly used dose-finding design for phase I clinical trials. Practical applications of this method have been restricted by two limitations: (1) the requirement that the toxicity outcome needs to be observed shortly after the initiation of the treatment; and (2) the potential sensitivity to the prespecified toxicity probability at each dose. To overcome these limitations, we naturally treat the unobserved toxicity outcomes as missing data, and use the expectation-maximization (EM) algorithm to estimate the dose toxicity probabilities based on the incomplete data to direct dose assignment. To enhance the robustness of the design, we propose prespecifying multiple sets of toxicity probabilities, each set corresponding to an individual CRM model. We carry out these multiple CRMs in parallel, across which model selection and model averaging procedures are used to make more robust inference. We evaluate the operating characteristics of the proposed robust EM-CRM designs through simulation studies and show that the proposed methods satisfactorily resolve both limitations of the CRM. Besides improving the MTD selection percentage, the new designs dramatically shorten the duration of the trial, and are robust to the prespecification of the toxicity probabilities. PMID:22375092

  16. Concept and approaches used in assessing individual and collective doses from releases of radioactive effluents

    International Nuclear Information System (INIS)

    1988-06-01

    To guide on the applications of the principles for limiting radioactive releases contained in Safety Series 77, the Agency is in the process of preparing a number of safety guides. The first one is this present document which deals with the principal aspects of the methods for the assessment of the individual and collective dose. It aims at giving a general guidance to those responsible for establishing programmes for the determination of individual doses as well as collective doses in connection with licensing a site for a nuclear installation. The document is concerned with the principles applied for calculating individual and collective doses from routine releases of radionuclides to the atmosphere and hydrosphere but not releases directly to the geosphere, as in waste management. These areas will be covered by other Agency publications. 75 refs, figs and tabs

  17. Dose assessment considering evolution of the biosphere

    International Nuclear Information System (INIS)

    Karlsson, Sara; Bergstroem, Ulla

    2002-01-01

    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)

  18. Proton dose distribution measurements using a MOSFET detector with a simple dose-weighted correction method for LET effects.

    Science.gov (United States)

    Kohno, Ryosuke; Hotta, Kenji; Matsuura, Taeko; Matsubara, Kana; Nishioka, Shie; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

    2011-04-04

    We experimentally evaluated the proton beam dose reproducibility, sensitivity, angular dependence and depth-dose relationships for a new Metal Oxide Semiconductor Field Effect Transistor (MOSFET) detector. The detector was fabricated with a thinner oxide layer and was operated at high-bias voltages. In order to accurately measure dose distributions, we developed a practical method for correcting the MOSFET response to proton beams. The detector was tested by examining lateral dose profiles formed by protons passing through an L-shaped bolus. The dose reproducibility, angular dependence and depth-dose response were evaluated using a 190 MeV proton beam. Depth-output curves produced using the MOSFET detectors were compared with results obtained using an ionization chamber (IC). Since accurate measurements of proton dose distribution require correction for LET effects, we developed a simple dose-weighted correction method. The correction factors were determined as a function of proton penetration depth, or residual range. The residual proton range at each measurement point was calculated using the pencil beam algorithm. Lateral measurements in a phantom were obtained for pristine and SOBP beams. The reproducibility of the MOSFET detector was within 2%, and the angular dependence was less than 9%. The detector exhibited a good response at the Bragg peak (0.74 relative to the IC detector). For dose distributions resulting from protons passing through an L-shaped bolus, the corrected MOSFET dose agreed well with the IC results. Absolute proton dosimetry can be performed using MOSFET detectors to a precision of about 3% (1 sigma). A thinner oxide layer thickness improved the LET in proton dosimetry. By employing correction methods for LET dependence, it is possible to measure absolute proton dose using MOSFET detectors.

  19. Calculation of dose conversion factors for doses in the fingernails to organ doses at external gamma irradiation in air

    International Nuclear Information System (INIS)

    Khailov, A.M.; Ivannikov, A.I.; Skvortsov, V.G.; Stepanenko, V.F.; Orlenko, S.P.; Flood, A.B.; Williams, B.B.; Swartz, H.M.

    2015-01-01

    Absorbed doses to fingernails and organs were calculated for a set of homogenous external gamma-ray irradiation geometries in air. The doses were obtained by stochastic modeling of the ionizing particle transport (Monte Carlo method) for a mathematical human phantom with arms and hands placed loosely along the sides of the body. The resulting dose conversion factors for absorbed doses in fingernails can be used to assess the dose distribution and magnitude in practical dose reconstruction problems. For purposes of estimating dose in a large population exposed to radiation in order to triage people for treatment of acute radiation syndrome, the calculated data for a range of energies having a width of from 0.05 to 3.5 MeV were used to convert absorbed doses in fingernails to corresponding doses in organs and the whole body as well as the effective dose. Doses were assessed based on assumed rates of radioactive fallout at different time periods following a nuclear explosion. - Highlights: • Elemental composition and density of nails were determined. • MIRD-type mathematical human phantom with arms and hands was created. • Organ doses and doses to nails were calculated for external photon exposure in air. • Effective dose and nail doses values are close for rotational and soil surface exposures.

  20. Improvement of dose evaluation method for employees at severe accident

    International Nuclear Information System (INIS)

    Onda, Takashi; Yoshida, Yoshitaka; Kudo, Seiichi; Nishimura, Kazuya

    2003-01-01

    It is expected that the selection of access routes for employees who engage in emergency work at a severe accident in a nuclear power plant makes a difference in their radiation dose values. In order to examine how much difference arises in the dose by the selection of the access routes, in the case of a severe accident in a pressurized water reactor plant, we improved the method to obtain the dose for employees and expanded the analyzing system. By the expansion of the system and the improvement of the method, we have realized the followings: (1) in the whole plant area, the dose evaluation is possible, (2) the efficiency of calculation is increased by the reduction of the number of radiation sources, etc, and (3) the function is improved by introduction of the sky shine calculation into the highest floor, etc. The improved system clarifies the followings: (1) the doses change by selected access routes, and this system can give the difference in the doses quantitatively, and (2) in order to suppress the dose, it is effective to choose the most adequate access route for the employees. (author)

  1. Dose rate evaluation of body phantom behind ITER bio-shield wall using Monte Carlo method

    International Nuclear Information System (INIS)

    Beheshti, A.; Jabbari, I.; Karimian, A.; Abdi, M.

    2012-01-01

    One of the most critical risks to humans in reactors environment is radiation exposure. Around the tokamak hall personnel are exposed to a wide range of particles, including neutrons and photons. International Thermonuclear Experimental Reactor (ITER) is a nuclear fusion research and engineering project, which is the most advanced experimental tokamak nuclear fusion reactor. Dose rates assessment and photon radiation due to the neutron activation of the solid structures in ITER is important from the radiological point of view. Therefore, the dosimetry considered in this case is based on the Deuterium-Tritium (DT) plasma burning with neutrons production rate at 14.1 MeV. The aim of this study is assessment the amount of radiation behind bio-shield wall that a human received during normal operation of ITER by considering neutron activation and delay gammas. To achieve the aim, the ITER system and its components were simulated by Monte Carlo method. Also to increase the accuracy and precision of the absorbed dose assessment a body phantom were considered in the simulation. The results of this research showed that total dose rates level near the outside of bio-shield wall of the tokamak hall is less than ten percent of the annual occupational dose limits during normal operation of ITER and It is possible to learn how long human beings can remain in that environment before the body absorbs dangerous levels of radiation. (authors)

  2. Repeated dose titration versus age-based method in electroconvulsive therapy: a pilot study

    NARCIS (Netherlands)

    Aten, J.J.; Oudega, M.L.; van Exel, E.; Stek, M.L.; van Waarde, J.A.

    2015-01-01

    In electroconvulsive therapy (ECT), a dose titration method (DTM) was suggested to be more individualized and therefore more accurate than formula-based dosing methods. A repeated DTM (every sixth session and dose adjustment accordingly) was compared to an age-based method (ABM) regarding treatment

  3. JADA: a graphical user interface for comprehensive internal dose assessment in nuclear medicine.

    Science.gov (United States)

    Grimes, Joshua; Uribe, Carlos; Celler, Anna

    2013-07-01

    The main objective of this work was to design a comprehensive dosimetry package that would keep all aspects of internal dose calculation within the framework of a single software environment and that would be applicable for a variety of dose calculation approaches. Our MATLAB-based graphical user interface (GUI) can be used for processing data obtained using pure planar, pure SPECT, or hybrid planar/SPECT imaging. Time-activity data for source regions are obtained using a set of tools that allow the user to reconstruct SPECT images, load images, coregister a series of planar images, and to perform two-dimensional and three-dimensional image segmentation. Curve fits are applied to the acquired time-activity data to construct time-activity curves, which are then integrated to obtain time-integrated activity coefficients. Subsequently, dose estimates are made using one of three methods. The organ level dose calculation subGUI calculates mean organ doses that are equivalent to dose assessment performed by OLINDA/EXM. Voxelized dose calculation options, which include the voxel S value approach and Monte Carlo simulation using the EGSnrc user code DOSXYZnrc, are available within the process 3D image data subGUI. The developed internal dosimetry software package provides an assortment of tools for every step in the dose calculation process, eliminating the need for manual data transfer between programs. This saves times and minimizes user errors, while offering a versatility that can be used to efficiently perform patient-specific internal dose calculations in a variety of clinical situations.

  4. Deterministic absorbed dose estimation in computed tomography using a discrete ordinates method

    International Nuclear Information System (INIS)

    Norris, Edward T.; Liu, Xin; Hsieh, Jiang

    2015-01-01

    Purpose: Organ dose estimation for a patient undergoing computed tomography (CT) scanning is very important. Although Monte Carlo methods are considered gold-standard in patient dose estimation, the computation time required is formidable for routine clinical calculations. Here, the authors instigate a deterministic method for estimating an absorbed dose more efficiently. Methods: Compared with current Monte Carlo methods, a more efficient approach to estimating the absorbed dose is to solve the linear Boltzmann equation numerically. In this study, an axial CT scan was modeled with a software package, Denovo, which solved the linear Boltzmann equation using the discrete ordinates method. The CT scanning configuration included 16 x-ray source positions, beam collimators, flat filters, and bowtie filters. The phantom was the standard 32 cm CT dose index (CTDI) phantom. Four different Denovo simulations were performed with different simulation parameters, including the number of quadrature sets and the order of Legendre polynomial expansions. A Monte Carlo simulation was also performed for benchmarking the Denovo simulations. A quantitative comparison was made of the simulation results obtained by the Denovo and the Monte Carlo methods. Results: The difference in the simulation results of the discrete ordinates method and those of the Monte Carlo methods was found to be small, with a root-mean-square difference of around 2.4%. It was found that the discrete ordinates method, with a higher order of Legendre polynomial expansions, underestimated the absorbed dose near the center of the phantom (i.e., low dose region). Simulations of the quadrature set 8 and the first order of the Legendre polynomial expansions proved to be the most efficient computation method in the authors’ study. The single-thread computation time of the deterministic simulation of the quadrature set 8 and the first order of the Legendre polynomial expansions was 21 min on a personal computer

  5. Method for simulating dose reduction in digital mammography using the Anscombe transformation.

    Science.gov (United States)

    Borges, Lucas R; Oliveira, Helder C R de; Nunes, Polyana F; Bakic, Predrag R; Maidment, Andrew D A; Vieira, Marcelo A C

    2016-06-01

    This work proposes an accurate method for simulating dose reduction in digital mammography starting from a clinical image acquired with a standard dose. The method developed in this work consists of scaling a mammogram acquired at the standard radiation dose and adding signal-dependent noise. The algorithm accounts for specific issues relevant in digital mammography images, such as anisotropic noise, spatial variations in pixel gain, and the effect of dose reduction on the detective quantum efficiency. The scaling process takes into account the linearity of the system and the offset of the detector elements. The inserted noise is obtained by acquiring images of a flat-field phantom at the standard radiation dose and at the simulated dose. Using the Anscombe transformation, a relationship is created between the calculated noise mask and the scaled image, resulting in a clinical mammogram with the same noise and gray level characteristics as an image acquired at the lower-radiation dose. The performance of the proposed algorithm was validated using real images acquired with an anthropomorphic breast phantom at four different doses, with five exposures for each dose and 256 nonoverlapping ROIs extracted from each image and with uniform images. The authors simulated lower-dose images and compared these with the real images. The authors evaluated the similarity between the normalized noise power spectrum (NNPS) and power spectrum (PS) of simulated images and real images acquired with the same dose. The maximum relative error was less than 2.5% for every ROI. The added noise was also evaluated by measuring the local variance in the real and simulated images. The relative average error for the local variance was smaller than 1%. A new method is proposed for simulating dose reduction in clinical mammograms. In this method, the dependency between image noise and image signal is addressed using a novel application of the Anscombe transformation. NNPS, PS, and local noise

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-11-01

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

  7. 78 FR 25440 - Request for Information and Citations on Methods for Cumulative Risk Assessment

    Science.gov (United States)

    2013-05-01

    ... Citations on Methods for Cumulative Risk Assessment AGENCY: Office of the Science Advisor, Environmental... influence exposures, dose-response or risk/hazard posed by environmental contaminant exposures, and methods... who wish to receive further information about submitting information on methods for cumulative risk...

  8. SU-E-T-329: Dosimetric Impact of Implementing Metal Artifact Reduction Methods and Metal Energy Deposition Kernels for Photon Dose Calculations

    International Nuclear Information System (INIS)

    Huang, J; Followill, D; Howell, R; Liu, X; Mirkovic, D; Stingo, F; Kry, S

    2015-01-01

    Purpose: To investigate two strategies for reducing dose calculation errors near metal implants: use of CT metal artifact reduction methods and implementation of metal-based energy deposition kernels in the convolution/superposition (C/S) method. Methods: Radiochromic film was used to measure the dose upstream and downstream of titanium and Cerrobend implants. To assess the dosimetric impact of metal artifact reduction methods, dose calculations were performed using baseline, uncorrected images and metal artifact reduction Methods: Philips O-MAR, GE’s monochromatic gemstone spectral imaging (GSI) using dual-energy CT, and GSI imaging with metal artifact reduction software applied (MARs).To assess the impact of metal kernels, titanium and silver kernels were implemented into a commercial collapsed cone C/S algorithm. Results: The CT artifact reduction methods were more successful for titanium than Cerrobend. Interestingly, for beams traversing the metal implant, we found that errors in the dimensions of the metal in the CT images were more important for dose calculation accuracy than reduction of imaging artifacts. The MARs algorithm caused a distortion in the shape of the titanium implant that substantially worsened the calculation accuracy. In comparison to water kernel dose calculations, metal kernels resulted in better modeling of the increased backscatter dose at the upstream interface but decreased accuracy directly downstream of the metal. We also found that the success of metal kernels was dependent on dose grid size, with smaller calculation voxels giving better accuracy. Conclusion: Our study yielded mixed results, with neither the metal artifact reduction methods nor the metal kernels being globally effective at improving dose calculation accuracy. However, some successes were observed. The MARs algorithm decreased errors downstream of Cerrobend by a factor of two, and metal kernels resulted in more accurate backscatter dose upstream of metals. Thus

  9. Calculation of Blood Dose in Patients Treated With 131I Using MIRD, Imaging, and Blood Sampling Methods.

    Science.gov (United States)

    Piruzan, Elham; Haghighatafshar, Mahdi; Faghihi, Reza; Entezarmahdi, Seyed Mohammad

    2016-03-01

    Radioiodine therapy is known as the most effective treatment of differentiated thyroid carcinoma (DTC) to ablate remnant thyroid tissue after surgery. In patients with DTC treated with radioiodine, internal radiation dosimetry of radioiodine is useful for radiation risk assessment. The aim of this study is to describe a method to estimate the absorbed dose to the blood using medical internal radiation dosimetry methods. In this study, 23 patients with DTC with different administrated activities, 3.7, 4.62, and 5.55 GBq after thyroidectomy, were randomly selected. Blood dosimetry of treated patients was performed with external whole body counting using a dual-head gamma camera imaging device and also with blood sample activity measurements using a dose calibrator. Absorbed dose to the blood was measured at 2, 6, 12, 24, 48, and 96 hours after the administration of radioiodine with the 2 methods. Based on the results of whole body counting and blood sample activity dose rate measurements, 96 hours after administration of 3.7, 4.62, and 5.55 GBq of radioiodine, absorbed doses to patients' blood were 0.65 ± 0.20, 0.67 ± 0.18, 0.79 ± 0.51 Gy, respectively. Increasing radioiodine activity from 3.7 to 5.55 GBq increased blood dose significantly, while there was no significant difference in blood dose between radioiodine dosages of 3.7 and 4.62 GBq. Our results revealed a significant correlation between the blood absorbed dose and blood sample activity and between the blood absorbed dose and whole body counts 24 to 48 hours after the administration of radioiodine.

  10. The assessment of the carcinogenic effects of low dose radiation

    International Nuclear Information System (INIS)

    Tubiana, M.; Lafuma, J.; Masse, R.; Latarjet, R.

    1991-01-01

    It is concluded that the exclusion of patients for the purposes of risk estimation, the choice of a particular relative risk projection model and of a dose reduction factor equal to 2 are all decisions which result in an overestimation of the actual risk. These choices can be understood when the aim is radiation protection and when it is safer to overestimate the risk; however, they are open to criticism if the aim is a realistic assessment of the risk. For low doses, below 50 mSv/year, and when all causes of uncertainty are added, the actual risk might be markedly lower than the risk estimated with the ICRP (1991) carcinogenic risk coefficient and the DRF estimated by ICRP. Future studies should aim at providing direct and more precise assessments of risk coefficients in the low dose region. (Author)

  11. Design study on dose evaluation method for employees at severe accident

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Yoshitaka; Irie, Takashi; Kohriyama, Tamio [Institute of Nuclear Safety Systems Inc., Mihama, Fukui (Japan); Kudo, Seiichi [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Nishimura, Kazuya [Computer Software Development Co., Ltd., Tokyo (Japan)

    2001-09-01

    When we assume a severe accident in a nuclear power plant, it is required for rescue activity in the plant, accident management, repair work of failed parts and evaluation of employees to obtain radiation dose rate distribution or map in the plant and estimated dose value for the above works. However it might be difficult to obtain them accurately along the progress of the accident, because radiation monitors are not always installed in the areas where the accident management is planned or the repair work is thought for safety-related equipments. In this work, we analyzed diffusion of radioactive materials in case of a severe accident in a pressurized water reactor plant, investigated a method to obtain radiation dose rate in the plant from estimated radioactive sources, made up a prototype analyzing system by modeling a specific part of components and buildings in the plant from this design study on dose evaluation method for employees at severe accident, and then evaluated its availability. As a result, we obtained the followings: (1) A new dose evaluation method was established to predict the radiation dose rate in any point in the plant during a severe accident scenario. (2) This evaluation of total dose including moving route and time for the accident management and the repair work is useful for estimating radiation dose limit for these actions of the employees. (3) The radiation dose rate map is effective for identifying high radiation areas and for choosing a route with lower radiation dose rate. (author)

  12. Design study on dose evaluation method for employees at severe accident

    International Nuclear Information System (INIS)

    Yoshida, Yoshitaka; Irie, Takashi; Kohriyama, Tamio; Kudo, Seiichi; Nishimura, Kazuya

    2001-01-01

    When we assume a severe accident in a nuclear power plant, it is required for rescue activity in the plant, accident management, repair work of failed parts and evaluation of employees to obtain radiation dose rate distribution or map in the plant and estimated dose value for the above works. However it might be difficult to obtain them accurately along the progress of the accident, because radiation monitors are not always installed in the areas where the accident management is planned or the repair work is thought for safety-related equipments. In this work, we analyzed diffusion of radioactive materials in case of a severe accident in a pressurized water reactor plant, investigated a method to obtain radiation dose rate in the plant from estimated radioactive sources, made up a prototype analyzing system by modeling a specific part of components and buildings in the plant from this design study on dose evaluation method for employees at severe accident, and then evaluated its availability. As a result, we obtained the followings: (1) A new dose evaluation method was established to predict the radiation dose rate in any point in the plant during a severe accident scenario. (2) This evaluation of total dose including moving route and time for the accident management and the repair work is useful for estimating radiation dose limit for these actions of the employees. (3) The radiation dose rate map is effective for identifying high radiation areas and for choosing a route with lower radiation dose rate. (author)

  13. Manual method for dose calculation in gynecologic brachytherapy; Metodo manual para o calculo de doses em braquiterapia ginecologica

    Energy Technology Data Exchange (ETDEWEB)

    Vianello, Elizabeth A.; Almeida, Carlos E. de [Instituto Nacional do Cancer, Rio de Janeiro, RJ (Brazil); Biaggio, Maria F. de [Universidade do Estado, Rio de Janeiro, RJ (Brazil)

    1998-09-01

    This paper describes a manual method for dose calculation in brachytherapy of gynecological tumors, which allows the calculation of the doses at any plane or point of clinical interest. This method uses basic principles of vectorial algebra and the simulating orthogonal films taken from the patient with the applicators and dummy sources in place. The results obtained with method were compared with the values calculated with the values calculated with the treatment planning system model Theraplan and the agreement was better than 5% in most cases. The critical points associated with the final accuracy of the proposed method is related to the quality of the image and the appropriate selection of the magnification factors. This method is strongly recommended to the radiation oncology centers where are no treatment planning systems available and the dose calculations are manually done. (author) 10 refs., 5 figs.

  14. Radiological dose assessment from the operation of Daeduk nuclear facilities

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Choi, Young Gil [Korea Atomic Energy Research Institute, Taejon (Korea)

    2000-02-01

    The objective of this project is to assure the public acceptance for nuclear facilities, and the environmental safety from the operation of Daeduk nuclear facilities, such as HANARO research reactor, nuclear fuel processing facilities and others. For identifying the integrity of their facilities, the maximum individual doses at the site boundary and on the areas with high population density were assessed. Also, the collective doses within radius 80 km from the site were assessed. The radiation impacts for residents around the site from the operation of Daeduk nuclear facilities in 1999 were neglectable. 8 refs., 10 figs., 27 tabs. (Author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Zodiates, A.M.; Willcock, A. [Cheshire, England (United Kingdom)

    1995-03-01

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

  16. Dose assessment of an accidental exposure at IPNS

    International Nuclear Information System (INIS)

    Torres, M.M.C.

    1996-01-01

    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 rates ranged from 550 mrem/min to 2,850 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. Cytogenic analyses of blood samples detected no positive exposure. The recommended TEDE rate was 158 mrem/min. The TEDE was 750 mrem

  17. MODARIA WG5: Towards a practical guidance for including uncertainties in the results of dose assessment of routine releases

    Energy Technology Data Exchange (ETDEWEB)

    Mora, Juan C. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas - CIEMAT (Spain); Telleria, Diego [International Atomic Energy Agency - IAEA (Austria); Al Neaimi, Ahmed [Emirates Nuclear Energy Corporation - ENEC (United Arab Emirates); Blixt Buhr, Anna Ma [Vattenfall AB (Sweden); Bonchuk, Iurii [Radiation Protection Institute - RPI (Ukraine); Chouhan, Sohan [Atomic Energy of Canada Limited - AECL (Canada); Chyly, Pavol [SE-VYZ (Slovakia); Curti, Adriana R. [Autoridad Regulatoria Nuclear - ARN (Argentina); Da Costa, Dejanira [Instituto de Radioprotecao e Dosimetria - IRD (Brazil); Duran, Juraj [VUJE Inc (Slovakia); Galeriu, Dan [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH (Romania); Haegg, Ann- Christin; Lager, Charlotte [Swedish Radiation Safety Authority - SSM (Sweden); Heling, Rudie [Nuclear Research and Consultancy Group - NRG (Netherlands); Ivanis, Goran; Shen, Jige [Ecometrix Incorporated (Canada); Iosjpe, Mikhail [Norwegian Radiation Protection Authority - NRPA (Norway); Krajewski, Pawel M. [Central Laboratory for Radiological Protection - CLOR (Poland); Marang, Laura; Vermorel, Fabien [Electricite de France - EdF (France); Mourlon, Christophe [Institut de Radioprotection et de Surete Nucleaire - IRSN (France); Perez, Fabricio F. [Belgian Nuclear Research Centre - SCK (Belgium); Woodruffe, Andrew [Federal Authority for Nuclear Regulation - FANR (United Arab Emirates); Zorko, Benjamin [Jozef Stefan Institute (Slovenia)

    2014-07-01

    MODARIA (Modelling and Data for Radiological Impact Assessments) project was launched in 2012 with the aim of improving the capabilities in radiation dose assessment by means of acquisition of improved data for model testing, model testing and comparison, reaching consensus on modelling philosophies, approaches and parameter values, development of improved methods and exchange of information. The project focuses on areas where uncertainties remain in the predictive capability of environmental models, emphasizing in reducing associated uncertainties or developing new approaches to strengthen the evaluation of the radiological impact. Within MODARIA, four main areas were defined, one of them devoted to Uncertainty and Variability. In this area four working groups were included, Working Group 5 dealing with the 'uncertainty and variability analysis for assessments of radiological impacts arising from routine discharges of radionuclides'. Whether doses are estimated by using measurement data, by applying models, or through a combination of measurements and calculations, the variability and uncertainty contribute to a distribution of possible values. The degree of variability and uncertainty is represented by the shape and extent of that distribution. The main objective of WG5 is to explore how to consider uncertainties and variabilities in the results of assessment of doses in planned situations for controlling the impact of routine releases from radioactive and nuclear installations to the environment. The final aim is to produce guidance for the calculation of uncertainties in these exposure situations and for the presentation of such results to the different stakeholders. To achieve that objective the main tasks identified were: to find tools and methods for uncertainty and variability analysis applicable to dose assessments in routine radioactive discharges, to define scenarios where information on uncertainty and variability of parameters is available

  18. Dose assessment for potential radionuclide emissions from stacks on the Hanford Site: NESHAP compliance

    International Nuclear Information System (INIS)

    Davis, W.E.; Barnett, J.M.; Kenoyer, J.L.

    1994-03-01

    The purpose of this document is to present the assessment results for the registered stacks on the Hanford Site for potential emissions, i.e. emissions with no control devices in place. Further, the document will identify those stacks requiring continuous monitoring, i.e. the effective dose equivalent from potential emissions >0.1 mrem/yr. The stack assessment of potential emissions was performed on 84 registered stacks on the Hanford Site. These emission sources represent individual point sources presently registered under Washington Administrative code 246-247 with the Washington Department of Health. The methods used in assessing the potential emissions from the stacks are described

  19. Computerized simulation methods for dose reduction, in radiodiagnosis

    International Nuclear Information System (INIS)

    Brochi, M.A.C.

    1990-01-01

    The present work presents computational methods that allow the simulation of any situation encountered in diagnostic radiology. Parameters of radiographic techniques that yield a standard radiographic image, previously chosen, and so could compare the dose of radiation absorbed by the patient is studied. Initially the method was tested on a simple system composed of 5.0 cm of water and 1.0 mm of aluminium and, after verifying experimentally its validity, it was applied in breast and arm fracture radiographs. It was observed that the choice of the filter material is not an important factor, because analogous behaviours were presented by aluminum, iron, copper, gadolinium, and other filters. A method of comparison of materials based on the spectral match is shown. Both the results given by this simulation method and the experimental measurements indicate an equivalence of brass and copper, both more efficient than aluminium, in terms of exposition time, but not of dose. (author)

  20. Design study on dose evaluation method for employees at severe accident

    International Nuclear Information System (INIS)

    Yoshida, Yoshitaka; Irie, Takashi; Kohriyama, Tamio; Kudo, Seiichi; Nishimura, Kazuya

    2002-01-01

    If a severe accident occurs in a pressurized water reactor plant, it is required to estimate dose values of operators engaged in emergency such as accident management, repair of failed parts. However, it might be difficult to measure radiation dose rate during the progress of an accident, because radiation monitors are not always installed in areas where the emergency activities are required. In this study, we analyzed the transport of radioactive materials in case of a severe accident, investigated a method to obtain radiation dose rate in the plant from estimated radioactive sources, made up a prototype analyzing system from this design study, and then evaluated its availability. As a result, we obtained the following: (1) A new dose evaluation method was established to predict the radiation dose rate at any point in the plant during a severe accident scenario. (2) This evaluation of total dose including access route and time for emergency activities is useful for estimating radiation dose limit for these employee actions. (3) The radiation dose rate map is effective for identifying high radiation areas and for choosing a route with lower radiation dose rate. (author)

  1. Use of electron paramagnetic resonance dosimetry with tooth enamel for retrospective dose assessment. Report of a co-ordinated research project

    CERN Document Server

    2002-01-01

    Electron paramagnetic resonance (EPR) dosimetry is a physical method for the assessment of absorbed dose from ionising radiation. It is based on the measurement of stable radiation induced radicals in human calcified tissues (primarily in tooth enamel). EPR dosimetry with teeth is now firmly established in retrospective dosimetry. It is a powerful method for providing information on exposure to ionising radiation many years after the event, since the 'signal' is 'stored' in the tooth or the bone. This technique is of particular relevance to relatively low dose exposures or when the results of conventional dosimetry are not available (e.g. in accidental circumstances). The use of EPR dosimetry, as an essential tool for retrospective assessment of radiation exposure is an important part of radioepidemiological studies and also provides data to select appropriate countermeasures based on retrospective evaluation of individual doses. Despite well established regulations and protocols for maintaining radiation pro...

  2. Outdoor solar UVA dose assessment with EBT2 radiochromic film using spectrophotometer and densitometer measurements.

    Science.gov (United States)

    Abukassem, I; Bero, M A

    2015-04-01

    Direct measurements of solar ultraviolet radiations (UVRs) have an important role in the protection of humans against UVR hazard. This work presents simple technique based on the application of EBT2 GAFCHROMIC(®) film for direct solar UVA dose assessment. It demonstrates the effects of different parts of the solar spectrum (UVB, visible and infrared) on performed UVA field measurements and presents the measurement uncertainty budget. The gradient of sunlight exposure level permitted the authors to establish the mathematical relationships between the measured solar UVA dose and two measured quantities: the first was the changes in spectral absorbance at the wavelength 633 nm (A633) and the second was the optical density (OD). The established standard relations were also applied to calculate the solar UVA dose variations during the whole day; 15 min of exposure each hour between 8:00 and 17:00 was recorded. Results show that both applied experimental methods, spectrophotometer absorbance and densitometer OD, deliver comparable figures for EBT2 solar UVA dose assessment with relative uncertainty of 11% for spectral absorbance measurements and 15% for OD measurements. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Sumi; Noguchi, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ryufuku, Susumu; Sasaki, Toshihisa; Kurosawa, Naohiro [Visible Information Center, Inc., Tokai, Ibaraki (Japan)

    2002-11-01

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

  4. Use of rank sum method in identifying high occupational dose jobs for ALARA implementation

    International Nuclear Information System (INIS)

    Cho, Yeong Ho; Kang, Chang Sun

    1998-01-01

    The cost-effective reduction of occupational radiation exposure (ORE) dose at a nuclear power plant could not be achieved without going through an extensive analysis of accumulated ORE dose data of existing plants. It is necessary to identify what are high ORE jobs for ALARA implementation. In this study, the Rank Sum Method (RSM) is used in identifying high ORE jobs. As a case study, the database of ORE-related maintenance and repair jobs for Kori Units 3 and 4 is used for assessment, and top twenty high ORE jobs are identified. The results are also verified and validated using the Friedman test, and RSM is found to be a very efficient way of analyzing the data. (author)

  5. Method for pulse to pulse dose reproducibility applied to electron linear accelerators

    International Nuclear Information System (INIS)

    Ighigeanu, D.; Martin, D.; Oproiu, C.; Cirstea, E.; Craciun, G.

    2002-01-01

    An original method for obtaining programmed beam single shots and pulse trains with programmed pulse number, pulse repetition frequency, pulse duration and pulse dose is presented. It is particularly useful for automatic control of absorbed dose rate level, irradiation process control as well as in pulse radiolysis studies, single pulse dose measurement or for research experiments where pulse-to-pulse dose reproducibility is required. This method is applied to the electron linear accelerators, ALIN-10 of 6.23 MeV and 82 W and ALID-7, of 5.5 MeV and 670 W, built in NILPRP. In order to implement this method, the accelerator triggering system (ATS) consists of two branches: the gun branch and the magnetron branch. ATS, which synchronizes all the system units, delivers trigger pulses at a programmed repetition rate (up to 250 pulses/s) to the gun (80 kV, 10 A and 4 ms) and magnetron (45 kV, 100 A, and 4 ms).The accelerated electron beam existence is determined by the electron gun and magnetron pulses overlapping. The method consists in controlling the overlapping of pulses in order to deliver the beam in the desired sequence. This control is implemented by a discrete pulse position modulation of gun and/or magnetron pulses. The instabilities of the gun and magnetron transient regimes are avoided by operating the accelerator with no accelerated beam for a certain time. At the operator 'beam start' command, the ATS controls electron gun and magnetron pulses overlapping and the linac beam is generated. The pulse-to-pulse absorbed dose variation is thus considerably reduced. Programmed absorbed dose, irradiation time, beam pulse number or other external events may interrupt the coincidence between the gun and magnetron pulses. Slow absorbed dose variation is compensated by the control of the pulse duration and repetition frequency. Two methods are reported in the electron linear accelerators' development for obtaining the pulse to pulse dose reproducibility: the method

  6. Method for calculating individual equivalent doses and cumulative dose of population in the vicinity of nuclear power plant site

    International Nuclear Information System (INIS)

    Namestek, L.; Khorvat, D; Shvets, J.; Kunz, Eh.

    1976-01-01

    A method of calculating the doses of external and internal person irradiation in the nuclear power plant vicinity under conditions of normal operation and accident situations has been described. The main difference between the above method and methods used up to now is the use of a new antropomorphous representation of a human body model together with all the organs. The antropomorphous model of human body and its organs is determined as a set of simple solids, coordinates of disposistion of the solids, sizes, masses, densities and composition corresponding the genuine organs. The use of the Monte-Carlo method is the second difference. The results of the calculations according to the model suggested can be used for determination: a critical group of inhabitans under conditions of normal plant operation; groups of inhabitants most subjected to irradiation in the case of possible accident; a critical sector with a maximum collective dose in the case of an accident; a critical radioisotope favouring the greatest contribution to an individual equivalent dose; critical irradiation ways promoting a maximum contribution to individual equivalent doses; cumulative collective doses for the whole region or for a chosen part of the region permitting to estimate a population dose. The consequent method evoluation suggests the development of separate units of the calculationg program, critical application and the selection of input data of physical, plysiological and ecological character and improvement of the calculated program for the separate concrete events [ru

  7. A phantom based method for deriving typical patient doses from measurements of dose-area product on populations of patients

    International Nuclear Information System (INIS)

    Chapple, C.-L.; Broadhead, D.A.

    1995-01-01

    One of the chief sources of uncertainty in the comparison of patient dosimetry data is the influence of patient size on dose. Dose has been shown to relate closely to the equivalent diameter of the patient. This concept has been used to derive a prospective, phantom based method for determining size correction factors for measurements of dose-area product. The derivation of the size correction factor has been demonstrated mathematically, and the appropriate factor determined for a number of different X-ray sets. The use of phantom measurements enables the effect of patient size to be isolated from other factors influencing patient dose. The derived factors agree well with those determined retrospectively from patient dose survey data. Size correction factors have been applied to the results of a large scale patient dose survey, and this approach has been compared with the method of selecting patients according to their weight. For large samples of data, mean dose-area product values are independent of the analysis method used. The chief advantage of using size correction factors is that it allows all patient data to be included in a survey, whereas patient selection has been shown to exclude approximately half of all patients. (author)

  8. Fully automated treatment planning for head and neck radiotherapy using a voxel-based dose prediction and dose mimicking method

    Science.gov (United States)

    McIntosh, Chris; Welch, Mattea; McNiven, Andrea; Jaffray, David A.; Purdie, Thomas G.

    2017-08-01

    Recent works in automated radiotherapy treatment planning have used machine learning based on historical treatment plans to infer the spatial dose distribution for a novel patient directly from the planning image. We present a probabilistic, atlas-based approach which predicts the dose for novel patients using a set of automatically selected most similar patients (atlases). The output is a spatial dose objective, which specifies the desired dose-per-voxel, and therefore replaces the need to specify and tune dose-volume objectives. Voxel-based dose mimicking optimization then converts the predicted dose distribution to a complete treatment plan with dose calculation using a collapsed cone convolution dose engine. In this study, we investigated automated planning for right-sided oropharaynx head and neck patients treated with IMRT and VMAT. We compare four versions of our dose prediction pipeline using a database of 54 training and 12 independent testing patients by evaluating 14 clinical dose evaluation criteria. Our preliminary results are promising and demonstrate that automated methods can generate comparable dose distributions to clinical. Overall, automated plans achieved an average of 0.6% higher dose for target coverage evaluation criteria, and 2.4% lower dose at the organs at risk criteria levels evaluated compared with clinical. There was no statistically significant difference detected in high-dose conformity between automated and clinical plans as measured by the conformation number. Automated plans achieved nine more unique criteria than clinical across the 12 patients tested and automated plans scored a significantly higher dose at the evaluation limit for two high-risk target coverage criteria and a significantly lower dose in one critical organ maximum dose. The novel dose prediction method with dose mimicking can generate complete treatment plans in 12-13 min without user interaction. It is a promising approach for fully automated treatment

  9. Assessment of Patients Radiation Dose During Interventional Radiological Procedure in PPUKM

    International Nuclear Information System (INIS)

    Mohd Khalid Matori; Husaini Salleh; Muhammad Jamal Muhammad Isa

    2014-01-01

    Interventional Radiology (IR) is a relatively new subspecialty of radiology. It is subspecialty where minimally invasive procedures are performed under radiological guidance using X-ray. This procedure can deliver high radiation doses compared with other radiological method due to long screening time. Because of these it is important to determine radiation doses received by patients undergoing IR procedures. It is to ensure that the dose is within the range deemed to be saved. A total of 128 patients undergoing IR procedures in PPUKM between 2012 and 2013 were study retrospectively. Dose area product (DAP) meter were used to measure the integral dose for the whole procedures. Mean kerma-area products for abdomen, head, pelvis, and thorax were 243.1, 107.3, 39.05 and 45.7 Gycm 2 , respectively. This study may provide the useful information which can be use to establish baseline patient dose data for dose optimizing study and carried out a recommendation on effective method of patient dose reduction during IR procedures. A more detail results of this study are presented in this paper. (author)

  10. Application of Glow Curve Deconvolution Method to Evaluate Low Dose TLD LiF

    International Nuclear Information System (INIS)

    Kurnia, E; Oetami, H R; Mutiah

    1996-01-01

    Thermoluminescence Dosimeter (TLD), especially LiF:Mg, Ti material, is one of the most practical personal dosimeter in known to date. Dose measurement under 100 uGy using TLD reader is very difficult in high precision level. The software application is used to improve the precision of the TLD reader. The objectives of the research is to compare three Tl-glow curve analysis method irradiated in the range between 5 up to 250 uGy. The first method is manual analysis, dose information is obtained from the area under the glow curve between pre selected temperature limits, and background signal is estimated by a second readout following the first readout. The second method is deconvolution method, separating glow curve into four peaks mathematically and dose information is obtained from area of peak 5, and background signal is eliminated computationally. The third method is deconvolution method but the dose is represented by the sum of area of peak 3,4 and 5. The result shown that the sum of peak 3,4 and 5 method can improve reproducibility six times better than manual analysis for dose 20 uGy, the ability to reduce MMD until 10 uGy rather than 60 uGy with manual analysis or 20 uGy with peak 5 area method. In linearity, the sum of peak 3,4 and 5 method yields exactly linear dose response curve over the entire dose range

  11. Potential radionuclide emissions from stacks on the Hanford site, Part 1: Dose assessment

    Energy Technology Data Exchange (ETDEWEB)

    Davis, W.E.; Barnett, J.M. [Westinghouse Hanford Company, Richland, WA (United States)

    1995-02-01

    On February 3, 1993, the U.S. Department of Energy, Richland Operations Office received a Compliance Order and Information Request from the Director of the Air and Toxics Division of the U.S. Environmental Protection Agency, Region 10. The Compliance Order requires RL to evaluate all radionuclide emission points at the Hanford Site to determine which are subject to continuous emission monitoring requirements in 40 CFR 61, Subpart H, and to continuously monitor radionuclide emissions in accordance with requirements in 40 CFR 61.93. The Information Request required RL to provide a written Compliance Plan to meet the requirements of the Compliance Order. A Compliance Plan was submitted to EPA, Region 10, on April 30, 1993. The Compliance Plan specified that a dose assessment would be performed for 84 Westinghouse Hanford Company stacks registered with the Washington State Department of Health on the Hanford Site. Stacks that have the potential emissions to cause an effective dose equivalent to a maximum exposed individual greater than 0.1 mrem/y must be monitored continuously for radionuclide emissions. Five methods were approved by EPA, Region 10 for performing the assessments: Release Fractions from Appendix D of 40 CFR 61, Back Calculations Using A HEPA Filtration Factor, Nondestructive Assay of HEPA Filters, A Spill Release Fraction, and Upstream of HEPA Filter Air Concentrations. The first two methods were extremely conservative for estimating releases. The third method, which used a state-of-the-art portable gamma spectrometer, yielded surprising results from the distribution of radionuclides on the HEPA filters. All five methods are described. Assessments using a HEPA Filtration Factor for back calculations identified 32 stacks that would have emissions that would cause an EDE to the MEI greater than 0.1 mrem y{sup {minus}1}. The number was reduced to 15 stacks when the other methods were applied. The paper discusses reasons for the overestimates.

  12. Characteristics of the graded wildlife dose assessment code K-BIOTA and its application

    Energy Technology Data Exchange (ETDEWEB)

    Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Kim, Byeong Ho; Choi, Yong Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-12-15

    This paper describes the technical background for the Korean wildlife radiation dose assessment code, K-BIOTA, and the summary of its application. The K-BIOTA applies the graded approaches of 3 levels including the screening assessment (Level 1 and 2), and the detailed assessment based on the site specific data (Level 3). The screening level assessment is a preliminary step to determine whether the detailed assessment is needed, and calculates the dose rate for the grouped organisms, rather than an individual biota. In the Level 1 assessment, the risk quotient (RQ) is calculated by comparing the actual media concentration with the environmental media concentration limit (EMCL) derived from a bench-mark screening reference dose rate. If RQ for the Level 1 assessment is less than 1, it can be determined that the ecosystem would maintain its integrity, and the assessment is terminated. If the RQ is greater than 1, the Level 2 assessment, which calculates RQ using the average value of the concentration ratio (CR) and equilibrium distribution coefficient (Kd) for the grouped organisms, is carried out for the more realistic assessment. Thus, the Level 2 assessment is less conservative than the Level 1 assessment. If RQ for the Level 2 assessment is less than 1, it can be determined that the ecosystem would maintain its integrity, and the assessment is terminated. If the RQ is greater than 1, the Level 3 assessment is performed for the detailed assessment. In the Level 3 assessment, the radiation dose for the representative organism of a site is calculated by using the site specific data of occupancy factor, CR and Kd. In addition, the K-BIOTA allows the uncertainty analysis of the dose rate on CR, Kd and environmental medium concentration among input parameters optionally in the Level 3 assessment. The four probability density functions of normal, lognormal, uniform and exponential distribution can be applied. The applicability of the code was tested through the

  13. Characteristics of the graded wildlife dose assessment code K-BIOTA and its application

    International Nuclear Information System (INIS)

    Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Kim, Byeong Ho; Choi, Yong Ho

    2015-01-01

    This paper describes the technical background for the Korean wildlife radiation dose assessment code, K-BIOTA, and the summary of its application. The K-BIOTA applies the graded approaches of 3 levels including the screening assessment (Level 1 and 2), and the detailed assessment based on the site specific data (Level 3). The screening level assessment is a preliminary step to determine whether the detailed assessment is needed, and calculates the dose rate for the grouped organisms, rather than an individual biota. In the Level 1 assessment, the risk quotient (RQ) is calculated by comparing the actual media concentration with the environmental media concentration limit (EMCL) derived from a bench-mark screening reference dose rate. If RQ for the Level 1 assessment is less than 1, it can be determined that the ecosystem would maintain its integrity, and the assessment is terminated. If the RQ is greater than 1, the Level 2 assessment, which calculates RQ using the average value of the concentration ratio (CR) and equilibrium distribution coefficient (Kd) for the grouped organisms, is carried out for the more realistic assessment. Thus, the Level 2 assessment is less conservative than the Level 1 assessment. If RQ for the Level 2 assessment is less than 1, it can be determined that the ecosystem would maintain its integrity, and the assessment is terminated. If the RQ is greater than 1, the Level 3 assessment is performed for the detailed assessment. In the Level 3 assessment, the radiation dose for the representative organism of a site is calculated by using the site specific data of occupancy factor, CR and Kd. In addition, the K-BIOTA allows the uncertainty analysis of the dose rate on CR, Kd and environmental medium concentration among input parameters optionally in the Level 3 assessment. The four probability density functions of normal, lognormal, uniform and exponential distribution can be applied. The applicability of the code was tested through the

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

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Rodolfo; Ekstroem, Per-Anders [Facilia AB, Bromma (Sweden); Kautsky, Ulrik [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2006-08-15

    In previous safety assessments Ecosystem Dose Factors (EDFs), were derived from estimates of doses to the most exposed group resulting from constant unit radionuclide release rates over 10,000 years to various ecosystem types, e.g. mires, agricultural lands, lakes and marine ecosystems. A number of limitations of the EDF approach have been identified. The objectives of this report is to further develop the EDF approach, in order to resolve the identified limitations, and to use the improved approach for deriving Dose Conversion Factors for use in the SR-Can risk assessments. The Dose Conversion Factors derived in this report are named Landscape Dose Factors (LDFs). It involves modelling the fate of the radionuclides in the whole landscape, which develops from a sea to a inland situation during 20,000 years. Both candidate sites studies in SR-Can, Forsmark and Laxemar, are included in the study. As a basis for the modelling, the period starting at the beginning of the last interglacial (8,000 BC) is used, over which releases from a hypothetical repository were assumed to take place. For the present temperate period, the overall development of the biosphere at each site is outlined in a 1,000 year perspective and beyond, essentially based on the ongoing shoreline displacement and the understanding on the impact this has on the biosphere. The past development, i.e. from deglaciation to the present time, is inferred from geological records and associated reconstructions of the shore-line. For each time step of 1,000 years, the landscape at the site is described as a number of interconnected biosphere objects constituting an integrated landscape model of each site. The water fluxes through the objects were estimated from the average run-off at the site, the areas of the objects and their associated catchment areas. Radionuclides in both dissolved and particulate forms were considered in the transport calculations. The transformation between ecosystems was modelled as

  15. Method of predicting the mean lung dose based on a patient's anatomy and dose-volume histograms

    Energy Technology Data Exchange (ETDEWEB)

    Zawadzka, Anna, E-mail: a.zawadzka@zfm.coi.pl [Medical Physics Department, Centre of Oncology, Maria Sklodowska-Curie Memorial Cancer Center, Warsaw (Poland); Nesteruk, Marta [Faculty of Physics, University of Warsaw, Warsaw (Poland); Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich (Switzerland); Brzozowska, Beata [Faculty of Physics, University of Warsaw, Warsaw (Poland); Kukołowicz, Paweł F. [Medical Physics Department, Centre of Oncology, Maria Sklodowska-Curie Memorial Cancer Center, Warsaw (Poland)

    2017-04-01

    The aim of this study was to propose a method to predict the minimum achievable mean lung dose (MLD) and corresponding dosimetric parameters for organs-at-risk (OAR) based on individual patient anatomy. For each patient, the dose for 36 equidistant individual multileaf collimator shaped fields in the treatment planning system (TPS) was calculated. Based on these dose matrices, the MLD for each patient was predicted by the homemade DosePredictor software in which the solution of linear equations was implemented. The software prediction results were validated based on 3D conformal radiotherapy (3D-CRT) and volumetric modulated arc therapy (VMAT) plans previously prepared for 16 patients with stage III non–small-cell lung cancer (NSCLC). For each patient, dosimetric parameters derived from plans and the results calculated by DosePredictor were compared. The MLD, the maximum dose to the spinal cord (D{sub max} {sub cord}) and the mean esophageal dose (MED) were analyzed. There was a strong correlation between the MLD calculated by the DosePredictor and those obtained in treatment plans regardless of the technique used. The correlation coefficient was 0.96 for both 3D-CRT and VMAT techniques. In a similar manner, MED correlations of 0.98 and 0.96 were obtained for 3D-CRT and VMAT plans, respectively. The maximum dose to the spinal cord was not predicted very well. The correlation coefficient was 0.30 and 0.61 for 3D-CRT and VMAT, respectively. The presented method allows us to predict the minimum MLD and corresponding dosimetric parameters to OARs without the necessity of plan preparation. The method can serve as a guide during the treatment planning process, for example, as initial constraints in VMAT optimization. It allows the probability of lung pneumonitis to be predicted.

  16. SU-G-BRC-08: Evaluation of Dose Mass Histogram as a More Representative Dose Description Method Than Dose Volume Histogram in Lung Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J; Eldib, A; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States); Lin, M [The University of Texas Southwestern Medical Ctr, Dallas, TX (United States); Li, J [Cyber Medical Inc, Xian, Shaanxi (China); Mora, G [Universidade de Lisboa, Codex, Lisboa (Portugal)

    2016-06-15

    Purpose: Dose-volume-histogram (DVH) is widely used for plan evaluation in radiation treatment. The concept of dose-mass-histogram (DMH) is expected to provide a more representative description as it accounts for heterogeneity in tissue density. This study is intended to assess the difference between DVH and DMH for evaluating treatment planning quality. Methods: 12 lung cancer treatment plans were exported from the treatment planning system. DVHs for the planning target volume (PTV), the normal lung and other structures of interest were calculated. DMHs were calculated in a similar way as DVHs expect that the voxel density converted from the CT number was used in tallying the dose histogram bins. The equivalent uniform dose (EUD) was calculated based on voxel volume and mass, respectively. The normal tissue complication probability (NTCP) in relation to the EUD was calculated for the normal lung to provide quantitative comparison of DVHs and DMHs for evaluating the radiobiological effect. Results: Large differences were observed between DVHs and DMHs for lungs and PTVs. For PTVs with dense tumor cores, DMHs are higher than DVHs due to larger mass weighing in the high dose conformal core regions. For the normal lungs, DMHs can either be higher or lower than DVHs depending on the target location within the lung. When the target is close to the lower lung, DMHs show higher values than DVHs because the lower lung has higher density than the central portion or the upper lung. DMHs are lower than DVHs for targets in the upper lung. The calculated NTCPs showed a large range of difference between DVHs and DMHs. Conclusion: The heterogeneity of lung can be well considered using DMH for evaluating target coverage and normal lung pneumonitis. Further studies are warranted to quantify the benefits of DMH over DVH for plan quality evaluation.

  17. Internal dose assessment in a case of continuous intake of Cs 137

    International Nuclear Information System (INIS)

    Gomez Parada, I.; Rojo, A.M.

    2000-01-01

    In 1997 the Argentine Nuclear Regulatory Authority (ARN) was invited to participate in the '3rd. European Intercomparison Exercise on Internal Dose Assessment'. This paper presents the solution submitted by the ARN to one of the cases proposed in the exercise. This is a real case of continuous ingestion of cesium 137 due to the environmental contamination arising from the Chernobyl accident. The subject was member of the public and the results of whole body counter measurements were provided. The monitoring period spanned from the first month after the accident to approximately 880 days later. The solution implied to estimate the total intake for the accident until the end of the monitoring period, the effective dose received by the subject in 1986 and 1987 respectively and the committed effective dose due to the total intake. For the intake assessment the code Cindy v 1.4 was used, assuming a constant rate of intake during the whole period of intake. The systemic retention model for caesium was that of the ICRP 30, with a modified biological half-life of the long-term retention. The dates of the beginning and end of the period of intake were chosen, using the same software, looking for the ones that fits better to the measurements data. This rate of intake and the same metabolic models used for the intake assessment were the input to the CINDY code to find the dose received by the subject in 1986 and 1987 respectively, as well as the committed effective dose. An alternative dose assessment was made, directly from body burden measurements, in order to compare the obtained values. In this approach, the software Origin 4.0 was used to graph the whole body activity measurements and the integrate it for the desired time intervals. Applying the corresponding Specific Effective Energy value obtained from LUPED 2.06 for the reference man, the effective doses were obtained directly from body burden. It was found that the values for the effective doses were almost the same

  18. A review of the uncertainties in internal radiation dose assessment for inhaled thorium

    International Nuclear Information System (INIS)

    Hewson, G.S.

    1989-01-01

    Present assessments of internal radiation dose to designated radiation workers in the mineral sands industry, calculated using ICRP 26/30 methodology and data, indicate that some workers approach and exceed statutory radiation dose limits. Such exposures are indicative of the need for a critical assessment of work and operational procedures and also of metabolic and dosimetric models used to estimate internal dose. This paper reviews past occupational exposure experience with inhaled thorium compounds, examines uncertainties in the underlying radiation protection models, and indicates the effect of alternative assumptions on the calculation of committed effective dose equivalent. The extremely low recommended inhalation limits for thorium in air do not appear to be well supported by studies on the health status of former thorium refinery workers who were exposed to thorium well in excess of presently accepted limits. The effect of cautious model assumptions is shown to result in internal dose assessments that could be up to an order of magnitude too high. It is concluded that the effect of such uncertainty constrains the usefulness of internal dose estimates as a reliable indicator of actual health risk. 26 refs., 5 figs., 3 tabs

  19. Dose and risk assessment of norm Contaminated waste released from trench disposal facility

    International Nuclear Information System (INIS)

    Abdel Geleel, M.; Ramadan, A.B.; Tawfik, A.A.

    2005-01-01

    Oil and gas extraction and processing operations accumulate naturally occurring radioactive material (NORM) at concentrations above normal in by-product waste streams. The petroleum industry adopted methods for managing of NORM that are more restrictive than past practices and are likely to provide greater isolation of the radioactivity. Trench was used as a disposal facility for NORM contaminated wastes at one site of the petroleum industry in Egypt. The aim of this work is to calculate the risk and dose assessment received from trench disposal facility directly and after closure (1000 year). RESRAD computer code was used. The results indicated that the total effective dose (TED) received after direct closure of trench disposal facility was 7.7E-4 mSv/y while after 1000 years, it will he 3.4E-4. The health cancer risk after direct closure was 3.3E-8 while after 1000 years post closure it was 6E-8. Results of this assessment will help examine policy issues concerning different options and regulation of NORM contaminated waste generated by petroleum industry

  20. Prescribing and evaluating target dose in dose-painting treatment plans

    DEFF Research Database (Denmark)

    Håkansson, Katrin; Specht, Lena; Aznar, Marianne C

    2014-01-01

    BACKGROUND: Assessment of target dose conformity in multi-dose-level treatment plans is challenging due to inevitable over/underdosage at the border zone between dose levels. Here, we evaluate different target dose prescription planning aims and approaches to evaluate the relative merit of such p......-painting and multi-dose-level plans. The tool can be useful for quality assurance of multi-center trials, and for visualizing the development of treatment planning in routine clinical practice....... of such plans. A quality volume histogram (QVH) tool for history-based evaluation is proposed. MATERIAL AND METHODS: Twenty head and neck cancer dose-painting plans with five prescription levels were evaluated, as well as clinically delivered simultaneous integrated boost (SIB) plans from 2010 and 2012. The QVH...

  1. Assessment of dose during an SGTR

    International Nuclear Information System (INIS)

    Adams, J.P.

    1993-01-01

    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

  2. Practical dose point-based methods to characterize dose distribution in a stationary elliptical body phantom for a cone-beam C-arm CT system

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jang-Hwan, E-mail: jhchoi21@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Constantin, Dragos [Microwave Physics R& E, Varian Medical Systems, Palo Alto, California 94304 (United States); Ganguly, Arundhuti; Girard, Erin; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Morin, Richard L. [Mayo Clinic Jacksonville, Jacksonville, Florida 32224 (United States); Dixon, Robert L. [Department of Radiology, Wake Forest University, Winston-Salem, North Carolina 27157 (United States)

    2015-08-15

    Purpose: To propose new dose point measurement-based metrics to characterize the dose distributions and the mean dose from a single partial rotation of an automatic exposure control-enabled, C-arm-based, wide cone angle computed tomography system over a stationary, large, body-shaped phantom. Methods: A small 0.6 cm{sup 3} ion chamber (IC) was used to measure the radiation dose in an elliptical body-shaped phantom made of tissue-equivalent material. The IC was placed at 23 well-distributed holes in the central and peripheral regions of the phantom and dose was recorded for six acquisition protocols with different combinations of minimum kVp (109 and 125 kVp) and z-collimator aperture (full: 22.2 cm; medium: 14.0 cm; small: 8.4 cm). Monte Carlo (MC) simulations were carried out to generate complete 2D dose distributions in the central plane (z = 0). The MC model was validated at the 23 dose points against IC experimental data. The planar dose distributions were then estimated using subsets of the point dose measurements using two proposed methods: (1) the proximity-based weighting method (method 1) and (2) the dose point surface fitting method (method 2). Twenty-eight different dose point distributions with six different point number cases (4, 5, 6, 7, 14, and 23 dose points) were evaluated to determine the optimal number of dose points and their placement in the phantom. The performances of the methods were determined by comparing their results with those of the validated MC simulations. The performances of the methods in the presence of measurement uncertainties were evaluated. Results: The 5-, 6-, and 7-point cases had differences below 2%, ranging from 1.0% to 1.7% for both methods, which is a performance comparable to that of the methods with a relatively large number of points, i.e., the 14- and 23-point cases. However, with the 4-point case, the performances of the two methods decreased sharply. Among the 4-, 5-, 6-, and 7-point cases, the 7-point case (1

  3. Personalized Assessment of kV Cone Beam Computed Tomography Doses in Image-guided Radiotherapy of Pediatric Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yibao [Beijing Key Lab of Medical Physics and Engineering, Peking University, Beijing (China); Yan Yulong [Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Nath, Ravinder [Department of Therapeutic Radiology, Yale University, New Haven, Connecticut (United States); Bao Shanglian [Beijing Key Lab of Medical Physics and Engineering, Peking University, Beijing (China); Deng Jun, E-mail: jun.deng@yale.edu [Department of Therapeutic Radiology, Yale University, New Haven, Connecticut (United States)

    2012-08-01

    Purpose: To develop a quantitative method for the estimation of kV cone beam computed tomography (kVCBCT) doses in pediatric patients undergoing image-guided radiotherapy. Methods and Materials: Forty-two children were retrospectively analyzed in subgroups of different scanned regions: one group in the head-and-neck and the other group in the pelvis. Critical structures in planning CT images were delineated on an Eclipse treatment planning system before being converted into CT phantoms for Monte Carlo simulations. A benchmarked EGS4 Monte Carlo code was used to calculate three-dimensional dose distributions of kVCBCT scans with full-fan high-quality head or half-fan pelvis protocols predefined by the manufacturer. Based on planning CT images and structures exported in DICOM RT format, occipital-frontal circumferences (OFC) were calculated for head-and-neck patients using DICOMan software. Similarly, hip circumferences (HIP) were acquired for the pelvic group. Correlations between mean organ doses and age, weight, OFC, and HIP values were analyzed with SigmaPlot software suite, where regression performances were analyzed with relative dose differences (RDD) and coefficients of determination (R{sup 2}). Results: kVCBCT-contributed mean doses to all critical structures decreased monotonically with studied parameters, with a steeper decrease in the pelvis than in the head. Empirical functions have been developed for a dose estimation of the major organs at risk in the head and pelvis, respectively. If evaluated with physical parameters other than age, a mean RDD of up to 7.9% was observed for all the structures in our population of 42 patients. Conclusions: kVCBCT doses are highly correlated with patient size. According to this study, weight can be used as a primary index for dose assessment in both head and pelvis scans, while OFC and HIP may serve as secondary indices for dose estimation in corresponding regions. With the proposed empirical functions, it is possible

  4. Dose calculation methods in photon beam therapy using energy deposition kernels

    International Nuclear Information System (INIS)

    Ahnesjoe, A.

    1991-01-01

    The problem of calculating accurate dose distributions in treatment planning of megavoltage photon radiation therapy has been studied. New dose calculation algorithms using energy deposition kernels have been developed. The kernels describe the transfer of energy by secondary particles from a primary photon interaction site to its surroundings. Monte Carlo simulations of particle transport have been used for derivation of kernels for primary photon energies form 0.1 MeV to 50 MeV. The trade off between accuracy and calculational speed has been addressed by the development of two algorithms; one point oriented with low computional overhead for interactive use and one for fast and accurate calculation of dose distributions in a 3-dimensional lattice. The latter algorithm models secondary particle transport in heterogeneous tissue by scaling energy deposition kernels with the electron density of the tissue. The accuracy of the methods has been tested using full Monte Carlo simulations for different geometries, and found to be superior to conventional algorithms based on scaling of broad beam dose distributions. Methods have also been developed for characterization of clinical photon beams in entities appropriate for kernel based calculation models. By approximating the spectrum as laterally invariant, an effective spectrum and dose distribution for contaminating charge particles are derived form depth dose distributions measured in water, using analytical constraints. The spectrum is used to calculate kernels by superposition of monoenergetic kernels. The lateral energy fluence distribution is determined by deconvolving measured lateral dose distributions by a corresponding pencil beam kernel. Dose distributions for contaminating photons are described using two different methods, one for estimation of the dose outside of the collimated beam, and the other for calibration of output factors derived from kernel based dose calculations. (au)

  5. Estimation and comparison of effective dose (E) in standard chest CT by organ dose measurements and dose-length-product methods and assessment of the influence of CT tube potential (energy dependency) on effective dose in a dual-source CT

    International Nuclear Information System (INIS)

    Paul, Jijo; Banckwitz, Rosemarie; Krauss, Bernhard; Vogl, Thomas J.; Maentele, Werner; Bauer, Ralf W.

    2012-01-01

    Highlights: ► The dual-energy protocol delivers the lowest effective dose of the investigated protocols for standard chest CT examinations, thus enabling functional imaging (like dual-energy perfusion) and can produce weighted images without dose penalty. ► The high-pitch protocol goes along with a 16% increase in dose compared to the standard 120 kV protocol and thus should preferably be used in pediatric, acute care settings (e.g. pulmonary embolism, aortic dissection and the like) or restless patients. ► The difference in effective dose estimates between ICRP 60 and 103 is minimal. ► Tube potential definitely has an effect on estimates of effective dose. - Abstract: Purpose: To determine effective dose (E) during standard chest CT using an organ dose-based and a dose-length-product-based (DLP) approach for four different scan protocols including high-pitch and dual-energy in a dual-source CT scanner of the second generation. Materials and methods: Organ doses were measured with thermo luminescence dosimeters (TLD) in an anthropomorphic male adult phantom. Further, DLP-based dose estimates were performed by using the standard 0.014 mSv/mGycm conversion coefficient k. Examinations were performed on a dual-source CT system (Somatom Definition Flash, Siemens). Four scan protocols were investigated: (1) single-source 120 kV, (2) single-source 100 kV, (3) high-pitch 120 kV, and (4) dual-energy with 100/Sn140 kV with equivalent CTDIvol and no automated tube current modulation. E was then determined following recommendations of ICRP publication 103 and 60 and specific k values were derived. Results: DLP-based estimates differed by 4.5–16.56% and 5.2–15.8% relatively to ICRP 60 and 103, respectively. The derived k factors calculated from TLD measurements were 0.0148, 0.015, 0.0166, and 0.0148 for protocol 1, 2, 3 and 4, respectively. Effective dose estimations by ICRP 103 and 60 for single-energy and dual-energy protocols show a difference of less than 0.04 m

  6. Effects of different premature chromosome condensation method on dose-curve of 60Co γ-ray

    International Nuclear Information System (INIS)

    Guo Yicao; Yang Haoxian; Yang Yuhua; Li Xi'na; Huang Weixu; Zheng Qiaoling

    2012-01-01

    Objective: To study the effect of traditional method and improved method of the premature chromosome condensation (PCC) on the dose-effect curve of 60 Co γ ray, for choosing the rapid and accurate biological dose estimating method for the accident emergency. Methods: Collected 3 healthy male cubits venous blood (23 to 28 years old), and irradiated by 0, 1.0, 5.0, 10.0, 15.0, 20.0 Gy 60 Co γ ray (absorbed dose rate: 0.635 Gy/min). Observed the relation of dose-effect curve in the 2 incubation time (50 hours and 60 hours) of the traditional method and improved method. Used the dose-effect curve to verify the exposure of 10.0 Gy (absorbed dose rate: 0.670 Gy/min). Results: (1) In the traditional method of 50-hour culture, the PCC cell count in 15.0 Gy and 20.0 Gy was of no statistical significance. But there were statistical significance in the traditional method of 60-hours culture and improved method (50-hour culture and 60-hour culture). Used the last 3 culture methods to make dose curve. (2) In the above 3 culture methods, the related coefficient between PCC ring and exposure dose was quite close (all of more than 0.996, P 0.05), the morphology of regression straight lines almost overlap. (3) Used the above 3 dose-effect curves to estimate the irradiation results (10.0 Gy), the error was less than or equal to 8%, all of them were within the allowable range of the biological experiment (15%). Conclusion: The 3 dose-effect curves of the above 3 culture methods can apply to biological dose estimating of large doses of ionizing radiation damage. Especially the improved method of 50-hour culture,it is much faster to estimate and it should be regarded as the first choice in accident emergency. (authors)

  7. Methodic of the gamma-rays absorbed dose measurements on tooth enamel

    International Nuclear Information System (INIS)

    Linev, S.V.; Muravskij, V.A.; Mashevskij, A.A.; Ugolev, I.I.

    1997-01-01

    The analysis of the metrological aspects of the tooth enamel ESR dosimetry has been done. The sample preparation and measurement methods have been elaborated. The methods have passed metrological certification. The methods include tabletting of the mixture of tooth enamel powder and MnO paramagnetic centres concentration additional standard, two loops of additional irradiation of samples by 1 Gy dose and ESR-spectra measurements, calculation of absorbed dose by maximum likelihood algorithm. The algorithm of dose calculation uses enamel spectrum model with axial anisotropic spin-Hamiltonian based on 126 spectra of enamel samples. The algorithm takes into account spectra of the empty cavity, the tube for a sample, the glue and MnO standard. Certificated ESR-station is based on the ESR-analyser PS-100X. ESR-station provides tooth enamel absorbed dose measurements from 0.05 to 0.25 Gy with error 35%, and from 0.25 to 3 Gy with error 20%. The set of tooth enamel absorbed dose standard samples has been created and certificated for the purposes of ESR-station testing and certification. The set consists of 12 tabletted samples of tooth enamel irradiated by doses from 0.05 to 4 Gy. (authors). 7 refs., 1 tab., 2 figs

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

    International Nuclear Information System (INIS)

    Allott, R.

    2001-01-01

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

  9. A comparison of the calculation methods of the maze shielding dose

    International Nuclear Information System (INIS)

    Li Wenqian; Li Junli; Li Pengyu; Tao Yinghua

    2009-01-01

    This paper gives a theoretical calculating method for the dose rate of the maze of the low-energy accelerators or high-energy accelerators, based on the NCRP report Nos.49, 51 and 151. The multi-legged maze of the Miyun CT workshop of the NUCTECH Company Limited and the arc maze of the radiation laboratory of the Academy of Military Medical Sciences were calculated using this method. The calculating results were compared with the MCNP simulating results and the measured results. For the commonly estimation of the maze dose rate, as long as the parameters chosen properly, this method can give a conservative result, and save time from simulation. It's hoped that this work could offer a reference for the maze design and the dose estimation method in the aftertime. (authors)

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

    International Nuclear Information System (INIS)

    Hayes, R.B.; Haskell, E.H.; Kenner, G.H.

    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

  11. Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans

    Energy Technology Data Exchange (ETDEWEB)

    Guberina, Nika; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany)

    2016-10-15

    The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use. (orig.)

  12. Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans

    International Nuclear Information System (INIS)

    Guberina, Nika; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian

    2016-01-01

    The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use. (orig.)

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

    Science.gov (United States)

    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

  14. Dose Rate Experiment at JET for Benchmarking the Calculation Direct One Step Method

    International Nuclear Information System (INIS)

    Angelone, M.; Petrizzi, L.; Pillon, M.; Villari, R.; Popovichev, S.

    2006-01-01

    Neutrons produced by D-D and D-T plasmas induce the activation of tokamak materials and of components. The development of reliable methods to assess dose rates is a key issue for maintenance and operating nuclear machines, in normal and off-normal conditions. In the frame of the EFDA Fusion Technology work programme, a computational tool based upon MCNP Monte Carlo code has been developed to predict the dose rate after shutdown: it is called Direct One Step Method (D1S). The D1S is an innovative approach in which the decay gammas are coupled to the neutrons as in the prompt case and they are transported in one single step in the same run. Benchmarking of this new tool with experimental data taken in a complex geometry like that of a tokamak is a fundamental step to test the reliability of the D1S method. A dedicated benchmark experiment was proposed for the 2005-2006 experimental campaign of JET. Two irradiation positions have been selected for the benchmark: one inner position inside the vessel, not far from the plasma, called the 2 upper irradiation end (IE2), where neutron fluence is relatively high. The second position is just outside a vertical port in an external position (EX). Here the neutron flux is lower and the dose rate to be measured is not very far from the residual background. Passive detectors are used for in-vessel measurements: the high sensitivity Thermo Luminescent Dosimeters (TLDs) GR-200A (natural LiF), which ensure measurements down to environmental dose level. An active detector of Geiger-Muller (GM) type is used for out of vessel dose rate measurement. Before their use the detectors were calibrated in a secondary gamma-ray standard (Cs-137 and Co-60) facility in term of air-kerma. The background measurement was carried-out in the period July -September 2005 in the outside position EX using the GM tube and in September 2005 inside the vacuum vessel using TLD detectors located in the 2 Upper irradiation end IE2. In the present work

  15. Radiation protection cabin for catheter-directed liver interventions: operator dose assessment

    International Nuclear Information System (INIS)

    Maleux, Geert; Bosmans, Hilde; Bergans, Niki; Bogaerts, Ria

    2016-01-01

    The number and complexity of interventional radiological procedures and in particular catheter-directed liver interventions have increased substantially. The current study investigates the reduction of personal doses when using a dedicated radiation protection cabin (RPC) for these procedures. Operator and assistant doses were assessed for 3 series of 20 chemo-infusion/chemoembolisation interventions, including an equal number of procedures with and without RPC. Whole body doses, finger doses and doses at the level of knees and eyes were evaluated with different types of TLD-100 Harshaw dosemeters. Dosemeters were also attached on the three walls of the RPC. The operator doses were significantly reduced by the RPC, but also without RPC, the doses appear to be limited as a result of thorough optimisation with existing radiation protection tools. The added value of the RPC should thus be determined by the outcome of balancing dose reduction and other aspects such as ergonomic benefits. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

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

    1986-11-01

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

  18. Assessment of organ doses by standard X-ray procedures in the GDR

    International Nuclear Information System (INIS)

    Tautz, M.; Brandt, G.A.

    1986-01-01

    A modern method has been described to assess the radiation burden by X-ray procedures with consideration of the standards of our Society for Medical Radiology in the GDR. The underlying methodology is a Monte Carlo computer technique, which simulates stochastically the energy deposition of X-ray photons in a mathematically described heterogeneous anthropomorphic phantom by Rosenstein (US Department of Health, Education and Welfare). To apply the procedure specific values for the following parameters must be determined for each dose estimation: projection and view, X-ray field size and location entrance exposure at skin surface, beam quality, source-to-image receptor distance. The base data are obtained in terms of tissue-air ratio. Organ doses were calculated for chest, urography, skull, cervical spine, thoracic spine, lumbar spine, pelvis and lymphography. Concluding possibilities have been discussed for reduction of radiation burden. 9 refs., 6 figs., 9 tabs. (author)

  19. Development of a dose assessment computer code for the NPP severe accident at intermediate level - Korean case

    International Nuclear Information System (INIS)

    Cheong, J.H.; Lee, K.J.; Cho, H.Y.; Lim, J.H.

    1993-01-01

    A real-time dose assessment computer code named RADCON (RADiological CONsequence analysis) has been developed. An approximation method describing the distribution of radionuclides in a puff was proposed and implemented in the code. This method is expected to reduce the time required to calculate the cloud shine (external dose from radioactive plumes). RADCON can simulate an NPP emergency situation by considering complex topography and continuous washout phenomena and provide a function of effective emergency planning. To verify the code results, RADCON has been compared with RASCAL, which was developed for the U.S. NRC by ORNL, for eight hypothetical accident scenarios. Sensitivity analysis was also performed for the important input parameters. (2 tabs., 3 figs.)

  20. Assessment of volumetric-modulated arc therapy for constant and variable dose rates

    Directory of Open Access Journals (Sweden)

    Mariluz De Ornelas-Couto

    2017-01-01

    Full Text Available Purpose: The aim of this study is to compare the effects of dose rate on volumetric-modulated arc therapy plans to determine optimal dose rates for prostate and head and neck (HN cases. Materials and Methods: Ten prostate and ten HN cases were retrospectively studied. For each case, seven plans were generated: one variable dose rate (VDR and six constant dose rate (CDR (100–600 monitor units [MUs]/min plans. Prescription doses were: 80 Gy to planning target volume (PTV for the prostate cases, and 70, 60, and 54 Gy to PTV1, PTV2, and PTV3, respectively, for HN cases. Plans were normalized to 95% of the PTV and PTV1, respectively, with the prescription dose. Plans were assessed using Dose-Volume-Histogram metrics, homogeneity index, conformity index, MUs, and delivery time. Results: For the prostate cases, significant differences were found for rectum D35 between VDR and all CDR plans, except CDR500. Furthermore, VDR was significantly different than CDR100 and 200 for bladder D50. Delivery time for all CDR plans and MUs for CDR400–600 were significantly higher when compared to VDR. HN cases showed significant differences between VDR and CDR100, 500 and 600 for D2 to the cord and brainstem. Significant differences were found for delivery time and MUs for all CDR plans, except CDR100 for number of MUs. Conclusion: The most significant differences were observed in delivery time and number of MUs. All-in-all, the best CDR for prostate cases was found to be 300 MUs/min and 200 or 300 MUs/min for HN cases. However, VDR plans are still the choice in terms of MU efficiency and plan quality.

  1. Mayak Film Dosimeter Response Studies Part III: Application to Worker Dose Assessment

    International Nuclear Information System (INIS)

    Smetanin, Mikhail; Vasilenko, E. K.; Scherpelz, Robert I.

    2007-01-01

    This paper describes the methods used to convert individual dosimeter readings for workers to obtain estimates of worker doses received in Mayak facilities. Film dosimeters were used at Mayak PA for worker monitoring from 1948 until 1992. The method requires a determination of the relationship between the absorbed dose in film emulsion and the dose in air under calibration conditions, then an extension of this relationship to exposures in the actual radiation fields of the workplace. Corrections needed to account for actual workplace exposure conditions were determined by modeling with the Monte-Carlo radiation transport computer code MCNP. Correction factors were developed to convert from dosimeter reading to a realistic worker dose. The method was applied as a basis for individual dose reconstruction using film dosimeters in realistic photon spectra and geometries at Mayak PA work areas

  2. EPA's Benchmark Dose Modeling Software

    Science.gov (United States)

    The EPA developed the Benchmark Dose Software (BMDS) as a tool to help Agency risk assessors facilitate applying benchmark dose (BMD) method’s to EPA’s human health risk assessment (HHRA) documents. The application of BMD methods overcomes many well know limitations ...

  3. [The methods of assessment of health risk from exposure to radon and radon daughters].

    Science.gov (United States)

    Demin, V F; Zhukovskiy, M V; Kiselev, S M

    2014-01-01

    The critical analysis of existing models of the relationship dose-effect (RDE) for radon exposure on human health has been performed. Conclusion about the necessity and possibility of improving these models has been made. A new improved version ofthe RDE has been developed. A technique for assessing the human health risk of exposure to radon, including the method for estimating of exposure doses of radon, an improved model of RDE, proper methodology risk assessment has been described. Methodology is proposed for the use in the territory of Russia.

  4. Biosphere model for assessing doses from nuclear waste disposal

    International Nuclear Information System (INIS)

    Zach, R.; Amiro, B.D.; Davis, P.A.; Sheppard, S.C.; Szekeley, J.G.

    1994-01-01

    The biosphere model, BIOTRAC, for predicting long term nuclide concentrations and radiological doses from Canada's nuclear fuel waste disposal concept of a vault deep in plutonic rock of the Canadian Shield is presented. This generic, boreal zone biosphere model is based on scenario analysis and systems variability analysis using Monte Carlo simulation techniques. Conservatism is used to bridge uncertainties, even though this creates a small amount of extra nuclide mass. Environmental change over the very long assessment period is mainly handled through distributed parameter values. The dose receptors are a critical group of humans and four generic non-human target organisms. BIOTRAC includes six integrated submodels and it interfaces smoothly with a geosphere model. This interface includes a bedrock well. The geosphere model defines the discharge zones of deep groundwater where nuclides released from the vault enter the biosphere occupied by the dose receptors. The size of one of these zones is reduced when water is withdrawn from the bedrock well. Sensitivity analysis indicates 129 I is by far the most important radionuclide. Results also show bedrock-well water leads to higher doses to man than lake water, but the former doses decrease with the size of the critical group. Under comparable circumstances, doses to the non-human biota are greater than those for man

  5. Dose Assessment Model for Chronic Atmospheric Releases of Tritium

    International Nuclear Information System (INIS)

    Shen Huifang; Yao Rentai

    2010-01-01

    An improved dose assessment model for chronic atmospheric releases of tritium was proposed. The proposed model explicitly considered two chemical forms of tritium.It was based on conservative assumption of transfer of tritiated water (HTO) from air to concentration of HTO and organic beam tritium (OBT) in vegetable and animal products.The concentration of tritium in plant products was calculated based on considering dividedly leafy plant and not leafy plant, meanwhile the concentration contribution of tritium in the different plants from the tritium in soil was taken into account.Calculating the concentration of HTO in animal products, average water fraction of animal products and the average weighted tritium concentration of ingested water based on the fraction of water supplied by each source were considered,including skin absorption, inhalation, drinking water and food.Calculating the annual doses, the ingestion doses were considered, at the same time the contribution of inhalation and skin absorption to the dose was considered. Concentrations in foodstuffs and dose of annual adult calculated with the specific activity model, NEWTRI model and the model proposed by the paper were compared. The results indicate that the model proposed by the paper can predict accurately tritium doses through the food chain from chronic atmospheric releases. (authors)

  6. Variability in CT lung-nodule volumetry: Effects of dose reduction and reconstruction methods.

    Science.gov (United States)

    Young, Stefano; Kim, Hyun J Grace; Ko, Moe Moe; Ko, War War; Flores, Carlos; McNitt-Gray, Michael F

    2015-05-01

    Measuring the size of nodules on chest CT is important for lung cancer staging and measuring therapy response. 3D volumetry has been proposed as a more robust alternative to 1D and 2D sizing methods. There have also been substantial advances in methods to reduce radiation dose in CT. The purpose of this work was to investigate the effect of dose reduction and reconstruction methods on variability in 3D lung-nodule volumetry. Reduced-dose CT scans were simulated by applying a noise-addition tool to the raw (sinogram) data from clinically indicated patient scans acquired on a multidetector-row CT scanner (Definition Flash, Siemens Healthcare). Scans were simulated at 25%, 10%, and 3% of the dose of their clinical protocol (CTDIvol of 20.9 mGy), corresponding to CTDIvol values of 5.2, 2.1, and 0.6 mGy. Simulated reduced-dose data were reconstructed with both conventional filtered backprojection (B45 kernel) and iterative reconstruction methods (SAFIRE: I44 strength 3 and I50 strength 3). Three lab technologist readers contoured "measurable" nodules in 33 patients under each of the different acquisition/reconstruction conditions in a blinded study design. Of the 33 measurable nodules, 17 were used to estimate repeatability with their clinical reference protocol, as well as interdose and inter-reconstruction-method reproducibilities. The authors compared the resulting distributions of proportional differences across dose and reconstruction methods by analyzing their means, standard deviations (SDs), and t-test and F-test results. The clinical-dose repeatability experiment yielded a mean proportional difference of 1.1% and SD of 5.5%. The interdose reproducibility experiments gave mean differences ranging from -5.6% to -1.7% and SDs ranging from 6.3% to 9.9%. The inter-reconstruction-method reproducibility experiments gave mean differences of 2.0% (I44 strength 3) and -0.3% (I50 strength 3), and SDs were identical at 7.3%. For the subset of repeatability cases, inter-reconstruction-method

  7. Dose Assessment using Chromosome Aberration Analyses in Human Peripheral Blood Lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Tae Ho; Kim, Jin-Hong; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The healthy five donors were recruited to establish the dose-response calibration curve for chromosomal aberrations by ionizing radiation exposure. Our cytogenetic results revealed that the mean frequency of chromosome aberration increased with increasing radiation dose. In this study, dicentric assay and CBMN assay were compared considering the sensitivity and accuracy of dose estimation. Therefore, these chromosome aberration analyses will be the foundation for biological dosimetric analysis with additional research methods such as translocation and PCC assay. The conventional analysis of dicentric chromosomes in HPBL was suggested by Bender and Gooch in 1962. This assay has been for many years, the golden standard and the most specific method for ionizing radiation damage. The dicentric assay technique in HPBL has been shown as the most sensitive biological method and reliable bio-indicator of quantifying the radiation dose. In contrast, the micronucleus assay has advantages over the dicentric assay since it is rapid and requires less specialized expertise, and accordingly it can be applied to monitor a big population. The cytokinesis-block micronucleus (CBMN) assay is a suitable method for micronuceli measurement in cultured human as well as mammalian cells. The aim of our study was to establish the dose response curve of radiation-induced chromosome aberrations in HPBL by analyzing the frequency of dicentrics and micronuclei.

  8. Dose assessment of the patient and the helper in emergency head computed tomography

    International Nuclear Information System (INIS)

    Chang, Rong-Chou; Yu, Cheng-Ching; Hsu, Fang-Yuh; Chen, Tou-Rong; Hsu, Shih-Ming; Tyan, Yeu-Sheng

    2011-01-01

    Computed Tomography (CT) becomes more and more important and is frequently used in modern diagnostic techniques. CT offers an effective diagnosis on lesion and pathology; however, it also delivers a radiation dose to patients. Besides, in some special emergency cases, the patient may require someone to help him in the examination room to perform the head CT, due to the patient lost intellectual and operational capacity. This study evaluated the delivered radiation dose and the risk of radiation-induced cancer for the patient and for the helper after carrying out the emergent head CT examination. A Rando phantom with thermoluminescent dosimeter (TLD) chips inside relevant organs was used to simulate the patient during head CT examination. An effective dose of 2.06 ± 0.16 mSv and 1.46 ± 0.07 mSv without and with wearing the lead apron were found respectively, considering ICRP 60 recommendation. ICRP 103 recommendations the readings would have been 1.29 ± 0.15 mSv and 0.71 ± 0.04 mSv. The effective dose determined from the dose-length product (DLP) method (2.19 mSv) was similar to the value (2.06 ± 0.16 mSv) estimated by TLD method considering the ICRP 60 recommendation (without lead apron). Assuming a 5% total risk for fatal cancer per Sv in the general population, risk of radiation-induced cancer for patients were 1.03 × 10 −2 % (without lead apron) and 7.80 × 10 −3 % (with lead apron) for ICRP 60, and were 6.45 × 10 −3 % (without lead apron) and 3.55 × 10 −3 % (with lead apron) for ICRP 103. The dose received by the helper was assessed by wearing a personal badge. The helper during emergent head CT examination may receive a personal dose equivalent (H p (10)) of 19.36 ± 5.89 μSv and 138.81 ± 101.28 μSv with and without lead apron, respectively, at distance of 0.3–1 m from the center of CT scanner. Based on the observed dose reduction of a factor of 7.17 we recommend that helpers wear lead apron in the CT examination room.

  9. Dose measurement method suitable for management of food irradiation

    International Nuclear Information System (INIS)

    Tanaka, Ryuichi

    1990-01-01

    The report describes major features of dose measurement performed for the management of food irradiation processes, and dose measuring methods suitable for this purpose, and outlines some activities for establishing international standards for dose measurement. Traceability studies made recently are also reviewed. Compared with the sterilization of medical materials, food irradiation is different in some major points from a viewpoint of dose measurement: foods can undergo significant changes in bulk density, depending on its properties, during irradiation, and the variation in the uniformity of bulk density can be large within an irradiation unit and among different units. An accurate dosimeter and well-established traceability are essential for food irradiation control, and basically a dosimeter should be high in reproducibility and stable in dose response, and should be easy to readjust for eliminating systematic errors. A new type of dosimeter was developed recently, in which ESR is used to measure the free radicals generated by radiations in crystals of alanine, an amino acid. Standardization of large dose measurement procedures has been carried out by committee E10 set up under ASTM. (N.K.)

  10. Monte Carlo assessment of the dose rates produced by spent fuel from CANDU reactors

    International Nuclear Information System (INIS)

    Pantazi, Doina; Mateescu, Silvia; Stanciu, Marcela

    2003-01-01

    One of the technical measures considered for biological protection is radiation shielding. The implementation process of a spent fuel intermediate storage system at Cernavoda NPP includes an evolution in computation methods related to shielding evaluation: from using simpler computer codes, like MicroShield and QAD, to systems of codes, like SCALE (which contains few independent modules) and the multipurpose and multi-particles transport code MCNP, based on Monte Carlo method. The Monte Carlo assessment of the dose rates produced by CANDU type spent fuel, during its handling for the intermediate storage, is the main objective of this paper. The work had two main features: -establishing of geometrical models according to description mode used in code MCNP, capable to account for the specific characteristics of CANDU nuclear fuel; - confirming the correctness of proposed models, by comparing MCNP results and the related results obtained with other computer codes for shielding evaluation and dose rates calculations. (authors)

  11. Monitoring requirements for assessment of internal dose

    International Nuclear Information System (INIS)

    Eckerman, K.F.

    1985-01-01

    Data obtained by routine personnel monitoring is usually not a sufficient basis for estimation of dose. Collected data must be interpreted carefully and supplemented with appropriate information before reasonably accurate estimates of dose (i.e., accurate enough to indicate whether or nor personnel are exposed in excess of recommended limits) can be developed. When the exposure is of sufficient magnitude that a rather precise estimate of dose is needed, the health physicist will bring to bear on the problem other, more refined, methods of dosimetry. These might include a reconstruction of the incident and, for internal emitters, an extensive series of in vivo measurements or analyses of excreta. Thus, cases of special significance must often be evaluated using techniques and resources beyond those routinely employed. This is not a criticism of most routine monitoring programs. These programs are usually carefully designed in a manner commensurate with the degree of exposure routinely encountered and the requirement of a practical program of radiation protection. 10 refs

  12. An effective dose assessment technique with NORM added consumer products using skin-point source on computational human phantom

    International Nuclear Information System (INIS)

    Yoo, Do Hyeon; Shin, Wook-Geun; Lee, Hyun Cheol; Choi, Hyun Joon; Testa, Mauro; Lee, Jae Kook; Yeom, Yeon Soo; Kim, Chan Hyeong; Min, Chul Hee

    2016-01-01

    The aim of this study is to develop the assessment technique of the effective dose by calculating the organ equivalent dose with a Monte Carlo (MC) simulation and a computational human phantom for the naturally occurring radioactive material (NORM) added consumer products. In this study, we suggests the method determining the MC source term based on the skin-point source enabling the convenient and conservative modeling of the various type of the products. To validate the skin-point source method, the organ equivalent doses were compared with that by the product modeling source of the realistic shape for the pillow, waist supporter, sleeping mattress etc. Our results show that according to the source location, the organ equivalent doses were observed as the similar tendency for both source determining methods, however, it was observed that the annual effective dose with the skin-point source was conservative than that with the modeling source with the maximum 3.3 times higher dose. With the assumption of the gamma energy of 1 MeV and product activity of 1 Bq g"−"1, the annual effective doses of the pillow, waist supporter and sleeping mattress with skin-point source was 3.09E-16 Sv Bq"−"1 year"−"1, 1.45E-15 Sv Bq"−"1 year"−"1, and 2,82E-16 Sv Bq"−"1 year"−"1, respectively, while the product modeling source showed 9.22E-17 Sv Bq"−"1 year"−"1, 9.29E-16 Sv Bq"−"1 year"−"1, and 8.83E-17 Sv Bq"−"1 year"−"1, respectively. In conclusion, it was demonstrated in this study that the skin-point source method could be employed to efficiently evaluate the annual effective dose due to the usage of the NORM added consumer products. - Highlights: • We evaluate the exposure dose from the usage of NORM added consumer products. • We suggest the method determining the MC source term based on the skin-point source. • To validate the skin-point source, the organ equivalent doses were compared with that the modeling source. • The skin-point source could

  13. The assessment of effects of low doses of ionizing radiations: contributions of epidemiology

    International Nuclear Information System (INIS)

    Verger, P.; Hubert, Ph.; Bard, D.

    1998-01-01

    After a brief recall of the history of the application of epidemiological studies to the field of ionizing radiations (actually to study the consequences of Hiroshima and Nagasaki bombing), and after having outlined that most of these epidemiological studies addressed carcinogenic effects of radiations on populations exposed to doses greater than 0,2 Gy, this article more particularly addresses epidemiological studies for low doses (lower than 0,5-1 Gy). The authors present objectives and methods (monitoring, etiological research, risk quantification), and discuss the limitations of epidemiology and its strengths. In the next part, they comment and discuss the main data sources used for the epidemiological assessment of low doses. These sources respectively deal with Hiroshima and Nagasaki (the Life Span Study, its results in terms of solid cancers and leukaemia, its limitations), with occupational exposures (radiologists, workers in nuclear installations, crews of intercontinental flights, Chernobyl liquidators, uranium minors exposed to radon), with environmental exposures (domestic exposures to radon, exposure to natural radiation, to nuclear test fallouts, and to Chernobyl accident fallouts, exposure about nuclear installations), and with other types of exposure

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

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN/MG), Belo Horizonte, MG (Brazil)], e-mail: gas@cdtn.br, e-mail: pls@cdtn.br, e-mail: fcp@cdtn.br, e-mail: lcmb@cdtn.br, e-mail: pabloag@cdtn.br

    2009-07-01

    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)

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

    International Nuclear Information System (INIS)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade

    2009-01-01

    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)

  16. Radiation Doses to Members of the U.S. Population from Ubiquitous Radionuclides in the Body: Part 2, Methods and Dose Calculations

    International Nuclear Information System (INIS)

    Watson, David J.; Strom, Daniel J.

    2011-01-01

    This paper is part two of a three-part series investigating annual effective doses to residents of the United States from intakes of ubiquitous radionuclides, including radionuclides occurring naturally, radionuclides whose concentrations are technologically enhanced, and anthropogenic radionuclides. This series of papers explicitly excludes intakes from inhaling 222Rn, 220Rn, and their short-lived decay products; it also excludes intakes of radionuclides in occupational and medical settings. Part one reviewed, summarized, characterized, and grouped all published and some unpublished data for U.S. residents on ubiquitous radionuclide concentrations in tissues and organs. Assumptions about equilibrium with long-lived parents are made for the 28 other radionuclides in these series lacking data. This paper describes the methods developed to group the collected data into source regions described in the Radiation Dose Assessment Resource (RADAR) dosimetric methodology. Methods for converting the various units of data published over 50 years into a standard form are developed and described. Often, meaningful values of uncertainty of measurements were not published so that variability in data sets is confounded with measurement uncertainty. A description of the methods developed to estimate variability is included in this paper. The data described in part one are grouped by gender and age to match the RADAR dosimetric phantoms. Within these phantoms, concentration values are grouped into source tissue regions by radionuclide, and they are imputed for source regions lacking tissue data. Radionuclide concentrations are then imputed for other phantoms source regions with missing concentration values, and the uncertainties of the imputed values are increased. The content concentrations of hollow organs are calculated, and activities are apportioned to the bone source regions using assumptions about each radionuclide's bone-seeking behavior. The data sets are then ready to be

  17. A method for calculating Bayesian uncertainties on internal doses resulting from complex occupational exposures

    International Nuclear Information System (INIS)

    Puncher, M.; Birchall, A.; Bull, R. K.

    2012-01-01

    Estimating uncertainties on doses from bioassay data is of interest in epidemiology studies that estimate cancer risk from occupational exposures to radionuclides. Bayesian methods provide a logical framework to calculate these uncertainties. However, occupational exposures often consist of many intakes, and this can make the Bayesian calculation computationally intractable. This paper describes a novel strategy for increasing the computational speed of the calculation by simplifying the intake pattern to a single composite intake, termed as complex intake regime (CIR). In order to assess whether this approximation is accurate and fast enough for practical purposes, the method is implemented by the Weighted Likelihood Monte Carlo Sampling (WeLMoS) method and evaluated by comparing its performance with a Markov Chain Monte Carlo (MCMC) method. The MCMC method gives the full solution (all intakes are independent), but is very computationally intensive to apply routinely. Posterior distributions of model parameter values, intakes and doses are calculated for a representative sample of plutonium workers from the United Kingdom Atomic Energy cohort using the WeLMoS method with the CIR and the MCMC method. The distributions are in good agreement: posterior means and Q 0.025 and Q 0.975 quantiles are typically within 20 %. Furthermore, the WeLMoS method using the CIR converges quickly: a typical case history takes around 10-20 min on a fast workstation, whereas the MCMC method took around 12-hr. The advantages and disadvantages of the method are discussed. (authors)

  18. Personnel neutron dose assessment upgrade: Volume 2, Field neutron spectrometer for health physics applications

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; Reece, W.D.; Miller, S.D.

    1988-07-01

    Both the (ICRP) and the (NCPR) have recommended an increase in neutron quality factors and the adoption of effective dose equivalent methods. The series of reports entitled Personnel Neutron Dose Assessment Upgrade (PNL-6620) addresses these changes. Volume 1 in this series of reports (Personnel Neutron Dosimetry Assessment) provided guidance on the characteristics, use, and calibration of personnel neutron dosimeters in order to meet the new recommendations. This report, Volume 2: Field Neutron Spectrometer for Health Physics Applications describes the development of a portable field spectrometer which can be set up for use in a few minutes by a single person. The field spectrometer described herein represents a significant advance in improving the accuracy of neutron dose assessment. It permits an immediate analysis of the energy spectral distribution associated with the radiation from which neutron quality factor can be determined. It is now possible to depart from the use of maximum Q by determining and realistically applying a lower Q based on spectral data. The field spectrometer is made up of two modules: a detector module with built-in electronics and an analysis module with a IBM PC/reg sign/-compatible computer to control the data acquisition and analysis of data in the field. The unit is simple enough to allow the operator to perform spectral measurements with minimal training. The instrument is intended for use in steady-state radiation fields with neutrons energies covering the fission spectrum range. The prototype field spectrometer has been field tested in plutonium processing facilities, and has been proven to operate satisfactorily. The prototype field spectrometer uses a 3 He proportional counter to measure the neutron energy spectrum between 50 keV and 5 MeV and a tissue equivalent proportional counter (TEPC) to measure absorbed neutron dose

  19. Influence of radiation dose and reconstruction algorithm in MDCT assessment of airway wall thickness: A phantom study

    International Nuclear Information System (INIS)

    Gomez-Cardona, Daniel; Nagle, Scott K.; Li, Ke; Chen, Guang-Hong; Robinson, Terry E.

    2015-01-01

    Purpose: Wall thickness (WT) is an airway feature of great interest for the assessment of morphological changes in the lung parenchyma. Multidetector computed tomography (MDCT) has recently been used to evaluate airway WT, but the potential risk of radiation-induced carcinogenesis—particularly in younger patients—might limit a wider use of this imaging method in clinical practice. The recent commercial implementation of the statistical model-based iterative reconstruction (MBIR) algorithm, instead of the conventional filtered back projection (FBP) algorithm, has enabled considerable radiation dose reduction in many other clinical applications of MDCT. The purpose of this work was to study the impact of radiation dose and MBIR in the MDCT assessment of airway WT. Methods: An airway phantom was scanned using a clinical MDCT system (Discovery CT750 HD, GE Healthcare) at 4 kV levels and 5 mAs levels. Both FBP and a commercial implementation of MBIR (Veo TM , GE Healthcare) were used to reconstruct CT images of the airways. For each kV–mAs combination and each reconstruction algorithm, the contrast-to-noise ratio (CNR) of the airways was measured, and the WT of each airway was measured and compared with the nominal value; the relative bias and the angular standard deviation in the measured WT were calculated. For each airway and reconstruction algorithm, the overall performance of WT quantification across all of the 20 kV–mAs combinations was quantified by the sum of squares (SSQs) of the difference between the measured and nominal WT values. Finally, the particular kV–mAs combination and reconstruction algorithm that minimized radiation dose while still achieving a reference WT quantification accuracy level was chosen as the optimal acquisition and reconstruction settings. Results: The wall thicknesses of seven airways of different sizes were analyzed in the study. Compared with FBP, MBIR improved the CNR of the airways, particularly at low radiation dose

  20. Influence of radiation dose and reconstruction algorithm in MDCT assessment of airway wall thickness: A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Cardona, Daniel [Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Nagle, Scott K. [Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53792 (United States); Department of Pediatrics, University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53792 (United States); Li, Ke; Chen, Guang-Hong, E-mail: gchen7@wisc.edu [Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53792 (United States); Robinson, Terry E. [Department of Pediatrics, Stanford School of Medicine, 770 Welch Road, Palo Alto, California 94304 (United States)

    2015-10-15

    Purpose: Wall thickness (WT) is an airway feature of great interest for the assessment of morphological changes in the lung parenchyma. Multidetector computed tomography (MDCT) has recently been used to evaluate airway WT, but the potential risk of radiation-induced carcinogenesis—particularly in younger patients—might limit a wider use of this imaging method in clinical practice. The recent commercial implementation of the statistical model-based iterative reconstruction (MBIR) algorithm, instead of the conventional filtered back projection (FBP) algorithm, has enabled considerable radiation dose reduction in many other clinical applications of MDCT. The purpose of this work was to study the impact of radiation dose and MBIR in the MDCT assessment of airway WT. Methods: An airway phantom was scanned using a clinical MDCT system (Discovery CT750 HD, GE Healthcare) at 4 kV levels and 5 mAs levels. Both FBP and a commercial implementation of MBIR (Veo{sup TM}, GE Healthcare) were used to reconstruct CT images of the airways. For each kV–mAs combination and each reconstruction algorithm, the contrast-to-noise ratio (CNR) of the airways was measured, and the WT of each airway was measured and compared with the nominal value; the relative bias and the angular standard deviation in the measured WT were calculated. For each airway and reconstruction algorithm, the overall performance of WT quantification across all of the 20 kV–mAs combinations was quantified by the sum of squares (SSQs) of the difference between the measured and nominal WT values. Finally, the particular kV–mAs combination and reconstruction algorithm that minimized radiation dose while still achieving a reference WT quantification accuracy level was chosen as the optimal acquisition and reconstruction settings. Results: The wall thicknesses of seven airways of different sizes were analyzed in the study. Compared with FBP, MBIR improved the CNR of the airways, particularly at low radiation dose

  1. Dose calculation method with 60-cobalt gamma rays in total body irradiation

    International Nuclear Information System (INIS)

    Scaff, Luiz Alberto Malaguti

    2001-01-01

    Physical factors associated to total body irradiation using 60 Co gamma rays beams, were studied in order to develop a calculation method of the dose distribution that could be reproduced in any radiotherapy center with good precision. The method is based on considering total body irradiation as a large and irregular field with heterogeneities. To calculate doses, or doses rates, of each area of interest (head, thorax, thigh, etc.), scattered radiation is determined. It was observed that if dismagnified fields were considered to calculate the scattered radiation, the resulting values could be applied on a projection to the real size to obtain the values for dose rate calculations. In a parallel work it was determined the variation of the dose rate in the air, for the distance of treatment, and for points out of the central axis. This confirm that the use of the inverse square law is not valid. An attenuation curve for a broad beam was also determined in order to allow the use of absorbers. In this work all the adapted formulas for dose rate calculations in several areas of the body are described, as well time/dose templates sheets for total body irradiation. The in vivo dosimetry, proved that either experimental or calculated dose rate values (achieved by the proposed method), did not have significant discrepancies. (author)

  2. Public Dose Assessment Modeling from Skyshine by Proton Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Mwambinga, S. A. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Yoo, S. J. [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2013-10-15

    In this paper, the skyshine dose by proton accelerator (230 MeV) has been evaluated. The amount of dose by skyshine is related to some influence factors which are emission angle (Height wall), the thickness of ceiling and distance from source to receptor (Human body). Empirical formula is made by using MCNPX code results. It can easily calculate and assess dose from skyshine by proton accelerator. The skyshine doses are calculated with MCNPX code and DCFs in ICRP 116. Thereafter, we made empirical formula which can calculate dose easily and be compared with the results of MCNPX. The maximum exposure point by skyshine is about 5 ∼ 10 m from source. Therefore, the licensee who wants to operate the proton accelerator must keep the appropriate distance from accelerator and set the fence to restrict the approach by the public. And, exposure doses by accelerator depend on operating time and proton beam intensities. Eq. (6) suggested in this study is just considered for mono energy proton accelerator. Therefore, it is necessary to expand the dose calculation to diverse proton energies. Radiations like neutron and photon generated by high energy proton accelerators over 10 MeV, are important exposure sources to be monitored to radiation workers and the public members near the facility. At that case, one of the exposure pathways to the public who are located in near the facility is skyshine. Neutrons and photons can be scattered by the atmosphere near the facility and exposed to public as scattered dose. All of the facilities using high energy radiation and NDI (Non-Destructive Inspection) which is tested at open field, skyshine dose must be taken into consideration. Skyshine dose is not related to the wall thickness of radiation shielding directly.

  3. Study on dose assessment in surrounding environment of the Tono Mine associated with closure activity

    International Nuclear Information System (INIS)

    Sasao, Eiji

    2012-07-01

    Dose assessment associated with closure activity of the Tono Mine has been performed. In this assessment, exposure dose has been calculated on groundwater and surface water migration of radionuclide from 1) waste rock in the waste rock dump facility, 2) mining waste in the mining waste facility, and 3) uranium ore and waste rock backfilled in the shafts and galleries. Direct and skyshine gamma rays and exposure of exhalated radon from the waste rock dump has also been evaluated. An evaluation tool developed for safety assessment for sub-surface disposal of radioactive waste is utilized for this assessment. Localities for dose evaluation are selected at the Higashihoragawa and Hiyoshigawa based on the topography around the Tono Mine and groundwater flow simulation. Evaluation scenarios are classified into 'Scenario for intake of agricultural product' as the base scenario, and 'Scenario for intake of groundwater' as the alternative scenario. Parameters for dose assessment are set-up based on the existing data. But the range and uncertainty of parameters are taken into account in the 'alternative cases'. As the result of dose assessment, maximum exposure dose of the base scenario is 0.08mSv/year, and 0.09mSv/year including direct and skyshine gamma rays and exposure of exhalatedradon at the Higashihoragawa. Maximum exposure dose of the alternative scenario is 0.08mSv/year (0.09mSv/year including direct and skyshine gamma rays and exposure of exhalated radon). On the alternative cases, exposure doses are calculated as 0.05-0.14mSv/year in both of the base and alternative scenarios. At the Hiyoshigawa, maximum exposure dose is less than 0.001mSv/year (1x10 -6 mSv/year) for the base scenario, and 0.001mSv/year for the alternative scenario. On the alternative cases, maximum exposure doses are less than 0.001mSv/year for all cases of the base scenario and 0.0006-0.002mSv/year for the alternative scenario. (author)

  4. High-Dose Atomoxetine Treatment of ADHD in Youths with Limited Response to Standard Doses

    Science.gov (United States)

    Kratochvil, Christopher J.; Michelson, David; Newcorn, Jeffrey H.; Weiss, Margaret D.; Busner, Joan; Moore, Rodney J.; Ruff, Dustin D.; Ramsey, Janet; Dickson, Ruth; Turgay, Atilla; Saylor, Keith E.; Luber, Stephen; Vaughan, Brigette; Allen, Albert J.

    2007-01-01

    Objective: To assess the utility and tolerability of higher than standard atomoxetine doses to treat attention-deficit/hyperactivity disorder (ADHD). Method: Two randomized, double-blind trials of atomoxetine nonresponders ages 6 to 16 years were conducted comparing continued treatment with same-dose atomoxetine to treatment using greater than…

  5. A comparison study of size-specific dose estimate calculation methods

    Energy Technology Data Exchange (ETDEWEB)

    Parikh, Roshni A. [Rainbow Babies and Children' s Hospital, University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Department of Radiology, Cleveland, OH (United States); University of Michigan Health System, Department of Radiology, Ann Arbor, MI (United States); Wien, Michael A.; Jordan, David W.; Ciancibello, Leslie; Berlin, Sheila C. [Rainbow Babies and Children' s Hospital, University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Department of Radiology, Cleveland, OH (United States); Novak, Ronald D. [Rainbow Babies and Children' s Hospital, University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Department of Radiology, Cleveland, OH (United States); Rebecca D. Considine Research Institute, Children' s Hospital Medical Center of Akron, Center for Mitochondrial Medicine Research, Akron, OH (United States); Klahr, Paul [CT Clinical Science, Philips Healthcare, Highland Heights, OH (United States); Soriano, Stephanie [Rainbow Babies and Children' s Hospital, University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Department of Radiology, Cleveland, OH (United States); University of Washington, Department of Radiology, Seattle, WA (United States)

    2018-01-15

    The size-specific dose estimate (SSDE) has emerged as an improved metric for use by medical physicists and radiologists for estimating individual patient dose. Several methods of calculating SSDE have been described, ranging from patient thickness or attenuation-based (automated and manual) measurements to weight-based techniques. To compare the accuracy of thickness vs. weight measurement of body size to allow for the calculation of the size-specific dose estimate (SSDE) in pediatric body CT. We retrospectively identified 109 pediatric body CT examinations for SSDE calculation. We examined two automated methods measuring a series of level-specific diameters of the patient's body: method A used the effective diameter and method B used the water-equivalent diameter. Two manual methods measured patient diameter at two predetermined levels: the superior endplate of L2, where body width is typically most thin, and the superior femoral head or iliac crest (for scans that did not include the pelvis), where body width is typically most thick; method C averaged lateral measurements at these two levels from the CT projection scan, and method D averaged lateral and anteroposterior measurements at the same two levels from the axial CT images. Finally, we used body weight to characterize patient size, method E, and compared this with the various other measurement methods. Methods were compared across the entire population as well as by subgroup based on body width. Concordance correlation (ρ{sub c}) between each of the SSDE calculation methods (methods A-E) was greater than 0.92 across the entire population, although the range was wider when analyzed by subgroup (0.42-0.99). When we compared each SSDE measurement method with CTDI{sub vol,} there was poor correlation, ρ{sub c}<0.77, with percentage differences between 20.8% and 51.0%. Automated computer algorithms are accurate and efficient in the calculation of SSDE. Manual methods based on patient thickness provide

  6. Method and apparatus for determining the dose value of neutrons

    International Nuclear Information System (INIS)

    Burgkhardt, B.; Piesch, E.

    1976-01-01

    A method is provided for determining the dose value of neutrons leaving a body as thermal and intermediate neutrons after having been scattered in the body. A first dose value of thermal and intermediate neutrons is detected on the surface of the body by means of a first detector for neutrons which is shielded against thermal and intermediate neutrons not emerging from the body. A second detector is used to measure a second dose value of the thermal and intermediate neutrons not emerging from the body. A first correction factor based on the first and second values is obtained from a calibration diagram and is applied to the first dose value to determine a first corrected first dose value. 21 Claims, 6 Drawing Figures

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

    International Nuclear Information System (INIS)

    Tsapaki, V.; Vardalaki, E.; Kottou, S.; Molfetas, M.; Neofotistou, V.

    2002-01-01

    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

  8. Discussion on the method of environmental radiological impact assessment for the highway construction project

    International Nuclear Information System (INIS)

    Qiu Guohua

    2008-01-01

    Based on the characteristics and environmental radiological impact of the highway construction project, the basic procedure of environmental radiological impact assessment for the highway construction project is put forward, including analysis and determination of contamination sources, selection of evaluation factors, determination of assessment range and dose limit, environmental investigation, environmental impact prediction and assessment. The working method of each procedure is analyzed. (authors)

  9. A method to adjust radiation dose-response relationships for clinical risk factors

    DEFF Research Database (Denmark)

    Appelt, Ane Lindegaard; Vogelius, Ivan R

    2012-01-01

    Several clinical risk factors for radiation induced toxicity have been identified in the literature. Here, we present a method to quantify the effect of clinical risk factors on radiation dose-response curves and apply the method to adjust the dose-response for radiation pneumonitis for patients...

  10. An assessment of mumps vaccine effectiveness by dose during an outbreak in Canada.

    Science.gov (United States)

    Deeks, Shelley L; Lim, Gillian H; Simpson, Mary Anne; Gagné, Louise; Gubbay, Jonathan; Kristjanson, Erik; Fung, Cecilia; Crowcroft, Natasha S

    2011-06-14

    This investigation was done to assess vaccine effectiveness of one and two doses of the measles, mumps and rubella (MMR) vaccine during an outbreak of mumps in Ontario. The level of coverage required to reach herd immunity and interrupt community transmission of mumps was also estimated. Information on confirmed cases of mumps was retrieved from Ontario's integrated Public Health Information System. Cases that occurred between Sept. 1, 2009, and June 10, 2010, were included. Selected health units supplied coverage data from the Ontario Immunization Record Information System. Vaccine effectiveness by dose was calculated using the screening method. The basic reproductive number (R(0)) represents the average number of new infections per case in a fully susceptible population, and R(0) values of between 4 and 10 were considered for varying levels of vaccine effectiveness. A total of 134 confirmed cases of mumps were identified. Information on receipt of MMR vaccine was available for 114 (85.1%) cases, of whom 63 (55.3%) reported having received only one dose of vaccine; 32 (28.1%) reported having received two doses. Vaccine effectiveness of one dose of the MMR vaccine ranged from 49.2% to 81.6%, whereas vaccine effectiveness of two doses ranged from 66.3% to 88.0%. If we assume vaccine effectiveness of 85% for two doses of the vaccine, vaccine coverage of 88.2% and 98.0% would be needed to interrupt community transmission of mumps if the corresponding reproductive values were four and six. Our estimates of vaccine effectiveness of one and two doses of mumps-containing vaccine were consistent with the estimates that have been reported in other outbreaks. Outbreaks occurring in Ontario and elsewhere serve as a warning against complacency over vaccination programs.

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

    International Nuclear Information System (INIS)

    Sayah, R.; Martinetti, F.; Donadille, L.; Clairand, I.; Delacroix, S.; De Oliveira, A.; Herault, J.

    2010-01-01

    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

  12. Dose assessment of an accidental exposure at the IPNS

    International Nuclear Information System (INIS)

    Campos Torres, M.M.

    1995-02-01

    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

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

    International Nuclear Information System (INIS)

    Unger, L.M.; Trubey, D.K.

    1982-05-01

    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

  14. Measurement of annual dose on porcelain using surface TLD method

    International Nuclear Information System (INIS)

    Xia Junding; Wang Weida; Leung, P.L.

    2001-01-01

    In order to improve accuracy of TL authentication test for porcelain, a method of measurement of annual dose using ultrathin (CaSO 4 :Tm) dosage layer on porcelain was studied. The TLD was placed on the part of porcelain without glaze. A comparison of measurement of annual dose for surface TLD, inside TLD and alpha counting on porcelain was made. The results show that this technique is suitable for measuring annual dose and improving accuracy of TL authentication test for both porcelain and pottery

  15. Generation of uniformly distributed dose points for anatomy-based three-dimensional dose optimization methods in brachytherapy.

    Science.gov (United States)

    Lahanas, M; Baltas, D; Giannouli, S; Milickovic, N; Zamboglou, N

    2000-05-01

    We have studied the accuracy of statistical parameters of dose distributions in brachytherapy using actual clinical implants. These include the mean, minimum and maximum dose values and the variance of the dose distribution inside the PTV (planning target volume), and on the surface of the PTV. These properties have been studied as a function of the number of uniformly distributed sampling points. These parameters, or the variants of these parameters, are used directly or indirectly in optimization procedures or for a description of the dose distribution. The accurate determination of these parameters depends on the sampling point distribution from which they have been obtained. Some optimization methods ignore catheters and critical structures surrounded by the PTV or alternatively consider as surface dose points only those on the contour lines of the PTV. D(min) and D(max) are extreme dose values which are either on the PTV surface or within the PTV. They must be avoided for specification and optimization purposes in brachytherapy. Using D(mean) and the variance of D which we have shown to be stable parameters, achieves a more reliable description of the dose distribution on the PTV surface and within the PTV volume than does D(min) and D(max). Generation of dose points on the real surface of the PTV is obligatory and the consideration of catheter volumes results in a realistic description of anatomical dose distributions.

  16. An assessment of effective dose to staff in external beam radiotherapy

    International Nuclear Information System (INIS)

    Rawlings, D.J.; Nicholson, L.

    1997-01-01

    Radiation safety in external beam radiotherapy is governed by national legislation. Annual doses recorded by radiographers and others associated with external beam radiotherapy are typically much lower than the relevant dose limit. However, it is possible that larger doses might be received as a result of an accidental irradiation. In the event of a significant exposure resulting in a dose at or near a relevant dose limit, an accurate conversion has to be made from the dose meter reading to the limiting quantity. A method was devised to demonstrate ratios of effective dose to personal dose equivalent which might be anticipated in the even of an individual other than the patient being irradiated within a radiotherapy treatment room consisting of a linear accelerator. The variation of ratios obtained under different conditions is discussed. (author)

  17. SU-E-T-616: Plan Quality Assessment of Both Treatment Planning System Dose and Measurement-Based 3D Reconstructed Dose in the Patient

    International Nuclear Information System (INIS)

    Olch, A

    2015-01-01

    Purpose: Systematic radiotherapy plan quality assessment promotes quality improvement. Software tools can perform this analysis by applying site-specific structure dose metrics. The next step is to similarly evaluate the quality of the dose delivery. This study defines metrics for acceptable doses to targets and normal organs for a particular treatment site and scores each plan accordingly. The input can be the TPS or the measurement-based 3D patient dose. From this analysis, one can determine whether the delivered dose distribution to the patient receives a score which is comparable to the TPS plan score, otherwise replanning may be indicated. Methods: Eleven neuroblastoma patient plans were exported from Eclipse to the Quality Reports program. A scoring algorithm defined a score for each normal and target structure based on dose-volume parameters. Each plan was scored by this algorithm and the percentage of total possible points was obtained. Each plan also underwent IMRT QA measurements with a Mapcheck2 or ArcCheck. These measurements were input into the 3DVH program to compute the patient 3D dose distribution which was analyzed using the same scoring algorithm as the TPS plan. Results: The mean quality score for the TPS plans was 75.37% (std dev=14.15%) compared to 71.95% (std dev=13.45%) for the 3DVH dose distribution. For 3/11 plans, the 3DVH-based quality score was higher than the TPS score, by between 0.5 to 8.4 percentage points. Eight/11 plans scores decreased based on IMRT QA measurements by 1.2 to 18.6 points. Conclusion: Software was used to determine the degree to which the plan quality score differed between the TPS and measurement-based dose. Although the delivery score was generally in good agreement with the planned dose score, there were some that improved while there was one plan whose delivered dose quality was significantly less than planned. This methodology helps evaluate both planned and delivered dose quality. Sun Nuclear Corporation has

  18. SU-E-T-616: Plan Quality Assessment of Both Treatment Planning System Dose and Measurement-Based 3D Reconstructed Dose in the Patient

    Energy Technology Data Exchange (ETDEWEB)

    Olch, A [University of Southern California, Los Angeles, CA (United States)

    2015-06-15

    Purpose: Systematic radiotherapy plan quality assessment promotes quality improvement. Software tools can perform this analysis by applying site-specific structure dose metrics. The next step is to similarly evaluate the quality of the dose delivery. This study defines metrics for acceptable doses to targets and normal organs for a particular treatment site and scores each plan accordingly. The input can be the TPS or the measurement-based 3D patient dose. From this analysis, one can determine whether the delivered dose distribution to the patient receives a score which is comparable to the TPS plan score, otherwise replanning may be indicated. Methods: Eleven neuroblastoma patient plans were exported from Eclipse to the Quality Reports program. A scoring algorithm defined a score for each normal and target structure based on dose-volume parameters. Each plan was scored by this algorithm and the percentage of total possible points was obtained. Each plan also underwent IMRT QA measurements with a Mapcheck2 or ArcCheck. These measurements were input into the 3DVH program to compute the patient 3D dose distribution which was analyzed using the same scoring algorithm as the TPS plan. Results: The mean quality score for the TPS plans was 75.37% (std dev=14.15%) compared to 71.95% (std dev=13.45%) for the 3DVH dose distribution. For 3/11 plans, the 3DVH-based quality score was higher than the TPS score, by between 0.5 to 8.4 percentage points. Eight/11 plans scores decreased based on IMRT QA measurements by 1.2 to 18.6 points. Conclusion: Software was used to determine the degree to which the plan quality score differed between the TPS and measurement-based dose. Although the delivery score was generally in good agreement with the planned dose score, there were some that improved while there was one plan whose delivered dose quality was significantly less than planned. This methodology helps evaluate both planned and delivered dose quality. Sun Nuclear Corporation has

  19. Baseline assessment of doses and risk due to natural radionuclides in edible biota of Domiasiat, Meghalaya, India

    International Nuclear Information System (INIS)

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

    2011-01-01

    Radiation dose-risk assessment was carried out for cereal species Brassica compestris var. dichotoma, Oryza sativa var. Shalum1, Zea mays, Lactuca indica, Cumunis sativum, and Clocasia esculanta due to naturally available radionuclides 40 K, 238 U and 232 Th in Domiasiat area. The activity in biota and corresponding soil was measured by precipitation method using NaI(TI) detector. Transfer factor (TF) was for Oryza spp. (1.00E-01- 40 K, 8.76E-05- 232 Th, and 9.11E-05- 238 U), for Brassica spp. (5.39E-01- 40 K, 8.17E-04- 232 Th and 2.96E-04- 238 U) and for Zea spp. (3.41E-01- 40 K, 5.84E-05- 232 Th, 8.87E-05- 238 U) etc., respectively. A detailed physio-morphological study of the biota and extensive investigation of ecosystem was carried out for assessment. The data was modeled using FASSET for dose estimation and obtained total dose was 1.58E-04 μGy h -1 in Oryza spp., 2.87E-04 μGy h -1 Brassica spp. and 6.90E-03 μGy h -1 in Zea spp. etc. The dose was compared with the UNSCEAR dataset for screening level dose for biota. Zea spp. was more susceptible for the chronic radiation exposure. (author)

  20. A method for describing the doses delivered by transmission x-ray computed tomography

    International Nuclear Information System (INIS)

    Shope, T.B.; Gagne, R.M.; Johnson, G.C.

    1981-01-01

    A method for describing the absorbed dose delivered by x-ray transmission computed tomography (CT) is proposed which provides a means to characterize the dose resulting from CT procedures consisting of a series of adjacent scans. The dose descriptor chosen is the average dose at several locations in the imaged volume of the central scan of the series. It is shown that this average dose, as defined, for locations in the central scan of the series can be obtained from the integral of the dose profile perpendicular to the scan plane at these same locations for a single scan. This method for estimating the average dose from a CT procedure has been evaluated as a function of the number of scans in the multiple scan procedure and location in the dosimetry phantom using single scan dose profiles obtained from five different types of CT systems. For the higher dose regions in the phantoms, the multiple scan dose descriptor derived from the single scan dose profiles overestimates the multiple scan average dose by no more than 10%, provided the procedure consists of at least eight scans

  1. Multicentre evaluation of a novel vaginal dose reporting method in 153 cervical cancer patients

    DEFF Research Database (Denmark)

    Westerveld, Henrike; de Leeuw, Astrid; Kirchheiner, Kathrin

    2016-01-01

    Background and purpose Recently, a vaginal dose reporting method for combined EBRT and BT in cervical cancer patients was proposed. The current study was to evaluate vaginal doses with this method in a multicentre setting, wherein different applicators, dose rates and protocols were used. Materia...

  2. Assessment of the doses due to natural radionuclide in the green leafy vegetables of Domiasiat, Meghalaya India

    International Nuclear Information System (INIS)

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

    2011-01-01

    A radiation dose assessment exercise was carried out for the Ipomea batata, Allium sativum, Dacaus carota, and Solanum tuberosum due to naturally available radionuclide 40 K, 238 U and 232 Th in the Domiasiat area of Meghalaya. The concentration of radionuclides in biota as well as corresponding soil was measured by precipitation method using NaI detector for continuous 12 months. Transfer factor was calculated and was, for 40 K(3.96E-05, 3.40E-05, 3.40E-05, 2.70E-05), for 232 Th(3.94E-05, 3.20E-05, 3.20E-054.93E-05), for 238 U(3.60E-05, 3.89E-05, 3.85E-054.57E-05), respectively in each biota due to each radionuclide. The point source dose distribution (source ↔ target) hypotheses was applied for the consideration of absorbed fraction. The generated data were modeled using the FASSET method and obtained dose was 8.42E-03, 8.36E-03, 7.78E-03, 7.74E-03 μGy h -1 , respectively and finally compared with the IAEA and UNSCEAR dataset for screening level dose for terrestrial biota. (author)

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

    International Nuclear Information System (INIS)

    Robison, W.L.

    1994-11-01

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

  4. Minimum dose method for walking-path planning of nuclear facilities

    International Nuclear Information System (INIS)

    Liu, Yong-kuo; Li, Meng-kun; Xie, Chun-li; Peng, Min-jun; Wang, Shuang-yu; Chao, Nan; Liu, Zhong-kun

    2015-01-01

    Highlights: • For radiation environment, the environment model is proposed. • For the least dose walking path problem, a path-planning method is designed. • The path-planning virtual–real mixed simulation program is developed. • The program can plan walking path and simulate. - Abstract: A minimum dose method based on staff walking road network model was proposed for the walking-path planning in nuclear facilities. A virtual–reality simulation program was developed using C# programming language and Direct X engine. The simulation program was used in simulations dealing with virtual nuclear facilities. Simulation results indicated that the walking-path planning method was effective in providing safety for people walking in nuclear facilities

  5. Integrated Worker Radiation Dose Assessment for the K Basins

    International Nuclear Information System (INIS)

    NELSON, J.V.

    1999-01-01

    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

  6. Ocular organ dose assessment of nuclear medicine workers handling diagnostic radionuclides

    International Nuclear Information System (INIS)

    Cho, Yong In; Kim, Ja Mee; Kim, Jung Hoon

    2017-01-01

    The dose distribution in the ocular organs of nuclear medicine workers during the handling of diagnostic radionuclides was assessed via simulation in virtual space. The cornea and lenses received the highest dose, and the dose distribution tended to be proportional to the gamma-ray energy emitted from the radiation source being handled. Moreover, calculations on the dose-reduction effects of eye-wear protectors for the eyes of the workers showed that the effects were inversely proportional to the emitted gamma-ray energy, with the dose-reduction effect decreasing in the order of "2"0"1Tl, "1"2"3I, "9"9mTc, "6"7Ga, "1"1"1In and "1"8F. Among the considered sources, the dose-reduction effect was significant for sources that emit relatively less energy, namely "1"2"3I, "2"0"1Tl and "9"9mTc, while it was lower for the remaining sources, namely "1"8F, "1"1"1In and "6"7Ga. (authors)

  7. Dose delivery verification and accuracy assessment of stereotaxy in stereotactic radiotherapy and radiosurgery

    International Nuclear Information System (INIS)

    Pelagade, S.M.; Bopche, T.T.; Namitha, K.; Munshi, M.; Bhola, S.; Sharma, H.; Patel, B.K.; Vyas, R.K.

    2008-01-01

    The outcome of stereotactic radiotherapy (SRT) and stereotactic radiosurgery (SRS) in both benign and malignant tumors within the cranial region highly depends on precision in dosimetry, dose delivery and the accuracy assessment of stereotaxy associated with the unit. The frames BRW (Brown-Roberts-Wells) and GTC (Gill- Thomas-Cosman) can facilitate accurate patient positioning as well as precise targeting of tumours. The implementation of this technique may result in a significant benefit as compared to conventional therapy. As the target localization accuracy is improved, the demand for treatment planning accuracy of a TPS is also increased. The accuracy of stereotactic X Knife treatment planning system has two components to verify: (i) the dose delivery verification and the accuracy assessment of stereotaxy; (ii) to ensure that the Cartesian coordinate system associated is well established within the TPS for accurate determination of a target position. Both dose delivery verification and target positional accuracy affect dose delivery accuracy to a defined target. Hence there is a need to verify these two components in quality assurance protocol. The main intention of this paper is to present our dose delivery verification procedure using cylindrical wax phantom and accuracy assessment (target position) of stereotaxy using Geometric Phantom on Elekta's Precise linear accelerator for stereotactic installation

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

    International Nuclear Information System (INIS)

    Olerud, H.M.

    1998-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Olerud, H M

    1998-06-01

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

  10. The Fukushima releases: an inverse modelling approach to assess the source term by using gamma dose rate observations

    Science.gov (United States)

    Saunier, Olivier; Mathieu, Anne; Didier, Damien; Tombette, Marilyne; Quélo, Denis; Winiarek, Victor; Bocquet, Marc

    2013-04-01

    The Chernobyl nuclear accident and more recently the Fukushima accident highlighted that the largest source of error on consequences assessment is the source term estimation including the time evolution of the release rate and its distribution between radioisotopes. Inverse modelling methods have proved to be efficient to assess the source term due to accidental situation (Gudiksen, 1989, Krysta and Bocquet, 2007, Stohl et al 2011, Winiarek et al 2012). These methods combine environmental measurements and atmospheric dispersion models. They have been recently applied to the Fukushima accident. Most existing approaches are designed to use air sampling measurements (Winiarek et al, 2012) and some of them use also deposition measurements (Stohl et al, 2012, Winiarek et al, 2013). During the Fukushima accident, such measurements are far less numerous and not as well distributed within Japan than the dose rate measurements. To efficiently document the evolution of the contamination, gamma dose rate measurements were numerous, well distributed within Japan and they offered a high temporal frequency. However, dose rate data are not as easy to use as air sampling measurements and until now they were not used in inverse modelling approach. Indeed, dose rate data results from all the gamma emitters present in the ground and in the atmosphere in the vicinity of the receptor. They do not allow one to determine the isotopic composition or to distinguish the plume contribution from wet deposition. The presented approach proposes a way to use dose rate measurement in inverse modeling approach without the need of a-priori information on emissions. The method proved to be efficient and reliable when applied on the Fukushima accident. The emissions for the 8 main isotopes Xe-133, Cs-134, Cs-136, Cs-137, Ba-137m, I-131, I-132 and Te-132 have been assessed. The Daiichi power plant events (such as ventings, explosions…) known to have caused atmospheric releases are well identified in

  11. Method for dose calculation in intracavitary irradiation of endometrical carcinoma

    International Nuclear Information System (INIS)

    Zevrieva, I.F.; Ivashchenko, N.T.; Musapirova, N.A.; Fel'dman, S.Z.; Sajbekov, T.S.

    1979-01-01

    A method for dose calculation for the conditions of intracavitary gamma therapy of endometrial carcinoma using spherical and linear 60 Co sources was elaborated. Calculations of dose rates for different amount and orientation of spherical radiation sources and for different planes were made with the aid of BEhSM-4M computer. Dosimet were made with the aid of BEhSM-4M computer. Dosimetric study of dose fields was made using a phantom imitating the real conditions of irradiation. Discrepancies between experimental and calculated values are within the limits of the experiment accuracy

  12. Poster — Thur Eve — 06: Dose assessment of cone beam CT imaging protocols as part of SPECT/CT examinations

    Energy Technology Data Exchange (ETDEWEB)

    Tonkopi, E; Ross, AA [Department of Diagnostic Imaging, Queen Elizabeth II Health Sciences Centre, CDHA (Canada); Department of Radiology, Dalhousie University (Canada)

    2014-08-15

    Purpose: To assess radiation dose from the cone beam CT (CBCT) component of SPECT/CT studies and to compare with other CT examinations performed in our institution. Methods: We used an anthropomorphic chest phantom and the 6 cc ion chamber to measure entrance breast dose for several CBCT and diagnostic CT acquisition protocols. The CBCT effective dose was calculated with ImPACT software; the CT effective dose was evaluated from the DLP value and conversion factor, dependent on the anatomic region. The RADAR medical procedure radiation dose calculator was used to assess the nuclear medicine component of exam dose. Results: The entrance dose to the breast measured with the anthropomorphic phantom was 0.48 mGy and 9.41 mGy for cardiac and chest CBCT scans; and 4.59 mGy for diagnostic thoracic CT. The effective doses were 0.2 mSv, 3.2 mSv and 2.8 mSv respectively. For a small patient represented by the anthropomorphic phantom, the dose from the diagnostic CT was lower than from the CBCT scan, as a result of the exposure reduction options available on modern CT scanners. The CBCT protocols used the same fixed scanning techniques. The diagnostic CT dose based on the patient data was 35% higher than the phantom dose. For most SPECT/CT studies the dose from the CBCT component was comparable with the dose from the radiopharmaceutical. Conclusions: The patient radiation dose from the cone beam CT scan can be higher than that from a diagnostic CT and should be taken into consideration in evaluating total SPECT/CT patient dose.

  13. The current state of knowledge on the use of the benchmark dose concept in risk assessment.

    Science.gov (United States)

    Sand, Salomon; Victorin, Katarina; Filipsson, Agneta Falk

    2008-05-01

    This review deals with the current state of knowledge on the use of the benchmark dose (BMD) concept in health risk assessment of chemicals. The BMD method is an alternative to the traditional no-observed-adverse-effect level (NOAEL) and has been presented as a methodological improvement in the field of risk assessment. The BMD method has mostly been employed in the USA but is presently given higher attention also in Europe. The review presents a number of arguments in favor of the BMD, relative to the NOAEL. In addition, it gives a detailed overview of the several procedures that have been suggested and applied for BMD analysis, for quantal as well as continuous data. For quantal data the BMD is generally defined as corresponding to an additional or extra risk of 5% or 10%. For continuous endpoints it is suggested that the BMD is defined as corresponding to a percentage change in response relative to background or relative to the dynamic range of response. Under such definitions, a 5% or 10% change can be considered as default. Besides how to define the BMD and its lower bound, the BMDL, the question of how to select the dose-response model to be used in the BMD and BMDL determination is highlighted. Issues of study design and comparison of dose-response curves and BMDs are also covered. Copyright (c) 2007 John Wiley & Sons, Ltd.

  14. Development of a dosimeter for high doses assessment based on Alanine/EPR

    International Nuclear Information System (INIS)

    Galante, O.L.; Rodrigues, O. Jr.; Campos, L.L.

    2000-01-01

    The increasing use of radiation sources of high activity for industrial and medical applications becomes important the research and the development of detectors and dosimetric methods for quality control of the applied doses. This work presents the current stage of the research at IPEN/CNEN-SP that has as objective the development of a standard dosimetric system for high doses assessment based on the alanine as radiation detector and electron paramagnetic resonance (EPR) as measurement technique. The developed system consists of the cylindrical container built in polyethylene of high density and the detector element based on DL-alanine commercially available. For the detector preparation different binding materials such as paraffin and acetate polyvinyl solution (pva) and also the use of a polyethylene tube of low density with 3.2 mm of external diameter, 2 mm of internal diameter and 30 mm of length were tested to provide the easier preparation method and the most sensitive detector. For the alanine + paraffin detector it was used 80% of alanine and 20% of paraffin, for the alanine + pva detector it was used 70% of alanine and 30% of pva solution, and pure alanine was encapsulated, compacted and sealed in the case of the polyethylene tube. The obtained results with respect to handling, packing and construction easiness showed that the polyethylene tube presents all characteristics to obtain of a good detector element. The validation of the dosimetric system was carried out with gamma radiation of the cobalt-60 with doses in the range between 0.2 Gy to 200 kGy. Type tests such as fading, lowest detection limit, reproducibility and energy dependence of the sign EPR were performed. All measurements were carried out at room temperature using a spectrometer of electron paramagnetic resonance (EPR) Bruker model MXE. Taking into account the results obtained: linearity of the EPR signal between 10 Gy and 50 kGy, reproducibility better than 3%, low fading associated with

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

    International Nuclear Information System (INIS)

    Clairand, I.; Bottollier, J.F.; Trompier, F.

    2003-01-01

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, Norio; Kojima, Noboru; Hayashi, Naomi [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

    2001-06-01

    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)

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

    International Nuclear Information System (INIS)

    Tsujimura, Norio; Kojima, Noboru; Hayashi, Naomi

    2001-01-01

    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)

  18. A method to combine three dimensional dose distributions for external beam and brachytherapy radiation treatments for gynecological neoplasms

    International Nuclear Information System (INIS)

    Narayana, V.; Sahijdak, W.M.; Orton, C.G.

    1997-01-01

    Purpose: Radiation treatment of gynecological neoplasms, such as cervical carcinoma, usually combines external radiation therapy with one or more intracavitary brachytherapy applications. Although the dose from external beam radiation therapy and brachytherapy can be calculated and displayed in 3D individually, the dose distributions are not combined. At most, combined point doses are calculated for select points using various time-dose models. In this study, we present a methodology to combine external beam and brachytherapy treatments for gynecological neoplasms. Material and Methods: Three dimensional bio-effect treatment planning to obtain complication probability has been outlined. CT scans of the patient's pelvis with the gynecological applicator in place are used to outline normal tissue and tumor volumes. 3D external beam and brachytherapy treatment plans are developed separately and an external beam dose matrix and a brachytherapy dose matrix was calculated. The dose in each voxel was assumed to be homogeneous. The physical dose in each voxel of the dose matrix was then converted into extrapolated response dose (ERD) based on the linear quadratic model that accounts for the dose per fraction, number of fractions, dose rate, and complete or incomplete repair of sublethal damage (time between fractions). The net biological dose delivered was obtained by summing the ERD grids from external beam and brachytherapy since there was complete repair of sublethal damage between external beam and brachytherapy treatments. The normal tissue complication probability and tumor control probability were obtained using the biological dose matrix based on the critical element model. Results: The outlined method of combining external beam and brachytherapy treatments was implemented on gynecological treatments using an applicator for brachytherapy treatments. Conclusion: Implementation of the biological dose calculation that combine different modalities is extremely useful

  19. Study on the evaluation method of radiation dose rate around spent fuel shipping casks

    International Nuclear Information System (INIS)

    Yamakoshi, Hisao

    1986-01-01

    This study aims at developing a simple calculation method which can evaluate radiation dose rate around casks with high accuracy in a short time. The method is based on a concept of the radiation shielding characteristics of cask walls. The concept was introduced to replace for ordinary radiation shielding calculation which requires a long calculation time and a large memory capacity of a computer in the matrix calculation. For the purpose of verifying the accuracy and reliability of the new method, it was applied to the analysis of the dose rate distribution around actual casks, which had been measured. The results of the analysis revealed that the newly proposed method was excellent for the forecast of radiation dose rate distribution around casks in view of the accuracy and calculation time. The short calculation time and high accuracy by the proposed method were attained by dividing the whole procedure of ordinary fine radiation shielding calculation into the calculation of radiation dose rate on a cask surface by the matrix expression of the characteristic function and the calculation of dose rate distribution using the simple analytical expression of dose rate distribution around casks. The effect of the heterogeneous array of spent fuel in different burnup state on dose rate distribution around casks was evaluated by this method. (Kako, I.)

  20. Methods for estimation of internal dose of the public from dietary

    International Nuclear Information System (INIS)

    Zhu Hongda

    1987-01-01

    Following the issue of its Publication 26, ICRP has successively published its Publication 30 to meet the great changes and improvements made in the Basic Recommendations since July of 1979. In Part 1 of Publcation 30, ICRP recommended a new method for internal dose estimation and pressented some important data. In this report, comparison is made among methods for estimation of internal dose for the public from dietary. They include: (1) the new method suggested by ICRP; (2) the simple and convenient method using transfer factors under equilibrium conditions; (3) the methods based on the similarities of several radionuclides to their chemical analogs. It is concluded that the first method is better than the others and should be used from now on

  1. Irrigation in dose assessments models

    Energy Technology Data Exchange (ETDEWEB)

    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

  2. Irrigation in dose assessments models

    International Nuclear Information System (INIS)

    Bergstroem, Ulla; Barkefors, Catarina

    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

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

    International Nuclear Information System (INIS)

    Liu, Jian-xiang; Huang, Min-yan; Ruan, Jian-lei; Bai, Yu-shu; Xu, Su

    2008-01-01

    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)

  4. Dose assessment at Bikini Atoll

    International Nuclear Information System (INIS)

    Robison, W.L.; Phillips, W.A.; Colsher, C.S.

    1977-01-01

    Bikini Atoll is one of two sites in the northern Marshall Islands that was used by the United States as testing grounds for the nuclear weapons program from 1946 to 1958. In 1969 a general cleanup began at Bikini Atoll. Subsistence crops, coconut and Pandanus fruit, were planted on Bikini and Eneu Islands, and housing was constructed on Bikini Island. A second phase of housing was planned for the interior of Bikini Island. Preliminary data indicated that external gamma doses in the interior of the island might be higher than in other parts of the island. Therefore, to select a second site for housing on the island with minimum external exposure, a survey of Bikini Atoll was conducted in June 1975. External gamma measurements were made on Bikini and Eneu Islands, and soil and vegetations samples collected to evaluate the potential doses via terrestrial food chains and inhalation. Estimates of potential dose via the marine food chain were based upon data collected on previous trips to the atoll. The terrestrial pathway contributes the greater percentage, external gamma exposure contributes the next highest, and inhalation and marine pathways contribute minor fractions of the total whole body and bone marrow doses. The radionuclides contributing the major fraction of the dose are 90 Sr and 137 Cs. All living patterns involving Bikini Island exceed federal guidelines for 30-yr population doses. The Eneu Island living pattern leads to doses that are slightly less than federal guidelines. All patterns evaluated for Bikini Atoll lead to higher doses than those on the southern islands at Enewetak Atoll

  5. Radiological dose assessments in the northern Marshall Islands (1989--1991)

    International Nuclear Information System (INIS)

    Sun, L.C.; Meinhold, C.B.; Moorthy, A.R.; Clinton, J.H.; Kaplan, E.

    1992-01-01

    The present Brookhaven National Laboratory (BNL) Marshall Islands Radiological Safety Program (MIRSP) began in 1987 with funding from the US Department of Energy (DOE). The objectives of the MIRSP are to determine the radionuclides present in the bodies of those people potentially exposed to residual radionuclide from weapon tests and fallout, and to assess their present and lifetime dose from external and internal sources. Field bioassay missions involving whole body counting (WBC) and urine sample collection have, therefore, been important components of the program. WBC is used to measure γ-emitters, such as 40 K, 60 Co and 137 Cs, present in individuals. Urine samples are used to measure α and β-emitting nuclides, such as 239 Pu and 90 Sr, that are undetectable by WBC routine methods

  6. The assessment of the collective dose for China population travelling by water

    International Nuclear Information System (INIS)

    Yue Qingyu; Jiang Ping; Jin Hua

    1992-01-01

    The exposure dose rate at 212 points in six shipping lines of the inshore and inland rivers has been measured and the average natural sources exposure dose rate which may be received by the travellers in each shipping line has got. The assessment of collective dose equivalent for the travellers on the shipping lines and the fishery people on the sea has done. In 1988, the collective dose equivalent from natural sources received by Chinese population travelled on the shipping lines of the inshore and inland rivers was 32.7 man·Sv, and the collective dose equivalent from natural sources received by fishery people on the sea was 265.3 man·Sv. The average dose equivalent rate from natural sources at various stayed point received by people of China is given

  7. Critical dose threshold for TL dose response non-linearity: Dependence on the method of analysis: It’s not only the data

    International Nuclear Information System (INIS)

    Datz, H.; Horowitz, Y.S.; Oster, L.; Margaliot, M.

    2011-01-01

    It is demonstrated that the method of data analysis, i.e., the method of the phenomenological/theoretical interpretation of dose response data, can greatly influence the estimation of the onset of deviation from dose response linearity of the high temperature thermoluminescence in LiF:Mg,Ti (TLD-100).

  8. Integrated technique for assessing environmental dose of radioactive waste storage installation

    Energy Technology Data Exchange (ETDEWEB)

    Bor-Jing Chang; Chien-Liang Shih; Ing-Jane Chen [Institute of Nuclear Energy Research, Lungtan, Taiwan (China); Ren-Dih Sheu; Shiang-Huei Jiang [National Tsing Hua University, Hsinchu, Taiwan (China); Shu-Jun Chang [Nuclear Science and Technology Association, Taiwan (China); Ruei-Ying Liao; Pei Yu; Chin-Yi Huang [Taiwan Power Company, Taipei, Taiwan (China)

    2000-05-01

    The ability to accurately predict exposure rates at large distances from a gamma radiation source is becoming increasingly important. This is because that the related regulation for the control of radiation levels in and around nuclear facilities becomes more stringent. Since the continuous increase of the radwaste storage capacity requirement on site, the requirement of a more realistic evaluation is very necessary. Those doses are usually at past time evaluated by QADCG/INER-2 code for direct dose and by SKYSHINE-III code for skyshine dose in which evaluation were over conservatively considered. This study is to update the evaluation code package accompanied with adequate methodology and to establish integrated analysis procedure. Thereafter, radiation doses can be accurately calculated in a reasonably conservative way. The purpose of the investigation is divided into three categories. First, SPECTRUM-506 is used instead of SPECTUM. Nuclide databases are enlarged from 100 up to 506. And the operation is ported to personal computer. Secondly, the QADCG/INER-3 code is developed to enhance the original QADCG/INER-2 code. The most important difference is the use of the geometric progression (GP) fitting function for the gamma-ray buildup factor. SKYSHINE-III code is replaced by McSKY and SKYDOSE codes. They are well benchmarked by using the Monte Carlo code MCNP and sensitive parameters are detailed investigated. Thirdly, the well developed analysis procedure is applicable for nuclear utility radwaste storage sites. Finally, the case studies were performed by using those packages to assess the radiological impact of utility radwaste storage site. The results are verified in detail by using Monte Carlo code MCNP and the results seems pretty consistent from both method. (author)

  9. Retrospective dose assessment for the population living in areas of local fallout from the Semipalatinsk nuclear test site. Part 1: external exposure

    International Nuclear Information System (INIS)

    Gordeev, Konstantin; Shinkarev, Sergey; Ilyin, Leonid; Bouville, Andre; Luckyanov, Nickolas; Simon, Steven L.; Hoshi, Masaharu

    2006-01-01

    A short analysis of all 111 atmospheric events conducted at the Semipalatinsk Test Site (STS) in 1949-1962 with regard to significant off-site exposure (more than 5 mSv of the effective dose during the first year after the explosion) has been made. The analytical method used to assess external exposure to the residents living in settlements near the STS is described. This method makes used of the archival data on the radiological conditions, including the measurements of exposure rate. Special attention was given to the residents of Dolon and Kanonerka villages exposed mainly as a result of the first test, detonated on August 29, 1949. For the residents of those settlements born in 1935, the dose estimates calculated according to the analytical method, are compared to those derived from the thermoluminescence measurements in bricks and electron paramagnetic resonance measurements in teeth. The methods described in this paper were used for external dose assessment for the cohort members at an initial stage of an ongoing epidemiological study conducted by the U.S. National Cancer Institute in the Republic of Kazakhstan. Recently revised methods and estimates of external exposure for that cohort are given in another paper (Simon et al.) in this conference. (author)

  10. Post-closure radiation dose assessment for Yucca Mountain repository

    International Nuclear Information System (INIS)

    Jia Mingyan; Zhang Xiabin; Yang Chuncai

    2006-01-01

    A brief introduction of post-closure long-term radiation safety assessment results was represented for the yucca mountain high-level waste geographic disposal repository. In 1 million years after repository closure, for the higher temperature repository operating mode, the peak annual dose would be 150 millirem (120 millirem under the lower-temperature operating mode) to a reasonably maximally exposed individual approximately 18 kilometers (11 miles) from the repository. The analysis of a drilling intrusion event occurring at 30,000 years indicated a peak of the mean annual dose to the reasonably maximally exposed individual approximately 18 kilometers (11 miles) downstream of the repository would be 0.002 millirem. The analysis of an igneous activity scenario, including a volcanic eruption event and igneous intrusion event indicated a peak of the mean annual dose to the reasonably maximally exposed individual approximately 18 kilometers downstream of the repository would be 0.1 millirem. (authors)

  11. Assessment of cosmic radiation doses received by air crew

    International Nuclear Information System (INIS)

    McAulay, I.R.

    1998-01-01

    Cosmic radiation in the atmosphere is such a complex mixture of radiation type that it is difficult to get a single instrument which is suitable for such measurements. Passive devices such as film badges and track etch detectors have also been used, but again present difficulties of interpretation and requirements of multiple devices to accommodate the different types of radiation encountered. In summary, air crew are the occupational group most highly exposed to radiation. The radiation doses experienced by them are sufficiently high as to require assessment on a regular basis and possible control by appropriate rostering. There appears little possibility of the dose limit for workers being exceeded, except possibly in the case of pregnant female crew. This category of air crew should be the subject of special controls aimed at ensuring that the dose limits for the foetus should not be exceeded

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

    International Nuclear Information System (INIS)

    Beshir, W.B.

    2014-01-01

    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. 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

  13. Simplified calculation method for radiation dose under normal condition of transport

    International Nuclear Information System (INIS)

    Watabe, N.; Ozaki, S.; Sato, K.; Sugahara, A.

    1993-01-01

    In order to estimate radiation dose during transportation of radioactive materials, the following computer codes are available: RADTRAN, INTERTRAN, J-TRAN. Because these codes consist of functions for estimating doses not only under normal conditions but also in the case of accidents, when nuclei may leak and spread into the environment by air diffusion, the user needs to have special knowledge and experience. In this presentation, we describe how, with a view to preparing a method by which a person in charge of transportation can calculate doses in normal conditions, the main parameters upon which the value of doses depends were extracted and the dose for a unit of transportation was estimated. (J.P.N.)

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

    Science.gov (United States)

    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

  15. A novel method for the evaluation of uncertainty in dose-volume histogram computation.

    Science.gov (United States)

    Henríquez, Francisco Cutanda; Castrillón, Silvia Vargas

    2008-03-15

    Dose-volume histograms (DVHs) are a useful tool in state-of-the-art radiotherapy treatment planning, and it is essential to recognize their limitations. Even after a specific dose-calculation model is optimized, dose distributions computed by using treatment-planning systems are affected by several sources of uncertainty, such as algorithm limitations, measurement uncertainty in the data used to model the beam, and residual differences between measured and computed dose. This report presents a novel method to take them into account. To take into account the effect of associated uncertainties, a probabilistic approach using a new kind of histogram, a dose-expected volume histogram, is introduced. The expected value of the volume in the region of interest receiving an absorbed dose equal to or greater than a certain value is found by using the probability distribution of the dose at each point. A rectangular probability distribution is assumed for this point dose, and a formulation that accounts for uncertainties associated with point dose is presented for practical computations. This method is applied to a set of DVHs for different regions of interest, including 6 brain patients, 8 lung patients, 8 pelvis patients, and 6 prostate patients planned for intensity-modulated radiation therapy. Results show a greater effect on planning target volume coverage than in organs at risk. In cases of steep DVH gradients, such as planning target volumes, this new method shows the largest differences with the corresponding DVH; thus, the effect of the uncertainty is larger.

  16. Dose comparison using deformed image registration method on breast cancer radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Won; Kim, Jung Hoon [Dept. of Radiation Oncology, KonYang University Hospital, Daejeon (Korea, Republic of); Won, Young Jin [Dept. of Radiation Oncology, InJe University Ilsan Paik Hospital, Goyang (Korea, Republic of)

    2017-03-15

    The purpose of this study is to reconstruct the treatment plan by applying CBCT and DIR to dose changes according to the change of the patient's motion and breast shape in the large breast cancer patients and to compare the doses using TWF, FIF and IMRT. CT and CBCT were performed with MIM6 to create DIRCT and each treatment plan was made. The patient underwent computed tomography simulation in both prone and supine position. The homogeneity index (HI), conformity index (CI), coverage index (CVI) to the left breast as planning target volume (PTV) were determined and the doses to the lung, heart, and right breast as organ at risk (OAR) were compared by using dose-volume histogram and the unique property of each organ. The value of HI of the PTV breast increased in all treatment planning methods using DIRCT, and CVI and CI were decreased in the treatment planning methods using DIRCT.

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

    International Nuclear Information System (INIS)

    Cheong, Jae Hak

    1993-02-01

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

  18. Evaluation of radiation dose to patients in intraoral dental radiography using Monte Carlo Method

    International Nuclear Information System (INIS)

    Park, Il; Kim, Kyeong Ho; Oh, Seung Chul; Song, Ji Young

    2016-01-01

    The use of dental radiographic examinations is common although radiation dose resulting from the dental radiography is relatively small. Therefore, it is required to evaluate radiation dose from the dental radiography for radiation safety purpose. The objectives of the present study were to develop dosimetry method for intraoral dental radiography using a Monte Carlo method based radiation transport code and to calculate organ doses and effective doses of patients from different types of intraoral radiographies. Radiological properties of dental radiography equipment were characterized for the evaluation of patient radiation dose. The properties including x-ray energy spectrum were simulated using MCNP code. Organ doses and effective doses to patients were calculated by MCNP simulation with computational adult phantoms. At the typical equipment settings (60 kVp, 7 mA, and 0.12 sec), the entrance air kerma was 1.79 mGy and the measured half value layer was 1.82 mm. The half value layer calculated by MCNP simulation was well agreed with the measurement values. Effective doses from intraoral radiographies ranged from 1 μSv for maxilla premolar to 3 μSv for maxilla incisor. Oral cavity layer (23⁓82 μSv) and salivary glands (10⁓68 μSv) received relatively high radiation dose. Thyroid also received high radiation dose (3⁓47 μSv) for examinations. The developed dosimetry method and evaluated radiation doses in this study can be utilized for policy making, patient dose management, and development of low-dose equipment. In addition, this study can ultimately contribute to decrease radiation dose to patients for radiation safety

  19. Evaluation of radiation dose to patients in intraoral dental radiography using Monte Carlo Method

    Energy Technology Data Exchange (ETDEWEB)

    Park, Il; Kim, Kyeong Ho; Oh, Seung Chul; Song, Ji Young [Dept. of Nuclear Engineering, Kyung Hee University, Yongin (Korea, Republic of)

    2016-11-15

    The use of dental radiographic examinations is common although radiation dose resulting from the dental radiography is relatively small. Therefore, it is required to evaluate radiation dose from the dental radiography for radiation safety purpose. The objectives of the present study were to develop dosimetry method for intraoral dental radiography using a Monte Carlo method based radiation transport code and to calculate organ doses and effective doses of patients from different types of intraoral radiographies. Radiological properties of dental radiography equipment were characterized for the evaluation of patient radiation dose. The properties including x-ray energy spectrum were simulated using MCNP code. Organ doses and effective doses to patients were calculated by MCNP simulation with computational adult phantoms. At the typical equipment settings (60 kVp, 7 mA, and 0.12 sec), the entrance air kerma was 1.79 mGy and the measured half value layer was 1.82 mm. The half value layer calculated by MCNP simulation was well agreed with the measurement values. Effective doses from intraoral radiographies ranged from 1 μSv for maxilla premolar to 3 μSv for maxilla incisor. Oral cavity layer (23⁓82 μSv) and salivary glands (10⁓68 μSv) received relatively high radiation dose. Thyroid also received high radiation dose (3⁓47 μSv) for examinations. The developed dosimetry method and evaluated radiation doses in this study can be utilized for policy making, patient dose management, and development of low-dose equipment. In addition, this study can ultimately contribute to decrease radiation dose to patients for radiation safety.

  20. A simple method for estimating the effective dose in dental CT. Conversion factors and calculation for a clinical low-dose protocol

    International Nuclear Information System (INIS)

    Homolka, P.; Kudler, H.; Nowotny, R.; Gahleitner, A.; Wien Univ.

    2001-01-01

    An easily appliable method to estimate effective dose including in its definition the high radio-sensitivity of the salivary glands from dental computed tomography is presented. Effective doses were calculated for a markedly dose reduced dental CT protocol as well as for standard settings. Data are compared with effective doses from the literature obtained with other modalities frequently used in dental care. Methods: Conversion factors based on the weighted Computed Tomography Dose Index were derived from published data to calculate effective dose values for various CT exposure settings. Results: Conversion factors determined can be used for clinically used kVp settings and prefiltrations. With reduced tube current an effective dose for a CT examination of the maxilla of 22 μSv can be achieved, which compares to values typically obtained with panoramic radiography (26 μSv). A CT scan of the mandible, respectively, gives 123 μSv comparable to a full mouth survey with intraoral films (150 μSv). Conclusion: For standard CT scan protocols of the mandible, effective doses exceed 600 μSv. Hence, low dose protocols for dental CT should be considered whenever feasable, especially for paediatric patients. If hard tissue diagnoses is performed, the potential of dose reduction is significant despite the higher image noise levels as readability is still adequate. (orig.) [de

  1. Measurement of radiotherapy CBCT dose in a phantom using different methods

    International Nuclear Information System (INIS)

    Hu, Naonori; McLean, Donald

    2014-01-01

    Cone beam computed tomography (CBCT) is used widely for the precise and accurate patient set up needed during radiation therapy, notably for hypo fractionated treatments, such as intensity modulated radiation therapy and stereotactic radiation therapy. Reported doses associated with CBCT indicate the potential to approach radiation tolerance levels for some critical organs. However while some manufacturers state the CBCT dose for each standard protocol, currently there are no standard or recognised protocols for CBCT dosimetry. This study has applied wide beam computed tomography dosimetry approaches as reported by the International Atomic Energy Agency and the American Association of Physicists in Medicine to investigate dosimetry for the Varian Trilogy linear accelerator with on-board imager v1.5. Three detection methods were used including (i) the use of both 100 mm and 300 mm pencil ionisation chambers, (ii) a 0.6 cm 3 ionisation chamber and (iii) gafchromic film. Measurements were performed using custom built 45 cm long PMMA phantoms as well as standard 15 cm long phantoms for both head and body simulation. The results showed good agreement between each other detector system (within 3 %). The measured CBCT dose for the above methods showed a large difference to the dose stated by Varian, with the measured dose being 40 % over the stated dose for the standard head protocol. This shows the importance of independently verifying the stated dose given by the vendor for standard procedures.

  2. Evaluation of mathematical methods for predicting optimum dose of gamma radiation in sugarcane (Saccharum sp.)

    International Nuclear Information System (INIS)

    Wu, K.K.; Siddiqui, S.H.; Heinz, D.J.; Ladd, S.L.

    1978-01-01

    Two mathematical methods - the reversed logarithmic method and the regression method - were used to compare the predicted and the observed optimum gamma radiation dose (OD 50 ) in vegetative propagules of sugarcane. The reversed logarithmic method, usually used in sexually propagated crops, showed the largest difference between the predicted and observed optimum dose. The regression method resulted in a better prediction of the observed values and is suggested as a better method for the prediction of optimum dose for vegetatively propagated crops. (author)

  3. Radiation doses in diagnostic radiology and methods for dose reduction. Report of a co-ordinated research programme (1991-1993)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    It is well recognized that diagnostic radiology is the largest contributor to the collective dose from all man-made sources of radiation. Large differences in radiation doses from the same procedures among different X ray rooms have led to the conclusion that there is a potential for dose reduction. A Co-ordinated Research Programme on Radiation Doses in Diagnostic Radiology and Methods for Dose Reduction, involving Member States with different degrees of development, was launched by the IAEA in co-operation with the CEC. This report summarizes the results of the second and final Research Co-ordination Meeting held in Vienna from 4 to 8 October 1993. 22 refs, 6 figs and tabs.

  4. Radiation doses in diagnostic radiology and methods for dose reduction. Report of a co-ordinated research programme (1991-1993)

    International Nuclear Information System (INIS)

    1995-04-01

    It is well recognized that diagnostic radiology is the largest contributor to the collective dose from all man-made sources of radiation. Large differences in radiation doses from the same procedures among different X ray rooms have led to the conclusion that there is a potential for dose reduction. A Co-ordinated Research Programme on Radiation Doses in Diagnostic Radiology and Methods for Dose Reduction, involving Member States with different degrees of development, was launched by the IAEA in co-operation with the CEC. This report summarizes the results of the second and final Research Co-ordination Meeting held in Vienna from 4 to 8 October 1993. 22 refs, 6 figs and tabs

  5. A study of different dose calculation methods and the impact on the dose evaluation protocol in lung stereotactic radiation therapy

    International Nuclear Information System (INIS)

    Takada, Takahiro; Furuya, Tomohisa; Ozawa, Shuichi; Ito, Kana; Kurokawa, Chie; Karasawa, Kumiko; Miura, Kohei

    2008-01-01

    AAA (analytical anisotropic algorithm) dose calculation, which shows a better performance for heterogeneity correction, was tested for lung stereotactic radiation therapy (SBRT) in comparison to conventional PBC (pencil beam convolution method) to evaluate its impact on tumor dose parameters. Eleven lung SBRT patients who were treated with photon 4 MV beams in our department between April 2003 and February 2007 were reviewed. Clinical target volume (CTV) was delineated including the spicula region on planning CT images. Planning target volume (PTV) was defined by adding the internal target volume (ITV) and set-up margin (SM) of 5 mm from CTV, and then an multileaf collimator (MLC) penumbra margin of another 5 mm was also added. Six-port non-coplanar beams were employed, and a total prescribed dose of 48 Gy was defined at the isocenter point with four fractions. The entire treatment for an individual patient was completed within 8 days. Under the same prescribed dose, calculated dose distribution, dose volume histogram (DVH), and tumor dose parameters were compared between two dose calculation methods. In addition, the fractionated prescription dose was repeatedly scaled until the monitor units (MUs) calculated by AAA reached a level of MUs nearly identical to those achieved by PBC. AAA resulted in significantly less D95 (irradiation dose that included 95% volume of PTV) and minimal dose in PTV compared to PBC. After rescaling of each MU for each beam in the AAA plan, there was no revision of the isocenter of the prescribed dose required. However, when the PTV volume was less than 20 cc, a 4% lower prescription resulted in nearly identical MUs between AAA and PBC. The prescribed dose in AAA should be the same as that in PBC, if the dose is administered at the isocenter point. However, planners should compare DVHs and dose distributions between AAA and PBC for a small lung tumor with a PTV volume less than approximately 20 cc. (author)

  6. Algorithm for assessment of mean annual gonad dose and genetically significant dose from the data of personal dosimetry

    International Nuclear Information System (INIS)

    Tomasevic, M.; Radovanovic, R.

    1986-01-01

    During one year more than 40,000 items of information on radiation exposure of personnel involved in the handling of radiation sources and more than 5,000,000 items on irradiation of other people are collected in the authors' laboratory. Considerable progress in assessment of mean annual gonad dose of genetically sifnificant dose was attained by means of an algorithm for a personal computer. This simple and inexpensive system has led to a higher accuracy in the application of protective measures. (author)

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

    International Nuclear Information System (INIS)

    Sato, Kaoru; Takahashi, Fumiaki; Endo, Akira; Ono, Koji; Ban, Nobuhiko; Hasegawa, Takayuki; Katsunuma, Yasushi; Yoshitake, Takayasu; Kai, Michiaki

    2015-01-01

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

  8. Wound trauma alters ionizing radiation dose assessment

    Directory of Open Access Journals (Sweden)

    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

  9. Dose sculpting with generalized equivalent uniform dose

    International Nuclear Information System (INIS)

    Wu Qiuwen; Djajaputra, David; Liu, Helen H.; Dong Lei; Mohan, Radhe; Wu, Yan

    2005-01-01

    With intensity-modulated radiotherapy (IMRT), a variety of user-defined dose distribution can be produced using inverse planning. The generalized equivalent uniform dose (gEUD) has been used in IMRT optimization as an alternative objective function to the conventional dose-volume-based criteria. The purpose of this study was to investigate the effectiveness of gEUD optimization to fine tune the dose distributions of IMRT plans. We analyzed the effect of gEUD-based optimization parameters on plan quality. The objective was to determine whether dose distribution to selected structures could be improved using gEUD optimization without adversely altering the doses delivered to other structures, as in sculpting. We hypothesized that by carefully defining gEUD parameters (EUD 0 and n) based on the current dose distributions, the optimization system could be instructed to search for alternative solutions in the neighborhood, and we could maintain the dose distributions for structures already satisfactory and improve dose for structures that need enhancement. We started with an already acceptable IMRT plan optimized with any objective function. The dose distribution was analyzed first. For structures that dose should not be changed, a higher value of n was used and EUD 0 was set slightly higher/lower than the EUD value at the current dose distribution for critical structures/targets. For structures that needed improvement in dose, a higher to medium value of n was used, and EUD 0 was set to the EUD value or slightly lower/higher for the critical structure/target at the current dose distribution. We evaluated this method in one clinical case each of head and neck, lung and prostate cancer. Dose volume histograms, isodose distributions, and relevant tolerance doses for critical structures were used for the assessment. We found that by adjusting gEUD optimization parameters, the dose distribution could be improved with only a few iterations. A larger value of n could lead to

  10. Doses and application methods of Azospirillum brasilense in irrigated upland rice

    Directory of Open Access Journals (Sweden)

    Nayara F. S. Garcia

    Full Text Available ABSTRACT The study was carried out in Selvíria-MS, in the 2011/12 and 2012/13 agricultural years, aiming to evaluate the efficiency of Azospirillum brasilense in nitrogen fixation in upland rice, as a function of doses and application methods of the inoculant containing this diazotrophic bacterium. The experimental design was randomized blocks, arranged in a 4 x 4 factorial scheme, with 4 doses of inoculant (control without inoculation, 100, 200 and 300 mL of the commercial product ha-1 and 4 application methods (seed inoculation, application in the sowing furrow, soil spraying after sowing, and foliar spraying at the beginning of plant tillering, with 4 replicates. During the experiment, the agronomic characteristics, production components and yield of the rice crop were evaluated. It was concluded that the inoculant containing Azospirillum brasilense promotes increase (19% in the yield of upland rice under sprinkler irrigation when used at the dose of 200 mL ha-1, regardless of the application methods.

  11. Method of estimating patient skin dose from dose displayed on medical X-ray equipment with flat panel detector

    International Nuclear Information System (INIS)

    Fukuda, Atsushi; Koshida, Kichiro; Togashi, Atsuhiko; Matsubara, Kousuke

    2004-01-01

    The International Electrotechnical Commission (IEC) has stipulated that medical X-ray equipment for interventional procedures must display radiation doses such as air kerma in free air at the interventional reference point and dose area product to establish radiation safety for patients (IEC 60601-2-43). However, it is necessary to estimate entrance skin dose for the patient from air kerma for an accurate risk assessment of radiation skin injury. To estimate entrance skin dose from displayed air kerma in free air at the interventional reference point, it is necessary to consider effective energy, the ratio of the mass-energy absorption coefficient for skin and air, and the backscatter factor. In addition, since automatic exposure control is installed in medical X-ray equipment with flat panel detectors, it is necessary to know the characteristics of control to estimate exposure dose. In order to calculate entrance skin dose under various conditions, we investigated clinical parameters such as tube voltage, tube current, pulse width, additional filter, and focal spot size, as functions of patient body size. We also measured the effective energy of X-ray exposure for the patient as a function of clinical parameter settings. We found that the conversion factor from air kerma in free air to entrance skin dose is about 1.4 for protection. (author)

  12. Method for assessing the probability of accumulated doses from an intermittent source using the convolution technique

    International Nuclear Information System (INIS)

    Coleman, J.H.

    1980-10-01

    A technique is discussed for computing the probability distribution of the accumulated dose received by an arbitrary receptor resulting from several single releases from an intermittent source. The probability density of the accumulated dose is the convolution of the probability densities of doses from the intermittent releases. Emissions are not assumed to be constant over the brief release period. The fast fourier transform is used in the calculation of the convolution

  13. QUANTITATION OF MOLECULAR ENDPOINTS FOR THE DOSE-RESPONSE COMPONENT OF CANCER RISK ASSESSMENT

    Science.gov (United States)

    Cancer risk assessment involves the steps of hazard identification, dose-response assessment, exposure assessment and risk characterization. The rapid advances in the use of molecular biology approaches has had an impact on all four components, but the greatest overall current...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-15

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

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

    International Nuclear Information System (INIS)

    Jimenez, M.A.; Martin-Valdepenas, J.M.; Garcia-Talavera, M.; Martin-Matarranz, J.L.; Salas, M.R.; Serrano, J.I.; Ramos, L.M.

    2011-01-01

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

  16. Method to account for dose fractionation in analysis of IMRT plans: Modified equivalent uniform dose

    International Nuclear Information System (INIS)

    Park, Clinton S.; Kim, Yongbok; Lee, Nancy; Bucci, Kara M.; Quivey, Jeanne M.; Verhey, Lynn J.; Xia Ping

    2005-01-01

    Purpose: To propose a modified equivalent uniform dose (mEUD) to account for dose fractionation using the biologically effective dose without losing the advantages of the generalized equivalent uniform dose (gEUD) and to report the calculated mEUD and gEUD in clinically used intensity-modulated radiotherapy (IMRT) plans. Methods and Materials: The proposed mEUD replaces the dose to each voxel in the gEUD formulation by a biologically effective dose with a normalization factor. We propose to use the term mEUD D o /n o that includes the total dose (D o ) and number of fractions (n o ) and to use the term mEUD o that includes the same total dose but a standard fraction size of 2 Gy. A total of 41 IMRT plans for patients with nasopharyngeal cancer treated at our institution between October 1997 and March 2002 were selected for the study. The gEUD and mEUD were calculated for the planning gross tumor volume (pGTV), planning clinical tumor volume (pCTV), parotid glands, and spinal cord. The prescription dose for these patients was 70 Gy to >95% of the pGTV and 59.4 Gy to >95% of the pCTV in 33 fractions. Results: The calculated average gEUD was 72.2 ± 2.4 Gy for the pGTV, 54.2 ± 7.1 Gy for the pCTV, 26.7 ± 4.2 Gy for the parotid glands, and 34.1 ± 6.8 Gy for the spinal cord. The calculated average mEUD D o /n o using 33 fractions was 71.7 ± 3.5 Gy for mEUD 70/33 of the pGTV, 49.9 ± 7.9 Gy for mEUD 59.5/33 of the pCTV, 27.6 ± 4.8 Gy for mEUD 26/33 of the parotid glands, and 32.7 ± 7.8 Gy for mEUD 45/33 of the spinal cord. Conclusion: The proposed mEUD, combining the gEUD with the biologically effective dose, preserves all advantages of the gEUD while reflecting the fractionation effects and linear and quadratic survival characteristics

  17. A real-time in vivo dosimetric verification method for high-dose rate intracavitary brachytherapy of nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Qi Zhenyu; Deng Xiaowu; Cao Xinping; Huang Shaomin; Lerch, Michael; Rosenfeld, Anatoly [State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060 (China) and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia); State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060 (China); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia)

    2012-11-15

    Purpose: A real-time in vivo dosimetric verification method using metal-oxide-semiconductor field effect transistor (MOSFET) dosimeters has been developed for patient dosimetry in high-dose rate (HDR) intracavitary brachytherapy of nasopharyngeal carcinoma (NPC). Methods: The necessary calibration and correction factors for MOSFET measurements in {sup 192}Iridium source were determined in a water phantom. With the detector placed inside a custom-made nasopharyngeal applicator, the actual dose delivered to the tumor was measured in vivo and compared to the calculated values using a commercial brachytherapy planning system. Results: Five MOSFETs were independently calibrated with the HDR source, yielding calibration factors of 0.48 {+-} 0.007 cGy/mV. The maximum sensitivity variation was no more than 7% in the clinically relevant distance range of 1-5 cm from the source. A total of 70 in vivo measurements in 11 NPC patients demonstrated good agreement with the treatment planning. The mean differences between the planned and the actually delivered dose within a single treatment fraction were -0.1%{+-} 3.8% and -0.1%{+-} 3.7%, respectively, for right and left side assessments. The maximum dose deviation was less than 8.5%. Conclusions: In vivo measurement using the real-time MOSFET dosimetry system is possible to evaluate the actual dose to the tumor received by the patient during a treatment fraction and thus can offer another line of security to detect and prevent large errors.

  18. Monte-Carlo Method Python Library for dose distribution Calculation in Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Randriantsizafy, R D; Ramanandraibe, M J [Madagascar Institut National des Sciences et Techniques Nucleaires, Antananarivo (Madagascar); Raboanary, R [Institut of astro and High-Energy Physics Madagascar, University of Antananarivo, Antananarivo (Madagascar)

    2007-07-01

    The Cs-137 Brachytherapy treatment is performed in Madagascar since 2005. Time treatment calculation for prescribed dose is made manually. Monte-Carlo Method Python library written at Madagascar INSTN is experimentally used to calculate the dose distribution on the tumour and around it. The first validation of the code was done by comparing the library curves with the Nucletron company curves. To reduce the duration of the calculation, a Grid of PC's is set up with listner patch run on each PC. The library will be used to modelize the dose distribution in the CT scan patient picture for individual and better accuracy time calculation for a prescribed dose.

  19. Monte-Carlo Method Python Library for dose distribution Calculation in Brachytherapy

    International Nuclear Information System (INIS)

    Randriantsizafy, R.D.; Ramanandraibe, M.J.; Raboanary, R.

    2007-01-01

    The Cs-137 Brachytherapy treatment is performed in Madagascar since 2005. Time treatment calculation for prescribed dose is made manually. Monte-Carlo Method Python library written at Madagascar INSTN is experimentally used to calculate the dose distribution on the tumour and around it. The first validation of the code was done by comparing the library curves with the Nucletron company curves. To reduce the duration of the calculation, a Grid of PC's is set up with listner patch run on each PC. The library will be used to modelize the dose distribution in the CT scan patient picture for individual and better accuracy time calculation for a prescribed dose.

  20. Assessment of Dose to the Nursing Infant from Radionuclides in Breast Milk

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, Richard Wayne [ORNL; Eckerman, Keith F [ORNL

    2010-03-01

    A computer software package was developed to predict tissue doses to an infant due to intake of radionuclides in breast milk based on bioassay measurements and exposure data for the mother. The package is intended mainly to aid in decisions regarding the safety of breast feeding by a mother who has been acutely exposed to a radionuclide during lactation or pregnancy, but it may be applied to previous intakes during the mother s adult life. The package includes biokinetic and dosimetric information needed to address intake of Co-60, Sr-90, Cs-134, Cs-137, Ir-192, Pu-238, Pu-239, Am-241, or Cf-252 by the mother. It has been designed so that the library of biokinetic and dosimetric files can be expanded to address a more comprehensive set of radionuclides without modifying the basic computational module. The methods and models build on the approach used in Publication 95 of the International Commission on Radiological Protection (ICRP 2004), Doses to Infants from Ingestion of Radionuclides in Mothers Milk . The software package allows input of case-specific information or judgments such as chemical form or particle size of an inhaled aerosol. The package is expected to be more suitable than ICRP Publication 95 for dose assessment for real events or realistic planning scenarios in which measurements of the mother s excretion or body burden are available.

  1. Negotiating NORM cleanup and land use limits: Practical use of dose assessment and cost benefit analysis

    International Nuclear Information System (INIS)

    Blanchard, A.D.H.

    1997-01-01

    Oil companies are presently faced with complex and costly environmental decisions, especially concerning NORM cleanup and disposal. Strict cleanup limits and disposal restrictions are established, in theory, to protect public health and environment. While public health is directly measured in terms of dose (mrem/yr), most NORM regulations adopt soil concentration limits to ensure future public health is maintained. These derived soil limits create the potential for unnecessary burden to operators without additional health benefit to society. Operators may use a dose assessment to show direct compliance with dose limits, negotiating less restrictive cleanup levels and land use limits. This paper discusses why a dose assessment is useful to Oilfield operators, NORM exposure scenarios and pathways, assessment advantages, variables and recommendations and one recent dose assessment application. Finally, a cost benefit analysis tool for regulatory negotiations will be presented allowing comparison of Oilfield NORM health benefit costs to that of other industries. One use for this tool--resulting in the savings of approximately $100,000--will be discussed

  2. Comparing different methods for estimating radiation dose to the conceptus

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rendon, X.; Dedulle, A. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); Walgraeve, M.S.; Woussen, S.; Zhang, G. [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Bosmans, H. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Zanca, F. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); GE Healthcare, Buc (France)

    2017-02-15

    To compare different methods available in the literature for estimating radiation dose to the conceptus (D{sub conceptus}) against a patient-specific Monte Carlo (MC) simulation and a commercial software package (CSP). Eight voxel models from abdominopelvic CT exams of pregnant patients were generated. D{sub conceptus} was calculated with an MC framework including patient-specific longitudinal tube current modulation (TCM). For the same patients, dose to the uterus, D{sub uterus}, was calculated as an alternative for D{sub conceptus}, with a CSP that uses a standard-size, non-pregnant phantom and a generic TCM curve. The percentage error between D{sub uterus} and D{sub conceptus} was studied. Dose to the conceptus and percent error with respect to D{sub conceptus} was also estimated for three methods in the literature. The percentage error ranged from -15.9% to 40.0% when comparing MC to CSP. When comparing the TCM profiles with the generic TCM profile from the CSP, differences were observed due to patient habitus and conceptus position. For the other methods, the percentage error ranged from -30.1% to 13.5% but applicability was limited. Estimating an accurate D{sub conceptus} requires a patient-specific approach that the CSP investigated cannot provide. Available methods in the literature can provide a better estimation if applicable to patient-specific cases. (orig.)

  3. On the absorbed dose determination method in high energy photon beams

    International Nuclear Information System (INIS)

    Scarlat, F.; Scarisoreanu, A.; Oane, M.; Mitru, E.; Avadanei, C.

    2008-01-01

    The absorbed dose determination method in water, based on standards of air kerma or exposure in high energy photon beams generated by electron with energies in the range of 1 MeV to 50 MeV is presented herein. The method is based on IAEA-398, AAPM TG-51, DIN 6800-2, IAEA-381, IAEA-277 and NACP-80 recommendations. The dosimetry equipment is composed of UNIDOS T 10005 electrometer and different ionization chambers calibrated in air kerma method in a Co 60 beam. Starting from the general formalism showed in IAEA-381, the determination of absorbed dose in water, under reference conditions in high energy photon beams, is given. This method was adopted for the secondary standard dosimetry laboratory (SSDL) in NILPRP-Bucharest

  4. Dose analysis in Brjansk region during the restoration period of nuclear accident and effects of dose reduction methods in Chernobyl

    International Nuclear Information System (INIS)

    Ramzaev, V.; Kovalenko, V.; Krivonsov, S.

    1999-01-01

    The exposure pathways to the people in this area were analysed and some decontamination methods and techniques were explained. The spatial dose rate, whole-body dose and external exposure of four kinds of classes such as pensioner, jobless person, outdoor laborer, indoor laborer and child were measured. New whole-body counter used can decrease the effect of external dose on 661 keV γ-ray. The relation coefficient between the soil contamination level and the external exposure was 0.99, but that between the cesium 137 content in soil and the internal exposure was -0.2, showing no correlation. Main source of cesium 137 in body was milk from private cow in each village. The concentration of radioactive cesium of 40% milk samples were more than 370 Bq/l. More than 75% mushroom and strawberry showed 600 Bq/kg and over. Other foods indicated less cesium content than that of above foods. The decontamination methods of roof, garden, milk and improved manure of grass were carried out in Smajalch. The most effective method seemed to be the filtration of milk. Each method came into effect to reduce the average annual dose to 1 mSv until the next year. (S.Y.)

  5. Optimization in radiotherapy treatment planning thanks to a fast dose calculation method

    International Nuclear Information System (INIS)

    Yang, Mingchao

    2014-01-01

    This thesis deals with the radiotherapy treatments planning issue which need a fast and reliable treatment planning system (TPS). The TPS is composed of a dose calculation algorithm and an optimization method. The objective is to design a plan to deliver the dose to the tumor while preserving the surrounding healthy and sensitive tissues. The treatment planning aims to determine the best suited radiation parameters for each patient's treatment. In this thesis, the parameters of treatment with IMRT (Intensity modulated radiation therapy) are the beam angle and the beam intensity. The objective function is multi-criteria with linear constraints. The main objective of this thesis is to demonstrate the feasibility of a treatment planning optimization method based on a fast dose-calculation technique developed by (Blanpain, 2009). This technique proposes to compute the dose by segmenting the patient's phantom into homogeneous meshes. The dose computation is divided into two steps. The first step impacts the meshes: projections and weights are set according to physical and geometrical criteria. The second step impacts the voxels: the dose is computed by evaluating the functions previously associated to their mesh. A reformulation of this technique makes possible to solve the optimization problem by the gradient descent algorithm. The main advantage of this method is that the beam angle parameters could be optimized continuously in 3 dimensions. The obtained results in this thesis offer many opportunities in the field of radiotherapy treatment planning optimization. (author) [fr

  6. Hormesis: from marginalization to mainstream A case for hormesis as the default dose-response model in risk assessment

    International Nuclear Information System (INIS)

    Calabrese, Edward J.

    2004-01-01

    The paper provides an account of how the hormetic dose response has emerged in recent years as a serious dose-response model in toxicology and risk assessment after decades of extreme marginalization. In addition to providing the toxicological basis of this dose-response revival, the paper reexamines the concept of a default dose model in toxicology and risk assessment and makes the argument that the hormetic model satisfies criteria (e.g., generalizability, frequency, application to risk assessment endpoints, false positive/negative potential, requirements for hazard assessment, reliability of estimating risks, capacity for validation of risk estimates, public health implications of risk estimates) for such a default model better than its chief competitors, the threshold and linear at low dose models. The selection of the hormetic model as the default model in risk assessment for noncarcinogens and specifically for carcinogens would have a profound impact on the practice of risk assessment and its societal implications

  7. Assessment of dose measurement uncertainty using RisoScan

    International Nuclear Information System (INIS)

    Helt-Hansen, Jakob; Miller, Arne

    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%, 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

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

    International Nuclear Information System (INIS)

    Leclerc, E.; Smith, G.; Lloyd, P.

    2009-01-01

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

  9. A phantom for assessing the personal dose equivalent, HP(10)

    International Nuclear Information System (INIS)

    Santoro, C.; Filho, J.A

    2013-01-01

    Characteristics of a phantom designed to evaluate the personal dose equivalent, H P (10), and appropriate for photographic dosimetry are presented. It is called HP(10) phantom due to cavities constructed to insert dosimetric films at a depth of 10 mm. The H P (10) phantom is irradiated with ionizing radiation energy, E, from 45 to 1250 keV, with doses ranging from 0.2 to 50 mSv. It is positioned in the direction α = 0 °, and the radiation field focusing perpendicular to its front surface. So, are established calibration curves of dosimeters in the position conventionally true and quantities H P (10). It made a comparison between the responses obtained with the H P (10) phantom and responses obtained when using the calibration procedure recommended by ISO dosimeters. The ISO recommends getting the air kerma, Ka, for photons at test point of the radiation field by an ionization chamber. And through conversion coefficients, h pK (10; E, α), becomes the air kerma for H P (10). The ISO 4037-3 recommendation has been studied by researchers to ensure that the low energy spectral differences occur in radiation fields which are generated by various X-ray equipment, and induce changes in the percentages of conversion coefficients on the order of 10% to 90% . On the basis of the recommendations ISO, this article develops phantom able to assess the dose to the influence of scattering and absorption of radiation, its implications with respect to dosimetry, providing improvement in the assessment of doses. (author)

  10. Assessment of Mean Glandular Dose in Mammography System with Different Anode-Filter Combinations Using MCNP Code.

    Science.gov (United States)

    Gholamkar, Lida; Mowlavi, Ali Asghar; Sadeghi, Mahdi; Athari, Mitra

    2016-10-01

    X-ray mammography is one of the general methods for early detection of breast cancer. Since glandular tissue in the breast is sensitive to radiation and it increases the risk of cancer, the given dose to the patient is very important in mammography. The aim of this study was to determine the average absorbed dose of X-ray radiation in the glandular tissue of the breast during mammography examinations as well as investigating factors that influence the mean glandular dose (MGD). One of the precise methods for determination of MGD absorbed by the breast is Monte Carlo simulation method which is widely used to assess the dose. We studied some different X-ray sources and exposure factors that affect the MGD. "Midi-future" digital mammography system with amorphous-selenium detector was simulated using the Monte Carlo N-particle extended (MCNPX) code. Different anode/filter combinations such as tungsten/silver (W/Ag), tungsten/rhodium (W/Rh), and rhodium/aluminium (Rh/Al) were simulated in this study. The voltage of X-ray tube ranged from 24 kV to 32 kV with 2 kV intervals and the breast phantom thickness ranged from 3 to 8 cm, and glandular fraction g varied from 10% to 100%. MGD was measured for different anode/filter combinations and the effects of changing tube voltage, phantom thickness, combination and glandular breast tissue on MGD were studied. As glandular g and X-ray tube voltage increased, the breast dose increased too, and the increase of breast phantom thickness led to the decrease of MGD. The obtained results for MGD were consistent with the result of Boone et al. that was previously reported. By comparing the results, we saw that W/Rh anode/filter combination is the best choice in breast mammography imaging because of the lowest delivered dose in comparison with W/Ag and Rh/Al. Moreover, breast thickness and g value have significant effects on MGD.

  11. Recommended environmental dose calculation methods and Hanford-specific parameters

    International Nuclear Information System (INIS)

    Schreckhise, R.G.; Rhoads, K.; Napier, B.A.; Ramsdell, J.V.; Davis, J.S.

    1993-03-01

    This document was developed to support the Hanford Environmental Dose overview Panel (HEDOP). The Panel is responsible for reviewing all assessments of potential doses received by humans and other biota resulting from the actual or possible environmental releases of radioactive and other hazardous materials from facilities and/or operations belonging to the US Department of Energy on the Hanford Site in south-central Washington. This document serves as a guide to be used for developing estimates of potential radiation doses, or other measures of risk or health impacts, to people and other biota in the environs on and around the Hanford Site. It provides information to develop technically sound estimates of exposure (i.e., potential or actual) to humans or other biotic receptors that could result from the environmental transport of potentially harmful materials that have been, or could be, released from Hanford operations or facilities. Parameter values and information that are specific to the Hanford environs as well as other supporting material are included in this document

  12. Recommended environmental dose calculation methods and Hanford-specific parameters

    Energy Technology Data Exchange (ETDEWEB)

    Schreckhise, R.G.; Rhoads, K.; Napier, B.A.; Ramsdell, J.V. (Pacific Northwest Lab., Richland, WA (United States)); Davis, J.S. (Westinghouse Hanford Co., Richland, WA (United States))

    1993-03-01

    This document was developed to support the Hanford Environmental Dose overview Panel (HEDOP). The Panel is responsible for reviewing all assessments of potential doses received by humans and other biota resulting from the actual or possible environmental releases of radioactive and other hazardous materials from facilities and/or operations belonging to the US Department of Energy on the Hanford Site in south-central Washington. This document serves as a guide to be used for developing estimates of potential radiation doses, or other measures of risk or health impacts, to people and other biota in the environs on and around the Hanford Site. It provides information to develop technically sound estimates of exposure (i.e., potential or actual) to humans or other biotic receptors that could result from the environmental transport of potentially harmful materials that have been, or could be, released from Hanford operations or facilities. Parameter values and information that are specific to the Hanford environs as well as other supporting material are included in this document.

  13. Comparative study of different methods used in assessment of population exposure to external environmental radiation

    International Nuclear Information System (INIS)

    Niewiadomski, T.

    1979-08-01

    Doses received by individuals and population from terrestial radiation sources were estimated using three approaches, 1) measurements of dose rates, 2) calculations on the basis of spectrometric analysis of the soil or local radiation field and 3) integrating dosimeters. The 1st approach was carried out by means of pressurised ionization chambers, scintillation counters or GM counters properly calibrated, and also by supplying individuals with dosimetric or radiometric instruments. The data for calculation assessment was based on measurements of dose rates both outdoors and indoors and often taken from spectrometric analysis of natural radionuclide. Several equations and calculation factors have been derived and computer programs developed for calculating the concentration of radionuclides in question and for estimating dose rates in π or 2π geometries. Integrating measurements were carried out using TL dosimeters. To assess the reliability of the methods, comparative measurements were carried out at statistically representative number of locations using a wide choice of techniques. The detailed methods used and the equipment are described in the research programme as well as the results of the measurements. The most reliable results are these obtained when measurements are carried out over a long period of time, e.g. one year

  14. Deciding which chemical mixtures risk assessment methods work best for what mixtures

    International Nuclear Information System (INIS)

    Teuschler, Linda K.

    2007-01-01

    The most commonly used chemical mixtures risk assessment methods involve simple notions of additivity and toxicological similarity. Newer methods are emerging in response to the complexities of chemical mixture exposures and effects. Factors based on both science and policy drive decisions regarding whether to conduct a chemical mixtures risk assessment and, if so, which methods to employ. Scientific considerations are based on positive evidence of joint toxic action, elevated human exposure conditions or the potential for significant impacts on human health. Policy issues include legislative drivers that may mandate action even though adequate toxicity data on a specific mixture may not be available and risk assessment goals that impact the choice of risk assessment method to obtain the amount of health protection desired. This paper discusses three important concepts used to choose among available approaches for conducting a chemical mixtures risk assessment: (1) additive joint toxic action of mixture components; (2) toxicological interactions of mixture components; and (3) chemical composition of complex mixtures. It is proposed that scientific support for basic assumptions used in chemical mixtures risk assessment should be developed by expert panels, risk assessment methods experts, and laboratory toxicologists. This is imperative to further develop and refine quantitative methods and provide guidance on their appropriate applications. Risk assessors need scientific support for chemical mixtures risk assessment methods in the form of toxicological data on joint toxic action for high priority mixtures, statistical methods for analyzing dose-response for mixtures, and toxicological and statistical criteria for determining sufficient similarity of complex mixtures

  15. Process-oriented dose assessment model for 14C due to releases during normal operation of a nuclear power plant

    International Nuclear Information System (INIS)

    Aquilonius, Karin; Hallberg, Bengt

    2005-01-01

    Swedish nuclear utility companies are required to assess doses due to releases of radionuclides during normal operation. In 2001, calculation methods used earlier were updated due to new authority regulations. The isotope 14 C is of special interest in dose assessments due to the role of carbon in the metabolism of all life forms. Earlier, factors expressing the ratio between concentration of 14 C in air and in various plants were used. In order to extend the possibility to take local conditions into account, a process-oriented assessment model for uptake of carbon and doses from releases of 14 C to air was developed (POM 14 C). The model uses part of Daisy which has been developed to model the turnover of carbon in crops. [Hansen, S., Jensen, H.E., Nielsen, N.E., Svendsen, H., 1993. Description of the Soil Plant System Model DAISY, Basic Principles and Modelling Approach. Simulation Model for Transformation and Transport of Energy and Matter in the Soil Plant Atmosphere System. Jordbruksfoerlaget, The Royal Veterianary and Agricultural University, Copenhagen, Denmark]. The main objectives were to test model performance of the former method, and to investigate if taking site specific parameters into account to a greater degree would lead to major differences in the results. Several exposure pathways were considered: direct consumption of locally grown cereals, vegetables, and root vegetables, as well as consumption of milk and meat from cows having eaten fodder cereals and green fodder from the area around the nuclear plant. The total dose of the earlier model was compared with that of POM 14 C. The result of the former was shown to be slightly higher than the latter, but POM 14 C confirmed that the earlier results were of a reasonable magnitude. When full account of local conditions was taken, e.g. as regards solar radiation, temperature, and concentration of 14 C in air at various places in the surroundings of each nuclear plant, a difference in dose between

  16. A method to evaluate the dose increase in CT with iodinated contrast medium

    International Nuclear Information System (INIS)

    Amato, Ernesto; Lizio, Domenico; Settineri, Nicola; Di Pasquale, Andrea; Salamone, Ignazio; Pandolfo, Ignazio

    2010-01-01

    Purpose: The objective of this study is to develop a method to calculate the relative dose increase when a computerized tomography scan (CT) is carried out after administration of iodinated contrast medium, with respect to the same CT scan in absence of contrast medium. Methods: A Monte Carlo simulation in GEANT4 of anthropomorphic neck and abdomen phantoms exposed to a simplified model of CT scanner was set up in order to calculate the increase of dose to thyroid, liver, spleen, kidneys, and pancreas as a function of the quantity of iodine accumulated; a series of experimental measurements of Hounsfield unit (HU) increment for known concentrations of iodinated contrast medium was carried out on a Siemens Sensation 16 CT scanner in order to obtain a relationship between the increment in HU and the relative dose increase in the organs studied. The authors applied such a method to calculate the average dose increase in three patients who underwent standard CT protocols consisting of one native scan in absence of contrast, followed by a contrast-enhanced scan in venous phase. Results: The authors validated their GEANT4 Monte Carlo simulation by comparing the resulting dose increases for iodine solutions in water with the ones presented in literature and with their experimental data obtained through a Roentgen therapy unit. The relative dose increases as a function of the iodine mass fraction accumulated and as a function of the Hounsfield unit increment between the contrast-enhanced scan and the native scan are presented. The data shown for the three patients exhibit an average relative dose increase between 22% for liver and 74% for kidneys; also, spleen (34%), pancreas (28%), and thyroid (48%) show a remarkable average increase. Conclusions: The method developed allows a simple evaluation of the dose increase when iodinated contrast medium is used in CT scans, basing on the increment in Hounsfield units observed on the patients' organs. Since many clinical protocols

  17. A method to evaluate the dose increase in CT with iodinated contrast medium

    Energy Technology Data Exchange (ETDEWEB)

    Amato, Ernesto; Lizio, Domenico; Settineri, Nicola; Di Pasquale, Andrea; Salamone, Ignazio; Pandolfo, Ignazio [Department of Radiological Sciences, University of Messina, Messina 98125 (Italy); Department of Physics, University of Messina, Messina 98166 (Italy); University Hospital ' ' G. Martino' ' , Messina 98125 (Italy); Department of Radiological Sciences, University of Messina, Messina 98125 (Italy) and University Hospital ' ' G. Martino' ' , Messina 98125 (Italy)

    2010-08-15

    Purpose: The objective of this study is to develop a method to calculate the relative dose increase when a computerized tomography scan (CT) is carried out after administration of iodinated contrast medium, with respect to the same CT scan in absence of contrast medium. Methods: A Monte Carlo simulation in GEANT4 of anthropomorphic neck and abdomen phantoms exposed to a simplified model of CT scanner was set up in order to calculate the increase of dose to thyroid, liver, spleen, kidneys, and pancreas as a function of the quantity of iodine accumulated; a series of experimental measurements of Hounsfield unit (HU) increment for known concentrations of iodinated contrast medium was carried out on a Siemens Sensation 16 CT scanner in order to obtain a relationship between the increment in HU and the relative dose increase in the organs studied. The authors applied such a method to calculate the average dose increase in three patients who underwent standard CT protocols consisting of one native scan in absence of contrast, followed by a contrast-enhanced scan in venous phase. Results: The authors validated their GEANT4 Monte Carlo simulation by comparing the resulting dose increases for iodine solutions in water with the ones presented in literature and with their experimental data obtained through a Roentgen therapy unit. The relative dose increases as a function of the iodine mass fraction accumulated and as a function of the Hounsfield unit increment between the contrast-enhanced scan and the native scan are presented. The data shown for the three patients exhibit an average relative dose increase between 22% for liver and 74% for kidneys; also, spleen (34%), pancreas (28%), and thyroid (48%) show a remarkable average increase. Conclusions: The method developed allows a simple evaluation of the dose increase when iodinated contrast medium is used in CT scans, basing on the increment in Hounsfield units observed on the patients' organs. Since many clinical

  18. Assessment of diurnal systemic dose of agrochemicals in regulatory toxicity testing--an integrated approach without additional animal use.

    Science.gov (United States)

    Saghir, Shakil A; Bartels, Michael J; Rick, David L; McCoy, Alene T; Rasoulpour, Reza J; Ellis-Hutchings, Robert G; Sue Marty, M; Terry, Claire; Bailey, Jason P; Billington, Richard; Bus, James S

    2012-07-01

    Integrated toxicokinetics (TK) data provide information on the rate, extent and duration of systemic exposure across doses, species, strains, gender, and life stages within a toxicology program. While routine for pharmaceuticals, TK assessments of non-pharmaceuticals are still relatively rare, and have never before been included in a full range of guideline studies for a new agrochemical. In order to better understand the relationship between diurnal systemic dose (AUC(24h)) and toxicity of agrochemicals, TK analyses in the study animals is now included in all short- (excluding acute), medium- and long-term guideline mammalian toxicity studies including reproduction/developmental tests. This paper describes a detailed procedure for the implementation of TK in short-, medium- and long-term regulatory toxicity studies, without the use of satellite animals, conducted on three agrochemicals (X11422208, 2,4-D and X574175). In these studies, kinetically-derived maximum doses (KMD) from short-term studies instead of, or along with, maximum tolerated doses (MTD) were used for the selection of the high dose in subsequent longer-term studies. In addition to leveraging TK data to guide dose level selection, the integrated program was also used to select the most appropriate method of oral administration (i.e., gavage versus dietary) of test materials for rat and rabbit developmental toxicity studies. The integrated TK data obtained across toxicity studies (without the use of additional/satellite animals) provided data critical to understanding differences in response across doses, species, strains, sexes, and life stages. Such data should also be useful in mode of action studies and to improve human risk assessments. Copyright © 2012 Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

    Paul, A.K.; Rahman, H.A.; Jahan, N.

    2002-01-01

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

  20. On - Site Assessment Methods For Environmental Radioactivity

    International Nuclear Information System (INIS)

    Petrinec, B.; Babic, D.; Bituh, T.

    2015-01-01

    A method for the rapid determination of radioactivity in cases of release into the environment as well as in cases of nuclear/radiological accidents is described. These measurements would enable a direct risk assessment for humans and biota, without any sampling and at a considerably larger number of locations than in previous studies. Thus obtained, the substantially expanded dataset is expected to shed more light on the properties of environmental radioactivity both in the region studied and in other similar areas. Field measurements will be performed and samples of soil and biota will be collected in order to compare field results with laboratory measurements. Once the method has been validated, previously unexplored locations will be included in the study. Our measurements at numerous locations will also provide control values for comparison in cases of any unplanned or accidental radiological event. An assessment of the possible effects of radionuclide concentrations on the human food chain and biota will be performed within the appropriate models used worldwide exactly for this purpose. In this way, the project should contribute to regional, European, and global efforts towards understanding the radiological impact on ecosystems. Field measurements will also address certain issues in the environmental metrology of radioactive substances, e.g., simultaneous determination of activity concentrations and related dose rates. This will serve as a tool for rapid risk assessment in emergency situations. (author).

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

    International Nuclear Information System (INIS)

    Smith, K.P.; Blunt, D.L.; Williams, G.P.

    1996-09-01

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

  2. Sequential multi-nuclide emission rate estimation method based on gamma dose rate measurement for nuclear emergency management

    International Nuclear Information System (INIS)

    Zhang, Xiaole; Raskob, Wolfgang; Landman, Claudia; Trybushnyi, Dmytro; Li, Yu

    2017-01-01

    Highlights: • Sequentially reconstruct multi-nuclide emission using gamma dose rate measurements. • Incorporate a priori ratio of nuclides into the background error covariance matrix. • Sequentially augment and update the estimation and the background error covariance. • Suppress the generation of negative estimations for the sequential method. • Evaluate the new method with twin experiments based on the JRODOS system. - Abstract: In case of a nuclear accident, the source term is typically not known but extremely important for the assessment of the consequences to the affected population. Therefore the assessment of the potential source term is of uppermost importance for emergency response. A fully sequential method, derived from a regularized weighted least square problem, is proposed to reconstruct the emission and composition of a multiple-nuclide release using gamma dose rate measurement. The a priori nuclide ratios are incorporated into the background error covariance (BEC) matrix, which is dynamically augmented and sequentially updated. The negative estimations in the mathematical algorithm are suppressed by utilizing artificial zero-observations (with large uncertainties) to simultaneously update the state vector and BEC. The method is evaluated by twin experiments based on the JRodos system. The results indicate that the new method successfully reconstructs the emission and its uncertainties. Accurate a priori ratio accelerates the analysis process, which obtains satisfactory results with only limited number of measurements, otherwise it needs more measurements to generate reasonable estimations. The suppression of negative estimation effectively improves the performance, especially for the situation with poor a priori information, where it is more prone to the generation of negative values.

  3. Sequential multi-nuclide emission rate estimation method based on gamma dose rate measurement for nuclear emergency management

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaole, E-mail: zhangxiaole10@outlook.com [Institute for Nuclear and Energy Technologies, Karlsruhe Institute of Technology, Karlsruhe, D-76021 (Germany); Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing, 100084 (China); Raskob, Wolfgang; Landman, Claudia; Trybushnyi, Dmytro; Li, Yu [Institute for Nuclear and Energy Technologies, Karlsruhe Institute of Technology, Karlsruhe, D-76021 (Germany)

    2017-03-05

    Highlights: • Sequentially reconstruct multi-nuclide emission using gamma dose rate measurements. • Incorporate a priori ratio of nuclides into the background error covariance matrix. • Sequentially augment and update the estimation and the background error covariance. • Suppress the generation of negative estimations for the sequential method. • Evaluate the new method with twin experiments based on the JRODOS system. - Abstract: In case of a nuclear accident, the source term is typically not known but extremely important for the assessment of the consequences to the affected population. Therefore the assessment of the potential source term is of uppermost importance for emergency response. A fully sequential method, derived from a regularized weighted least square problem, is proposed to reconstruct the emission and composition of a multiple-nuclide release using gamma dose rate measurement. The a priori nuclide ratios are incorporated into the background error covariance (BEC) matrix, which is dynamically augmented and sequentially updated. The negative estimations in the mathematical algorithm are suppressed by utilizing artificial zero-observations (with large uncertainties) to simultaneously update the state vector and BEC. The method is evaluated by twin experiments based on the JRodos system. The results indicate that the new method successfully reconstructs the emission and its uncertainties. Accurate a priori ratio accelerates the analysis process, which obtains satisfactory results with only limited number of measurements, otherwise it needs more measurements to generate reasonable estimations. The suppression of negative estimation effectively improves the performance, especially for the situation with poor a priori information, where it is more prone to the generation of negative values.

  4. Integration method of 3D MR spectroscopy into treatment planning system for glioblastoma IMRT dose painting with integrated simultaneous boost

    International Nuclear Information System (INIS)

    Ken, Soléakhéna; Cassol, Emmanuelle; Delannes, Martine; Celsis, Pierre; Cohen-Jonathan, Elizabeth Moyal; Laprie, Anne; Vieillevigne, Laure; Franceries, Xavier; Simon, Luc; Supper, Caroline; Lotterie, Jean-Albert; Filleron, Thomas; Lubrano, Vincent; Berry, Isabelle

    2013-01-01

    To integrate 3D MR spectroscopy imaging (MRSI) in the treatment planning system (TPS) for glioblastoma dose painting to guide simultaneous integrated boost (SIB) in intensity-modulated radiation therapy (IMRT). For sixteen glioblastoma patients, we have simulated three types of dosimetry plans, one conventional plan of 60-Gy in 3D conformational radiotherapy (3D-CRT), one 60-Gy plan in IMRT and one 72-Gy plan in SIB-IMRT. All sixteen MRSI metabolic maps were integrated into TPS, using normalization with color-space conversion and threshold-based segmentation. The fusion between the metabolic maps and the planning CT scans were assessed. Dosimetry comparisons were performed between the different plans of 60-Gy 3D-CRT, 60-Gy IMRT and 72-Gy SIB-IMRT, the last plan was targeted on MRSI abnormalities and contrast enhancement (CE). Fusion assessment was performed for 160 transformations. It resulted in maximum differences <1.00 mm for translation parameters and ≤1.15° for rotation. Dosimetry plans of 72-Gy SIB-IMRT and 60-Gy IMRT showed a significantly decreased maximum dose to the brainstem (44.00 and 44.30 vs. 57.01 Gy) and decreased high dose-volumes to normal brain (19 and 20 vs. 23% and 7 and 7 vs. 12%) compared to 60-Gy 3D-CRT (p < 0.05). Delivering standard doses to conventional target and higher doses to new target volumes characterized by MRSI and CE is now possible and does not increase dose to organs at risk. MRSI and CE abnormalities are now integrated for glioblastoma SIB-IMRT, concomitant with temozolomide, in an ongoing multi-institutional phase-III clinical trial. Our method of MR spectroscopy maps integration to TPS is robust and reliable; integration to neuronavigation systems with this method could also improve glioblastoma resection or guide biopsies

  5. Animal data on GI-tract uptake of plutonium - implications for environmental dose assessments

    International Nuclear Information System (INIS)

    Kocher, D.C.; Ryan, M.T.

    1983-01-01

    A selection of published data on GI-tract uptake of ingested plutonium in animals is reviewed for the purpose of estimating an uptake fraction which would be appropriate for environmental dose assessments in adult humans. Recent data in the adult rat and guinea pig suggest that a GI-tract uptake fraction of 10 -3 would be a reasonable and prudent choice for ingestion of environmental plutonium by adults. This value is a factor of ten larger than the value currently recommended by the International Commission on Radiological Protection for assessing doses from occupational exposures. (author)

  6. Incorporating organ movements in inverse planning: assessing dose uncertainties by Bayesian inference

    International Nuclear Information System (INIS)

    Unkelbach, J; Oelfke, U

    2005-01-01

    We present a method to calculate dose uncertainties due to inter-fraction organ movements in fractionated radiotherapy, i.e. in addition to the expectation value of the dose distribution a variance distribution is calculated. To calculate the expectation value of the dose distribution in the presence of organ movements, one estimates a probability distribution of possible patient geometries. The respective variance of the expected dose distribution arises for two reasons: first, the patient is irradiated with a finite number of fractions only and second, the probability distribution of patient geometries has to be estimated from a small number of images and is therefore not exactly known. To quantify the total dose variance, we propose a method that is based on the principle of Bayesian inference. The method is of particular interest when organ motion is incorporated in inverse IMRT planning by means of inverse planning performed on a probability distribution of patient geometries. In order to make this a robust approach, it turns out that the dose variance should be considered (and minimized) in the optimization process. As an application of the presented concept of Bayesian inference, we compare three approaches to inverse planning based on probability distributions that account for an increasing degree of uncertainty. The Bayes theorem further provides a concept to interpolate between patient specific data and population-based knowledge on organ motion which is relevant since the number of CT images of a patient is typically small

  7. Assessment of prior image induced nonlocal means regularization for low-dose CT reconstruction: Change in anatomy.

    Science.gov (United States)

    Zhang, Hao; Ma, Jianhua; Wang, Jing; Moore, William; Liang, Zhengrong

    2017-09-01

    Repeated computed tomography (CT) scans are prescribed for some clinical applications such as lung nodule surveillance. Several studies have demonstrated that incorporating a high-quality prior image into the reconstruction of subsequent low-dose CT (LDCT) acquisitions can either improve image quality or reduce data fidelity requirements. Our proposed previous normal-dose image induced nonlocal means (ndiNLM) regularization method for LDCT is an example of such a method. However, one major concern with prior image based methods is that they might produce false information when the prior image and the current LDCT image show different structures (for example, if a lung nodule emerges, grows, shrinks, or disappears over time). This study aims to assess the performance of the ndiNLM regularization method in situations with change in anatomy. We incorporated the ndiNLM regularization into the statistical image reconstruction (SIR) framework for reconstruction of subsequent LDCT images. Because of its patch-based search mechanism, a rough registration between the prior image and the current LDCT image is adequate for the SIR-ndiNLM method. We assessed the performance of the SIR-ndiNLM method in lung nodule surveillance for two different scenarios: (a) the nodule was not found in a baseline exam but appears in a follow-up LDCT scan; (b) the nodule was present in a baseline exam but disappears in a follow-up LDCT scan. We further investigated the effect of nodule size on the performance of the SIR-ndiNLM method. We found that a relatively large search-window (e.g., 33 × 33) should be used for the SIR-ndiNLM method to account for misalignment between the prior image and the current LDCT image, and to ensure that enough similar patches can be found in the prior image. With proper selection of other parameters, experimental results with two patient datasets demonstrated that the SIR-ndiNLM method did not miss true nodules nor introduce false nodules in the lung nodule

  8. SU-G-TeP4-02: A Method for Evaluating the Direct Impact of Failed IMRT QAs On Patient Dose

    International Nuclear Information System (INIS)

    Geneser, S; Butkus, M

    2016-01-01

    Purpose: We developed a method to calculate patient doses corresponding to IMRT QA measurements in order to determine and assess the actual dose delivered for plans with failed (or borderline) IMRT QA. This work demonstrates the feasibility of automatically computing delivered patient dose from portal dosimetry measurements in the Varian TPS system, which would provide a valuable and clinically viable IMRT QA tool for physicists and physicians. Methods: IMRT QA fluences were measured using portal dosimetry, processed using in-house matlab software, and imported back into Eclipse to calculate dose on the planning CT. To validate the proposed workflow, the Eclipse calculated portal dose for a 5-field sliding window prostate boost plan was processed as described above. The resulting dose was compared to the planned dose and found to be within 0.5 Gy. Two IMRT QA results for the prostate boost plan (one that failed and one that passed) were processed and the resulting patient doses were evaluated. Results: The max dose difference between IMRT QA #1 and the original planned and approved dose is 4.5 Gy, while the difference between the planned and IMRT QA #2 dose is 4.0 Gy. The inferior portion of the PTV is slightly underdosed in both plans, and the superior portion is slightly overdosed. The patient dose resulting from IMRT QA #1 and #2 differs by only 0.5 Gy. With this new information, it may be argued that the evaluated plan alteration to obtain passing gamma analysis produced clinically irrelevant differences. Conclusion: Evaluation of the delivered QA dose on the planning CT provides valuable information about the clinical relevance of failed or borderline IMRT QAs. This particular workflow demonstrates the feasibility of pushing the measured IMRT QA portal dosimetry results directly back onto the patient planning CT within the Varian system.

  9. SU-G-TeP4-02: A Method for Evaluating the Direct Impact of Failed IMRT QAs On Patient Dose

    Energy Technology Data Exchange (ETDEWEB)

    Geneser, S; Butkus, M [Yale University School of Medicine/YNHH Radiology, New Haven, CT (United States)

    2016-06-15

    Purpose: We developed a method to calculate patient doses corresponding to IMRT QA measurements in order to determine and assess the actual dose delivered for plans with failed (or borderline) IMRT QA. This work demonstrates the feasibility of automatically computing delivered patient dose from portal dosimetry measurements in the Varian TPS system, which would provide a valuable and clinically viable IMRT QA tool for physicists and physicians. Methods: IMRT QA fluences were measured using portal dosimetry, processed using in-house matlab software, and imported back into Eclipse to calculate dose on the planning CT. To validate the proposed workflow, the Eclipse calculated portal dose for a 5-field sliding window prostate boost plan was processed as described above. The resulting dose was compared to the planned dose and found to be within 0.5 Gy. Two IMRT QA results for the prostate boost plan (one that failed and one that passed) were processed and the resulting patient doses were evaluated. Results: The max dose difference between IMRT QA #1 and the original planned and approved dose is 4.5 Gy, while the difference between the planned and IMRT QA #2 dose is 4.0 Gy. The inferior portion of the PTV is slightly underdosed in both plans, and the superior portion is slightly overdosed. The patient dose resulting from IMRT QA #1 and #2 differs by only 0.5 Gy. With this new information, it may be argued that the evaluated plan alteration to obtain passing gamma analysis produced clinically irrelevant differences. Conclusion: Evaluation of the delivered QA dose on the planning CT provides valuable information about the clinical relevance of failed or borderline IMRT QAs. This particular workflow demonstrates the feasibility of pushing the measured IMRT QA portal dosimetry results directly back onto the patient planning CT within the Varian system.

  10. Investigation of radioactive pollution on land at Thule and assessment of radiation doses

    International Nuclear Information System (INIS)

    2011-12-01

    Risoe National Laboratory at the Technical University of Denmark has carried out research on the terrestrial contamination in the Thule area, Greenland, after the radioactive contents of four nuclear weapons were dispersed following the crash of an American B-52 bomber in 1968. The results of this research are described in the report ''Thule-2007 - Investigation of radioactive pollution on land''. Based on this report, the National Board of Health made an assessment of radiation doses and the risk for individuals in the Thule area. The results of the assessment are described in the report ''The Thule accident. Assessment of radiation doses from terrestrial radioactive contamination''. The present report is a summary of these two reports. (ln)

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

    Science.gov (United States)

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

    2011-12-01

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

  12. Excipient Usage Technical Risk Assessment for Generic Solid Dose Products

    Directory of Open Access Journals (Sweden)

    Ajay Babu Pazhayattil

    2017-09-01

    Full Text Available This paper proposes an assessment methodology for solid dose generic small molecule drug products. It addresses the ‘usage of the excipient’ portion of the trinomial by utilizing the systematic approach of Risk Identification, Risk Analysis and Risk Evaluation as per ICH Q9 Quality Risk Management outlined for developing risk control strategies. The assessment and maintenance of excipient risk profile is essential to minimize any potential risk associated to excipients impacting patients.

  13. Kodak EDR2 film for patient skin dose assessment in cardiac catheterization procedures.

    Science.gov (United States)

    Morrell, R E; Rogers, A T

    2006-07-01

    Patient skin doses were measured using Kodak EDR2 film for 20 coronary angiography (CA) and 32 percutaneous transluminal coronary angioplasty (PTCA) procedures. For CA, all skin doses were well below 1 Gy. However, 23% of PTCA patients received skin doses of 1 Gy or more. Dose-area product (DAP) was also recorded and was found to be an inadequate indicator of maximum skin dose. Practical compliance with ICRP recommendations requires a robust method for skin dosimetry that is more accurate than DAP and is applicable over a wider dose range than EDR2 film.

  14. Assessment of mean glandular dose to patients from digital mammography systems

    International Nuclear Information System (INIS)

    Pwamang, Caroline K.

    2016-07-01

    Mean glandular dose assessment of patients undergoing digital mammography examination has been done. A total of 297 patient data was used for the study. Basic Quality Control tests were done to ascertain the performance of the equipment used. The results of Quality Control tests indicated that the three Mammography units used for this study were functioning within the internationally acceptable performance criteria. Patients with a breast thickness of 30 mm within the two age groups of 40-49 yrs and 50-64 yrs received doses slightly higher than the acceptable dose levels. A patient in the category 40-49 yrs with breast thickness of 30 mm received 1.83 mGy as calculated Mean Glandular Dose, 2.10 mGy was the recorded dose and 1.58 mGy was recorded under the age group 50-64 yrs. These values have deviated by -22%, -40%, and -5.33% respectively from 1.5 mGy which is the recommended dose for a breast thickness of 30 mm. Also patients with breast thickness of 70 mm under the age group 40–49 yrs had a recorded dose of 6.58 mGy, which deviated by -1.21% from the recommended value of 6.5 mGy for that breast thickness. Aside these values, all the other values were within the recommended dose values. The percentage deviation between the recommended values and the calculated values was within ±25% which was a working limit that was set for this work. Doses delivered by the Full-field Digital mammography equipment were higher than doses delivered by the Computered Radiography equipment. The calculated Mean Glandular Doses for the three facilities were within recommended dose values. (author)

  15. A comparison of newborn stylized and tomographic models for dose assessment in paediatric radiology

    International Nuclear Information System (INIS)

    Staton, R J; Pazik, F D; Nipper, J C; Williams, J L; Bolch, W E

    2003-01-01

    Establishment of organ doses from diagnostic and interventional examinations is a key component to quantifying the radiation risks from medical exposures and for formulating corresponding dose-reduction strategies. Radiation transport models of human anatomy provide a convenient method for simulating radiological examinations. At present, two classes of models exist: stylized mathematical models and tomographic voxel models. In the present study, organ dose comparisons are made for projection radiographs of both a stylized and a tomographic model of the newborn patient. Sixteen separate radiographs were simulated for each model at x-ray technique factors typical of newborn examinations: chest, abdomen, thorax and head views in the AP, PA, left LAT and right LAT projection orientation. For AP and PA radiographs of the torso (chest, abdomen and thorax views), the effective dose assessed for the tomographic model exceeds that for the stylized model with per cent differences ranging from 19% (AP abdominal view) to 43% AP chest view. In contrast, the effective dose for the stylized model exceeds that for the tomographic model for all eight lateral views including those of the head, with per cent differences ranging from 9% (LLAT chest view) to 51% (RLAT thorax view). While organ positioning differences do exist between the models, a major factor contributing to differences in effective dose is the models' exterior trunk shape. In the tomographic model, a more elliptical shape is seen thus providing for less tissue shielding for internal organs in the AP and PA directions, with corresponding increased tissue shielding in the lateral directions. This observation is opposite of that seen in comparisons of stylized and tomographic models of the adult

  16. Evaluation of a post-analysis method for cumulative dose distribution in stereotactic body radiotherapy

    International Nuclear Information System (INIS)

    Imae, Toshikazu; Takenaka, Shigeharu; Saotome, Naoya

    2016-01-01

    The purpose of this study was to evaluate a post-analysis method for cumulative dose distribution in stereotactic body radiotherapy (SBRT) using volumetric modulated arc therapy (VMAT). VMAT is capable of acquiring respiratory signals derived from projection images and machine parameters based on machine logs during VMAT delivery. Dose distributions were reconstructed from the respiratory signals and machine parameters in the condition where respiratory signals were without division, divided into 4 and 10 phases. The dose distribution of each respiratory phase was calculated on the planned four-dimensional CT (4DCT). Summation of the dose distributions was carried out using deformable image registration (DIR), and cumulative dose distributions were compared with those of the corresponding plans. Without division, dose differences between cumulative distribution and plan were not significant. In the condition Where respiratory signals were divided, dose differences were observed over dose in cranial region and under dose in caudal region of planning target volume (PTV). Differences between 4 and 10 phases were not significant. The present method Was feasible for evaluating cumulative dose distribution in VMAT-SBRT using 4DCT and DIR. (author)

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

    International Nuclear Information System (INIS)

    Rojo, Ana M.; Michelin, Severino C.

    2004-01-01

    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: 99m Tc, 131 I, 201 Tl and 67 Ga. 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)

  18. Biological indicators for radiation absorbed dose: a review

    International Nuclear Information System (INIS)

    Paul, S.F.D.; Venkatachalam, P.; Jeevanram, R.K.

    1996-01-01

    Biological dosimetry has an important role to play in assessing the cumulative radiation exposure of persons working with radiation and also in estimating the true dose received during accidents involving external and internal exposure. Various biodosimetric methods have been tried to estimate radiation dose for the above purposes. Biodosimetric methods include cytogenetic, immunological and mutational assays. Each technique has certain advantages and disadvantages. We present here a review of each technique, the actual method used for detection of dose, the sensitivity of detection and its use in long term studies. (author)

  19. Assessment of serum magnesium levels and its outcome in neonates of eclamptic mothers treated with low-dose magnesium sulfate regimen

    Science.gov (United States)

    Das, Monalisa; Chaudhuri, Patralekha Ray; Mondal, Badal C.; Mitra, Sukumar; Bandyopadhyay, Debasmita; Pramanik, Sushobhan

    2015-01-01

    Objectives: Magnesium historically has been used for treatment and/or prevention of eclampsia. Considering the low body mass index of Indian women, a low-dose magnesium sulfate regime has been introduced by some authors. Increased blood levels of magnesium in neonates is associated with increased still birth, early neonatal death, birth asphyxia, bradycardia, hypotonia, gastrointestinal hypomotility. The objective of this study was to assess safety of low-dose magnesium sulfate regimen in neonates of eclamptic mothers treated with this regimen. Materials and Methods: This was a cross-sectional observational study of 100 eclampsia patients and their neonates. Loading dose and maintenance doses of magnesium sulfate were administered to patients by combination of intravenous and intramuscular routes. Maternal serum and cord blood magnesium levels were estimated. Neonatal outcome was assessed. Results: Bradycardia was observed in 18 (19.15%) of the neonates, 16 (17.02%) of the neonates were diagnosed with hypotonia. Pearson Correlation Coefficient showed Apgar scores decreased with increase in cord blood magnesium levels. Unpaired t-test showed lower Apgar scores with increasing dose of magnesium sulfate. The Chi-square/Fisher's exact test showed significant increase in hypotonia, birth asphyxia, intubation in delivery room, Neonatal Intensive Care Unit (NICU) care requirement, with increasing dose of magnesium sulfate. (P ≤ 0.05). Conclusion: Several neonatal complications are significantly related to increasing serum magnesium levels. Overall, the low-dose magnesium sulfate regimen was safe in the management of eclamptic mothers, without toxicity to their neonates. PMID:26600638

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

    International Nuclear Information System (INIS)

    Brenk, H.D.; Vogt, K.J.

    1982-12-01

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

  1. Safety objectives for nuclear power plants in terms of dose-frequency targets; a comparison exercise performed by the Commission of the European Communities on dose assessment within a licencing framework

    International Nuclear Information System (INIS)

    Lange, F.; Tolley, B.; Kelly, N.; Harbison, S.; Gilby, E.

    1987-01-01

    The Task Force on Safety Objectives (T.F.S.O.) of the CEC has initiated a benchmark exercise with the purpose to review the methods and data used in dose assessment being adopted in various countries to estimate doses from design basis accidents of nuclear power plants within a regulatory framework. This benchmark exercise forms one of the initiatives of the T.F.S.O. to enable a comprehensive intercomparison of the degree of coherence between the dose-frequency targets used in different Members States for application to design basis accidents. The structure, contents and results of the benchmark exercise in which eight countries/institutions participated are described. Some of the more important findings and conclusions and the relation to a parallel benchmark exercise on source terms for design basis accidents are discussed. (orig.)

  2. Intercomparison exercise on internal dose assessment. Final report of a joint IAEA-IDEAS project

    International Nuclear Information System (INIS)

    2007-09-01

    There have been several intercomparison exercises organized already at national and international levels for the assessment of occupational exposure due to intakes of radionuclides. These intercomparison exercises revealed significant differences in approaches, methods and assumptions, and consequently in the results. Because of the relevance of the issue for internal dosimetrists, the IAEA organized a new intercomparison exercise in cooperation with the IDEAS project General Guidelines for the Evaluation of Incorporation Monitoring Data, launched under the 5th EU Framework Programme (EU Contract No. FIKR-CT2001-00160). This new intercomparison exercise focused especially on the effect of the guidelines for harmonization of internal dosimetry. It also considered the following aspects: - to provide possibilities for the participating laboratories to check the quality of their internal dose assessment methods in applying the recent ICRP recommendations (e.g. for the new respiratory tract model); - to compare different approaches in interpretation of internal contamination monitoring data; - to quantify the differences in internal dose assessments based on the new guidelines or on other procedures, respectively; - to provide some figures for 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 this exercise with the aim of covering a wide range of practices in the nuclear fuel cycle and in medical applications. The cases were: 1. Acute intake of HTO; 2. Acute inhalation of fission products 137 Cs and 90 Sr; 3. Intake of 60 Co; 4. Repeated intakes of 131 I; 5. Intake of enriched uranium; 6. Single intake of plutonium radionuclides and 241 Am. An Internet based approach had been used for the presentation of the cases, collection of responses and potential discussion of the results. Solutions to these cases were reported by 80 participants worldwide. This report

  3. Method of preparing radionuclide doses

    International Nuclear Information System (INIS)

    Kuperus, J.H.

    1987-01-01

    A method is described of preparing aliquot dosea of a tracer material useful in diagnostic nuclear medicine comprising: storing discrete quantities of a lyophilized radionuclide carrier in separate tubular containers from which air and moisture is excluded, selecting from the tubular containers a container in which is stored a carrier appropriate for a nuclear diagnostic test to be performed, interposing the selected container between the needle and the barrel of a hypodermic syringe, and drawing a predetermined amount of a liquid containing a radionuclide tracer in known concentration into the hypodermic syringe barrel through the hypodermic needle and through the selected container to dissolve the discrete quantity of lyophilized carrier therein to combine the carrier with the radionuclide tracer to form an aliquot dose of nuclear diagnostic tracer material, as needed

  4. A new assessment method for demonstrating the sufficiency of the safety assessment and the safety margins of the geological disposal system

    International Nuclear Information System (INIS)

    Ohi, Takao; Kawasaki, Daisuke; Chiba, Tamotsu; Takase, Toshio; Hane, Koji

    2013-01-01

    A new method for demonstrating the sufficiency of the safety assessment and safety margins of the geological disposal system has been developed. The method is based on an existing comprehensive sensitivity analysis method and can systematically identify the successful conditions, under which the dose rate does not exceed specified safety criteria, using analytical solutions for nuclide migration and the results of a statistical analysis. The successful conditions were identified using three major variables. Furthermore, the successful conditions at the level of factors or parameters were obtained using relational equations between the variables and the factors or parameters making up these variables. In this study, the method was applied to the safety assessment of the geological disposal of transuranic waste in Japan. Based on the system response characteristics obtained from analytical solutions and on the successful conditions, the classification of the analytical conditions, the sufficiency of the safety assessment and the safety margins of the disposal system were then demonstrated. A new assessment procedure incorporating this method into the existing safety assessment approach is proposed in this study. Using this procedure, it is possible to conduct a series of safety assessment activities in a logical manner. (author)

  5. Dose-response relationship in the treatment of gastrointestinal disorders.

    Science.gov (United States)

    Weihrauch, T R; Demol, P

    1989-08-01

    Numerous clinical studies have been performed to establish efficacy and safety of drugs in gastroenterological disorders. Only in a few if any of these studies, however, the rationale for the optimal dose and the dose regimens, respectively, have been addressed. Adequate and well-controlled dose finding studies play a key role in the clinical assessment of new drugs and in the evaluation of new indications. Hereby the range from the minimal effective dose to the maximal effective and well tolerated dose can be assessed and thus the optimal dose-range and dosage regimen be determined. Meaningful pharmacodynamic studies can be performed in the gastrointestinal tract also in healthy volunteers provided that a method with a high predictability for the desired therapeutic effect is available such as measurement of gastric acid secretion and its inhibition by a drug. Dose finding studies in gastroenterology can be carried out under two main aspects: First, to assess the pharmacodynamic and therapeutic effect of a compound on the gastrointestinal tract (e.g. anti-ulcer drug). Second, to evaluate the side effects of a drug on the gastrointestinal tract (e.g. gastric mucosal damage by non-steroidal anti-inflammatory drugs). For the evaluation of new drugs in gastrointestinal therapy a number of methods are available which yield accurate and reproducible data. While careful clinical-pharmacological dose-response studies using these methods have been carried out already more than a decade ago, it is surprising that therapeutic dose finding studies have become available only during the past few years. For scientific as well as for ethical reasons more trials which determine the optimal therapeutic dose are warranted.

  6. SU-E-T-86: A Systematic Method for GammaKnife SRS Fetal Dose Estimation

    Energy Technology Data Exchange (ETDEWEB)

    Geneser, S; Paulsson, A; Sneed, P; Braunstein, S; Ma, L [UCSF Comprehensive Cancer Center, San Francisco, CA (United States)

    2015-06-15

    Purpose: Estimating fetal dose is critical to the decision-making process when radiation treatment is indicated during pregnancy. Fetal doses less than 5cGy confer no measurable non-cancer developmental risks but can produce a threefold increase in developing childhood cancer. In this study, we estimate fetal dose for a patient receiving Gamma Knife stereotactic radiosurgery (GKSRS) treatment and develop a method to estimate dose directly from plan details. Methods: A patient underwent GKSRS on a Perfexion unit for eight brain metastases (two infratentorial and one brainstem). Dose measurements were performed using a CC13, head phantom, and solid water. Superficial doses to the thyroid, sternum, and pelvis were measured using MOSFETs during treatment. Because the fetal dose was too low to accurately measure, we obtained measurements proximally to the isocenter, fitted to an exponential function, and extrapolated dose to the fundus of the uterus, uterine midpoint, and pubic synthesis for both the preliminary and delivered plans. Results: The R-squared fit for the delivered doses was 0.995. The estimated fetal doses for the 72 minute preliminary and 138 minute delivered plans range from 0.0014 to 0.028cGy and 0.07 to 0.38cGy, respectively. MOSFET readings during treatment were just above background for the thyroid and negligible for all inferior positions. The method for estimating fetal dose from plan shot information was within 0.2cGy of the measured values at 14cm cranial to the fetal location. Conclusion: Estimated fetal doses for both the preliminary and delivered plan were well below the 5cGy recommended limit. Due to Pefexion shielding, internal dose is primarily governed by attenuation and drops off exponentially. This is the first work that reports fetal dose for a GK Perfexion unit. Although multiple lesions were treated and the duration of treatment was long, the estimated fetal dose remained very low.

  7. SU-E-T-86: A Systematic Method for GammaKnife SRS Fetal Dose Estimation

    International Nuclear Information System (INIS)

    Geneser, S; Paulsson, A; Sneed, P; Braunstein, S; Ma, L

    2015-01-01

    Purpose: Estimating fetal dose is critical to the decision-making process when radiation treatment is indicated during pregnancy. Fetal doses less than 5cGy confer no measurable non-cancer developmental risks but can produce a threefold increase in developing childhood cancer. In this study, we estimate fetal dose for a patient receiving Gamma Knife stereotactic radiosurgery (GKSRS) treatment and develop a method to estimate dose directly from plan details. Methods: A patient underwent GKSRS on a Perfexion unit for eight brain metastases (two infratentorial and one brainstem). Dose measurements were performed using a CC13, head phantom, and solid water. Superficial doses to the thyroid, sternum, and pelvis were measured using MOSFETs during treatment. Because the fetal dose was too low to accurately measure, we obtained measurements proximally to the isocenter, fitted to an exponential function, and extrapolated dose to the fundus of the uterus, uterine midpoint, and pubic synthesis for both the preliminary and delivered plans. Results: The R-squared fit for the delivered doses was 0.995. The estimated fetal doses for the 72 minute preliminary and 138 minute delivered plans range from 0.0014 to 0.028cGy and 0.07 to 0.38cGy, respectively. MOSFET readings during treatment were just above background for the thyroid and negligible for all inferior positions. The method for estimating fetal dose from plan shot information was within 0.2cGy of the measured values at 14cm cranial to the fetal location. Conclusion: Estimated fetal doses for both the preliminary and delivered plan were well below the 5cGy recommended limit. Due to Pefexion shielding, internal dose is primarily governed by attenuation and drops off exponentially. This is the first work that reports fetal dose for a GK Perfexion unit. Although multiple lesions were treated and the duration of treatment was long, the estimated fetal dose remained very low

  8. A track length estimator method for dose calculations in low-energy X-ray irradiations. Implementation, properties and performance

    Energy Technology Data Exchange (ETDEWEB)

    Baldacci, F.; Delaire, F.; Letang, J.M.; Sarrut, D.; Smekens, F.; Freud, N. [Lyon-1 Univ. - CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Centre Leon Berard (France); Mittone, A.; Coan, P. [LMU Munich (Germany). Dept. of Physics; LMU Munich (Germany). Faculty of Medicine; Bravin, A.; Ferrero, C. [European Synchrotron Radiation Facility, Grenoble (France); Gasilov, S. [LMU Munich (Germany). Dept. of Physics

    2015-05-01

    The track length estimator (TLE) method, an 'on-the-fly' fluence tally in Monte Carlo (MC) simulations, recently implemented in GATE 6.2, is known as a powerful tool to accelerate dose calculations in the domain of low-energy X-ray irradiations using the kerma approximation. Overall efficiency gains of the TLE with respect to analogous MC were reported in the literature for regions of interest in various applications (photon beam radiation therapy, X-ray imaging). The behaviour of the TLE method in terms of statistical properties, dose deposition patterns, and computational efficiency compared to analogous MC simulations was investigated. The statistical properties of the dose deposition were first assessed. Derivations of the variance reduction factor of TLE versus analogous MC were carried out, starting from the expression of the dose estimate variance in the TLE and analogous MC schemes. Two test cases were chosen to benchmark the TLE performance in comparison with analogous MC: (i) a small animal irradiation under stereotactic synchrotron radiation therapy conditions and (ii) the irradiation of a human pelvis during a cone beam computed tomography acquisition. Dose distribution patterns and efficiency gain maps were analysed. The efficiency gain exhibits strong variations within a given irradiation case, depending on the geometrical (voxel size, ballistics) and physical (material and beam properties) parameters on the voxel scale. Typical values lie between 10 and 103, with lower levels in dense regions (bone) outside the irradiated channels (scattered dose only), and higher levels in soft tissues directly exposed to the beams.

  9. Conversion from tooth enamel dose to organ doses for electron spin resonance dosimetry

    International Nuclear Information System (INIS)

    Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Saito, Kimiaki; Hamada, Tatsuji

    2002-01-01

    Conversion from tooth enamel dose to organ doses was analyzed to establish a method of retrospective individual dose assessment against external photon exposure by electron spin resonance (ESR) dosimetry. Dose to tooth enamel was obtained by Monte Carlo calculations using a modified MIRD-type phantom with a teeth part. The calculated tooth enamel doses were verified by measurements with thermo-luminescence dosimeters inserted in a physical head phantom. Energy and angular dependences of tooth enamel dose were compared with those of other organ doses. Additional Monte Carlo calculations were performed to study the effect of human model on the tooth enamel dose with a voxel-type phantom, which was based on computed tomography images of the physical phantom. The data derived with the modified MIRD-type phantom were applied to convert from tooth enamel dose to organ doses against external photon exposure in a hypothesized field, where scattered radiation was taken into account. The results indicated that energy distribution of photons incident to a human body is required to evaluate precisely an individual dose based on ESR dosimetry for teeth. (author)

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

    International Nuclear Information System (INIS)

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

    1995-10-01

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

  11. Radiation dose reduction for CT assessment of urolithiasis using iterative reconstruction. A prospective intra-individual study

    Energy Technology Data Exchange (ETDEWEB)

    Harder, Annemarie M. den; Willemink, Martin J.; Wessels, Frank J.; Schilham, Arnold M.R.; Leiner, Tim; Jong, Pim A. de [Utrecht University Medical Center, Department of Radiology, Utrecht (Netherlands); Doormaal, Pieter J. van; Budde, Ricardo P.J. [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands); Lock, M.T.W.T. [University Medical Center, Department of Urology, Utrecht (Netherlands)

    2018-01-15

    To assess the performance of hybrid (HIR) and model-based iterative reconstruction (MIR) in patients with urolithiasis at reduced-dose computed tomography (CT). Twenty patients scheduled for unenhanced abdominal CT for follow-up of urolithiasis were prospectively included. Routine dose acquisition was followed by three low-dose acquisitions at 40%, 60% and 80% reduced doses. All images were reconstructed with filtered back projection (FBP), HIR and MIR. Urolithiasis detection rates, gall bladder, appendix and rectosigmoid evaluation and overall subjective image quality were evaluated by two observers. 74 stones were present in 17 patients. Half the stones were not detected on FBP at the lowest dose level, but this improved with MIR to a sensitivity of 100%. HIR resulted in a slight decrease in sensitivity at the lowest dose to 72%, but outperformed FBP. Evaluation of other structures with HIR at 40% and with MIR at 60% dose reductions was comparable to FBP at routine dose, but 80% dose reduction resulted in non-evaluable images. CT radiation dose for urolithiasis detection can be safely reduced by 40 (HIR)-60 (MIR) % without affecting assessment of urolithiasis, possible extra-urinary tract pathology or overall image quality. (orig.)

  12. Assessment of Effective Dose Equivalent of Indoor 222Rn Daughters in Inchass

    International Nuclear Information System (INIS)

    Ali, E.M.; Taha, T.M.; Gomaa, M.A.; El-Hussein, A.M.; Ahmad, A.A.

    2000-01-01

    The dominant component of natural radiation dose for the general population comes from the radon gas 222 Rn and its short-lived decay products, Ra A ( 214 Po), Ra B ( 214 Pb), Ra C ( 214 Bi), Ra C( 214 Po) in the breathing air. The objective of the present work is to assess the affective dose equivalent of the inhalation exposure of indoor 222 Rn for occupational workers. Average indon concentrations (Bqm -3 ) were monitored in several departments in Nuclear Research Center by radon monitor. We have calculated the lung dose equivalent and the effective dose equivalent for the Egyptian workers due to inhalation exposure of an equilibrium equivalent concentrations of radon daughters which varies from 0.27 to 2.5 mSvy -1 and 0.016 to 0.152mSvy -1 respectively. The annual effective doses obtained are within the accepted range of ICRP recommendations

  13. Comparison between evaluating methods about the protocols of different dose distributions in radiotherapy

    International Nuclear Information System (INIS)

    Ju Yongjian; Chen Meihua; Sun Fuyin; Zhang Liang'an; Lei Chengzhi

    2004-01-01

    Objective: To study the relationship between tumor control probability (TCP) or equivalent uniform dose (EUD) and the heterogeneity degree of the dose changes with variable biological parameter values of the tumor. Methods: According to the definitions of TCP and EUD, calculating equations were derived. The dose distributions in the tumor were assumed to be Gaussian ones. The volume of the tumor was divided into several voxels, and the absorbed doses of these voxels were simulated by Monte Carlo methods. Then with the different values of radiosensitivity (α) and potential doubling time of the clonogens (T p ), the relationships between TCP or EUD and the standard deviation of dose (S d ) were evaluated. Results: The TCP-S d curves were influenced by the variable α and T p values, but the EUD-S d curves showed little variation. Conclusion: When the radiotherapy protocols with different dose distributions are compared, if the biological parameter values of the tumor have been known exactly, it's better to use the TCP, otherwise the EUD will be preferred

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

    International Nuclear Information System (INIS)

    Sato, Kaoru; Takahashi, Fumiaki; Satoh, Daiki; Endo, Akira

    2011-12-01

    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)

  15. Fluoxetine Dose and Administration Method Differentially Affect Hippocampal Plasticity in Adult Female Rats

    Science.gov (United States)

    Pawluski, Jodi L.; van Donkelaar, Eva; Abrams, Zipporah; Steinbusch, Harry W. M.; Charlier, Thierry D.

    2014-01-01

    Selective serotonin reuptake inhibitor medications are one of the most common treatments for mood disorders. In humans, these medications are taken orally, usually once per day. Unfortunately, administration of antidepressant medications in rodent models is often through injection, oral gavage, or minipump implant, all relatively stressful procedures. The aim of the present study was to investigate how administration of the commonly used SSRI, fluoxetine, via a wafer cookie, compares to fluoxetine administration using an osmotic minipump, with regards to serum drug levels and hippocampal plasticity. For this experiment, adult female Sprague-Dawley rats were divided over the two administration methods: (1) cookie and (2) osmotic minipump and three fluoxetine treatment doses: 0, 5, or 10 mg/kg/day. Results show that a fluoxetine dose of 5 mg/kg/day, but not 10 mg/kg/day, results in comparable serum levels of fluoxetine and its active metabolite norfluoxetine between the two administration methods. Furthermore, minipump administration of fluoxetine resulted in higher levels of cell proliferation in the granule cell layer (GCL) at a 5 mg dose compared to a 10 mg dose. Synaptophysin expression in the GCL, but not CA3, was significantly lower after fluoxetine treatment, regardless of administration method. These data suggest that the administration method and dose of fluoxetine can differentially affect hippocampal plasticity in the adult female rat. PMID:24757568

  16. Fluoxetine Dose and Administration Method Differentially Affect Hippocampal Plasticity in Adult Female Rats

    Directory of Open Access Journals (Sweden)

    Jodi L. Pawluski

    2014-01-01

    Full Text Available Selective serotonin reuptake inhibitor medications are one of the most common treatments for mood disorders. In humans, these medications are taken orally, usually once per day. Unfortunately, administration of antidepressant medications in rodent models is often through injection, oral gavage, or minipump implant, all relatively stressful procedures. The aim of the present study was to investigate how administration of the commonly used SSRI, fluoxetine, via a wafer cookie, compares to fluoxetine administration using an osmotic minipump, with regards to serum drug levels and hippocampal plasticity. For this experiment, adult female Sprague-Dawley rats were divided over the two administration methods: (1 cookie and (2 osmotic minipump and three fluoxetine treatment doses: 0, 5, or 10 mg/kg/day. Results show that a fluoxetine dose of 5 mg/kg/day, but not 10 mg/kg/day, results in comparable serum levels of fluoxetine and its active metabolite norfluoxetine between the two administration methods. Furthermore, minipump administration of fluoxetine resulted in higher levels of cell proliferation in the granule cell layer (GCL at a 5 mg dose compared to a 10 mg dose. Synaptophysin expression in the GCL, but not CA3, was significantly lower after fluoxetine treatment, regardless of administration method. These data suggest that the administration method and dose of fluoxetine can differentially affect hippocampal plasticity in the adult female rat.

  17. The relative importance of ingestion for multiple pathway dose assessments

    International Nuclear Information System (INIS)

    Wicker, W.; Grogan, H.; Bergstroem, U.; Hoffman, O.

    1991-01-01

    The general purpose of this report is to examine the relative importance of ingestion pathways, and particularly food chain transport in overall dose assessment. The importance of ingestion pathways is examined for various release scenarios and radionuclides because the findings are expected to differ with circumstances. The degree to which contaminated food products contribute to the total dose will affect the importance of accuracy and uncertainty of food chain model predictions, which is the main thrust of the Biospheric Model Validation Study (BIOMOVS). This analysis requires that all modes of radiation exposure be examined, including inhalation, external exposure, and the various ingestion pathways. (2 figs., 2 tabs.)

  18. Radiological-dose assessments of atolls in the northern Marshall Islands

    International Nuclear Information System (INIS)

    Robison, W.L.

    1983-04-01

    The Marshall Islands in the Equatorial Pacific, specifically Enewetak and Bikini Atolls, were the site of US nuclear testing from 1946 through 1958. In 1978, the Northern Marshall Islands Radiological Survey was conducted to evaluate the radiological conditions of two islands and ten atolls downwind of the proving grounds. The survey included aerial external gamma measurements and collection of soil, terrestrial, and marine samples for radionuclide analysis to determine the radiological dose from all exposure pathways. The methods and models used to estimate doses to a population in an environment where natural processes have acted on the source-term radionuclides for nearly 30 y, data bases developed for the models, and results of the radiological dose analyses are described

  19. Experimental assessment of absorbed dose to mineralized bone tissue from internal emitters: An electron paramagnetic resonance study

    International Nuclear Information System (INIS)

    Desrosiers, M.F.

    1994-01-01

    EPR resonances attributable to radiation-induced centers in hydroxyapatite were not detectable in bone samples supplied by the USTUR. These centers are the basis for imaging and dose assessment. Presumable, the short range of the alpha particles emitted precluded the formation of appreciable amounts of hydroxyapatite centers. However, one bone sample did offer a suggestion of hydroxyapatite centers and newly-developed methods to extract this information will be pursued

  20. Collective dose IRSN view on its indications and contraindications

    International Nuclear Information System (INIS)

    Supervil, S.

    2002-10-01

    The concept of collective protection appeared in 1959 in the first report of the international commission on Radiological Protection (ICRP). During the course of the next decades, ICRP gave details on the use of collective dose, in particular on its role in the process of optimization of protection. The collective dose, effective and /or equivalent, may be used to assess the dosimetric impact of an activity or a source over a group of people, to assess the number of stochastic effects that could result from the exposure of a group of people. The methods of calculating the collective dose are considered, assessment of the levels of exposure, assessment of the health effects. I.R.S.N. reminds that the collective dose constitutes an indicator of the risk of stochastic effects for example in the field of regulatory dose limits. Consequently, the collective dose cannot in any case constitute an indicator of the deterministic effects. (N.C.)