Reliability of the ICRP's Dose Coefficients for Members of the Public, II. Uncertainties in the Absorption of Ingested Radionuclides and the Effect on Dose Estimates

Harrison, J.; Leggett, Richard W.; Noßke, D.; Paquet, Fabien; Phipps, D M; Taylor, David; Métivier, Henri

doi:10.1093/oxfordjournals.rpd.a006554

Cited by 45 publications

(29 citation statements)

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“…Fractional absorption of uranium from the alimentary tract after escalation from the respiratory tract cannot be determined directly due to simultaneous absorption of uranium from the respiratory tract. Estimated fractional absorption of uranium after oral intake ranges from less than 0.001 to about 0.06 for individual subjects (Leggett and Harrison 1995;Harrison et al 2001 (Leggett and Harrison 1995).…”

Section: Gastrointestinal Absorption Of Uraniummentioning

confidence: 99%

Controlling intake of uranium in the workplace: Applications of biokinetic modeling and occupational monitoring data

Leggett¹,

Eckerman²,

McGinn³

et al. 2012

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This report provides methods to interpret and apply occupational uranium monitoring data. The methods are based on current international radiation protection guidance, current information on the chemical toxicity of uranium, and best available biokinetic models for uranium. Emphasis is on air monitoring data and three types of bioassay data: the concentration of uranium in urine; the concentration of uranium in feces; and the externally measured content of uranium in the chest. Primary Reference guidance levels for prevention of chemical effects and limitation of radiation effects are selected based on a review of current scientific data and regulatory principles for setting standards. Generic investigation levels and immediate action levels are then defined in terms of these primary guidance levels. The generic investigation and immediate actions levels are stated in terms of radiation dose and concentration of uranium in the kidneys. These are not directly measurable quantities, but models can be used to relate the generic levels to the concentration of uranium in air, urine, or feces, or the total uranium activity in the chest. Default investigation and immediate action levels for uranium in air, urine, feces, and chest are recommended for situations in which there is little information on the form of uranium taken into the body. Methods are prescribed also for deriving case-specific investigation and immediate action levels for uranium in air, urine, feces, and chest when there is sufficient information on the form of uranium to narrow the range of predictions of accumulation of uranium in the main target organs for uranium: kidneys for chemical effects and lungs for radiological effects. In addition, methods for using the information herein for alternative guidance levels, different from the ones selected for this report, are described. v FOREWORDThis report provides a detailed description of uranium biokinetics and bioassays applicable to evaluation of health risks from potential intakes in an occupational setting. The report addresses both the radiotoxicity and chemical (renal) toxicity of uranium. For reference occupational exposure scenarios, predictions of the time-dependent concentration of uranium in tissues and bioassay are based on biokinetic models currently recommended by the International Commission on Radiological Protection (ICRP). The ICRP's models and default assumptions for uranium were based primarily on data for human subjects exposed to uranium in controlled studies or in occupational or environmental settings. In addition, the ICRP considered an extensive database for uranium in laboratory animals. Sensitivity studies examine the robustness of these models and assumptions to ensure that radiation doses and accumulation of uranium in the kidneys are not underestimated. For example, analyses indicate that a default 5 µm activity median aerodynamic diameter particle size can lead to an underestimation of radiation dose as well as the concentration of uranium in the kidneys if inhal...

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Section: Gastrointestinal Absorption Of Uraniummentioning

confidence: 99%

Controlling intake of uranium in the workplace: Applications of biokinetic modeling and occupational monitoring data

Leggett¹,

Eckerman²,

McGinn³

et al. 2012

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“…Table 3 contains a summary of the masses, with their respective uncertainties, used in the Doses-2005 algorithm and subsequent analysis. Whereas the biokinetic data for the model parameters are often obtained from dog studies such as research performed using beagles (Hickman et al 1995;Polig 1997;Gilbert et al 1998;Polig et al 2000), significant efforts have been executed to confirm the reliability of such data for human studies (Leggett 2001(Leggett , 2003Harrison et al 2001). …”

Section: The Doses-2005 Modelmentioning

confidence: 99%

“…However, using the Birchall and James algorithm with multiple radionuclides could significantly slow down the calculations when generating doses for multiple time periods (Peace 2003). Transport and dose assessment studies have been performed for multiple radionuclides using ICRP models by O'Brien (2003).…”

Section: Analyses Specific To the Investigationmentioning

confidence: 99%

Uncertainties Analysis for the Plutonium Dosimetry Model, Doses-2005, Using Mayak Bioassay Data

Bess¹,

Krahenbuhl²,

Miller

et al. 2007

Health Physics

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The Doses-2005 model is a combination of the International Commission on Radiological Protection (ICRP) models modified using data from the Mayak Production Association cohort. Surrogate doses from inhaled plutonium can be assigned to approximately 29% of the Mayak workers using their urine bioassay measurements and other history records. The purpose of this study was to quantify and qualify the uncertainties in the estimates for radiation doses calculated with the Doses-2005 model by using Monte Carlo methods and perturbation theory. The average uncertainty in the yearly dose estimates for most organs was approximately 100% regardless of the transportability classification. The relative source of the uncertainties comes from three main sources: 45% from the urine bioassay measurements, 29% from the Doses-2005 model parameters, and 26% from the reference masses for the organs. The most significant reduction in the overall dose uncertainties would result from improved methods in bioassay measurement with additional improvements generated through further model refinement. Additional uncertainties were determined for dose estimates resulting from changes in the transportability classification and the smoking toggle. A comparison was performed to determine the effect of using the model with data from either urine bioassay or autopsy data; no direct correlation could be established. Analysis of the model using autopsy data and incorporation of results from other research efforts that have utilized plutonium ICRP models could improve the Doses-2005 model and reduce the overall uncertainty in the dose estimates.

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“…There is no specific ICRP Publication on the issue of uncertainty, but a series of papers discussed the reliability of the ICRP's biokinetic models and the resulting dose coefficients for members of the public and evaluated the sources of uncertainty in the biokinetic models (Leggett et al 1998(Leggett et al , 2007Harrison et al 2001;Leggett 2001Leggett , 2003. In the ICRP framework, an uncertainty associated with a biokinetic or dosimetric quantity will be expressed in terms of lower and upper bounds, A and B, such that there is judged to be roughly a 90% probability that the true central value is no less than A and no greater than B.…”

Section: Introductionmentioning

confidence: 99%

Reliability of a New Biokinetic Model of Zirconium in Internal Dosimetry: Part I, Parameter Uncertainty Analysis

Greiter

Oeh

et al. 2011

Health Physics

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The reliability of biokinetic models is essential in internal dose assessments and radiation risk analysis for the public, occupational workers, and patients exposed to radionuclides. In this paper, a method for assessing the reliability of biokinetic models by means of uncertainty and sensitivity analysis was developed. The paper is divided into two parts. In the first part of the study published here, the uncertainty sources of the model parameters for zirconium (Zr), developed by the International Commission on Radiological Protection (ICRP), were identified and analyzed. Furthermore, the uncertainty of the biokinetic experimental measurement performed at the Helmholtz Zentrum München-German Research Center for Environmental Health (HMGU) for developing a new biokinetic model of Zr was analyzed according to the Guide to the Expression of Uncertainty in Measurement, published by the International Organization for Standardization. The confidence interval and distribution of model parameters of the ICRP and HMGU Zr biokinetic models were evaluated. As a result of computer biokinetic modelings, the mean, standard uncertainty, and confidence interval of model prediction calculated based on the model parameter uncertainty were presented and compared to the plasma clearance and urinary excretion measured after intravenous administration. It was shown that for the most important compartment, the plasma, the uncertainty evaluated for the HMGU model was much smaller than that for the ICRP model; that phenomenon was observed for other organs and tissues as well. The uncertainty of the integral of the radioactivity of 95 Zr up to 50 y calculated by the HMGU model after ingestion by adult members of the public was shown to be smaller by a factor of two than that of the ICRP model. It was also shown that the distribution type of the model parameter strongly influences the model prediction, and the correlation of the model input parameters affects the model prediction to a certain extent depending on the strength of the correlation. In the case of model prediction, the qualitative comparison of the model predictions with the measured plasma and urinary data showed the HMGU model to be more reliable than the ICRP model; quantitatively, the uncertainty model prediction by the HMGU systemic biokinetic model is smaller than that of the ICRP model. The uncertainty information on the model parameters analyzed in this study was used in the second part of the paper regarding a sensitivity analysis of the Zr biokinetic models. Health Phys. 101(6):660 -676; 2011

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Reliability of the ICRP's Dose Coefficients for Members of the Public, II. Uncertainties in the Absorption of Ingested Radionuclides and the Effect on Dose Estimates

Cited by 45 publications

References 0 publications

Controlling intake of uranium in the workplace: Applications of biokinetic modeling and occupational monitoring data

Controlling intake of uranium in the workplace: Applications of biokinetic modeling and occupational monitoring data

Uncertainties Analysis for the Plutonium Dosimetry Model, Doses-2005, Using Mayak Bioassay Data

Reliability of a New Biokinetic Model of Zirconium in Internal Dosimetry: Part I, Parameter Uncertainty Analysis

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