This report is the first in a series of reports replacing Publications 30 and 68 to provide revised dose coefficients for occupational intakes of radionuclides by inhalation and ingestion. The revised dose coefficients have been calculated using the Human Alimentary Tract Model (Publication 100) and a revision of the Human Respiratory Tract Model (Publication 66) that takes account of more recent data. In addition, information is provided on absorption into blood following inhalation and ingestion of different chemical forms of elements and their radioisotopes. In selected cases, it is judged that the data are sufficient to make material-specific recommendations. Revisions have been made to many of the models that describe the systemic biokinetics of radionuclides absorbed into blood, making them more physiologically realistic representations of uptake and retention in organs and tissues, and excretion. The reports in this series provide data for the interpretation of bioassay measurements as well as dose coefficients, replacing Publications 54 and 78. In assessing bioassay data such as measurements of whole-body or organ content, or urinary excretion, assumptions have to be made about the exposure scenario, including the pattern and mode of radionuclide intake, physical and chemical characteristics of the material involved, and the elapsed time between the exposure(s) and measurement. This report provides some guidance on monitoring programmes and data interpretation.

https://journals.sagepub.com/doi/pdf/10.1177/0146645315577539

ICRP Publication 130: Occupational Intakes of Radionuclides: Part 1.

The Mayak Production Association, which began operation in 1948, was the first facility in the former Soviet Union for the production of plutonium. Significant worker and population exposure occurred as a result of failures in the technological processes in the late 1940's and early 1950's. Members of the public were exposed via discharge of about 1017 Bq of liquid wastes into the Techa River during 1949-1956, an explosion in the radioactive waste-storage facility in 1957, and gaseous aerosol releases within the first decades of the facility's operation. Residents of many villages downstream on the Techa River were exposed via a variety of pathways; the more significant included drinking of water from the river and external gamma exposure due to proximity to sediments and shoreline. The specific aim of this project is to enhance the reconstruction of external and internal radiation doses for individuals in the Extended Techa River Cohort. The purpose of this paper is to present the details of the methods that are being used in this enhanced dose-reconstruction effort and to provide example and representative results of the calculations. The methods of dose assessment currently being developed for the exposed population [termed the Techa River Dosimetry System-2000 (TRDS-2000)], which are a significant improvement on past methods (TRDS-1996), are presented. The new TRDS-2000 doses from the ingestion of radionuclides are substantially higher for the gastrointestinal tract, due to consideration of short-lived radionuclides. The TRDS-2000 doses from external exposure are substantially lower due to improvements in several factors. Assessment of uncertainty and validation of the "new" doses are significant issues currently under investigation.

Dose reconstruction system for the exposed population living along the Techa River.

The Mayak Production Association (MPA) was the first facility in the former Soviet Union for the production of plutonium. Significant worker and population exposures occurred as a result of failures in the technological processes in the late 1940's and early 1950's. Residents of many villages downstream on the Techa River were exposed via a variety of pathways; the more significant included drinking of water from the river and external gamma exposure due to proximity to contaminated bottom sediment and shoreline. After the extent of the major contamination of the Techa River became known, several villages on the upper part of the Techa River were evacuated. Organ doses are being reconstructed on the basis of derivation of an historical source term and a simple river model used to simulate the transport of radionuclides downstream and their retention on sediments; measurements of 90Sr content in teeth and the whole body of half of the members of the cohort; and development of the "Techa River Dosimetry System" for computation of the doses.

The Techa River dosimetry system: methods for the reconstruction of internal dose.

Doses from intakes of radionuclides cannot be measured but must be assessed from monitoring, such as whole body counting or urinary excretion measurements. Such assessments require application of a biokinetic model and estimation of the exposure time, material properties, etc. Because of the variety of parameters involved, the results of such assessments may vary over a wide range, according to the skill and the experience of the assessor. The need for harmonisation of assessment procedures has been recognised in a research project carried out under the EU 5 th Framework Programme. The aim of the project IDEAS (partly funded by the European Commission under contract No. FIKR-CT2001-00160) was to develop general guidelines for assessments of intakes and internal doses from individual monitoring data. The IDEAS project started in October 2001 and ended in June 2005. To ensure that the guidelines are applicable to a wide range of practical situations, a database was compiled of cases of internal contamination that include monitoring data suitable for assessment. About 50 cases from the database were analized by different assessors, the results were collated, and differences in assumptions identified, with their effects on the assessed doses. From the results, and other investigations, draft guidelines were prepared, to provide a systematic procedure for estimating the required parameter values that are not part of the measurement data. A virtual workshop was held on the Internet, open to internal dosimetry professionals, to discuss the draft guidelines, which were revised accordingly. In collaboration with the IAEA, an intercomparison exercise on internal dose assessment was then conducted, which was also open to all involved in internal dosimetry. Six cases were developed and circulated with a copy of the revised guidelines, which participants were encouraged to follow, to test their applicability and effectiveness. The results were collated and a Workshop held to discuss the results with the participants. The guidelines were refined on the basis of the experience and discussion. The guidelines are based on a general philosophy of: • Harmonisation: by following the Guidelines any two assessors should obtain the same estimate of dose from a given data set. • Accuracy: the "best" estimate of dose should be obtained from the available data. • Proportionality: the effort applied to the evaluation should be proportionate to the dose - the lower the dose, the simpler the process should be. Following these principles, the Guidelines use the following "Levels of task" to structure the approach to an evaluation: Level 0: Annual dose 6 mSv). The guidelines provide: • Background information about the biokinetic models and the corresponding bioassay functions for the interpretation of monitoring data. • Detailed information about the handling and evaluation of monitoring data. • A structured approach to dose assessment consisting of a step-by-step procedure described in well-defined flowcharts with accompanying explanatory text.

/pdf/general-guidelines-for-the-estimation-of-committed-effective-3ueauhnvh5.pdf

General guidelines for the estimation of committed effective dose from incorporation monitoring data : (Project IDEAS - EU contract no. FIKR-CT2001-00160)

This paper describes the effect on over 3,000 sets of internal dose estimates of using photon Specific Absorbed Fractions (SAFs) calculated using two different types of phantoms, specifically the MIRD-type anthropomorphic phantom originally developed by Snyder and the new adult male voxel phantom, GOLEM, developed at GSF. The SAFs based on the MIRD-type phantom are currently used by the International Commission on Radiological Protection (ICRP) in internal dose calculations, but there are suggestions of moving towards SAFs generated from voxel phantoms, thus there is an interest in the potential differences in internal doses. Overall, it is found that some tissue doses calculated using the voxel phantoms can differ significantly from those of the MIRD-type phantom; however, the effective dose appears to be quite robust to changes in photon SAFs.

Impact On Internal Doses Of Photon Safs Derived With The Gsf Adult Male Voxel Phantom

Internal dosimetry support system (IDSS) implements a full set of the ICRP internal dosimetry models, including the new respiratory tract model: it is a 32-bit program that operates under Windows 95. It enables the calculation of the time course of activity. the dose rate, the dynamics of dose accumulation and the committed dose in any tissue of the body; the daily urinary and faecal excretion rates also are available. The results may be accessed for the analysis and interpretation in graphical or numerical form and may be stored for future retrieval. Additional capabilities provide the means for stochastic simulation. IDSS allows analysis of the standard and non-standard exposure conditions and assists in assessment of the dose reliability. The main distinguishing features of IDSS are: processing of an arbitrary time course of the intake function, extended possibilities of data analysis, an orientation to a wide spectrum of research problems, an object-oriented logical structure and a modularity of the code. IDSS assists in the assessment of doses under normal or accidental conditions, both for prospective and retrospective dosimetry problems.

Internal Dosimetry Support System: Multipurpose Research Computer Code

The purposes of this study were to investigate the influence of the consequences of the lack of primary bioassay information and to elaborate approaches which could improve the reliability of dose assessments. The aggregated time-dependent functions 'dose per unit organ (excretion) content' z(t) have been proposed in this study as a convenient and reliable tool for bioassay. The analysis of the variation of z with changes of AMAD has demonstrated the existence of areas of the relative invariance of z, which permits the selection of one (reference) function z for the whole area of stability. Within the framework of such an approach an arbitrary set of bioassay data can be approximated by the linear combination F(t) = sum(i) E(i)/z(t - tau(i)), where F(t) = function of time t, which approximates the observed bioassay time trend; tau(i) = time shift of the acute intake i; E(i) = effective dose, associated with the acute intake i (the two last parameters are results of the approximation procedure).

'Dose per unit content' functions: A robust tool for the interpretation of bioassay data

Occupational Intakes of Radionuclides: Part 5

The 'Individual Monitoring for Internal Exposure' (IMIE) computer codes are the family of interactive tools for interpretation of the bioassay data and individual dose assessments. During 10 y of the IMIE evolution, the extensive experience in the IMIE application has been accumulated and the underlying methodology has undergone essential improvements. The main distinguished feature of the IMIE ideology is the automated numerical analysis of all examined exposure scenarios with the succeeding interactive identification of events of intake(s) and assessment of associated doses. The numerical deconvolution algorithms and the massive library of tabulated 'bioassay/dose response functions' are employed for the processing of an arbitrary pattern of intake and complex exposure conditions. This article discusses details implemented in the IMIE algorithms and examples of IMIE application.

IMIE computer codes: 10 y in the internal dosimetry

A detailed study of the time dynamics of radiation dose formation after inhalation of alpha-emitting aerosols has been carried out, using the Internal Dosimetry Support System (IDSS) computer code. The deformation of the primary aerosol size distribution has been calculated for all respiratory tract regions. The role of endogenous short-range radiation sources (body fluids) in the irradiation of lung tissues had been studied. The ICRP 66 Respiratory Tract model takes no account of energy self-absorption within aerosol particles so non-standard calculations of alpha particle energy transport were performed to investigate this effect. For UO2 particles of 20 and 100 μm AMAD containing uniformly distributed 239 Pu the committed equivalent dose to the extrathoracic tissues is reduced by factors of 1.1 and 3.9, respectively. The corresponding factors for committed effective dose are 1.1 and 3.2, respectively.

G. Ratia

Papers

Internal Dosimetry Support System: Multipurpose Research Computer Code

'Dose per unit content' functions: A robust tool for the interpretation of bioassay data

Occupational Intakes of Radionuclides: Part 5

IMIE computer codes: 10 y in the internal dosimetry

Time-Spatial Peculiarities of Dose Formation after Inhalation of Alpha Emitters