Internal dose assessment of 210Po using biokinetic modeling and urinary excretion measurement

The mysterious death of Mr. Alexander Litvinenko who was most possibly poisoned by Polonium-210 (210Po) in November 2006 in London attracted the attention of the public to the kinetics, dosimetry and the risk of this high radiotoxic isotope in the human body. In the present paper, the urinary excretion of seven persons who were possibly exposed to traces of 210Po was monitored. The values measured in the GSF Radioanalytical Laboratory are in the range of natural background concentration. To assess the effective dose received by those persons, the time-dependence of the organ equivalent dose and the effective dose after acute ingestion and inhalation of 210Po were calculated using the biokinetic model for polonium (Po) recommended by the International Commission on Radiological Protection (ICRP) and the one recently published by Leggett and Eckerman (L&E). The daily urinary excretion to effective dose conversion factors for ingestion and inhalation were evaluated based on the ICRP and L&E models for members of the public. The ingestion (inhalation) effective dose per unit intake integrated over one day is 1.7 × 10−8 (1.4 × 10−7) Sv Bq−1, 2.0 × 10−7 (9.6 × 10−7) Sv Bq−1 over 10 days, 5.2 × 10−7 (2.0 × 10−6) Sv Bq−1 over 30 days and 1.0 × 10−6 (3.0 × 10−6) Sv Bq−1 over 100 days. The daily urinary excretions after acute ingestion (inhalation) of 1 Bq of 210Po are 1.1 × 10−3 (1.0 × 10−4) on day 1, 2.0 × 10−3 (1.9 × 10−4) on day 10, 1.3 × 10−3 (1.7 × 10−4) on day 30 and 3.6 × 10−4 (8.3 × 10−5) Bq d−1 on day 100, respectively. The resulting committed effective doses range from 2.1 × 10−3 to 1.7 × 10−2 mSv by an assumption of ingestion and from 5.5 × 10−2 to 4.5 × 10−1 mSv by inhalation. For the case of Mr. Litvinenko, the mean organ absorbed dose as a function of time was calculated using both the above stated models. The red bone marrow, the kidneys and the liver were considered as the critical organs. Assuming a value of lethal absorbed dose of 5 Gy to the bone marrow, 6 Gy to the kidneys and 8 Gy to the liver, the amount of 210Po which Mr. Litvinenko might have ingested is therefore estimated to range from 27 to 1,408 MBq, i.e 0.2–8.5 μg, depending on the modality of intake and on different assumptions about blood absorption

Parametric analysis of a biokinetic model: a contribution to the study of model reliability

I M. C. Lourenc, II J. L. Lipsztein and III C. L. Szwarcwald/ 1 Instituto de Radioproteção e Dosimetria Av. Salvador Allende, s/n, CEP 22780–160, Rio de Janeiro – RJ, Brazil / 2 Instituto de Biologia, Universidade do Estado do Rio de Janeiro Av. 28 de Setembro, 87, CEP 20551–030, Rio de Janeiro – RJ, Brazil/ 3 Departamento de Saúde, Fundação Oswaldo Cruz Av. Brasil, 4365, CEP 21045–900, Rio de Janeiro – RJ, BrazilMade available in DSpace on 2010-08-23T16:58:36Z (GMT). No. of bitstreams: 3 license.txt: 1848 bytes, checksum: c1e4622844147e1ffa7fb904370b866a (MD5) LANDMANN_Parametric Analysis Biokinetic_1998.pdf: 34180 bytes, checksum: 8316bfeb8d5f44135fb59e8aa558ce3f (MD5) LANDMANN_Parametric Analysis Biokinetic_1998.pdf.txt: 19050 bytes, checksum: c9f06ee7b2adb8333ee76518dc7b35e1 (MD5) Previous issue date: 1998Made available in DSpace on 2010-11-04T14:20:03Z (GMT). No. of bitstreams: 3 LANDMANN_Parametric Analysis Biokinetic_1998.pdf.txt: 19050 bytes, checksum: c9f06ee7b2adb8333ee76518dc7b35e1 (MD5) LANDMANN_Parametric Analysis Biokinetic_1998.pdf: 34180 bytes, checksum: 8316bfeb8d5f44135fb59e8aa558ce3f (MD5) license.txt: 1848 bytes, checksum: c1e4622844147e1ffa7fb904370b866a (MD5) Previous issue date: 1998Instituto de Radioproteção e Dosimetria. Rio de Janeiro, RJ, Brasil.Universidade do Estado do Rio de Janeiro. Instituto de Biologia. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Comunicação e Informação Científica e Tecnologia em Saúde. Rio de Janeiro, RJ, Brasil.Models for simulating radionuclide distribution in the human body involve assumptions on the biokinetic behaviour of the material. An important problem in biokinetic modelling is the correct assignment of transfer coefficients and biological half-lives to tissue compartments. The purpose of this study is the analysis of the variations of the radionuclide contents in the tissue compartments related to variations in the transfer coefficients from blood to the compartments and to variations in the compartments' biological half-lives. A generalised systemic recycling model, consisting of four tissue compartments and two excretion pathways, was used for the parametric analysis. A continuous intake directly to the blood was chosen for this study. Activities in the compartments were calculated for different times, following random selection of the transfer coefficients and half-lives. A computer code was developed to perform the random selection of parameters. Three different case studies were analysed, where different intervals of variation of half-lives in the four compartments were chosen: (a) the same range of variation was assigned to all compartments, (b) the intervals were chosen so that one compartment had a significantly longer half-life than the others, and (c) one compartment had a significantly shorter half-life than the others. Two cases for the intervals of variation of the transfer coefficients were investigated: (a) the same range for the variation of all transfer coefficients from blood to compartments was assumed, and (b) the interval of the variation of one transfer coefficient was significantly larger than the others. A multiple regression analysis method was applied to analyse the results. In this paper the detailed results of the parametric analysis are presented

Review of methods and computer codes for interpretation of bioassay data

International audienc

ICRP Publication 134: Occupational Intakes of Radionuclides: Part 2

Authors on Behalf of ICRPThe 2007 Recommendations of the International Commission on Radiological Protection (ICRP, 2007) introduced changes that affect the calculation of effective dose, and implied a revision of the dose coefficients for internal exposure, published previously in the Publication 30 series (ICRP, 1979, 1980, 1981, 1988b) and Publication 68 (ICRP, 1994b). In addition, new data are available that support an update of the radionuclide-specific information given in Publications 54 and 78 (ICRP, 1988a, 1997b) for the design of monitoring programmes and retrospective assessment of occupational internal doses. Provision of new biokinetic models, dose coefficients, monitoring methods, and bioassay data was performed by Committee 2, Task Group 21 on Internal Dosimetry, and Task Group 4 on Dose Calculations. A new series, the Occupational Intakes of Radionuclides (OIR) series, will replace the Publication 30 series and Publications 54, 68, and 78. Part 1 of the OIR series has been issued (ICRP, 2015), and describes the assessment of internal occupational exposure to radionuclides, biokinetic and dosimetric models, methods of individual and workplace monitoring, and general aspects of retrospective dose assessment. The following publications in the OIR series (Parts 2–5) will provide data on individual elements and their radioisotopes, including information on chemical forms encountered in the workplace; a list of principal radioisotopes and their physical half-lives and decay modes; the parameter values of the reference biokinetic model; and data on monitoring techniques for the radioisotopes encountered most commonly in workplaces. Reviews of data on inhalation, ingestion, and systemic biokinetics are also provided for most of the elements. Dosimetric data provided in the printed publications of the OIR series include tables of committed effective dose per intake (Sv per Bq intake) for inhalation and ingestion, tables of committed effective dose per content (Sv per Bq measurement) for inhalation, and graphs of retention and excretion data per Bq intake for inhalation. These data are provided for all absorption types and for the most common isotope(s) of each element. The electronic annex that accompanies the OIR series of reports contains a comprehensive set of committed effective and equivalent dose coefficients, committed effective dose per content functions, and reference bioassay functions. Data are provided for inhalation, ingestion, and direct input to blood. The present publication provides the above data for the following elements: hydrogen (H), carbon (C), phosphorus (P), sulphur (S), calcium (Ca), iron (Fe), cobalt (Co), zinc (Zn), strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), and technetium (Tc)