TL;DR: The undisturbed metabolism of Pu and Am can be derived from the data since no decorporation measures had been taken, and the estimated committed effective dose is in the order of 1 Sv.
Abstract: In 1983, a young man inhaled accidentally a large amount of plutonium and americium. This case was carefully followed until 2013. Since no decorporation measures had been taken, the undisturbed metabolism of Pu and Am can be derived from the data. First objective was to determine the amount of inhaled radionuclides and to estimate committed effective dose. In vivo and excretion measurements started immediately after the inhalation, and for quality assurance, all types of measurements were performed by different labs in Europe and the USA. After dose assessment by various international groups were completed, the measurements were continued to produce scientific data for model validation. The data have been analysed here to estimate lung absorption parameter values for the inhaled plutonium and americium oxide using the proposed new ICRP Human Respiratory Tract Model. As supplement to the biokinetic modelling, biological data from three different cytogenetic markers have been added. The estimated committed effective dose is in the order of 1 Sv. The subject is 30 y after the inhalation, of good health, according to a recent medical check-up.
An estimate of the isotopic composition of the inhaled material is necessary to determine the initial amount of americium and plutonium deposited in the lungs.
Note that this effect is achieved even if liver and skeleton data are not included in the fitting because it is mainly driven by the urine data.
Figures 1–4 show measurements and best-fit model predictions for a subset of the datasets.
In summary, the significant increase of symmetrical aberrations, while no enhancement of dicentric chromosomes is observed, provides evidence for a past radiation exposure of the blood forming tissue and/or ongoing chronic low dose exposure.
TL;DR: The 2007 Recommendations 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 and Publications 54, 68, and 78.
Abstract: The 2007 Recommendations (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, 1979a,b, 1980a, 1981, 1988) and Publication 68 (ICRP, 1994b). In addition, new data are now available that support an update of the radionuclide-specific information given in Publications 54 and 78 (ICRP, 1989a, 1997) 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 and its task groups. A new series, the Occupational Intakes of Radionuclides (OIR) series, will replace the Publication 30 series and Publications 54, 68, and 78. OIR Part 1 (ICRP, 2015) 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. OIR Part 2 (ICRP, 2016), OIR Part 3 (ICRP, 2017), this current publication, and the final publication in the OIR series (OIR Part 5) 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 models; and data on monitoring techniques for the radioisotopes most commonly encountered 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 online electronic files that accompany the OIR series of publications 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. This fourth publication in the OIR series provides the above data for the following elements: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), actinium (Ac), protactinium (Pa), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), and fermium (Fm).
47 citations
Additional excerpts
...(598) Zalikin (1966a) followed the tissue distribution of (233)Pa for 128 d after administration of protactinium citrate (pH 3) to rats by intratracheal instillation....
TL;DR: In this paper, established and emerging dosimetry methods are reviewed, which can be used immediately and retrospectively following external ionising radiation exposure, and individual characteristics of these techniques, their limitations and potential for further development are discussed, and their usefulness in specific exposure scenarios is discussed.
Abstract: The current focus on networking and mutual assistance in the management of radiation accidents or incidents has demonstrated the importance of a joined-up approach in physical and biological dosimetry. To this end, the European Radiation Dosimetry Working Group 10 on 'Retrospective Dosimetry' has been set up by individuals from a wide range of disciplines across Europe. Here, established and emerging dosimetry methods are reviewed, which can be used immediately and retrospectively following external ionising radiation exposure. Endpoints and assays include dicentrics, translocations, premature chromosome condensation, micronuclei, somatic mutations, gene expression, electron paramagnetic resonance, thermoluminescence, optically stimulated luminescence, neutron activation, haematology, protein biomarkers and analytical dose reconstruction. Individual characteristics of these techniques, their limitations and potential for further development are reviewed, and their usefulness in specific exposure scenarios is discussed. Whilst no single technique fulfils the criteria of an ideal dosemeter, an integrated approach using multiple techniques tailored to the exposure scenario can cover most requirements.
TL;DR: These studies suggest investigating the possibility of employing low-dose alpha-radiation, such as from 239PuO2 inhalation, as a prophylaxis against lung cancer.
Abstract: Several studies on the effect of inhaled plutonium-dioxide particulates and the incidence of lung tumors in dogs reveal beneficial effects when the cumulative alpha-radiation dose is low. There is a threshold at an exposure level of about 100 cGy for excess tumor incidence and reduced lifespan. The observations conform to the expectations of the radiation hormesis dose-response model and contradict the predictions of the LNT hypothesis. These studies suggest investigating the possibility of employing low-dose alpha-radiation, such as from 239PuO2 inhalation, as a prophylaxis against lung cancer.
20 citations
Cites background from "30-Y follow-up of a PU/AM inhalatio..."
...Furthermore, the 30-year follow-up of a plutonium-americium inhalation exposure, with a committed effective dose of the order of 100 cSv, shows no evidence of lung cancer; the subject is in good health (Wernli et al. 2015)....
TL;DR: In this article, the dicentric chromosome assay (DCA) results were homogeneous between participants and matched well with the reference doses (≥95% of estimates within ± 0.5 Gy of the reference).
Abstract: PURPOSE Biological and/or physical assays for retrospective dosimetry are valuable tools to recover the exposure situation and to aid medical decision making. To further validate and improve such biological and physical assays, in 2019, EURADOS Working Group 10 and RENEB performed a field exercise in Lund, Sweden, to simulate various real-life exposure scenarios. MATERIALS AND METHODS For the dicentric chromosome assay (DCA), blood tubes were located at anthropomorphic phantoms positioned in different geometries and were irradiated with a 1.36 TBq 192Ir-source. For each exposure condition, dose estimates were provided by at least one laboratory and for four conditions by 17 participating RENEB laboratories. Three radio-photoluminescence glass dosimeters were placed at each tube to assess reference doses. RESULTS The DCA results were homogeneous between participants and matched well with the reference doses (≥95% of estimates within ±0.5 Gy of the reference). For samples close to the source systematic underestimation could be corrected by accounting for exposure time. Heterogeneity within and between tubes was detected for reference doses as well as for DCA doses estimates. CONCLUSIONS The participants were able to successfully estimate the doses and to provide important information on the exposure scenarios under conditions closely resembling a real-life situation.
TL;DR: For example, USTUR participants living ten years longer than those not exposed to high levels of transuranics were found to be 10% more likely to develop lung cancer as discussed by the authors.
Abstract: Single large radioactive particles are not carcinogenic in the lung. Plutonium dioxide is not the most toxic chemical compound known. About a million grams of plutonium have been initially entrained in the air from nuclear weapon testing. An initial inhaled concentration of >100,000 submicron diameter 239-plutonium dioxide particles per gram lung are associated with formation of large particle aggregates in the lung, giving a threshold dose to the lung of about 1 Gy for lung tumor development in rats, dogs and humans. Evidence of radiation hormesis has been found in animals and plutonium workers. A nuclear technician accidentally exposed to americium, delivering enormous radiation doses to the lung, liver and skeleton, died eleven years later at the age of 75 without any evidence of cancer. USTUR participants lived ten years longer than those not exposed to high levels of transuranics.
TL;DR: In this article, the HPGe detectors are modeled with the aid of Monte Carlo software and the resulting models are used for computational calibrations and for the optimization of the counting setups.
Abstract: SUMMARY In this work, a new system with both whole-body and partialbody counting capabilities is developed, installed and tested with both sample and real contamination cases. The new system amends the old scintillators with new HPGe detectors, improving the attainable resolution and also allowing a broader range of measurements. The HPGe detectors are modeled with the aid of Monte Carlo software and the resulting models are used for computational calibrations and for the optimization of the counting setups. Software is also developed to handle the different steps of measurements.
4 citations
"30-Y follow-up of a PU/AM inhalatio..." refers background or methods in this paper
...Additional simulations found the efficiency for the skull to decrease by 50 % for a 2-cm slide of the subject down the reclined stretcher [see the pictures in (2)]....
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...Over the last few years, organ measurements were performed with highly specialised instruments at Karlsruhe Institute for Technology (KIT)((2)) and the excretion measurements were done again at Paul Scherrer Institute (PSI)((1))....
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...The calculation of the activity for (241)Am in each organ was performed using both ICRP Man and ICRP Female as calibration phantoms, and the calibration data were obtained using MCNPX((4)) after a validation of the method((2))....
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...Recent in vivo measurements have been performed at KIT Karlsruhe using a system of four HPGe detectors((2))....
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...RECENT IN VIVO MEASUREMENTS
Instruments and method
Recent in vivo measurements have been performed at KIT Karlsruhe using a system of four HPGe detectors(2)....