Modèles dosimétriques pour les radionucléides incorporés par les travailleurs

Chevalier, C.; Roy, M.; Malarbet, J.L.

doi:10.1051/radiopro:1997102

Cited by 2 publications

(2 citation statements)

References 10 publications

(5 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This led to the assessment of rapid fraction f, expressed in % and rapid and slow transfer rate to blood, s, and s, expressed in d-l, defined in ICRP Publication 66 (1994a) for blood absorption; and dose calculation using LUDEP computer program (Birchall et al 1991) which is designed to implement the respiratory tract model, and which includes the systemic model of uranium defined in ICRP Publication 69 (1995), and summarized by Chevalier et al (1997).…”

mentioning

confidence: 99%

Assessment Of Physico-Chemical And Biokinetic Properties Of Uranium Peroxide Hydrate UO4

Ansoborlo

Chazel²,

Houpert³

et al. 1998

Health Physics

View full text Add to dashboard Cite

Comprehensive studies on the radiotoxicological risk of an intermediate compound UO4, which is not specified in ICRP Recommendations, were motivated by its increased use in the nuclear fuel cycle and the lack of information such as physico-chemical and biokinetic properties. The aim of this work was to give an experimental basis for assessing the appropriate limits on intake for workers exposed to UO4 and to provide guidance for the interpretation of personal monitoring data. Particle size measurement of the UO4 dust indicated a geometric diameter D of 0.5 microm, which corresponds to an activity median aerodynamic diameter (AMAD) of 1.1 microm. In vitro experiments conducted in culture medium showed that UO4 is a soluble compound with 66.2% dissolved in 1.9 d and 33.8% in 78 d. Results of dissolution obtained with macrophages showed a significant decrease of 50% at 1 d in terms of solubility. Biokinetic data in the rat obtained from two in vivo studies involving intratracheal instillation in rats indicated half-times in the lung of 0.5 d (96.6%) and 27 d (3.4%) for an initial lung deposit (ILD) of 195 microg, and 1.2 d (90.3%) and 38 d (9.7%) for an ILD of 7.6 microg. Absorption parameters to blood as defined in the ICRP Publication 66 human respiratory tract model were calculated with the specific software GIGAFIT and led to the rapid fraction fr (0.800 to 0.873), the rapid rate sr (0.525 to 0.928 d(-1)), and the slow rate ss (1.57 x 10(-2) to 2.42 x 10(-3) d(-1)). Effective dose coefficients by inhalation for this UO4 compound using the in vivo experimental results were calculated to be between 0.52 and 0.70 x 10(-6) Sv Bq(-1). Comparison of these values with effective dose coefficients defined in ICRP Publication 68 for workers showed that UO4 could be considered as a fast soluble compound of Type F.

show abstract

mentioning

confidence: 99%

Assessment Of Physico-Chemical And Biokinetic Properties Of Uranium Peroxide Hydrate UO4

Ansoborlo

Chazel²,

Houpert³

et al. 1998

Health Physics

View full text Add to dashboard Cite

show abstract

“…The structure of the biokinetic model for earth-alkaline metals is applied to uranium, and the model for actinides to thorium (with specific parameters for each metal). The models differ in particular in the structure of the bone tissue (ICRP 1995a, 1997; Chevalier et al 1997 ). As route of intake, we considered the administration of soluble compounds by intravenous injection, ingestion, or inhalation (type “F” compounds, absorption fraction for adults f = 0.02 and 0.0005 for uranium and thorium, respectively) (ICRP 1995b ) For thorium, we also considered the exposure to a poorly soluble compound by inhalation to take into account the hazards associated to the spread of thorium-232 by the detonation of an anti-tank missile (type “S” compound, f = 0.0005 similar to “F” compounds, but slower dissolution rates in the inhalational absorption model).…”

Section: Methodsmentioning

confidence: 99%

A comparison of the chemo- and radiotoxicity of thorium and uranium at different enrichment grades

et al. 2023

View full text Add to dashboard Cite

Uranium and thorium are heavy metals, and all of their isotopes are radioactive, so it is impossible to study chemical effects entirely independent of the radiation effects. In the present study, we tried to compare the chemo- and radiotoxicity of both metals, taking into account deterministic radiation damages reflected by acute radiation sickness and stochastic radiation damages leading to long-term health impairments (e.g., tumor induction). We made at first a literature search on acute median lethal doses that may be expected to be caused by chemical effects, as even acute radiation sickness as a manifestation of acute radiotoxicity occurs with latency. By simulations based on the biokinetic models of the International Commission on Radiological Protection and using the Integrated Modules for Bioassay Analysis software, we determined the amounts of uranium at different enrichment grades and thorium-232 leading to a short-term red bone marrow equivalent dose of 3.5 Sv considered to cause 50% lethality in humans. Different intake pathways for incorporation were considered, and values were compared to the mean lethal doses by chemotoxicity. To assess stochastic radiotoxicity, we calculated the uranium and thorium amounts leading to a committed effective dose of 200 mSv that is often considered critical. Mean lethal values for uranium and thorium are in the same order of magnitude so that the data do not give evidence for substantial differences in acute chemical toxicity. When comparing radiotoxicity, the reference units (activity in Bq or weight in g) must always be taken into account. The mean lethal equivalent dose to the red bone marrow of 3.5 Sv is reached by lower activities of thorium compared to uranium in soluble compounds. However, for uranium as well as thorium-232, acute radiation sickness is expected only after incorporation of amounts exceeding the mean lethal doses by chemotoxicity. Thus, acute radiation sickness is not a relevant clinical issue for either metal. Concerning stochastic radiation damages, thorium-232 is more radiotoxic than uranium if incorporating the same activities. Using weight units for comparison show that for soluble compounds, thorium-232 is more radiotoxic than low-enriched uranium in the case of ingestion but even more toxic than high-enriched uranium after inhalation or intravenous administration. For insoluble compounds, the situation differs as the stochastic radiotoxicity of thorium-232 ranges between depleted and natural uranium. For acute effects, the chemotoxicity of uranium, even at high enrichment grades, as well as thorium-232 exceeds deterministic radiotoxicity. Simulations show that thorium-232 is more radiotoxic than uranium expressed in activity units. If the comparison is based on weight units, the rankings depend on the uranium enrichment grades and the route of intake.

show abstract

Modèles dosimétriques pour les radionucléides incorporés par les travailleurs

Cited by 2 publications

References 10 publications

Assessment Of Physico-Chemical And Biokinetic Properties Of Uranium Peroxide Hydrate UO4

Assessment Of Physico-Chemical And Biokinetic Properties Of Uranium Peroxide Hydrate UO4

A comparison of the chemo- and radiotoxicity of thorium and uranium at different enrichment grades

Contact Info

Product

Resources

About