Metrics, Dose, and Dose Concept: The Need for a Proper Dose Concept in the Risk Assessment of Nanoparticles

In: International Journal of Environmental Research and Public Health, Vol. 11 (2014), No. 4, 4026-4048; DOI: 10.3390/ijerph110404026In order to calculate the dose for nanoparticles (NP), (i) relevant information about the dose metrics and (ii) a proper dose concept are crucial. Since the appropriate metrics for NP toxicity are yet to be elaborated, a general dose calculation model for nanomaterials is not available. Here we propose how to develop a dose assessment model for NP in analogy to the radiation protection dose calculation, introducing the so-called “deposited and the equivalent dose”. As a dose metric we propose the total deposited NP surface area (SA), which has been shown frequently to determine toxicological responses e.g. of lung tissue. The deposited NP dose is proportional to the total surface area of deposited NP per tissue mass, and takes into account primary and agglomerated NP. By using several weighting factors the equivalent dose additionally takes into account various physico-chemical properties of the NP which are influencing the biological responses. These weighting factors consider the specific surface area, the surface textures, the zeta-potential as a measure for surface charge, the particle morphology such as the shape and the length-to-diameter ratio (aspect ratio), the band gap energy levels of metal and metal oxide NP, and the particle dissolution rate. Furthermore, we discuss how these weighting factors influence the equivalent dose of the deposited NP

Characterisation, implementation and quality assurance of biokinetic models. The experience of the CONRAD Task Group 5.2.

CONRAD (Coordinated Network on Radiation Dosimetry) was an action funded by the European Commission within the 6th Framework Programme in order to link groups undertaking research relating to radiation dosimetry at workplaces. Workpackage 5 of CONRAD was dedicated to internal dosimetry. Task Group 5.2 Research Studies on Biokinetic Models" dealt with the development, implementation, characterization and quality assurance of biokinetic models. The new ICRP model of the human alimentary tract (HATM), the new NCRP model for contaminated wounds, new systemic recycling models of the biokinetics of radioisotopes of polonium and plutonium presented in the scientific literature were implemented into the computer codes of five different institutions. Also new systemic biokinetic models for zirconium and molybdenum, developed on the basis of own results from stable tracer studies, were implemented. The excellent agreement among the results obtained by the different groups indicate that all the present models can be easily implemented into available software codes and that the outputs are independent of the computational approach used. It was also possible to better characterize the systemic models of plutonium by use of a partition factor expressing the relative distribution of material between skeleton and liver, and the NCRP wound model, by derivation of the exact analytical solutions for the wound retention resulting from the model formulation.&quot

Technical recommendations for monitoring individuals for occupational intakes of radionuclides

International audienceThe TECHREC project, funded by the European Commission, will provide Technical Recommendations for Monitoring Individuals for Occupational Intakes of Radionuclides. It is expected that the document will be published by the European Commission as a report in its Radiation Protection Series during 2016. The project is coordinated by the European Radiation Dosimetry Group (EURADOS) and is being carried out by members of EURADOS Working Group 7 (Internal Dosimetry). This paper describes the aims and purpose of the Technical Recommendations, and explains how the project is organised. © Crown copyright 2015

Review of methods and computer codes for interpretation of bioassay data

International audienc

Eurados coordinated action on research, quality assurance and training of internal dose assessments

EURADOS working group on 'Internal Dosimetry (WG7)' represents a frame to develop activities in the field of internal exposures as coordinated actions on quality assurance (QA), research and training. The main tasks to carry out are the update of the IDEAS Guidelines as a reference document for the internal dosimetry community, the implementation and QA of new ICRP biokinetic models, the assessment of uncertainties related to internal dosimetry models and their application, the development of physiology-based models for biokinetics of radionuclides, stable isotope studies, biokinetic modelling of diethylene triamine pentaacetic acid decorporation therapy and Monte-Carlo applications to in vivo assessment of intakes. The working group is entirely supported by EURADOS; links are established with institutions such as IAEA, US Transuranium and Uranium Registries (USA) and CEA (France) for joint collaboration actions. © The Author 2010. Published by Oxford University Press. All rights reserved