Monitoring and Dose Assessment for Children Following a Radiation Emergency-Part II: Calibration Factors for Thyroid Monitoring.

Past radiological and nuclear accidents have demonstrated that monitoring a large number of children following a radiological and nuclear emergency can be challenging, in accommodating their needs as well as adapting monitoring protocols and applying age-specific biokinetics to account for various ages and body sizes. This paper presents the derived calibration factors for thyroid monitoring of children of all ages recommended by the International Commission on Radiological Protection using four selected detectors at given times following a short-term (acute) intake of I by inhalation. These calibration factors were derived by Monte Carlo simulations using the models of various detectors and pediatric voxel phantoms. A collection of lookup tables is presented in this paper which may be directly used as a quick reference by emergency response personnel or technical experts performing thyroid monitoring and assessment without doing time-consuming calculations.

Collateral contamination concomitant to the polonium-210 poisoning of Mr Alexander Litvinenko.

Mr Litvinenko died on 23 November 2006, having been poisoned with polonium-210 on 1 November, with evidence of a previous poisoning attempt during October 2006. Measurements of 210Po in urine samples were made for a large number of people to determine whether they may have been contaminated. In the majority of cases, measured levels were attributable to the presence of 210Po from normal dietary sources. For a small number of cases, elevated levels provided evidence of direct contamination associated with the poisonings. For one individual, while estimated doses were below thresholds for irreversible organ damage, a notably increased risk of cancer can be inferred. The use of the chelating agent, unithiol, to increase 210Po excretion in this case was only moderately effective in reducing doses received.

Managing Internal Radiation Contamination Following an Emergency: Identification of Gaps and Priorities.

Following a radiological or nuclear emergency, first responders and the public may become internally contaminated with radioactive materials, as demonstrated during the Goiânia, Chernobyl and Fukushima accidents. Timely monitoring of the affected populations for potential internal contamination, assessment of radiation dose and the provision of necessary medical treatment are required to minimize the health risks from the contamination. This paper summarizes the guidelines and tools that have been developed, and identifies the gaps and priorities for future projects.

Worker doses and potential health effects resulting from the accident at the Fukushima nuclear power plant in 2011.

PURPOSE: The reliability of exposure scenarios used in the World Health Organization's Health Risk Assessment (HRA) for Fukushima workers was examined. HRA risk estimates for cancer incidence in these workers were then reviewed. MATERIALS AND METHODS: The HRA constructed four exposure scenarios to estimate worker radiation doses; recent individual dosimetric data were used to assess their reliability. Risks of specified cancer types attributable to radiation exposure were estimated in the HRA by calculating Lifetime Attributable Risks (LAR) for each scenario, and comparisons of LAR are provided. RESULTS: The scenarios were confirmed as reliable for the purposes of the HRA. For the lowest dose scenario (Scenario 1: 69% of the workforce), the HRA found that any elevated cancer risk was insignificant. Significantly elevated cancer risks were, however, found for the three higher dose scenarios. CONCLUSIONS: For the highest dose scenario (Scenario 4: 13 workers), LAR values for thyroid cancer up to 3.5% were estimated, but a radiation-related increase in thyroid cancer incidence is unlikely to be observed because of the small number of workers. For the two intermediate dose scenarios, a small number of cancer cases may occur, but these are unlikely to be observed because the variability in baseline rates of cancer incidence is much larger than the predicted radiation-related incidence rates.

A revised model for the deposition and clearance of inhaled particles in human extra-thoracic airways.

The International Commission on Radiological Protection (ICRP) Task Group that developed the Human Respiratory Tract Model for Radiological Protection (HRTM) identified a lack of published information on aspects of the clearance of inhaled particles deposited in the human nasal passage. Using the results of a recent human volunteer study on the clearance of inhaled particles from the nose, a revised model of clearance from the extra-thoracic (ET) airways has been developed that addresses important issues for which simplifying assumptions had to be made in the ICRP Publication 66 HRTM ET model. This ET clearance model has been adopted by ICRP for inclusion in the revised HRTM. The derivation of the model and parameter values from the experimental data are explained.