Radiological Emergency Situations Research Articles

OSL dosimetry with table salt for mass screening of individual doses during radiological or nuclear emergencies

The ongoing war in Ukraine is associated with unprecedented radiological threats to the public in Ukraine and the neighboring countries. This calls for fundamental revision of the preparedness plans and established approaches to radiological monitoring of the populations affected by potential radiological emergencies. Dosimetric information will be needed for triage of victims and support to decision makers for prioritizing mitigation actions. Retrospective dosimetry methods strive to find a solution that would achieve this and enable fast and accurate feedback with information on individual doses to the concerned public. All known approaches to emergency dosimetry, both in biological and physical (instrumental) dosimetry have limitations, in particular – preventive cost, limited availability of samples for analysis, insufficient sensitivity (high dose threshold) and/or stability of radiation-induced markers (i.e. high fading). At the moment each of considered dose assessment methods possesses some combination of the aforesaid limitations. A suggestion to overcome these deficiencies is to use ordinary table salt (NaCl), read by optically stimulated luminescence (OSL), with well-known good dosimetric properties, and which allows anybody to prepare improvised individual dosemeters at home to be carried like a regular personal dosemeter until readout of the OSL signal is possible. This paper considers pros and cons of the use of NaCl as an OSL dosemeter in an emergency situation, with emphasis on practical aspects of its application for mass dose assessments for individuals among populations affected by radiological emergency situations.

An Autonomous Clutter Inspection Approach for Radiological Survey Using Mobile Robot

In the event of a radiological emergency, scattered clutters around the accident sites should be thoroughly inspected as they are potentially contaminated and require proper safety handling. The goal of this work was to localise the position of the hotspot within the clutters and estimate their respective radiation intensity using a mobile robot. Given the information from a 2D occupancy map, we proposed a strategy to identify the position of clutters and formulate waypoints that simultaneously serve as sampling positions to acquire radiation measurement. Particle filter was adapted to fuse the measured data and provide the results in real-time. We also introduced clutter contamination analysis that takes into account the limitations of the detector to derive the worst-case scenario; thus, preventing misclassifications of hotspots with low radiation intensity as clean areas. The approach was implemented in ROS and a commercial mobile robot with a Geiger Muller detector. Finally, we evaluated the overall performance in simulation and real-world experiments. Note to Practitioners—This work was motivated by the goal of realising automation of clutter inspection using a mobile robot to complement the current achievement in robotics radiation mapping. Currently, we still rely on human workers to conduct a thorough radiation survey, including detailed inspections on all clutters, before clearing any radiological accident or incident site. The theoretical framework in this paper proposed a practical solution to localise and estimate the intensity of the hotspot within the clutter in real-time. We demonstrated the versatility and performance of our proposed approach using a small commercial robot and Geiger Muller tube (typically available in any radiation facilities). This method reduces radiation exposure to human workers and provides a cost-effective solution for preliminary screening in radiological emergency situations.

Planning and decommissioning of a disused Theratron- 780 teletherapy machine and the dose assessment methodology for normal and radiological emergency conditions

The present work represents a technical guideline for decommissioning a disused teletherapy machine model Theratron-780 and contains category one 60Co radioactive source. The first section predicts the dose rate from the source in case of normal and radiological emergency situations via FLUKA-MC simulation code. Moreover, the dose assessment for the occupational during the whole process is calculated and compared to the measured values. A suggested cordoned area for safety and security in a radiological emergency is simulated. The second section lists the whole process's technical procedures, including (preview, dismantle, securing, transport and storage) of the disused teletherapy machine. Results show that the maximum obtained accumulated dose for occupational were found to be 24.5 ± 4.9 μSv in the dismantle and securing process in addition to 3.5 ± 1.8 μSv during loading on the transport vehicle and unloading at the storage facility. It was found that the measured accumulated dose for workers is in good agreement with the estimated one by uncertainty not exceeding 5% in normal operating conditions.

Design of a protective shield for a radiological emergency intervention using Monte Carlo simulation and an anthropomorphic phantom.

Due to the increasing use of radioactive sources, new challenges appear for the protection of humans and the environment against ionizing radiation. Thus, organizations handling these sources must be endowed with plans how to react in case of any radiological emergency situations. Monte Carlo simulations are among the most widely employed methods used for the management and reconstruction of radiological incidents and accidents. In this work, results of a Monte Carlo simulation study with the Geant4 simulation toolkit using a digital anthropomorphic phantom are reported. The investigated scenario included an emergency intervention carried out inside the ionization cell of the National Institute of Agronomic Research (NIAR) of Tangier/Morocco, which houses a 60Co gamma irradiator. In this scenario, a radiological incident was assumed where the source cage of the gamma irradiator is stuck in the guide tube and not completely inserted into its storage container. The objective of this work was to design a radiation shield to protect an operator during the emergency intervention and make sure that any radiation exposure is below the recommended dose limits, taking into account the date of occurrence (which determines the activity of the source at the time of the emergency situation) of the accident and economic aspects of shielding design. In this work, the maximum time available for the operator to accomplish the operation intervention while remaining protected is calculated. The results obtained show that the shielding prototype developed gives the operator a time between 3 and 300s, depending on shielding design. It is concluded that shielding of the type investigated in the present study will allow any facility to manage the assumed emergency scenario, should it occur.

Complementary lessons learned from the testing strategies used for radiation emergencies and COVID-19: A white paper from The International Association of Biological and Electron Paramagnetic Resonance (EPR) Radiation Dosimetry (IABERD)

As COVID-19 emerged, there are parallels between the responses needed for managing SARS-CoV-2 infections and radiation injuries. While some SARS-CoV-2-infected individuals present as asymptomatic, others exhibit a range of symptoms including severe and rapid onset of high-risk indicators of mortality. Similarly, a variety of responses are also observed after a radiological exposure depending on radiation dose, dose heterogeneity, and biological variability. The impact of acute radiation syndrome (ARS) has guided the identification of many biomarkers of radiation exposure, the establishment of medical management strategies, and development of medical countermeasures in the event of a radiation public health emergency. Biodosimetry has a prominent role for identifying exposed persons during a large scale radiological emergency situation. Identifying exposed individuals is also critical in the case of pandemics such as COVID-19, with the additional goal of controlling the spread of disease. Conclusions and significance: IABERD has taken advantage of its competences in biodosimetry to draw lessons from current practices of managing the testing strategy for nuclear accidents to improve responses to SARS-CoV-2. Conversely, lessons learned from managing SARS-CoV-2 can be used to inform best practices in managing radiological situations. Finally, the potential need to deal with testing modalities simultaneously and effectively in both situations is considered.

Route Optimization Methods for Response to Radiological Emergency Situations

The work actualizes the need for regional authorities to be ready to respond to possible radiological emergencies due to the ever-expanding use of radiation sources in various fields of activity (besides nuclear reactors) to ensure the safety of sustainable development of cities, territories and regions taking into account the human factor. Described are the developed routing optimization algorithms using mathematical modelling methods to minimize the radiological impact on emergency formations personnel while eliminating possible radiological emergencies. Presented are the results of computational experiments to assess the reduction of personnel exposure during route optimization of work in radiation-hazardous conditions. The recommendations on the use of the developed algorithms during the operation and decommissioning of nuclear facilities are formulated.

OA114] Train the trainer workshop on medical physics support for nuclear or radiological emergencies

Purpose If the event occurs with energy released from a nuclear chain reaction or from the decay of the products of a chain reaction (nuclear explosions etc.) then the event is called a nuclear event/emergency (5). There is no nuclear explosion in radiological events (5). Methods and results Goals of emergency response: • Regain control of the situation and mitigate consequences • Save Lives • Avoid or minimize severe deterministic effects • Render first aid, provide critical medical treatment and manage treatment of radiation injuries • Reduce the risk of stochastic effects • Keep the public informed and maintain public trust • Mitigate, to the extent practicable, property and the environment • Prepare, to the extent practicable, for the resumption of normal social and economic activity (5,11). Patient contamination measurement: • Priority is the treatment of the patient. • Measurements can be taken during patient treatment. • Measurement Order: • Wounds • Face/ body cavities • Skin • Measurements are recorded. • Measurements are repeated (same distance). • All areas of the patient are measured (sides and back). Conclusions On May 23–27, 2016, at the meeting held with the participation of medical physicits from 19 different countries specialized in radiotherapy or nuclear medicine fields, it is emphasized that the key role belongs to medical physicists or who have similar education to direct radiological and nuclear emergency situations, direct the distinction according to the level of contamination of accident victims, direct physicians and nurses in the emergency response team and assist the countries in emergency response plans. There are approximately 20000 medical physicists around the world and these are people with similar and rapidly educated potentials for adapting quickly to emergencies and are expected to provide support to neighboring countries as well, not only in their own country. Medical Physicists are available to assist in developing radiological emergency response plans and in taking the appropriate actions. Medical physicists play key roles as Radiological Assessor on the scene, supporting multiple on-site teams including decontamination teams.

Evaluation of different methods for measuring 89Sr and 90Sr: Measurement uncertainty for the different methods as a function of the activity ratio

In case of a radiological emergency situation involving e.g. fission of uranium or plutonium, analysis of radioactive strontium will be of importance. The primary radionuclides of interest are 90Sr, its progeny 90Y and 89Sr. A few days following an event, 89Sr will be the predominant radioisotope of strontium. Most methods found in the literature are valid and applicable when measuring 90Sr, but when samples contain both 89Sr/90Sr interference problematics arise. How these interferences are dealt with will have an effect on the uncertainty of the 90Sr determination.This work aims at evaluating three measurement approaches, all mentioned in the literature, with respect to the measurement uncertainty when determining 90Sr in an emergency preparedness situation and to propose a suitable measurement strategy.

Luminescence properties of common salt (NaCl) available in Nigeria for use as accident dosimeter in radiological emergency situation

In the event of a radiological accident or attack, it is important to assess and quantify radiation dose to the population. This could be done using materials in the vicinity that are sensitive to ionizing radiation. Common salt (NaCl) is known to be a sensitive thermoluminescence (TL) phosphor. Luminescence properties of common salt (NaCl) used in Nigeria were investigated using an automated luminescence reader Risø TL/OSL-DA-15, with attention focused more on the Optically Stimulated Luminescence (OSL). Strong radiation-induced TL and OSL signals were observed. The TL peaks occurred at about 100 °C, 240 °C and 280 °C. The dose response of both the TL and OSL signals showed a linear relationship. From the OSL pulse anneal curve with TL curve, a preheat temperature of 190 °C for 10 s was found adequate for the OSL measurements. There was no significant difference in the OSL decay for stimulation temperatures of 100 and 120 °C. Fading experiment over a storage period of 14 days showed about 13 and 3% decrease in the OSL signal of sample 1 and sample 2, respectively. The ratios of measured to given dose for dose recovery test were within ±19% of unity. Within the limit of error the samples could be used as a complementary emergency dosimeter in radiological accident situation.

Evaluation of Reference Urinary Excretion Concentrations of Selected Radionuclides Corresponding to Clinical Decision Guides for Application in Radiological and in Nuclear Emergencies

Radiological or nuclear emergency situations could lead to incorporation of radionuclides by the population. Intakes of radionuclides can be evaluated through measurements of radionuclides present in organs and tissues, or in urinary and/or fecal excretion. In an emergency situation involving a large number of people, the decision to provide medical treatment to an individual will likely be based on a single measurement. For that purpose, the National Council on Radiation Protection and Measurements (NCRP) has presented the Clinical Decision Guide (CDG) quantity, which corresponds to an intake amount of a radionuclide by an individual for which treatment is recommended. However, the NCRP recommends using one-fifth of the CDG for pregnant women and children which could result in an effective or equivalent dose in excess of the dose constraint. Tables of reference urinary excretion concentrations which are associated with an intake of one CDG for inhalation and ingestion intake scenarios of several forms of 60Co, 90Sr, 137Cs, 192Ir, 238Pu, 239Pu and 241Am have been calculated and are presented for the following categories of members of the public: 3 months old, 1 y, 5 y, 10 y, 15 y, adult and pregnant woman.

Capabilities of the RENEB network for research and large scale radiological and nuclear emergency situations

Purpose: To identify and assess, among the participants in the RENEB (Realizing the European Network of Biodosimetry) project, the emergency preparedness, response capabilities and resources that can be deployed in the event of a radiological or nuclear accident/incident affecting a large number of individuals. These capabilities include available biodosimetry techniques, infrastructure, human resources (existing trained staff), financial and organizational resources (including the role of national contact points and their articulation with other stakeholders in emergency response) as well as robust quality control/assurance systems.Materials and methods: A survey was prepared and sent to the RENEB partners in order to acquire information about the existing, operational techniques and infrastructure in the laboratories of the different RENEB countries and to assess the capacity of response in the event of radiological or nuclear accident involving mass casualties. The survey focused on several main areas: laboratory’s general information, country and staff involved in biological and physical dosimetry; retrospective assays used, the number of assays available per laboratory and other information related to biodosimetry and emergency preparedness. Following technical intercomparisons amongst RENEB members, an update of the survey was performed one year later concerning the staff and the available assays.Conclusions: The analysis of RENEB questionnaires allowed a detailed assessment of existing capacity of the RENEB network to respond to nuclear and radiological emergencies. This highlighted the key importance of international cooperation in order to guarantee an effective and timely response in the event of radiological or nuclear accidents involving a considerable number of casualties. The deployment of the scientific and technical capabilities existing within the RENEB network members seems mandatory, to help other countries with less or no capacity for biological or physical dosimetry, or countries overwhelmed in case of a radiological or nuclear accident involving a large number of individuals.

SU‐F‐E‐16: A Specific Training Package for Medical Physicists in Support to Nuclear and Radiological Emergency Situations

Purpose:To provide the professional medical physicists with adequate competencies and skills in order to help them get prepared to support Nuclear or Radiological Emergency (NRE) situations.Methods:Although clinical medical physicists working have in‐depth knowledge in radiation dosimetry, including dose reconstruction and dose measurements, they are usually not involved in NRE situations. However, in a few instances where medical physicists were involved in NREs, it appeared that many lacked specific knowledge and skills that are required in such situations. This lack of specific knowledge and skills is probably due to the fact that most current medical physics curricula do not include a specific module on this topic. As a response to this finding, the IAEA decided to initiate a project to develop a specific training package to help prepare medical physicists to support NRE situations. The training package was developed with the kind support of the Government of Japan and in collaboration with Fukushima Medical University (FMU) and the National Institute of Radiological Sciences (NIRS).Results:The first International Workshop to test the training package was held in Fukushima, Japan in June 2015. It consisted of lectures, demonstrations, simulation, role play, and practical sessions followed by discussions. The training was delivered through 14 modules which were prepared with the support of 12 lecturers. A knowledge assessment test was done before the workshop, followed by the same test done at the end of the Workshop, to assess the knowledge acquired during the training.Conclusion:The Workshop was successfully implemented. The overall rating of the workshop by the participants was excellent and all participants reported that they acquired a good understanding of the main issues that are relevant to medical physics support in case of NRE situations. They are expected to disseminate the knowledge to other medical physicists in their countries.

Voluntary Health Registry of French Nationals after the Great East Japan Earthquake, Tsunami, and Fukushima Daiichi Nuclear Power Plant Accident: Methods, Results, Implications, and Feedback.

Introduction The 11th of March 2011, a magnitude 9.0 earthquake struck alongside the north-east coast of Honshu Island, Japan, causing a tsunami and a major nuclear accident. The French Institute for Public Health Surveillance (InVS) set up, within one week after the triple catastrophe, an Internet-based registry for French nationals who were in Japan at the time of the disasters. In this string of disasters, in this context of uncertainties about the nuclear risks, the aim of this registry was to facilitate the: (1) realization of further epidemiologic studies, if needed; and (2) contact of people if a medical follow-up was needed. The purpose of this report was to describe how the health registry was set up, what it was used for, and to discuss further utilization and improvements to health registries after disasters. The conception of the questionnaire to register French nationals was based on a form developed as part of the Steering Committee for the management of the post-accident phase in the event of nuclear accident or a radiological emergency situation (CODIRPA) work. The questionnaire was available online. The main objective was achieved since it was theoretically possible to contact again the 1,089 persons who completed the form. According to the data collected on their space-time budget, to the result of internal contamination measured by the French Institute for Radiological Protection and Nuclear Safety (IRSN) and dosimetric expertise published by the World Health Organization (WHO), it was not suitable to conduct an epidemiologic follow-up of adverse effects of exposure to ionizing radiations among them. However, this registry was used to launch a qualitative study on exposure to stress and psychosocial impact of the Great East Japan Earthquake on French nationals who were in Japan in March 2011. Setting a registry after a disaster is a very important step in managing the various consequences of a disaster. This experience showed that it is quickly feasible and does not raise adverse side effects in involved people. Motreff Y , Pirard P , Lagrée C , Roudier C , Empereur-Bissonnet P . Voluntary health registry of French nationals after the Great East Japan Earthquake, tsunami, and Fukushima Daiichi Nuclear Power Plant accident: methods, results, implications, and feedback. Prehosp Disaster Med. 2016;31(3):326-329.

Microwave assisted rapid and improved radiochemical method for the estimation of uranium in leaf samples

In this paper, we report the development of a rapid and improved radiochemical method assisted by microwave technique for the determination of uranium in leafy samples for use in radiological emergency situations, where quick assessment of radioactivity is required. About 200 g of fresh leaf sample was ashed in a microwave muffle furnace, followed by digestion in a microwave digester and radiochemically separated using UTEVA resin. Counting was performed in a passivated ion implanted planar silicon alpha spectrometer after electroplating the separated sample for uranium. By this method, the time of sample processing and analysis was reduced to few hours from about 2 days and also the radiochemical recovery of uranium has considerably enhanced as compared to conventional methods.

Attenuation of X and Gamma Rays in Personal Radiation Shielding Protective Clothing.

A collection of personal radiation shielding protective clothing, suitable for use in case of accidents in nuclear facilities or radiological emergency situations involving radioactive agents, was gathered and tested at the Nuclear Protection Department of the National Institute for Nuclear, Chemical and Biological Protection, Czech Republic. Attenuating qualities of shielding layers in individual protective clothing were tested via spectra measurement of x and gamma rays, penetrating them. The rays originated from different radionuclide point sources, the gamma ray energies of which cover a broad energy range. The spectra were measured by handheld spectrometers, both scintillation and High Purity Germanium. Different narrow beam geometries were adjusted using a special testing bench and a set of various collimators. The main experimentally determined quantity for individual samples of personal radiation shielding protective clothing was x and gamma rays attenuation for significant energies of the spectra. The attenuation was assessed comparing net peak areas (after background subtraction) in spectra, where a tested sample was placed between the source and the detector, and corresponding net peak areas in spectra, measured without the sample. Mass attenuation coefficients, which describe attenuating qualities of shielding layers materials in individual samples, together with corresponding lead equivalents, were determined as well. Experimentally assessed mass attenuation coefficients of the samples were compared to the referred ones for individual heavy metals.

SU‐E‐I‐89: Real‐Time Information and Decision Support for Radiological Emergency Response

Purpose: Emergency response and medical preparedness for radiological incidents is one of the critical cornerstones for Homeland Security, along with biological and chemical incidents. The recent Fukushima Daiichi nuclear plant incidents underscore the paramount importance of such preparedness and response capability. Such needs are wide‐spread as many nations employ nuclear plants for energy generation. In this work, we focus on development and deployment of a real‐time simulation and decision support system, RealOpt‐CRC, along with the knowledge data bank that can be used by regional/local radiation/public health administrators to prepare for and deal with radiological emergency situations. Methods: Large‐scale simulator for modeling systems operations and performance, computer graphics for mouse‐click facility design and optimization for resource allocation are designed and implemented into a web‐base secured system. The RealOpt system offers operations capability to i)rapidly setup shelters to house the displaced/at‐risk population, ii)determine optimal resource allocation and operations for rapid screening and decontamination; iii)recommend and facilitate practical steps to minimize exposure risk; iv)perform effective population registry for long‐term health monitoring; and v)service the displaced population on day‐to‐day needs. Results: Comparison of current planning versus plans from our system shows a 5‐fold efficiency improvement. This translates to more people being screened and decontaminated within limited time and resources and thus improve safety and health monitoring for the affected population. Further, workers are more confident and operations are smoother and more organized, thus ensuring public confidence and team‐morale. Conclusions: The system has real‐time computation capability and can be used by emergency management administrators for actual strategic and operational planning and execution; to educate and train current and future personnel on decision making under uncertainties; and to simulate responses to catastrophic events through systematic analysis of numerous scenarios, including worst‐case, to learn of erratic as well as efficient response strategies. Real‐time data‐feeds allow re‐configuration on‐the‐fly as the event unfolds. National Science Foundation

EQUIVOX: AN EXAMPLE OF ADAPTATION USING AN ARTIFICIAL NEURAL NETWORK ON A CASE-BASED REASONING PLATFORM

In case of a radiological emergency situation involving accidental human exposure, a dosimetry evaluation must be established as soon as possible. In most cases, this evaluation is based on numerical representations and models of victims. Unfortunately, personalized and realistic human representations are often unavailable for the exposed subjects. However, accuracy of treatment depends on the similarity of the phantom to the victim. The EquiVox platform (Research of Equivalent Voxel phantom) developed in this study uses case-based reasoning (CBR) principles to retrieve and adapt, from among a set of existing phantoms, the one to represent the victim. This paper introduces the EquiVox platform and the artificial neural network (ANN) developed to interpolate the victim's 3D lung contours. The results obtained for the choice and construction of the contours are presented and discussed.

Case study on the improved use of collective dose for nuclear and/or radiological emergencies

The improved use of collective dose following the 2007 ICRP recommendations is studied for nuclear and radiological emergency situations. To study the accumulation of low individual doses to the collective dose the collective dose is calculated as a function of the minimum individual dose for three cases including nuclear as well as radiological accidents. It is found that the use of collective dose in this way can have an added value in nuclear emergency preparedness and response in particular related to decisions on overall protective actions following an accident.

Preparedness for radiological emergency situations in Austria

This article presents the Austrian system of emergency preparedness for nuclear and radiological emergency situations. It demonstrates, in particular, the legal basis, the roles and competencies of the competent authorities, international and bilateral conventions on early notification of nuclear accidents, the Austrian emergency plans, the Austrian radiation monitoring system, the operated prognosis and decision support systems and the results of an estimation of possible impacts of nuclear power plant disasters on Austria.

International data and information exchange in Europe - systems to assist the EU Member States in radiological and nuclear emergency situations

During the early phase of a large-scale accident with release of radioactivity to the atmosphere, it is essential to notify and inform competent authorities as early and as extensively as possible. Only when the accident is rapidly notified and information is continuously made available in the form of real-time monitoring data and dispersion forecasts are decision makers able to define appropriate countermeasures. The Chernobyl accident taught us that information exchange should be carried out in a harmonised and consistent manner. Although several European countries already had developed automatic monitoring networks by 1986 and in some cases established bilateral agreements to exchange this information, the size of the accident demonstrated the need to extend such schemes to the continental scale. It became important to have commonly agreed international data formats and procedures in place. Over the past 25 years, the European Commission has invested in improving the rapid exchange of information and data in the event of a major accident. For the early phase of emergency support, it has focussed on three closely related systems: the early notification system ECURIE, the automatic data exchange platform EURDEP and the atmospheric dispersion model exchange and evaluation system ENSEMBLE. Starting from the legal background, we describe these information systems in detail with an emphasis on their current status and their planned future developments.