Rethinking the Role of Biodosimetry to Assess Risks for Acute Radiation Syndrome in Very Large Radiation Events: Reconsidering Legacy Concepts

The development of effective uses of biodosimetry in large-scale events has been hampered by residual, i.e., "legacy" thinking based on strategies that scale up from biodosimetry in small accidents. Consequently, there remain vestiges of unrealistic assumptions about the likely magnitude of victims in "large" radiation events and incomplete analyses of the logistics for making biodosimetry measurements/assessments in the field for primary triage. Elements remain from an unrealistic focus on developing methods to use biodosimetry in the initial stage of triage for a million or more victims. Based on recent events and concomitant increased awareness of the potential for large-scale events as well as increased sophistication in planning and experience in the development of biodosimetry, a more realistic assessment of the most effective roles of biodosimetry in large-scale events is urgently needed. We argue this leads to a conclusion that the most effective utilization of biodosimetry in very large events would occur in a second stage of triage, after initially winnowing the population by identifying those most in need of acute medical attention, based on calculations of geographic sites where significant exposures could have occurred. Understanding the potential roles and limitations of biodosimetry in large-scale events involving significant radiation exposure should lead to development of the most effective and useful biodosimetric techniques for each stage of triage for acute radiation syndrome injuries, i.e., based on more realistic assumptions about the underlying event and the logistics for carrying out biodosimetry for large populations.

Pediatric Medical Countermeasures: Antidotes and Cytokines for Radiological and Nuclear Incidents and Terrorism

The war in Ukraine raises concerns for potential hazards of radiological and nuclear incidents. Children are particularly vulnerable in these incidents and may need pharmaceutical countermeasures, including antidotes and cytokines. Searches found no published study comparing pediatric indications and dosing among standard references detailing pediatric medications for these incidents. This study addresses this gap by collecting, tabulating, and disseminating this information to healthcare professionals caring for children. Expert consensus chose the following references to compare their pediatric indications and dosing of medical countermeasures for radiation exposure and internal contamination with radioactive materials: Advanced Hazmat Life Support (AHLS) for Radiological Incidents and Terrorism, DailyMed, Internal Contamination Clinical Reference, Medical Aspects of Radiation Incidents, and Medical Management of Radiological Casualties, as well as Micromedex, POISINDEX, and Radiation Emergency Medical Management (REMM). This is the first study comparing pediatric indications and dosing for medical countermeasures among commonly used references for radiological and nuclear incidents.

The convergence approach may be critical to improving early situational awareness in hostile radioactive environments

This study explores the impact of a simulated radiological dispersal device (RDD) event in an urban area on young adults around 20 years old. The RDD releases radioactive Cs-137 (7.0E+3 Ci), a common industrial sterilization source. The study aims to demonstrate that combining computational codes and epidemiological models can produce valuable data to guide initial actions when confronting a hostile radioactive environment. The HotSpot Health Physics and RESRAD-RDD codes were used in the simulation to evaluate the event's initial phase. The codes were executed together, and the HotSpot output data was input into RESRAD-RDD. Based on simulated radiation dose levels, estimated doses were incorporated into radioepidemiological models proposed by the Committee on Biological Effects of Ionizing Radiation (BEIR V or VII report). Despite limitations, data transfer between the models revealed no discontinuities or antagonisms. Radiation doses were simulated under three exposure conditions and two atmospheric release modes (day or night), suggesting that atmospheric conditions, sex, and exposure routine can strongly influence the perception of radiation impacts. This combination of methods can increase situational awareness and help with decision-making and developing coping strategies.

Radiation and Chemical Program Research for Multi-Utility and Repurposed Countermeasures: A US Department of Health and Human Services Agencies Perspective

Although chemical and radiological agents cause toxicity through different mechanisms, the multiorgan injuries caused by these threats share similarities that convene on the level of basic biological responses. This publication will discuss these areas of convergence and explore "multi-utility" approaches that could be leveraged to address common injury mechanisms underlying actions of chemical and radiological agents in a threat-agnostic manner. In addition, we will provide an overview of the current state of radiological and chemical threat research, discuss the US Government's efforts toward medical preparedness, and identify potential areas for collaboration geared toward enhancing preparedness and response against radiological and chemical threats. We also will discuss previous regulatory experience to provide insight on how to navigate regulatory paths for US Food and Drug Administration (FDA) approval/licensure/clearance for products addressing chemical or radiological/nuclear threats. This publication follows a 2022 trans-agency meeting titled, "Overlapping Science in Radiation and Sulfur Mustard Exposures of Skin and Lung: Consideration of Models, Mechanisms, Organ Systems, and Medical Countermeasures," sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), a part of the National Institutes of Health (NIH). Discussions from this meeting explored the overlapping nature of radiation and chemical injury and spurred increased interest in how preparedness for one threat leads to preparedness for the other. Herein, subject matter experts from the NIAID and the Biomedical Advanced Research and Development Authority (BARDA), a part of the Administration for Strategic Preparedness and Response (ASPR), summarize the knowledge gained from recently funded biomedical research, as well as insights from the 2022 meeting. These topics include identification of common areas for collaboration, potential use of biomarkers of injury to identify injuries caused by both hazards, and common and widely available treatments that could treat damage caused by radiological or chemical threats.

Radiation-Related Thyroid Cancer

Radiation is an environmental factor that elevates the risk of developing thyroid cancer. Actual and possible scenarios of exposures to external and internal radiation are multiple and diverse. This article reviews radiation doses to the thyroid and corresponding cancer risks due to planned, existing, and emergency exposure situations, and medical, public, and occupational categories of exposures. Any exposure scenario may deliver a range of doses to the thyroid, and the risk for cancer is addressed along with modifying factors. The consequences of the Chornobyl and Fukushima nuclear power plant accidents are described, summarizing the information on thyroid cancer epidemiology, treatment, and prognosis, clinicopathological characteristics, and genetic alterations. The Chornobyl thyroid cancers have evolved in time: becoming less aggressive and driver shifting from fusions to point mutations. A comparison of thyroid cancers from the 2 areas reveals numerous differences that cumulatively suggest the low probability of the radiogenic nature of thyroid cancers in Fukushima. In view of continuing usage of different sources of radiation in various settings, the possible ways of reducing thyroid cancer risk from exposures are considered. For external exposures, reasonable measures are generally in line with the As Low As Reasonably Achievable principle, while for internal irradiation from radioactive iodine, thyroid blocking with stable iodine may be recommended in addition to other measures in case of anticipated exposures from a nuclear reactor accident. Finally, the perspectives of studies of radiation effects on the thyroid are discussed from the epidemiological, basic science, and clinical points of view.

Resilience after a nuclear accident: readiness in using mobile phone applications to measure radiation and health indicators in various groups (SHAMISEN SINGS project)

An anonymous web-based survey was developed to check different aspects (SHAMISEN SINGS project): stakeholder awareness and perceptions of available mobile applications (apps) for measuring ionising radiation doses and health/well-being indicators; whether they would be ready to use them in the post-accidental recovery; and what are their preferred methodologies to acquire information etc. The results show that participation of the citizens would be most beneficial during post-accident recovery, providing individual measurements of external ionizing dose and health/well-being parameters, with possible follow-up. Also, participants indicated different preferences for sources to gain knowledge on ionising radiation and for the functions that an ideal app should have. The level of awareness and readiness to use apps to measure ionising radiation dose depended on two main aspects: individual differences (age & gender) and whether people were from countries affected by the previous major accidents. We concluded that stakeholders could have benefits from the data management plan: (1) it potentiates resilience at individual and community level; (2) citizens' measurements contribute to environmental monitoring and public health screening; (3) linkages between different types of data (environmental exposure, individual behavioural diaries, and measurements of health indicators) allow to perform more rigorous epidemiological studies.

STATUS OF THE CURRENT DOMESTIC REGULATORY BASE FOR ENSURING RADIATION SAFETY AND ANTI-RADIATION PROTECTION OF MILITARY PERSONNEL DURING THE PERIOD OF MARTIAL STATUS

Prerequisite. In the conditions of a full-scale invasion, the issue of radiation safety and anti-radiation protection in the Armed Forces of Ukraine (AFU) occupies a special place, since the aggressor country violated global geopolitical international decisions, occupied civilian nuclear facilities, in the process of their liberation servicemen mayhave to act in conditions of increased radiation risk, the possibility of using tactical nuclear weapons also is not excluded.

OBJECTIVE

to investigate the state of the current national regulatory framework for ensuring radiation safety and anti-radiation protection of military personnel during the period of martial law.

METHODS

bibliographic, analytical, historical, systematic approach.

RESULTS

The main normative document on the organization of radiation safety and anti-radiation protection of both personnel and the population in Ukraine, as well as military personnel, currently in everyday conditions and in case of radiation accidents since 1998 and until now, are the State Hygienic Standards «Radiation Safety Standards of Ukraine (NRBU-97)». But neither in this document, nor in the transition to NRBU-2021-P, the issue of exposure to such a category as military personnel during the performance of combat (special) tasks is considered. The system of monitoring the radiation situation in Ukraine, documents on the organization of medical support for military personnel, including the Guidelines on the Medical Support of the Armed Forces of Ukraine for a Special Period (2019)and the Guidelines on the Organization of Radiation Safety in the Armed Forces of Ukraine (2020), were analyzed.modules of radiation safety principles in the Armed Forces of Ukraine were proposed.

CONCLUSION

The unsolved problem of normalization of the radiation factor in the case of man-made and socio-political emergencies can create significant problems in the organization of anti-radiation protection of troops and the population in the case of the use of nuclear weapons or radiation accidents in a special period and requires anurgent solution. It is obvious that there is a need to develop regulatory documents regarding the response and planning of continuous activities to respond to potential nuclear and radiation threats during martial law, including relationships at all levels of the management vertical and methods of communication in the event of a threat.

LARCalc, a tool to estimate sex- and age-specific lifetime attributable risk in populations after nuclear power plant fallout

A tool called LARCalc, for calculating the radiological consequences of accidental large scale nuclear power plant releases based on estimates of 137Cs ground deposition, is presented. LARCalc is based on a previously developed models that has been further developed and packaged into an easy-to-use decision support tool for training of decision makers. The software visualises the radiological impact of accidental nuclear power plant releases and the effects of various protective measures. It is thus intended as a rapid alternative for planning protective measures in emergency preparedness management. The tool predicts projected cumulative effective dose, projected lifetime attributable cancer risk, and residual dose for some default accidental release scenarios. Furthermore, it can predict the residual dose and avertable cumulative lifetime attributable risk (LAR) resulting from various protective measures such as evacuation and decontamination. It can also be used to predict the avertable collective dose and the increase in cancer incidence within the specified population. This study presents the theoretical models and updates to the previous models, and examples of different nuclear fallout scenarios and subsequent protective actions to illustrate the potential use of LARCalc.

STATE INSTITUTION «NATIONAL RESEARCH CENTER FOR RADIATION MEDICINE OF THE NATIONAL ACADEMY OF MEDICAL SCIENCES OF UKRAINE» - RESEARCH ACTIVITIES AND SCIENTIFIC ADVANCE IN 2022

Research activities and scientific advance achieved in 2022 at the State Institution «National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine» (NRCRM) concerning medical problems of the Chornobyl disaster, radiation medicine, radiobiology, radiation hygiene and epidemiology in collaboration with the WHO network of medical preparedness and assistance in radiation accidents are outlined in the annual report. The report presents the results of fundamental and applied research works of the study of radiation effects and health effects of the Chornobyl accident. The report also shows the results of scientificorganizational and health care work, staff training. The Scientific Council meeting of NAMS approved the NRCRM Annual Report.

Experiences from the ARGOS user group nuclear emergency exercise

The Accident Reporting and Guiding Operational System (ARGOS) is a decision support system used to assist in the Emergency Preparedness and Response (EPR) to nuclear and radiological incidents. The ARGOS user group has been formed that is made up of government agencies across many countries that have a role in EPR to nuclear and radiological incidents. In 2020, a desktop exercise was organised for the members of the ARGOS user group. The exercise involved two hypothetical accidents at different times on the same date, namely a radiological release from a floating nuclear power plant (NPP) off the Norwegian coast and from the Loviisa NPP in Finland. The objectives of the exercise were to train and increase knowledge of the ARGOS system, to perform a comparison of model outputs, and to compare the recommendations of protective actions. In the case of the floating NPP the source term was provided, while in the Loviisa NPP scenario the participants were required to provide their own source term based on a description of the accident. The results on radiological consequences based on dispersion modelling, protective actions, source terms and dispersion modelling settings were collected from participants. A comparison was made between each of these reported aspects. In general, it was found that there was general agreement between the results for the floating nuclear power plant scenario in the sense of plume direction and extent, while in the case of the Loviisa NPP scenario, there was much greater variation, with the difference in source term estimates between the participants being an influencing factor. The participants acknowledged that taking part in an exercise of this nature increased their knowledge and understanding about using decision support tools such as ARGOS in planning and responding to nuclear and radiological emergencies.

COGNITIVE ASPECTS OF DEPRESSION IN VICTIMS OF RADIATION ACCIDENTS, THE COVID-19 PANDEMIC, AND WARS

The relevance of the work is due to the significant increase in depression with cognitive disorders (CD) worldwide, and in Ukraine in particular, in victims of emergencies situations (ES), and the importance, but insufficient development of clinical and psychopathological aspects of medical and psychological-psychiatric care for this contingent of people. Despite the modern achievements of psychiatry in the study of depression in ES, an important problem is CD, which worsen the quality of life of patients, increase the risk of relapse, progressive course, and suicidal behavior. In order to improve the level of psychological and psychiatric care for depressed patients with CD in post-stress disorders by radiation accidents, the COVID-19 pandemic, and wars, the study of domestic and foreign literature on these disorders, which have both common features and certain differences, was conducted.Conclusions. The study confirms the significant prevalence of depression with CD in victims of radiation accidents, the COVID-19 pandemic, and wars, the insufficient development of clinical and psychopathological aspects and theneed for further study of this problem, as well as the creation of state measures of psychological and psychiatric care for these patients.

Long-term study (1987-2023) on the distribution of 137Cs in soil following the Chernobyl nuclear accident: a comparison of temporal migration measurements and compartment model predictions

After the Chernobyl accident, a designated area of ~1000 m2 within the University farm of Aristotle University of Thessaloniki in Northern Greece was utilized as a test ground for radioecological measurements. The profile of 137Cs in the soil was monitored from 1987 to 2023, with soil samples collected in 5-cm-thick slices (layers) down to a depth of 30 cm. The mean total deposition of 137Cs in the area, backdated to the time of the Chernobyl accident, was determined to be 18.6 ± 1.8 kBq m-2 based on four follow-up profile measurements of 137Cs in the soil for the years 2022 and 2023. It is noteworthy that this value is similar the total deposition at the site, which was independently measured to be about 20 kBq m-2 during the first year after the Chernobyl accident. The fractional contribution of each soil layer (e.g., 0-5 cm, 5-10 cm, 10-15 cm, etc.) to the total deposition of 137Cs (0-30 cm) is presented and analyzed. A compartment model was utilized to forecast the temporal evolution of fractional contributions of the different soil layers to the total deposition of 137Cs (0-30 cm). In this model, each soil layer is represented as a separate compartment. The model assumes that the transfer rates between adjacent compartments are equal. The agreement between the measured fractional contributions and the model predictions suggests that the compartment model with equal transfer rates can capture the broad patterns of 137Cs migration within the soil layers over the long period of 1987-2023. However, the use of a second compartment model with increasing transfer rates between consecutive soil layers did not align with the observed outcomes. This indicates that diffusion may not be the primary migration mechanism over the 36-y period covered by our study.

A comparison of different detection techniques for 137Cs measurements of cattle in vivo

Agricultural lands with farm animals (e.g. cattle) can be significantly affected by radioactive contamination following nuclear or radiation accidents. In order to optimise the techniques for measuring 137Cs in contaminated cattle, selected radiation detectors have been tested and calibrated using volumetric radiation sources. In addition, a mathematical phantom of a cow was created within Monte Carlo simulations. The main aim of the research was to propose a method for making rapid measurements of 137Cs in cattle in vivo/in situ and to select the most suitable measurement set-up. Measurements of contaminated cattle in vivo were carried out in Belarus with one selected detector, and were then compared with measurements of meat in a laboratory and with measurements of a control group of cows. The proposed measurement method was also tested on measurements of 137Cs in wild boars in Czechia with higher levels of the 137Cs activity.

Risk assessment for the optimization of the grid of a telemetric network monitoring system

The goal of this work was to develop a methodology for risk assessment in case of an accident originating from a nuclear power plant, and consequently, to improve the relevant radiation monitoring network. In specific, the study involved risk estimation in Greece from a transboundary nuclear power plant accident. The tool employed was JRODOS (Java-based Real-time Decision Support), which is a system for off-site emergency management of radioactive material in the environment. This tool, widely used to generate and study scenarios for nuclear accidents worldwide, provides valuable insight to facilitate emergency preparedness and response. The probability of the plume arriving at numerous regions within the country was calculated, along with the maximum dose rates in case of transport. A risk assessment was performed, and geographical regions were prioritized in terms of risk-based environmental radioactivity burden. A total of 29 administrative districts were identified as low to medium-risk regions. Acquired results were used to determine the optimal spatial distribution of detectors for upgrading the existing monitoring network of environmental radioactivity.

Effectiveness of simplified dose estimation equations for triage after criticality accident-a case study of dose assessment in the JCO criticality accident

The dosimetry for the triage of personnel encountering a criticality accident was investigated. The JCO criticality accident of 1999 was selected as a case study, and attention was paid to the identification and the segregation of severely exposed personnel. A series of Monte Carlo calculations revealed that simplified equations proposed by ANSI to estimate dose with respect to distance work well to determine the region of interest for triage.

[The advantages of the fire department nurse in managing a CBRN event]

Nuclear, radiological, biological and chemical hazards are caused by agents of very different origins. They can be blatant or insidious, difficult to detect, accidental or intentional. In all cases, in addition to treating victims, the aim is to avoid contamination of hospital services. Faced with these risks, which are often seen as unlikely or too complex, the firefighter nurse represents an asset for his or her establishment, in terms of both crisis anticipation and management.

The NIAID/RNCP Biodosimetry Program: An Overview

Established in 2004, the Radiation and Nuclear Countermeasures Program (RNCP), within the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health has the central mission to advance medical countermeasure mitigators/therapeutics, and biomarkers and technologies to assess, triage, and inform medical management of patients experiencing acute radiation syndrome and/or the delayed effects of acute radiation exposure. The RNCP biodosimetry mission space encompasses: (1) basic research to elucidate novel approaches for rapid and accurate assessment of radiation exposure, (2) studies to support advanced development for US Food and Drug Administration (FDA) clearance of promising triage or treatment devices/approaches, (3) characterization of biomarkers and/or assays to determine degree of tissue or organ dose that can predict outcome of radiation injuries (i.e., organ failure, morbidity, and/or mortality), and (4) outreach efforts to facilitate interactions with researchers developing cutting edge biodosimetry approaches. Thus far, no biodosimetry device has been FDA cleared for use during a radiological/nuclear incident. At NIAID, advancement of radiation biomarkers and biodosimetry approaches is facilitated by a variety of funding mechanisms (grants, contracts, cooperative and interagency agreements, and Small Business Innovation Research awards), with the objective of advancing devices and assays toward clearance, as outlined in the FDA's Radiation Biodosimetry Medical Countermeasure Devices Guidance. The ultimate goal of the RNCP biodosimetry program is to develop and establish accurate and reliable biodosimetry tools that will improve radiation preparedness and ultimately save lives during a radiological or nuclear incident.

On the value and costs of protective actions in a nuclear emergency

This paper reviews the current orthodoxy for the prompt application of shelter and evacuation advice in the event of a nuclear emergency in the light of the reassessment of the perceived costs and benefits of these protective actions that followed the Fukushima event. In particular, it discusses the mechanisms and criteria for the withdrawal of protective action advice or their continuation for more than a few hours and their impact on public perception. It suggests that lack of thought given to this area may lead to protective actions being kept in place for longer than necessary leading to more harm than good. It also considers the language used to recommend protective actions and to modify them as the event unfolds. Would over strong language used at the start of the event to encourage compliance contribute to public concerns later? Finally, the report poses some discussion points.

Radiation risks and information needs of pregnant and lactating women

This a historical review and current information regarding risks and effects of ionizing radiation in the context of human pregnancy and in particular the information needed for pregnant women to understand the type and magnitude of risks placing them in a realistic context. Much of our understanding comes from early animal studies but has been supported by studies of human exposure to medical radiation, radiation accidents and nuclear weapons.

Radioactive contamination in feral dogs in the Chernobyl exclusion zone: Population body-burden survey and implications for human radiation exposure

This report describes a two-year effort to survey the internal 137Cs and external β-emitter contamination present in the feral dog population near the Chernobyl nuclear power plant (ChNPP) site, and to understand the potential for human radiation exposure from this contamination. This work was performed as an integral part of the radiation safety and control procedures of an animal welfare oriented trap-neuter-release (TNR) program. The measurement program focused on external contamination surveys using handheld β-sensitive probes, and internal contamination studies using a simple whole-body counter. Internal 137Cs burden was measured non-invasively during post-surgical observation and recovery. External β contamination surveys performed during intake showed that 21/288 animals had significant, removable external contamination, though not enough to pose a large hazard for incidental contact. Measurements with the whole-body counter indicated internal 137Cs body burdens ranging from undetectable (minimum detection level ∼100 Bq/kg in 2017, ∼30 Bq/kg in 2018) to approximately 30,000 Bq/kg. A total of 33 animals had 137Cs body-burdens above 1 kBq/kg, though none posed an external exposure hazard. The large variation in the 137Cs concentration in these animals is not well-understood, could be due to prey selection, access to human food scraps, or extended residence in highly contaminated areas. The small minority of animals with external contamination may pose a contamination risk allowing exposures in excess of regulatory standards.

Chemical species of cesium and iodine in condensed vaporized microparticles formed by melting nuclear fuel components with concrete materials

In this study, we report chemical species of Cs and I in condensed vaporized particles (CVPs) produced by melting experiments using nuclear fuel components containing CsI with concrete. Analyses of CVPs by SEM with EDX showed the formation of many round particles containing Cs and I of diameters less than ∼20 μm. X-ray absorption near-edge-structure and SEM-EDX analyses showed two kinds of particles: one containing large amounts of Cs and I, suggesting the presence of CsI, and the other containing small amounts of Cs and I with large Si content. When CVSs were placed in contact with deionized water, most of the CsI from both particles was dissolved. In contrast, some fractions of Cs remained from the latter particles and possessed different chemical species from CsI. In addition, the remaining Cs was concomitantly present with Si, resembling chemical components in the highly radioactive cesium-rich microparticles (CsMPs) released by nuclear plant accidents into the surrounding environments. These results strongly suggest that Cs was incorporated in CVSs along with Si by melting nuclear fuel components to form sparingly-soluble CVMPs.

Development and application of an in-situ shipboard device for the measurement of gamma-ray emitters in seawater

An optimized device based on an HPGe detector and an electro-mechanical cooler combined with a small-sized lead shield was developed for flow-through seawater gamma radionuclide measurement. The system was optimized to operate in mobile or underway mode with suitable integration on available ships. The background spectrum, detection efficiency, and the impact of acquisition time on the minimum detectable activity were obtained at sea. The system MDAs in a 1 h acquisition period for ¹³⁷Cs (661.7 KeV) and ⁶⁰Co (1332.5 KeV) in seawater were 0.45 Bq/L and 0.24 Bq/L, and the MDAs in 20 min were 0.73 Bq/L and 0.47Bq/L, respectively. This device could be used as an efficient tool in emergency monitoring in response to a nuclear accident.

Combined radiation injury and its impacts on radiation countermeasures and biodosimetry

PURPOSE

Preparedness for medical responses to major radiation accidents and the increasing threat of nuclear warfare worldwide necessitates an understanding of the complexity of combined radiation injury (CI) and identifying drugs to treat CI is inevitably critical. The vital sign and survival after CI were presented. The molecular mechanisms, such as microRNA pathways, NF-κB-iNOS-IL-18 pathway, C3 production, the AKT-MAPK cross-talk, and TLR/MMP increases, underlying CI in relation to organ injury and mortality were analyzed. At present, no FDA-approved drug to protect, mitigate, or treat CI is available. The development of CI-specific medical countermeasures was reviewed. Because of the worsened acute radiation syndrome resulting from CI, diagnostic triage can be problematic. Therefore, biodosimetry and CI are bundled together with the need to establish effective triage methods with CI.

CONCLUSIONS

CI mouse model studies at AFRRI are reviewed addressing molecular responses, findings from medical countermeasures, and a proposed plasma proteomic biodosimetry approach based on a panel of radiation-responsive biomarkers (i.e., CD27, Flt-3L, GM-CSF, CD45, IL-12, TPO) negligibly influenced by wounding in an algorithm used for dose predictions is described.

The delayed effects of acute radiation exposure (DEARE): characteristics, mechanisms, animal models, and promising medical countermeasures

PURPOSE

Terrorist use of nuclear weapons and radiation accidents put the human population at risk for exposure to life-threatening levels of radiation. Victims of lethal radiation exposure face potentially lethal acute injury, while survivors of the acute phase are plagued with chronic debilitating multi-organ injuries for years after exposure. Developing effective medical countermeasures (MCM) for the treatment of radiation exposure is an urgent need that relies heavily on studies conducted in reliable and well-characterized animal models according to the FDA Animal Rule. Although relevant animal models have been developed in several species and four MCM for treatment of the acute radiation syndrome are now FDA-approved, animal models for the delayed effects of acute radiation exposure (DEARE) have only recently been developed, and there are no licensed MCM for DEARE. Herein, we provide a review of the DEARE including key characteristics of the DEARE gleaned from human data as well as animal, mechanisms common to multi-organ DEARE, small and large animal models used to study the DEARE, and promising new or repurposed MCM under development for alleviation of the DEARE.

CONCLUSIONS

Intensification of research efforts and support focused on better understanding of mechanisms and natural history of DEARE are urgently needed. Such knowledge provides the necessary first steps toward the design and development of MCM that effectively alleviate the life-debilitating consequences of the DEARE for the benefit of humankind worldwide.

Semi-mechanistic analysis of emergency planning zones for 20 MWe lead-cooled fast reactor by hypothetical accidents during Korea's arctic exploration

Small modular reactors or micro modular reactors have been considered as an alternative power source for merchant ships because of minimal carbon emission and a long lifecycle without refueling. Ahead of the operation, however, their emergency planning zones (EPZs) should be optimally set and approved to ensure both radiological safety and cost efficiency in case of nuclear accidents. Thus, the required size of EPZs was analyzed based on semi-mechanistic assumptions for hypothetical accidents with MicroURANUS, a micro modular fast reactor type of 20-MW lead-bismuth-cooled, used to power an icebreaker during Korea's Arctic missions. For meteorological data, actual icebreaker data acquired in 2020s Artic exploration were utilized. The results showed that EPZ sizes, rationalized in terms of stability class, wind directions, and inherent radioprotection design, ranged within the assumed icebreaker boundary. When comparing various regulations among countries and the International Atomic Energy Agency, dose criteria of Korea (10 mSv/2 d) were found to be strictest. Since major contribution to the whole-body dose was from noble gases (over 96%), a high-quality air filtration system in addition to external shielding would significantly reduce hazards. The emergency situation could be successfully controlled without evacuation and sheltering, avoiding overestimated socioeconomic costs.

PROBLEMATIC ASPECTS, COMPLICATIONS, MISCONCEPTIONS AND DEBATABLE ISSUES OF IODINE PROPHYLAXIS IN RADIATION EVENTS (REVIEW)

Prerequisite. Since the advent of nuclear energy, industry and weapons, a possibility of radiation events i.e. incidents and accidents had emerged. Given the presence of radioactive iodine as part of environmental contamination, the response of authorities and medical services consists, in particular, in carrying out the emergency iodine prophylaxis among specialists and general population. And along with the fact that emergency iodine prophylaxis is a generally accepted measure in radiation events accompanied by the release of radioactive iodine, some methods of its implementation were and remain in certain sources and instructions/recommendations contradictory and even false. Such inconsistency increases the potential risks of health effects of radioactive iodine and exacerbates the sense of fear and uncertainty among the population involved in the incident.

OBJECTIVE

to consider and review the essence of emergency iodine prophylaxis during radiation events, physiological aspects of iodine metabolism in the body, properties of individual iodine prophylaxis agents that are recommended, and to justify the rationality of using some of them along with absurdity/inadmissibility of others; substantiate the creation of a unified preventive information strategy regarding the event in order to reduce anxiety and other negative psychological consequences among the affected population.

MATERIALS AND METHODS

The review was performed by searching the abstract and scientometric databases and printed publications.

RESULTS

In the event of serious radiation events at nuclear power plants and industry facilities, radioactive iodine is highly likely to enter the environment. With the threat of radioactive iodine incorporation or with its incorporation that has already begun, it is absolutely necessary to carry out the emergency iodine prophylaxis. Such prevention should be carried out with stable iodine preparations such as potassium iodide or potassium iodate in special pharmaceutical formulas. Dosing of drugs in age and population groups should be carried out by specialists in radiation medicine and radiation safety in accordance with internationally recognized guidelines. The use of iodinecontaining food additives, iodine solution for external use and Lugol's solution is categorically unacceptable due to complete ineffectiveness, impracticality of implementation, and sometimes due to the threat of serious harm to health.

CONCLUSIONS

Clear preparedness plans for possible radiation accidents and incidents, as well as successfullyimplemented appropriate preventive measures, including emergency iodine prophylaxis, are crucial for the effective and successful response to such events. Emergency iodine prophylaxis during radiation events should be carried out exclusively under the guidance of specialists in radiation medicine and radiation safety using special pharmaceutical formulas of potassium iodide or potassium iodate in doses recognized by the international scientific community. Other means of emergency iodine prophylaxis, including «handicraft»/home preparations, are absolutely unacceptable. Implementation of this protective measure should be accompanied by a coordinated information campaign in order to minimize purely radiation risks and to preserve the psychological well-being of the population.

Combined radiation burn injuries: A note

Combined radiation injury occurs when radiation is accompanied by any other form of trauma. The past experiences of Hiroshima, Nagasaki, and Chernobyl have revealed that a large number of victims of such nuclear accidents or attacks suffer from combined radiation injuries. The possibility of a nuclear attack seems very far-fetched, but the destruction that would occur in such an event would be massive, with a huge lossof lives. Therefore, preparedness for the same should be done beforehand. The severity of combined radiation depends upon various factors, such as radiation dose, type, tissues affected, and traumas. The article focuses on combined radiation burn injury (CRBI) which may arise due to the combination of ionising radiation with thermal burns. CRBI can have varied effects on different organs like the hematopoietic, digestive, lymphatic, cardiovascular, and respiratory systems. Some of the most profound lethal effects are hematopoietic dysfunction, gastrointestinal leakage, bacterial translocation to other organ sites, pulmonary fibrosis, and pneumonitis. In this article, we have attempted to accumulate the knowledge of ongoing research on the functioning of different organ systems, which are affected due to CRBI and possible countermeasures to minimize the effects, thus improving survival.

Radiological risk evaluation applied to aerial evacuation procedures in a nuclear scenario

This study evaluates the risk assessment of a hypothetical scenario where an off-site radioactive release occurs at a nuclear power plant. By using the code Accident Reporting and Guiding Operational System (Prolog Development Center - PDC/ARGOS) a numerical simulation was performed to simulate exposure conditions in an atmospheric plume of contamination. Crews on a rescue mission traverse the plume through a pre-defined path to evaluate the risk from a hypothetical radiological exposure. Applying a sophisticated epidemiological assessment methodology, radiation doses and risks on the teams were evaluated. Core variables such as gender, age and radiation dose were considered in relation to specific morbidities. It was possible to propose a methodology capable of contributing to the reduction of risks to the personnel involved by connecting the results from the computer simulation and the epidemiological risk assessment.

ESTIMATION OF RADIATION DOSES IN THE AREA OF THE MAIN PRODUCTION BLOCK OF THE NUCLEAR POWER PLANT AFTER A REACTOR ACCIDENT

The aim of this work is to propose methodology for estimations the characteristics of the radiation fields (and derived quantities from the field of dosimetry and radiation protection) in knowledge of a distribution of radionuclides released into the main production unit (or just a containment) area after a nuclear reactor accident. For such task stochastic Monte Carlo method has been chosen. Because of dimensions and thick shielding (concrete) barriers in the facility, application of the variance reduction techniques has been necessary. Monte Carlo code Monaco in sequence MAVRIC (from package SCALE 6.2.3) with variance reduction techniques using CADIS methodology has been employed for designing the proposed methodology. Procedure has been tested on a simulation model of a main production unit described by inspiration from the block of a nuclear power plant with a VVER-1000 reactor (installed in the Czech Republic, Central Europe).

Mental health and psychosocial consequences linked to radiation emergencies-increasingly recognised concerns

A major radiological or nuclear emergency may, apart from causing a substantial loss of life and physical damage, also put a substantial strain on affected societies with social, economic and political consequences. Although such emergencies are relatively uncommon, it is now being increasingly recognised that their subsequent psychosocial impact can be widespread and long lasting. Mental health effects, such as depression, anxiety and post-traumatic stress disorder, are highly represented in a population affected by a radiation disaster. In order to reach the majority of the people affected by radiation accidents, we need to be aware of how to distribute relevant and accurate information related to both short- and long-term medical effects. Effective risk communication is associated with improved compliance with any given recommendations. It is important to protect the public from physical radiation damage, but it is also essential to take into account the social and mental health effects that radiation disasters may induce. This article provides a brief review of recent reporting on the psychological consequences after a major radiation emergency.

Citizens’ Communication Needs and Attitudes to Risk in a Nuclear Accident Scenario: A Mixed Methods Study

The potential devastation that a nuclear accident can cause to public health and the surrounding environment demands robust emergency preparedness. This includes gaining a greater knowledge of citizens’ needs in situations involving radiation risk. The present study examines citizens’ attitudes to a remediation scenario and their information and communication needs, using focus group data (n = 39) and survey data (n = 2291) from Sweden. The focus groups uniquely showed that adults of all ages express health concerns regarding young children, and many also do so regarding domestic animals. Said protective sentiments stem from a worry that even low-dose radiation is a transboundary, lingering health risk. It leads to doubts about living in a decontaminated area, and high demands on fast, continuous communication that in key phases of decontamination affords dialogue. Additionally, the survey results show that less favorable attitudes to the remediation scenario—worry over risk, doubt about decontamination effectiveness, and preferences to move away from a remediation area—are associated with the need for in-person meetings and dialogue. Risk managers should thus prepare for the need for both in-person meetings and frequent information provision tasks, but also that in-person, citizen meetings are likely to feature an over-representation of critical voices, forming very challenging communication tasks.

Returning Home after Decontamination? Applying the Protective Action Decision Model to a Nuclear Accident Scenario

Studies of the aftermath of nuclear power plant accidents show that affected citizens assess higher risks and adopt more risk-avoidant behaviors than authorities expect. This results in differences between the planned recovery and actual outcomes. Based on this knowledge, this study examined the factors that affect citizens’ preference to continue living in a decontaminated area. Testing the key aspects of the protective action decision model (PADM), this study analyzed Swedish survey data (N = 2291) regarding such an accident scenario. Several aspects of the PADM, from the layperson’s view of threats and protective actions, to stakeholders and situational factors, were strongly supported. The most influential variables affecting settlement choices are perceptions of radiation risk, perceptions of decontamination effectiveness, government information, living with certain restrictions, and attachment to an area because of one’s work. A novel contribution of this study is that it ranked the significance of such effects on behavioral intentions in an emergency scenario. Regarding the policy recommendations, this study concluded that a recovery program must facilitate most aspects of people’s lives and provide trustworthy information on decontamination efficiency. As some people will avoid potential health risks and leave a decontaminated area, planning to implement one solution for everyone would likely not be optimal.

Atmospheric dispersion modeling for an accidental release from a SLOWPOKE-2 research reactor: a case study

Atmospheric dispersion modeling was performed for a postulated design basis accident at a SLOWPOKE research reactor. The MCNP-5 computer code was used to estimate the neutron flux spectrum which was then used in the ORIGEN-S code to perform core depletion calculations and determine the radiological source term. The HotSpot health physics code was then used to model the atmospheric transport of the radioactive material released to estimate the resulting doses to the population downwind of the reactor. The highest total effective dose (TED) for a release from the reactor's exhaust stack in predominant meteorological conditions, stability class C, was 0.37 mSv, while a maximum TED of 4.29 mSv was estimated for a release at ground level. Ground deposition was estimated to be 3900 kBq/m². It was shown that any hypothetical release of radioactive material resulting from such an accident would have no significant adverse effect on the municipal water reservoir close to the reactor.

EPR dosimetry in glass: a review

Electron Paramagnetic Resonance (EPR) spectroscopy enables detection of paramagnetic centers generated in solids by ionising radiation. In the last years, the ubiquity of glass in personal utility items increased significance of fortuities retrospective dosimetry based on EPR in glass parts of mobile phones and watches. Despite of fading of the signals and their susceptibility to light, it enables dosimetry at medical triage level of 1-2 Gy. In this article information relevant for assessment of applicability and planning of the EPR dosimetry is presented-particularly at dose levels typical for radiation accidents. Reported data on fading of the radiation-induced spectral components are presented and compared. Effects of light on background spectra and on the dosimetric signals are also presented. It is concluded that when properly accounting for the fading and for the obscuring effects of light, the EPR dosimetry in glasses from mobile phones and watches can be used in dose assessment after radiation accidents.

Improving the estimation accuracy of multi-nuclide source term estimation method for severe nuclear accidents using temporal convolutional network optimized by Bayesian optimization and hyperband

During a nuclear accident, estimating the source terms using environmental measurements is vital for emergency decision-making. In this study, we propose a forecasting model based on a temporal convolutional network to estimate the release rates of seven radionuclides (Kr-88, Te-132, I-131, Xe-133, Cs-137, Ba-140, and Ce-144) based on off-site sequential gamma dose rates and meteorological monitoring data. To determine the best structure of the neural network, Bayesian optimization and hyperband (BOHB) was used on the hyperparameters of the model to reduce the testing loss. Additionally, a gradient boosting regression model was used to predict missing gamma dose rates to ensure the model offers a relatively reliable estimate under certain circumstances. The international radiological assessment system (InterRAS) was used to generate datasets for model training and testing. The results showed that the optimal hyperparameters selected by BOHB can reduce the valid loss of the model to 0.0153, and the mean absolute percentage error of prediction for the seven radionuclides was below 12%, three of which (Kr-88, Te-132, Cs-137) reached 8% at 10 h. When the first and second time-steps of the data were missing, the mean absolute percentage error of the prediction for all radionuclides was less than 30% after using a gradient boosting regression.

SEED: An Operational Numerical Tool for Dosimetric Reconstruction in Case of External Radiological Overexposure

ABSTRACT

In the event of a radiological accident involving external exposure of one or more victims and potential high doses, it is essential to know the dose distribution within the body in order to sort the victims according to the severity of the irradiation and then to take them to the most suitable medical facilities. However, there are currently few techniques that can be rapidly deployed on field and capable of characterizing an irradiation. Therefore, a numerical simulation tool has been designed. It can be implemented by a doctor/physicist pairing, projected within a limited time as close as possible to the irradiation accident and emergency response teams. Called SEED (Simulation of External Exposures & Dosimetry), this tool (dedicated to dose reconstruction in case of external exposure) allows a rapid modeling of the irradiation scene and a visual exchange with the victims and witnesses of the event. The user can navigate in three dimensions in the accident scene thanks to a graphical user interface including a "first person" camera. To validate the performance of the SEED tool, two dosimetric benchmarking exercises were performed. The first consisted in comparing the dose value provided by SEED to that given by a reference calculation code: MCNPX. The purpose of the second validation was to perform an experiment irradiating a physical dummy equipped with dosimeters and to reconstruct this irradiation using SEED. These two validation protocols have shown satisfactory results with mean difference less than 2% and 12% for the first and second exercises, respectively. They confirm that this new tool is able to provide useful information to medical teams in charge of dosimetric triage in case of a major external exposure event.

The METREPOL criteria-are they still relevant?

The medical management of radiation accidents manual on the acute radiation syndrome proposed a successful strategic approach to diagnosing and treating acute radiation syndrome: the response category concept. Based on clinical and laboratory parameters, this approach aimed to assess damage to critical organ systems as a function of time, categorising different therapeutical approaches. After 20 years of its publication, the following paper attempts to provide a broad overview of this important document and tries to respond if proposed criteria are still relevant for the medical management of radiation-induced injuries. In addition, a critical analysis of its limitations and perspectives is proposed.

Reconstructive dosimetry and radiation dose evaluation of workers and public due to a Brazilian radiological accident in industrial radiography

Radiological accidents occur mainly in the practices recognized as high risk and which are classified by the International Atomic Energy Agency (IAEA) as Categories 1 and 2: radiotherapy, industrial irradiators and industrial radiography. In Brazil, five important cases in industrial gamma radiography occurred from 1985 to 2018, involving seven radiation workers and 19 members of the public. The accidents caused localized radiation lesions on the hands and fingers. One of these accidents is the focus of this paper. In this accident, a 3.28 TBq¹⁹²Ir radioactive source was left unshielded for 9 h in a non-destructive testing (NDT) company parking lot, and many radiation workers, employees and public, including teachers of a primary school were exposed. The radioactive source was also directly handled by a security worker for about 1.5 min causing severe radiation injuries in the hand and fingers. This paper presents radiation dose estimates for all accidentally exposed individuals. Four scenarios were considered, and three internationally recognised and updated reconstructive dosimetry techniques were used, named, Brazilian visual Monte Carlo Dose Calculation (VMC), virtual environment for radiological and nuclear accidents simulation (AVSAR) and RADPRO Calculator®. The main radiation doses estimated by VMC were the absorbed dose of 34 Gy for the security worker's finger and his effective dose of 91 mSv; effective doses from 43 to 160 mSv for radiation workers and NDT employees; and effective doses of 9 mSv for teachers in the schoolyard.

Cutaneous and local radiation injuries

The threat of a large-scale radiological or nuclear (R/N) incident looms in the present-day climate, as noted most recently in an editorial in Scientific American (March 2021). These large-scale incidents are infrequent but affect large numbers of people. Smaller-scale R/N incidents occur more often, affecting smaller numbers of people. There is more awareness of acute radiation syndrome (ARS) in the medical community; however, ionising radiation-induced injuries to the skin are much less understood. This article will provide an overview of radiation-induced injuries to the skin, deeper tissues, and organs. The history and nomenclature; types and causes of injuries; pathophysiology; evaluation and diagnosis; current medical management; and current research of the evaluation and management are presented. Cutaneous radiation injuries (CRI) or local radiation injuries (LRI) may lead to cutaneous radiation syndrome, a sub-syndrome of ARS. These injuries may occur from exposure to radioactive particles suspended in the environment (air, soil, water) after a nuclear detonation or an improvised nuclear detonation (IND), a nuclear power plant incident, or an encounter with a radioactive dispersal or exposure device. These incidents may also result in a radiation-combined injury; a chemical, thermal, or traumatic injury, with radiation exposure. Skin injuries from medical diagnostic and therapeutic imaging, medical misadministration of nuclear medicine or radiotherapy, occupational exposures (including research) to radioactive sources are more common but are not the focus of this manuscript. Diagnosis and evaluation of injuries are based on the scenario, clinical picture, and dosimetry, and may be assisted through advanced imaging techniques. Research-based multidisciplinary therapies, both in the laboratory and clinical trial environments, hold promise for future medical management. Great progress is being made in recognising the extent of injuries, understanding their pathophysiology, as well as diagnosis and management; however, research gaps still exist.

How often does it happen? A review of unintended, unnecessary and unavoidable high-dose radiation exposures

High-dose radiation exposures of humans occur every year around the world, and may lead to harmful tissue reactions. This review aims to look at the available information sources that can help answering the question of how often these events occur yearly on a global scale. In the absence of comprehensive databases of global occurrence, publications on radiation accidents in all uses of radiation and on rates of high-dose events in different medical uses of radiation have been reviewed. Most high-dose radiation exposures seem to occur in the medical uses of radiation, reflecting the high number of medical exposures performed. In therapeutic medical uses, radiation doses are purposely often given at levels known to cause deterministic effects, and there is a very narrow range in which the medical practitioner can operate without causing severe unacceptable outcomes. In interventional medical uses, there are scenarios in which the radiation dose given to a patient may reach or exceed a threshold for skin effects, where this radiation dose may be unavoidable, considering all benefits and risks as well as benefits and risks of any alternative procedures. Regardless of if the delivered dose is unintended, unnecessary or unavoidable, there are estimates published of the rates of high-dose events and of radiation-induced tissue injuries occurring in medical uses. If this information is extrapolated to a global scenario, noting the inherent limitations in doing so, it does not seem unreasonable to expect that the global number of radiation-induced injuries every year may be in the order of hundreds, likely mainly arising from medical uses of radiation, and in particular from interventional fluoroscopy procedures and external beam radiotherapy procedures. These procedures are so frequently employed throughout the world that even a very small rate of radiation-induced injuries becomes a substantial number when scaled up to a global level.

THE EXPRESSION OF THE MAIN AND ALTERNATIVE TRANSCRIPT (SORL1 Delta2) OF THE SORL1 GENE IN CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS AFFECTED BY THE CHORNOBYL ACCIDENT

OBJECTIVE

to study clinical-hematological data and expression of the main and alternative transcripts of SORL1 genein chronic lymphocytic leukemia (CLL) patients affected by the Chornobyl catastrophe.

METHODS

Analysis was performed in the main group of 34 CLL patients irradiated due to the Chornobyl NPP acci-dent (30 clean-up workers, and 4 evacuees) and in the control group of 27 non-irradiated CLL patients. Groups ofpatients were comparable by age, sex, stage of disease, mutational status of IGHV genes. Expression of the main andalternative transcripts of SORL1 gene was evaluated by Quantitative Real-time polymerase chain reaction (PCR). TheIGHV gene mutational status, TP53 and SF3B1 mutations were studied by PCR followed by direct sequencing. Data wereanalyzed with the SPSS software package, version 20.0.

RESULTS

Relative expression level of the main transcript of SORL1 gene was low (mean 1.71 ± 0.55, median 0.57),did not correlate with the IGHV gene mutational status, TP53 and SF3B1 mutations, stage of disease. The expressionof B transcript was not detected, F transcript was expressed at a very low level in 9 patients. The average relativeexpression level of SORL1-Δ2 transcript was 14.1 ± 6.04 (median 3.48; range 0.01-90.51). The expression of SORL1-Δ2transcript above the median was more frequent among patients on C stage (p = 0.001), and in patients with unmu-tated IGHV genes was associated with an extremely negative course of CLL (median of overall survival 9 months vs61 months at low expression). Relative expression levels of the main and alternative transcripts of SORL1 gene inpatients of the main and the control groups did not differ.

CONCLUSIONS

Our preliminary data suggest that increased expression of SORL1-Δ2 transcript in CLL patients withunmutated IGHV genes can be considered as a negative prognostic marker.

SUBCLINICAL INFLAMMATION IN NON/ALCOHOLIC FATTY LIVER DISEASE AT THE REMOTE PERIOD AFTER THE CHORNOBYL ACCIDENT

OBJECTIVE

to evaluate the parameters of inflammatory reaction and oxidative stress in patients with non-alcoholicfatty liver disease (NAFLD) in the remote period after the influence of the Chornobyl accident factors.

MATERIALS AND METHODS

Eighty two patients with NAFLD who had been exposed to ionizing radiation as a result ofthe Chornobyl accident and have concomitant cardiovascular pathology were examined. Hematological parametersand the level of highly sensitive C-reactive protein (hsCRP) were determined, and the content of products of oxida-tive modification of lipids and proteins was evaluated.

RESULTS

Activation of the processes of oxidative modification of lipids and proteins was observed in most patientswith NAFLD. According to the level of hsCRP, the presence of subclinical inflammation and the risk of developingcomplicated cardiovascular pathology was found in 58 % of patients with NAFLD. The neutrophil / lymphocyte ratiocorrelates positively with hsCRP and can be used as an available routine clinical marker for selection among patientswith NAFLD persons with increased risk of cardiovascular complications.

CONCLUSIONS

HsCRP, oxidative modification products of lipids and proteins, ESR, and leukograms should be used toassess the degree of systemic inflammation in people affected by the Chornobyl accident, suffering NAFLD with con-comitant cardiovascular disease.

THE BRONCHOPULMONARY SYSTEM DAMAGE UNDER THE INFLUENCE OF IONIZING RADIATION EXPOSURE AND RADIONUCLIDES INHALATION IN THE CONDITIONS OF THE CHORNOBYL CATASTROPHE (SUMMARIZING OF 35 YEARS RESEARCH EXPERIENCE)

The review is devoted to the summarizing of 35 years of research of ionizing radiation exposure and radionuclidesinhalation influence on the bronchopulmonary system of clean-up workers of the Chornobyl NPP accident. Radiationand hygienic preconditions for the formation of chronic respiratory pathology are considered, taking into accountthe dosimetric data of irradiation of the bronchopulmonary system.The main clinical symptoms, features of disorders of pulmonary ventilation capacity and endoscopic forms of lesionsof the bronchopulmonary system of participants in the liquidation of the accident were determined.On the basis of pathomorphological, microbiological and immunological researches the pathomorphosis of chronicnonspecific lung diseases in the conditions of the Chernobyl catastrophe is proved.It is proved that under combined influence of external irradiation and inhalation of a fragmentary mixture ofradionuclides in the condition of the Chernobyl catastrophe, the bronchopulmonary system has become one of themain «targets»-tissues, of realization of stochastic and nonstochastic effects.

Recent advances in medical countermeasure development against acute radiation exposure based on the US FDA animal rule

Recent advances in medical countermeasures (MCMs) has been dependent on the Food and Drug Administration (FDA) animal rule (AR) and the final guidance document provided for industry on product development. The criteria outlined therein establish the path for approval under the AR. The guidance document, along with the funding and requirements from the federal agencies provided the basic considerations for animal model development in assessing radiation effects and efficacy against the potential lethal effects of acute radiation injury and the delayed effects of acute exposure. Animal models, essential for determining MCM efficacy, were developed and validated to assess organ-specific, potentially lethal, radiation effects against the gastrointestinal (GI) and hematopoietic acute radiation syndrome (H-ARS), and radiation-induced delayed effects to lung and associated comorbidities of prolonged immune suppression, GI, kidney and heart injury. Partial-body irradiation models where marginal bone marrow was spared resulted in the ability to evaluate the concomitant evolution of multiple organ injury in the acute and delayed effects in survivors of acute radiation exposure. There are no MCMs for prophylaxis against the major sequelae of the ARS or the delayed effects of acute exposure. Also lacking are MCMs that will mitigate the GI ARS consequent to potentially lethal exposure from a terrorist event or major radiation accident. Additionally, the gap in countermeasures for prophylaxis may extend to mixed neutron/gamma radiation if current modelling predicts prompt exposure from an improvised nuclear device. However, progress in the field of MCM development has been made due to federal and corporate funding, clarification of the critical criteria for efficacy within the FDA AR and the concomitant development and validation of additional animal models. These models provided for a strategic and tactical approach to determine radiation effects and MCM efficacy.

Medical management of heavily exposed victims: an experience at the Tokaimura criticality accident

A criticality accident occurred at the uranium conversion plant in Tokaimura, Ibaraki Prefecture, Japan on 30 September 1999. When uranyl nitrate was overloaded to a critical mass level, uncontrolled fission reaction occurred. A procedure was carried out according to the JCO manual, although not an officially approved manual. Three workers were heavily exposed to neutrons andγ-rays produced by nuclear fission, and they subsequently developed acute radiation syndrome (ARS). The average doses to the whole body of the three workers were approximately 25, 9, and 3 GyEq (biologically equivalent dose ofγ-exposure), respectively; dose distribution analysis later revealed extreme heterogeneity of these doses in two workers. They were triaged according to the predicted clinical needs. Two of these workers developed severe bone marrow failure and received haematopoietic stem cell transplantation: one with peripheral stem cell transplantation from his Human Leukocyte Antigen compatible sister and the other with umbilical cord blood transplantation. The graft was initially successful in both workers; autologous haematopoietic recovery was observed after donor/recipient mixed chimerism in one of them. Despite of all medical efforts available including haematopoietic stem cell transplantation, investigational drugs, skin graft, two workers died of multiple organ involvement and failure 83 and 211 days after the accident, respectively. Clinically as well as pathologically, the direct cause of death was deemed to be intractable gastrointestinal (GI) bleeding in one, and thoraco-abdominal compartment syndrome due to dermal fibrosis/sclerosis in the other. The third worker also developed bone marrow suppression but was treated with granulocyte colony-stimulating factor. He recovered without major complications and is now under periodical medical follow-up. These experiences suggest that treatment of bone marrow is not a limiting factor for saving the life of ARS victims severely exposed. Successful treatment of other organs such as lungs, skin, and GI tract is also essential. Furthermore, the whole-body dose may not always reflect the prognosis of ARS victims because of the nature of accidental exposure, heterogenous exposure.