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.

Preparedness for a 'no-notice' mass-casualty incident: a nuclear detonation scenario

PURPOSE

An effective response for a mass-casualty incident requires understanding the relevant basic science and physical impact; detailed preparedness among jurisdictions; and clear, sequential response planning, including formal operational exercises, logistics, interagency, and public-private coordination, rapid activation of resilience, and continual improvement from lessons learned and new knowledge. This ConRad 2021 meeting report describes steps for civilian medical and public health response planning for a nuclear detonation; the utility of this type of planning for broader application; and extension of this planning to the international community.

CONCLUSION

A nuclear detonation requires a response within minutes to what will be a large-scale disaster complicated by radiation, including some elements that are similar to a broad range of incidents. The response could be further complicated if multiple incidents occur simultaneously. Required are detailed planning, preparedness and scripting for an immediate operational response, addressing clinical manifestations of evolving radiation illness, and flexibility to adapt to a rapidly changing situation. This need translates into the use of just-in-time information; effective, credible communication; situational awareness on a global scale; and a template upon which to apply capabilities in a multi-sector response. This effort is greatly facilitated using a 'playbook' approach, the basics of which are presented.

Association of Instrumental Activities of Daily Living, Physical Function, and Mental Health among Older Returnees after the Fukushima Daiichi Nuclear Power Station Accident

The 2011 Great East Japan Earthquake and consequent Fukushima Daiichi Nuclear Power Station accident caused a large-scale evacuation, generating various health issues. Although residents gradually returned, their independence of daily living and associated factors remain unknown. This study examines the hypothesis that physical and mental status are associated with the instrumental activities of daily living (IADL) of older returnees (65 years and above) after the disaster. Older returnees to Kawauchi Village, Fukushima Prefecture, located 20–30 km southwest of the power plants, were recruited. IADL was assessed using the Japan Science and Technology Agency Index of Competence, physical function via the 30-s chair stand test, and mental health via the Japanese version of the World Health Organization Five Well-Being Index. To examine the association of IADL and possible factors, a t-test or Pearson’s product-moment correlation coefficient was used, stratified by sex. The data of 29 participants (75.5 ± 7.4 years, 19 female) were analyzed. Physical function was associated with IADL in females. Mental health was associated with IADL in males and females. Taking measures to strengthen physical function in females, as well as to improve mental health in both sexes, for enhancing IADL ability could be beneficial.

Medical management: major lessons learned from the Chernobyl accident (the review)

Thirty-five years have passed since the moment of the disaster at the Chernobyl nuclear power plant. It is quite a sufficient period to assess the correctness of the organisation of medical care for victims, to summarise the results of monitoring the health status of various groups of persons involved in the accident, including its direct participants. Radiation from a massive source of relatively uniform gamma radiation and a heterogeneous source of beta radiation can cause affected people to develop acute radiation syndrome (ARS) of varying severity, including non-curable forms of the disease ARS developed in 134 patients; 28 patients from 134 with ARS died in a short time (100 d) after exposure. Among the patients whose disease ended in death, 2/3 of the outcome could be due to radiation skin lesions (19 people). Treatment of ARS varying severity, which was combined with common skin burns with beta radiation, requires long-term specialised treatment. The experience of treating this group of patients has demonstrated that the indications for bone marrow transplantation in the curable form of ARS are limited. The percentage of victims who have absolute indications for allogeneic bone marrow transplantation and in whom this procedure will lead to an improved prognosis for life is very small. Recovery of own myelopoiesis and survival are possible after whole-body irradiation from 6 to 8 Gy, which was found after rejection of haploidentical human leucocyte antigen transplantation, as well as in patients who did not use bone marrow transplantation due to the absence of a corresponding donor. Patients who have undergone ARS need lifelong medical supervision and the provision of necessary medical care.

Intercomparison of conventional and QuickScan dicentric scoring for the validation of individual biodosimetry analysis in Taiwan

PURPOSE

The dicentric chromosome assay (DCA), the gold standard for radiation biodosimetry, evaluates an individual absorbed radiation dose by the analysis of DNA damage in human lymphocytes. The conventional (C-DCA) and QuickScan (QS-DCA) scoring methods are sensitive for estimating radiation dose. The Biodosimetry Laboratory at Institute of Nuclear Energy Research (INER), Taiwan, participated in intercomparison exercises conducted by Health Canada (HC) in 2014, 2015 and 2018 to validate the laboratory's accuracy and performance.

MATERIAL AND METHODS

Blood samples for the conventional dose response curve for Taiwan were irradiated with 0, 0.25, 0.5, 1, 2, 3, 4 and 5 Gy. Ten blind blood samples were provided by HC. Either or both of two methods of conventional (C) or QuickScan (QS) scoring could be chosen for the HC's intercomparison. For C-DCA triage scoring, only cells with 46 centromeres were counted and each scorer recorded the number of dicentrics in the first 50 metaphases or stopped scoring when 30 dicentrics were reached. Scorers also recorded how much time it took to analyze 10, 20, and 50 cells. Subsequently, the data were entered into the Dose Estimate software (DoseEstimate_v5.1) and dose estimates were calculated. With QS-DCA scoring, a minimum of 50 metaphase cells (or 30 dicentrics) were scored in apparently complete metaphases without verification of exactly 46 centromeres.

RESULTS

For the blinded blood samples irradiated at HC and shipped to INER, the mean absolute deviation (MAD) derived after scoring 50 cells for C-DCA and QS-DCA was <0.5 Gy for all three intercomparisons, meeting the criteria for acceptance.

CONCLUSION

The results indicated that the Biodosimetry Laboratory at INER can provide reliable dose estimates in the case of a large-scale radiation accident.

Is there a role for haematopoietic cell transplants after radiation and nuclear accidents?

My task is to consider whether haematopoietic cell transplants would be considered appropriate today in persons with features like victims of high-dose and dose-rate ionizing radiations after the Chernobyl nuclear power facility accident in 1986 given knowledge and experience gained over the past 35 years. First I consider the conceptual bases for considering an intervention appropriate and then the metric for deciding whether a transplant is appropriate in similar persons. Data needed to support this decision-making process include estimates of dose, dose-rate, dose uniformity, synchronous or metachronous injuries, donor availability and alternative interventions. Many of these co-variates have substantial uncertainties. Fundamental is a consideration of potential benefit-to-risk and risk-to-benefit ratios under conditions of substantial inaccuracy and imprecision. The bottom line is probably fewer transplants would be done and more victims would receive molecularly-cloned haematopoietic growth factors.

Physical dosimetry reconstructions of significant radiation exposure at an industrial accelerator facility in Tianjin (China)

The goal of this thesis is to estimate the physical radiation doses for two victims who were accidently exposed to an industrial electron beam at an industrial accelerator facility on 7 July 7 2016 in Tianjin, China. On the basis of the radiation source parameters, irradiation situation and irradiation time, physical dose reconstruction was carried out at the accident site by using a Bottle-Manikin-Absorption (BOMAB) phantom and an Alderson Radiation Therapy (ART) phantom. With thermoluminscent dosimeters (TLDs), skin estimation was conducted for the feet, calves, upper arms, left side of the body and neck, and the mean dose was estimated to be 14.1 ± 5.6 Gy. The foot and leg skin received the highest dose, which was >16.3 Gy. In addition, the mean dose estimated for the eye lens was 0.18 ± 0.07 Gy. The organ effective dose estimated and the total organs effective dose estimated were 0.46-4.94 mSv and 0.21 Sv, respectively. In the course of the accident, the damage caused by the electron radiation field to the exposed person was mainly to the skin, and the contributions to other radiation-sensitive organs were small. The damage to the organs other than the skin was mainly caused by the X-rays generated by the bremsstrahlung of the electron beam from the environment or the human body.

BRAIN AND EYE AS POTENTIAL TARGETS FOR IONIZING RADIATION IMPACT. Part І. THE CONSEQUENCES OF IRRADIATION OF THE PARTICIPANTS OF THE LIQUIDATION OF THE CHORNOBYL ACCIDENT

BACKGROUND

Exposure to ionizing radiation could affect the brain and eyes leading to cognitive and vision impairment, behavior disorders and performance decrement during professional irradiation at medical radiology, includinginterventional radiological procedures, long-term space flights, and radiation accidents.

OBJECTIVE

The objective was to analyze the current experimental, epidemiological, and clinical data on the radiation cerebro-ophthalmic effects.

MATERIALS AND METHODS

In our analytical review peer-reviewed publications via the bibliographic and scientometric bases PubMed / MEDLINE, Scopus, Web of Science, and selected papers from the library catalog of NRCRM - theleading institution in the field of studying the medical effects of ionizing radiation - were used.

RESULTS

The probable radiation-induced cerebro-ophthalmic effects in human adults comprise radiation cataracts,radiation glaucoma, radiation-induced optic neuropathy, retinopathies, angiopathies as well as specific neurocognitive deficit in the various neuropsychiatric pathology including cerebrovascular pathology and neurodegenerativediseases. Specific attention is paid to the likely stochastic nature of many of those effects. Those prenatally and inchildhood exposed are a particular target group with a higher risk for possible radiation effects and neurodegenerative diseases.

CONCLUSIONS

The experimental, clinical, epidemiological, anatomical and pathophysiological rationale for visualsystem and central nervous system (CNS) radiosensitivity is given. The necessity for further international studieswith adequate dosimetric support and the follow-up medical and biophysical monitoring of high radiation riskcohorts is justified. The first part of the study currently being published presents the results of the study of theeffects of irradiation in the participants of emergency works at the Chornobyl Nuclear Power Plant (ChNPP).

Pharmaceutical drugs supporting regeneration of small-intestinal mucosa severely damaged by ionizing radiation in mice

Accidental exposure of the abdomen to high-dose radiation leads to severe consequences initiated by disruption of the mucosa in the small intestine. Therapeutic options are limited, even though various treatments have been investigated, particularly in the field of regenerative therapy. In order to identify readily available treatment methods, we included several current pharmaceutical drugs, for which the clinical trials have already been completed, in tests on mice that had undergone severe mucosal damage by radiation. The drugs were injected into mice 24 h after exposure to 15.7 Gy X-rays. The effects of the drugs on the damaged mucosa of the small intestine were evaluated using early regeneration indices [the expression of c-myb mRNA, and proliferation of epithelial cells in the form of microcolonies (MCs) by Days 4 and 5 post-irradiation] and the survival rate of the mice. Enhancement of mucosal regeneration at Day 4 (c-myb: P < 0.01, MC: P < 0.05) and improvement of the survival rate (P < 0.05) were observed when a clinical dose of gonadotropin, a stimulator of androgen, was injected. Similarly, a clinical dose of thiamazole (which prevents secretion of thyroid hormone) stimulated mucosal growth by Day 5 (c-myb: P < 0.01, MC: P < 0.05) and also improved the survival rate (P < 0.05). The nonclinical drugs histamine and high-dose octreotide (a growth hormone antagonist) also gave significant survival-enhancing benefits (P < 0.01 and P < 0.05, respectively). These results can be used to construct therapeutic programs and applied in various experimental studies to control the regeneration of damaged mucosa.

Radiation-induced biomarkers for the detection and assessment of absorbed radiation doses

Radiation incident involving living organisms is an uncommon but a very serious situation. The first step in medical management including triage is high-throughput assessment of the radiation dose received. Radiation exposure levels can be assessed from viability of cells, cellular organelles such as chromosome and different intermediate metabolites. Oxidative damages by ionizing radiation result in carcinogenesis, lowering of the immune response and, ultimately, damage to the hematopoietic system, gastrointestinal system and central nervous system. Biodosimetry is based on the measurement of the radiation-induced changes, which can correlate them with the absorbed dose. Radiation biomarkers such as chromosome aberration are most widely used. Serum enzymes such as serum amylase and diamine oxidase are the most promising biodosimeters. The level of gene expression and protein are also good biomarkers of radiation.