The article presents a methodology for assessing the radiological criteria for the use of the territory (a land plot with buildings) with residual radioactive contamination from the so-called “green area”, i.e., complete release from radiation control until a number of restrictions are imposed on the use of the territory. In accordance with the further use of the territory, a range of scenarios and pathways for the exposure of the population was considered. A set of models and their parameters, corresponding to the number of the considered pathways of exposure, was defined. Assuming a uniform distribution of a radionuclide with a unit concentration in the source zone, the distribution of effective doses for the population living in the territory with the residual radioactive contamination for different irradiation scenarios was calculated by stochastic modeling, 95% of the quantile of which was attributed to the dose in the representatives of the critical population group. Next, the value of radiological criteria, depending on the implemented scenario, was determined as the ratio of the dose constraint E_L = 0,3 mSv/yr and 95% quantile in the distribution of the effective dose from a unit contamination. The numerical values of radiological criteria for the presence of radionuclides in the soil are presented, both for the radiation scenarios that correspond to the permanent residence of the population in the contaminated territory and for recreational use. A further consideration is given to the so-called worker scenario, which corresponds to the limited time spent on the contaminated territory and the simultaneous effects of radionuclides contained both in the soil and in the construction of the buildings. A comparison of the results of the own calculations with the data of other authors was carried out.

To evaluate correlation between brain structural damages and radiation exposure level for the Chernobyl nuclear power plant accident liquidators, routine and diffusion tensor magnetic resonance imaging methods are efficient to visualize and evaluate those damages; it is also important to compare magnetic resonance imaging data of liquidators with results, received for people of the same age and the same stage of cerebral vascular disease (the discirculatory encephalopathy of I and II stage), but who did not participate in the Chernobyl accident liquidation and did not suffer from other liquidation factors and radiation catastrophe aftermaths. As a result, the Chernobyl accident liquidators group (49 subjects) and group of control (50 subjects) were examined with routine magnetic resonance imaging methods and standard protocols. In addition, the innovative method of diffusion tensor magnetic resonance imaging was applied to examine 11 cerebral tracts, bilaterally (22 tracts in both hemispheres) for every subject of the research. It was for the first time when diffusion tensor magnetic resonance imaging was applied to conduct visual analysis of polymorphic brain changes for the Chernobyl accident liquidators and special research conducted to find correlation between fractional anisotropy coefficient and radiation exposure for these patients. The results of diffusion tensor magnetic resonance imaging indicated no statistically significant (p > 0,05) difference in the level of cerebral morphological changes and between average fraction anisotropy coefficient value in any cerebral tract for both sub-groups of liquidators with different level of irradiation: 28 subjects, who were exposed by low and very low radiation doses (0–100 micro-Sv, sub-group A) and 21 subjects, who were exposed by mean radiation doses (100–1000 micro-Sv, sub-group B). However, comparing diffusion tensor magnetic resonance imaging results of control group and liquidators group, statistically significant (p < 0,05) reduction of average fraction anisotropy coefficient was detected in frontal and temporal lobes. It proves significant micro-structural damages of mentioned brain areas caused by different factors of the Chernobyl accident liquidation.

This study presents an overview of the most common positron emission tomography examinations in Russia, as well as the acquisition protocols and patient doses. The data collection was performed in 2012–2017 in 19 positron emission tomography departments in 12 regions of the Russian Federation by questioning the staff. The majority of the Russian positron emission tomography departments were equipped by modern positron emission tomography scanners combined with computed tomography. In each investigated department, data on all types of positron emission tomography examinations, radiopharmaceuticals, administered activities used for standard patient (body mass 70±5 kg) and parameters of computed tomography protocols was collected. The effective doses of patients from combined positron emission computed tomography examinations were estimated as a sum of the dose from the internal exposure (injected radiopharmaceutical) and the external exposure (computed tomography scan). Whole body positron emission tomography examinations in Russia were commonly performed with 18F-fluorodeoxyglucose (¹⁸F-FDG), ¹⁸F-choline, ¹¹С-choline, ⁶⁸GaPSMA, ⁶⁸Ga-DOTA-TATE, ⁶⁸Ga-DOTA-NOC, brain examinations – ¹⁸F-FDG, ¹¹С-metionine, ¹⁸F-choline, ¹⁸F-tyrosine, myocardial perfusion – ¹³N-ammonie.

The highest patient effective doses (about 17 mSv) were observed for whole-body positron emission computed tomography examinations; for brain examinations – 3,4 – 4,8 mSv; for myocardial perfusion – 2,8 mSv. The computed tomography scan contributes up to 65 – 95% to the total patient effective dose for whole body examinations; 20 – 30% for head examinations. For the multiphase computed tomography scan effective doses may be increased to: 15 mSv for head examinations, 25 – 30 mSv for whole body examinations and 35 – 40 mSv for myocardial examinations. A standardization of acquisition and processing protocols is necessary for optimization of positron emission tomography examinations in Russia and for the intercomparison of results obtained in different positron emission tomography departments. Low dose computed tomography protocols, justification of diagnostic and multiphase computed tomography protocols, application of tube current modulation system and modern reconstruction algorithms, education and training of the staff in the field of radiation protection should be used for optimization of radiation protection of patient. 

One of the important stages of risk communication is the analysis of publications in traditional media and the Internet, which largely shape people’s attitudes to various issues. At the same time, the availability of large amounts of information relating to any subject area complicates the possibility of manual analysis and adequate description of all of the information. On the other hand, the availability of information causes the urgency of developing methods to improve the effectiveness of its analysis. One way to automate the analysis of large amounts of information is the development of databases or automated information systems containing information materials on the subject matter under study and suggesting the possibility of automated processing. The objective of this work is to analyze the experience of developing such systems and databases by the research teams of the St. Petersburg Institute of Radiation Hygiene and St. Petersburg State University and to identify key features of the use of bases Data for social research. The results of the analysis showed that the methodological approaches used were very close. The analysis is performed according to the method of autoethnographical research. The strategy application of the comparative analysis allows identifying common features characterizing the situation of development and implementation of databases to practice of the risk communication studies. The article discusses the features associated with them, the limitations of the primary data, such as text, discursive nature of most of the materials, information noise, high dependence on context, variability, different structure, format and appearance of materials. The important parameters for solving problems of the qualitative and quantitative analysis are given in the article. An important condition of creating effective, from the point of view of socio-communication studies information system is to implement the processing capabilities of the collected social data available to researchers programs. The requirement for automation of certain functions depends on a high degree of uniqueness of the materials, which is overcome only by the manual pre- and post-processing, which must be considered when designing research programs.

Object: The purpose was to refine the quasi-biological model of the incidence of radiogenic solid cancer (published by the authors earlier in the journal “Radiation hygiene”) to ensure better consistency with the Japanese cohort data and with the ICRP model in part of the description of the effect of age at exposure.

Results: Initial presuppositions of a mathematical model was supplemented by the assumption that stem cells, received the “pre-cancerous” defect of DNA, with a higher probability compared to the intact cells follow the path of reproduction but not of differentiation. Structure of the refined model and its properties did not change, but one parameter was added. Analysis of the base mathematical relations of the supplemented model showed that there was no contradiction between the models of radiogenic cancer incidence presented in the Publication 103 ICRP and in the UNSCEAR 2006, despite their external differences.

Conclusion: Further work with the model requires the verification of parameter values by comparison with the epidemiological data, primarily with data on the incidence of solid cancers in the Japanese cohort. However, since some of the assumptions of the model, including the new one, are not purely radiobiological, it would require analysis of a wider range of biological and cancer patterns.

The study of deviations in health status of children whose parents were exposed to radiation on production enterprise is important for radiation safety of people of reproductive age and their subsequent generations.

The purpose of the study: the analysis of endocrine-metabolic pathology in the offspring of female workers of nuclear production, which had accumulated preconceptual doses of external gamma-irradiation.

Material and methods: Retrospective data analysis of medical records of 650 children under 15 years old was carried out, 130 of whom were the offspring of mothers exposed to radiation in the workplace. Methods of nonparametric statistics were applied. To identify latent factors, factor analysis by the main component method was used.

Results: The range of preconceptive doses of external gamma irradiation to mothers’ gonads was 0.09–3523.7 mGy, the average absorbed dose for gonads was 423.2±52.2 mGy. The structure of the class «Endocrine, nutritional and metabolic diseases» among the descendants of irradiated and intact mothers did not significantly differ. There was predominance of rickets, malnutrition among infants in both groups. Iodine-deficiency-related thyroid disorders were most frequently recorded in the structure of thyroid gland diseases without statistically significant differences in the groups. The gender dependence was noted: endocrine-metabolic pathology occurred in girls by 1.8 times more often than among boys. Frequent occurrence of polypathies and secondary endocrine pathology were indicated in the group of children of irradiated mothers. Factor analysis in study group identified four factors characterizing the antenatal period in children (19.4% of the variance), obstetric-gynecologic anamnesis (14.1% of the variance), mothers’ bad health habits (10.6% of the variance) and preconceptional external gamma-radiation exposure of female workers (9.6% of the variance).

Conclusion: The features identified in the analysis of endocrine-metabolic pathology in offspring of irradiated mothers may be useful for medical monitoring of children health status in this risk group. Increase in the observation period and in the number of children whose mothers were exposed to radiation in the workplace is necessary for further epidemiological study of the parental exposure contribution to postnatal pathology in the offspring.

The article focuses on the procedure for exemption of the sealed and unsealed radionuclide sources of gamma radiation from regulatory control. The contradictory nature of the existing set of exemption criteria has been noted, leading, in some cases, to paradoxical situations. It is shown that the exempt activity values determined in NRB-99/2009 and in the international basic safety standards of the IAEA are significantly overestimated (in comparison with the activity values of a point source creating the ambient dose equivalent rate of 1 μSv / h at a distance of 0.1 m) for a number of the most widely used gamma-emitting radionuclides, including ²²Na, ⁵⁴Mn, ⁷⁵Se, ¹⁵2Eu and ¹⁵⁴Eu. It is proposed to revise the current values of exempt activity, bringing them in line with the dose rate criterion for the exempt of sealed radionuclide sources of gamma radiation, and to present them with one significant digit. The corrected values of exempt activity for  seven selected radionuclides are proposed for further use in the process of revision of the national radiation safety standards.

The Chernobyl accident in 1986 is one of the most large-scale radiation accidents in the world. It led to radioactive contamination of large areas in the European part of the Russian Federation and at the neighboring countries. Now, there are more than 4000 settlements with the total population of 1.5 million in the radioactively contaminated areas of the Russian Federation. The Bryansk region is the most intensely contaminated region. For example, the Krasnogorskiy district still has settlements with the level of soil contamination by cesium-137 exceeding 40 Ci/km². The regions of Tula, Kaluga and Orel are also significantly affected. In addition to these four regions, there are ten more regions with the radioactively contaminated settlements. After the Chernobyl accident, the affected areas were divided into zones of radioactive contamination. The attribution of the settlements to a particular zone is determined by the level of soil contamination with ¹³⁷Cs and by a value of the average annual effective dose that could be formed in the absence of: 1) active measures for radiation protection, and 2) self-limitation in consumption of the local food products. The main regulatory document on this issue is the Federal law № 1244-1 (dated May, 15 1991) “On the social protection of the citizens who have been exposed to radiation as a result of the accident at the Chernobyl nuclear power plant”. The law extends to the territories, where, since 1991: 1) the average annual effective dose for the population exceeds 1 mSv (the value of effective dose that could be formed in the absence of active radiation protection measures and self-limitation in consumption of the local food products); 2) soil surface contamination with cesium-137 exceeds 1 Ci/km².

The paper presents results of calculations of the average effective doses in 2017. The purpose was to use the dose values (SGED₉₀) in zonation of contaminated territories. Therefore, the calculations have been done under the assumption that the doses were formed in the absence of active radiation protection measures and self-limitation in consumption of the local food products. The dose to population, rather than the density of radioactive contamination of soil by ¹³⁷Cs, is the most objective characteristic of the actual radiation exposure to the residents of the contaminated areas.