Reducing radiation exposure in computed tomography is a relevant medical task due to the growing number of studies and the lack of generally accepted approaches to their conduct in the radiological community. One way to reduce the effective dose in contrast-enhanced computed tomography of the abdomen is to optimize the protocol of examination, which can include four scans: in the native, arterial, venous and delayed phases. However while providing repeated studies in patients with oncological diseases, it is possible to confine one or two phases, which will allow the radiologist to visualize observed pathological changes and to evaluate the response to the treatment, as well as detect the recurrence in case of the monitoring of the patients. In the present study, two groups were formed on the basis of a sample of 514 patients. In group 1 (control), CTB was performed according to a three- or four-phase protocol. In group 2, the same patients with an interval from 1 to 5.5 months were performed with computed tomography -OBP according to a single or two-phase protocol depending on the degree of vascularization of the tumor tissue and the clinical situation. At the same time, a decrease in the average effective dose in patients in group 2 compared with group 1 was demonstrated by 63% (p<0.05). In all cases, the various pathological changes that characterize the oncological process and were diagnosed with a three- or four-phase protocol were visualized with a single- or two-phase protocol. Thus, the informative value of computed tomography examination did not decrease.

The aim of the work is the radiation-hygienic assessment of ⁹⁰Sr and  ¹³⁷Cs content in fish of the Ob-Irtysh river system and the study of the basic laws of the radionuclides accumulation in the ichthyofauna of these rivers. To perform this task, long-term results of radioecological studies of fish from the Techa, Irtysh and Ob rivers for the period 2004-2016 were used. Fish as a food product was evaluated according to two criteria: a) permissible levels of radionuclides specific activity (SanPiN 2.3.2.1078-01); b) using the indicator of conformity В and uncertainty of its definition ΔВ (GOST 32161-2013 and GOST 32163-2013). It is shown that a higher content of radionuclides is observed in the ichthyofauna of the Techa river (1379.1 Bq/kg for ⁹⁰Sr and 41.9 Bq/kg for ¹³⁷Cs). On the Ob and Irtysh rivers, the average specific activity of radionuclides in fish was significantly lower and slightly changed during the surveyed area: for ⁹⁰Sr in the range of 6.0 ÷ 8.1 Bq/kg (mean 6.8), for ¹³⁷Cs – 0.6 ÷ 1.9 Bq/kg (mean 1.3). Assessment for compliance with radiation safety criteria using the indicator of compliance and its uncertainty (В+ΔВ) confirmed the unsuitability of use for food purposes by the radiation factor of all studied fish species from the Techa river (45÷55 >1). Fish from all other studied areas of the Ob-Irtysh river system can be used for food without restrictions (0,06÷0,53 < 1). The distribution of ⁹⁰Sr and ¹³⁷Cs in the ichthyofauna of the Ob-Irtysh river system part over a 2400 km is presented in the form of empirical regression models. The models describe a sharp decrease in the radionuclides specific activity in fish in the Techa and Iset rivers by two orders for ⁹⁰Sr (from 2000 to 20 Bq/kg), and by one order for ¹³⁷Cs (from 40 to 2 Bq/kg). With a high degree of reliability (R²>0.86 for ⁹⁰Sr and R²>0.92 for ¹³⁷Cs), the presence of power relationships between the content of radionuclides in the ichthyofauna and their content in water was shown, with adequacy confirmed by Fisher’s F-criteria. This can be used for a preliminary assessment of the radionuclides level in fish based on the results of measurements of the average annual concentrations of these radionuclides in water.

Vertical distribution of natural and man-made radionuclides in the soil profile is a decisive parameter when calculating the dose rate of gamma radiation in the air above the ground and the effective dose of external human exposure. The main purpose of this work was to determine vertical distribution of ¹³⁷Cs in soddy-podzolic sandy and sandy-loam soils in forests and grasslands in the south-western districts of the Bryansk region in the remote period after the Chernobyl accident. In 2015–2016, soil cores were sampled in 7 virgin meadows and 13 forested areas to a depth of 20 cm. The cores were cut into horizontal layers 2 cm thick. The ¹³⁷Cs activity in the samples was determined using a semiconductor gamma spectrometer. The activity concentration in samples of dry soil (n = 200) ranged from 6.35 Bq/kg to 83300 Bq/kg with an average of 4550 Bq/kg. In the meadows in three cases, the maximum activity concentration was determined in the uppermost layer. With increasing depth, the activity concentration decreased and reached a minimum in the deepest layers. A difference between the surface layer and the deepest layer was two to three orders of magnitude. The three other meadows showed a relatively uniform distribution of ¹³⁷Cs in the upper 4–6 cm, followed by a decrease in activity concentration with an increase in depth. In one meadow area, a peak of the ¹³⁷Cs activity was found at a depth of 4–6 cm. In the forest, the most typical (in 10 cases) was the presence of a pronounced maximum activity concentration of ¹³⁷Cs in the uppermost layer. The experimentally obtained values of the ¹³⁷Cs inventory in the upper 20 cm of soil at the surveyed sites ranged from 42 to 1940 kBq/m². The values of ¹³⁷Cs inventory positively and statistically significantly correlated with officially established levels of ¹³⁷Cs surface ground contamination for the territory of nearby settlements. Vertical migration of ¹³⁷Cs in the soil in the surveyed areas was mainly limited to the upper 10 centimeters. The layer on average contained 94% of the total ¹³⁷Cs inventory. Less than 1% of the total ¹³⁷Cs inventory was found in the deepest soil layer sampled (18–20 cm). The obtained ¹³⁷Сs activity distributions were used to calculate kerma rate in the air at a height of 1 m above the ground at the surveyed sites. The air kerma rate ranged from 52 to 2240 nGy/h (on average, 807 nGy/h). The caesium-137 deposit in the upper 6 cm of soil determined about 95% and 90% of the air kerma rate in the forests and in meadows, respectively. Radioactive caesium, which migrated into the soil to a depth of more than 10–12 cm, gave a negligible contribution (less than 1%) to the gamma-radiation dose rate in the air. In practical terms, it indicates that the depth of soil sampling equal to 20 cm is currently quite sufficient to estimate the dose rate of gamma radiation in the air in virgin grasslands and in forests.

Objectives. To create the model of relation between volume activity of tritium in urine of Ozyorsk residents and physical and biological factors. To define the correspondence of internal exposure doses of Ozyorsk residents obtained from tritium to standards and requirements of present-day radiation security system. In the framework of the objectives the following tasks were solved: measurement of volume activity of tritium in the urine; detection of main factors affecting the volume activity of tritium in the urine; estimation of the distribution of committed effective dose equivalent of internal exposure due to tritium intake in 2016 among Ozyorsk residents under stable radiation environment.

Material and methods. 30 samples of urine were taken from resident of Ozyorsk Chelyabinsk region never employed at the Mayak Production Association in 2016. Measurement of tritium volume activity in the urine was performed using up-to-date ultra low level beta spectrometer Quantulus-1220. A questionary was developed that allowed collection of individual data on the water intake regime, on the occupational activity and the living conditions of people under study. Statistical processing was performed using software Excel-2013 and R. In order to develop models of dependency of tritium volume activity in urine of the residents from continuous and/or category variables we used correlation and regression methods of analysis. In order to compare two samples by mean value of tritium volume activity Student t-criterion was used. In order to verify normality of dose distribution Shapiro-Wilk test was used.

Results. Volume activity of tritium in urine of adult Ozyorsk residents in 2016 was in average 18.5 ± 1.1 Bq/dm³, volume activity of tritium in urine of children – 12.6 ± 2.3 Bq/dm³ in average. Major statistical characteristics of estimates of committed effective dose equivalent from tritium in Ozyorsk residents due to intake on 2016 under stable radiation environment obtained from a sample of 30 individuals were the following: minimum value made 0.07 µSv, mean value was 0.27 µSv, coefficient of variation made 36%, maximum value made 0.49 µSv. A model of dependence of tritium volume activity in urine of Ozyorsk residents from the water supply source was obtained.

Conclusions. Estimates of committed effective dose equivalent of internal exposure from tritium among Ozyorsk residents due to intake in 2016 made: mean value of committed effective dose equivalent was 0.027 and maximum value made 0.05% from the annual effective dose limit for residents under unifactor tritium intake. In 2016, the levels of tritium volume activity in the bodies of adult and children population of Ozyorsk city depended on volume activity of tritium in drinking water supply sourced more than on the age. As of 2016, under stable radiation environment at Mayak Production Association, tritium did not pose any threat for Ozyorsk population.

Publications of the IAEA, ICRP, the Decree of the President of the Russian Federation of October 13, 2018 No. 585 “On the Approval of the Basic Principles of State Policy of the Russian Federation in the Field of Nuclear and Radiation Safety until 2025 and beyond” emphasize the increasing role of public in decision-making in the use of ionizing radiation. Sociological research is a part of the preparatory stage in the organization of interaction with stakeholders. During that stage, the participants in the information interaction (stakeholders) have an opportunity to study each other’s attitudes, so that the interaction is as constructive as possible. Sociological studies allow to determine the positions of stakeholders on the subject of risk communication at the initial stage of the process, in the implementation of decisions and in assessing the effectiveness of risk communication. The basis of the sociological study is the program. In forming a sociological research program, it is necessary to pre-identify important factors that can influence the attitude to a particular management decision of different stakeholders. The main purpose of the sociological research is to study the range of opinions and features of perception of the planned management decision by various participants in the process of risk communication. In assessing sociological research, one of the main tasks is to determine the nature of possible contradictions in the positions of the stakeholders, which largely determines the willingness of the interested parties to dialogue. In the consensus risk communication, the results of sociological research are useful in the formation of three sections of information materials: general information about the event, benefit assessment, and threat assessment.

The article provides data on the radiation situation on the research of the year 2018 territory adjacent to the site of the peaceful nuclear explosion “Globus-1” after carrying out rehabilitation works (2014-2015), made with the purpose of removal accidental contamination. We analyzed the dynamics of radiation situation during the period from 2008 to 2018 year and assessed the effectiveness of rehabilitation works on basic indicators: the values of the dose of technogenic radionuclides content in soil, water and other objects the environment. According to the results of comparing the number of measurements exceeding the dose rate of 50 nSv/h (background value for outside contamination 2014 years) in samples of 2014 and 2018 years found that 80% of exceedances, enshrined in the year 2014, percentage of exceedances in 2018 year amounted to only 3%. Another performance indicator associated with the feature to the rehabilitation of this object. A large number of low level activity in soil was inappropriate to remove the burial and the decision to use the ground as a lower layer of reclamation was justified. Research has shown that in the spectral composition of gamma background rehabilitated territory intensity peaks of caesium-137 is many times greater than background levels. In selected soil samples recorded elevated levels of cesium-137 (up to 32500 Bq/kg on wet weight), and collected on such soil samples of herbs have elevated concentrations of cesium-137 (up to 2000 Bq/kg) and strontium-90 (up to 400 Bq/kg)on the dry weight basis. All elevated levels of activity concentration of cesium-137 were found in local areas, within the path of radioactive contamination, selected in year 2014. After carrying out rehabilitation work there has been a significant decrease in the levels of external radiation man-made radionuclides and on formal grounds completed rehabilitation work provided the requirement of Russian Safety Norms 2.6.1. 2819-10 and radiation dose does not exceed 0.3 mSv/year, however, high dose rate recorded in separate locations on the recultivated territories indicate incomplete and insufficient as completed rehabilitation.

The purpose of the study is to evaluate the effective doses of patients for the most common radiographic dental studies, comparing the obtained data with the literature and reference values given in the guidelines “Filling in the forms of the federal state statistical observation No. 3-DOZ” and are still often used for form filling instead of measured values. In the framework of this work in 2016-2018, 44 X-ray units were examined at 37 dental medical facilities in St. Petersburg and the Leningrad Region. Seven radiographic studies were included: radiographs of three groups of teeth (incisors, premolars, and molars) for the upper and lower jaw and bite radiography. Physical-technical and geometrical parameters were collected for selected types of the standard patient studies: X-ray tube voltages, total filtration, radiation output, combination of the time and the current of exposure or the exposure, area of the study, size of the irradiation field; the focal length. Further, the input (surface) dose was calculated from the radiation output of the device. Then, based on the initial information about the parameters of the procedures and the input dose, the absorbed doses and the effective dose were calculated using the PCXMC program. For most devices, the dose values are in the range of 0.5 to 10.7 µSv, which is significantly lower than the values used to fill in the 3-DOS form. The results of evaluating the effective dose for these devices are fairly homogeneous, but on one device, there were doses exceeding not only the values of doses on other devices, but also the values from the recommendations for 3-DOS for devices with digital receivers, as well as those approaching similar values for film devices. An almost linear dependence of the effective dose on the exposure time was established, while a similar dependence on the voltage on the X-ray tube was not found. The median value of the effective dose for the units with films detectors was 3.2 µSv for the maxillary incisors, 3.8 µSv for the maxillary premolars, 6.8 µSv for the maxillary molars, and for the mandibular incisors, premolars and molars – 3.2, 3.4 and 5.8 µSv, and for bitewing – 6.7 µSv. For the unit with digital detectors, effective doses were 1 µSv, 1,2 µSv, 2,2 µSv for maxilla, 1 µSv, 1,3 µSv, 2 µSv for mandibula and 2,8 µSv for bitewing. Attention is drawn to the substantial width of the ranges without emissions for the examination of premolars of the upper jaw, molars of both jaws and occlusion, which is the reason for the possible enhancement of optimization measures in these studies. When comparing with published data, it was found that the effective doses in St. Petersburg and the regional institutions are lower than the values obtained using standard round collimator and medium and high sensitivity films (class D and F, respectively), as well as lower dose levels in the European Commission Guidelines. In addition, the dose values deduced in this study are significantly lower than the values given in the guidelines “Filling in the forms of federal state statistical observation No. 3-DOZ” and which are still often used to fill in the form instead of the measured values. This indicates an overestimation of estimates of patient doses when using reference values from the 3-DOZ manual and the need to use individual patient doses, obtained on the basis of measurements. However, the effective doses in St. Petersburg and the Leningrad Region are higher than those obtained using a square collimator and high-sensitivity films. The above results suggest that it is necessary and possible to carry out optimization in X-ray dental studies in St. Petersburg and the Leningrad Region. Analysis of similar studies on other X-ray diagnostic techniques allows to extrapolate this statement to other regions of Russia.

The paper presents the results of a refined calculation of the average individual annual effective doses to the population of the regions of Russia from exposure to the cosmic radiation. The population-weighted average values of the altitude and latitude of the main settlements, which are home to at least 50 percent of the population of the region, were used as the altitude and latitude of the region. In addition, all settlements with a population of at least 20 thousand people were included in the calculation. Coverage of the population of the regions of Russia in the calculation varies from 50.1 to 95.8 percent (excluding three cities of Federal importance with 100 percent coverage) with the average value of 62.4 percent. The number of settlements included in the calculation in different regions ranges from 1 to 63. The methodology of the dose calculation is based on the approach described in the UNSCEAR 2000 Report. The obtained dose values for different regions range from 0.310 to 0.413 mSv. For Russia as a whole country, the population-weighted average individual annual effective dose from exposure to the cosmic radiation is 0.338 mSv.

A review of literature data regarding the heritable effects in offspring due to parents’ contact with mutagenic risk factors is presented. Studies on various factors of adverse effects on the hereditary apparatus, including chemical, infectious, physical and biological, are considered. The influence of smoking and parents’ age on the occurrence of de novo mutations is shown. Particular attention is paid to the review of publications on the role of the radiation factor in the genesis of hereditary disorders in offspring. Development stages of radiation genetics, the evolution of conception about radiation harm are described. The results of experimental, cytogenetic, molecular genetic, epidemiological studies analyzing the contribution of parental exposure to inherited pathology in progeny are presented. Special attention is paid to the “untargeted” effects of radiation and studies which prove the possibility of transgenerative transmission of genome instability are presented. The special contribution of studies on the cohort of atomic bomb victims offspring in Hiroshima and Nagasaki, which is considered as the main scientific platform for radiation risk assessment, is noted. There are articles about the offspring of persons who underwent therapeutic exposure, who had professional contact with ionizing radiation, who were exposed to radiation as a result of the Chernobyl accident, nuclear weapons tests at the Semipalatinsk test site, chronic radiation in the radioactively contaminated territory of the Techa river, areas with naturally increased radioactivity. As a result, it was noted that, despite numerous confirmations of radiation-induced effects in offspring obtained within experimental and molecular genetic studies, the results of epidemiological studies remain controversial. Possible reasons for these discrepancies are considered. An idea of views evolution regarding heritable effects in the international system of radiation safety is given. A new approach of the International Commission on Radiological Protection to heritable effects is described; the dynamics of tissue weighting factors for gonads in the assessment of effective radiation dose is shown. Methods for evaluating heritable effects are presented: the direct method and the doubling dose method. Attention is focused on the uncertainties that remain in the modern assessment of radiation genetic damage. The necessity of further study of radiation-induced heritable effects is shown. The perspective directions of studying the heritable effects are considered. The possibility of the analysis of heritable effects is described using the example of a cohort of the Mayak Production Association workers’ offspring – the country’s first nuclear industry enterprise.

The article identifies areas of joint activities and mechanisms of interaction of Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor) and Federal Medical and Biology Agency (FMBA of Russia), their territorial bodies and institutions in the event of radiation accidents. Extensive practical experience gained by specialists of FMBA of Russia and Rospotrebnadzor, was the basis for the development of the draft of Concept “Organization of radiation and hygienic measures in emergency situations of a radiation nature and coordination the activities of forces and means of FMBA of Russia and Rospotrebnadzor organizations and institutions” (2018). The article presents the main provisions of the draft document, which, after discussion and refinement, as the authors hope, this publication will contribute, draft of Concept can be submitted for approval. The modern infrastructure of Rospotrebnadzor and FMBA of Russia has all the necessary elements and prerequisites for coordinated work of expert support groups, use of the mobile specialized radiation-hygienic teams in emergency situations. The possible types of radiation accidents that may require joint activities of the bodies and institutions of Rospotrebnadzor and FMBA of Russia are considered. In the initial period of a radiation accident in conditions of large uncertainties related to the assessment of the radiation situation and doses on personnel and the public, it is necessary to ensure operative preparedness of consolidated proposals on making decisions on a complex of sanitary, hygienic, anti-epidemic and protective measures. Much attention is paid to mutual notification and information interaction. An important element in ensuring emergency preparedness, working out algorithms of the interaction of management bodies and practical skills of the personnel of Rospotrebnadzor and FMBA of Russia is the joint planning, organization and conduct of training and exercises.

The paper presents the activities of Rospotrebnadzor to ensure radiation safety in the framework of nuclear and radiation terrorism counteractions during the FIFA World Cup 2018 in Russia. One of the main activities of Rospotrebnadzor was to ensure radiation safety of food and drinking water. This task was solved by placing stationary radiation monitoring systems and organizing of continuous radiation monitoring of all foodstuffs and drinking water incoming to all sports facilities. In addition, selective radiation monitoring of samples of cooked food and drinking water at the catering facilities of the stadiums was organized. The second important activity was to ensure the radiation safety at the sites of mass people crowding with the use of portable equipment and/or car-borne radiological laboratories. The third activity was the identification and examination of the identified sources of ionizing radiation in case of alarm of radiation monitoring systems. The last but not the least activity was the interdepartmental cooperation, the effectiveness of which directly affects the response and resolution of issues related to emergency situations or situations that threaten radiation safety. The paper also briefly described the activities of the Saint-Petersburg Research Institute of Radiation Hygiene after Professor P.V. Ramzaev in the framework of ensuring radiation safety at the FIFA World Cup 2018.

For the provision of the radiation safety of the public during the termination of the nuclear and radiation legacy within the boundaries of the Federal Targeted Program “Provision of the nuclear and radiation safety for 2016-2020 and up to 2030”, the following documents were developed: draft of the sanitary rules “Hygienic requirements for the remediation of the facilities and territories contaminated by man-made and natural radionuclides due to the past activities of the facilities of nuclear and non-nuclear branches of industry” and three methodical guidelines on the survey of the remediated territories, buildings and structures and assessment of the doses of the public residing in the zone of influence of the nuclear legacy facilities. The sanitary rules were based on the directions of the future use of the remediated territories, buildings and structures as well as on the radiation-hygienic safety criteria. It was assumed that dose criteria for the public considering the quota (0.3 mSv/year) is applied for remediated sites of the nuclear facilities (radiation facilities). The remediation of the radioactively contaminated areas with the residing public is based on the requirements of the Federal Law № 1244-1, 15.05.1991 “On the social protection of the citizens exposed due to the Chernobyl NPP accident”. Originally the drafts of documents were developed considering the approval in 2019 of the new Norms of the Radiation Safety – 2019, harmonized with the international recommendations and standards. Due to prolongation of the existing Norms of the Radiation Safety 99//2009 for the extra five years, the drafts of the regulations are adapted to the existing NRB 99/2009 and OSPORB 99/2010.

The current study was aimed at the justification and proposal of the supplements and corrections that are planned for the implementation in the updated version of the Methodical guidelines “Control of the effective doses of the patients from the X-ray examinations” (MU 2.6.1.2944-11). This study included estimation and/ or update of the values of the conversion coefficients from measurable dose characteristics (entrance-surface dose, dose-area product) to the effective dose for various X-ray examinations. Estimation of the updated conversion coefficients was based both on the home analytical and experimental studies based on the modern protocols of the X-ray examinations, and the results of the published data. Updated values of the conversion coefficients were presented for: fluoroscopic examinations of the gastro-intestinal tract with barium media for adult and pediatric patients; interventional examinations of the adult patients; computed tomography examinations for adult and pediatric patients; dental intraoral examinations. For the first time, the methods of the estimation of the effective dose and corresponding conversion coefficients were presented for: computed tomography of the extremities, whole body, scan of several anatomic regions; angiographic examinations of the heart vessels of the pediatric patients of different age categories; slot-scanning X-ray examinations; bone densitometry.