The article presents results of a study on the tritium content in surface and ground waters in the area of peaceful underground nuclear explosions of the “Dnepr” series. Low-yield thermonuclear explosions (1.8–2.1 kt of TNT equivalent) were carried out inside Mount Kuel’por (Khibiny Massif, Kola Peninsula, Murmansk Oblast, the Russian Federation) in 1972 and 1984. The purpose of the explosions was to crush the ore body (apatite minerals), followed by the extraction of the crushed rock to the ground surface. The main long-term problem generated by these explosions was the flow of tritium-contaminated groundwater onto the ground surface. The area where the explosions took place is actively visited by tourists. Water from local reservoirs, in particular from the Kuniyok River, is used by people for drinking. The purpose of this study was to assess the drinkability of the local waters in terms of activity concentration of tritium. To achieve this goal, 35 water samples were taken in 2019 from wells, boreholes, rivers, streams, lakes and other accessible environmental waterbodies. Activity concentration of tritium in the samples was determined using the Quantulus 1220 low-background liquid scintillation spectrometer. The activity concentration of tritium in the water samples was in a rather wide range: from less than 2 Bq/kg up to 1510 Bq/kg. The maximum value was up to three orders of magnitude higher than the regional background level of approximately 2 Bq/kg. At the same time, the maximum activity concentration was significantly lower compared to the intervention level for drinking water (7600 Bq/kg, according to Sanitary Norms and Rules of the Russian Federation). Based on the results of this study and data obtained by other researchers earlier, it became possible to assess the half-time for decrease of activity concentration of tritium in surface and ground waters in the period 2008–2019. The mean value (± standard error of the mean) of the effective half-time of tritium in water from the mine, the boreholes, and the Kuniyok River was estimated as 4.4 ± 0.2 year. The decrease in activity concentration of tritium in water depended more on ecological processes (dilution with “pure” water) than on physical decay of the radionuclide. In 2019, the estimated value of the effective dose due to ingestion of tritium in drinking water from the Kuniyok River was 0.17 μSv; this was negligible compared to the dose limit of 1 mSv per year for the public.

The objective of the current study was to assess the cancer mortality risk in the cohort of the exposed population on the territory of the East Urals Radioactive Trace over a 57-year follow-up period from 1957 to 2014 using individual doses. Materials and methods: At the end of September 1957 as a result of an accident in the cooling system of storage tanks with liquid radioactive waste, an explosion occurred on the territory of the Mayak PA which led to the formation of the East Urals Radioactive Trace. The population living in the contaminated settlements of the Chelyabinsk and Sverdlovsk regions has been affected by prolonged external and internal exposure. The cohort of individuals exposed in the territory of the East Urals Radioactive Trace numbers 21,384 people, of whom 2,055 persons had lived in Techa riverside settlements before the 1957 accident and received additional radiation exposure. The mean stomach dose for members of the East Urals Radioactive Trace cohort was 36 mGy, the maximum dose was 1130 mGy. The updated TRDS-2016 dosimetry system was used to assess individualized doses. Over the 57-year follow-up period of the cohort (1957-2014), 1294 deaths from cancer were registered in the catchment area. The number of person-years at risk was 511278. The analysis of the cancer mortality risk was carried out with the EPICURE statistical package using the Poisson regression method. Confidence intervals were calculated using the maximum likelihood method. Results: In the course of the cancer mortality analysis in the East Urals Radioactive Trace cohort over a 57-year period, a statistically significant excess relative risk of mortality per 100 mGy equal to 0.05 (95% CI: 0.002; 0.11, p = 0.04) was obtained in the entire East Urals Radioactive Trace cohort. If individuals who received additional exposure on the Techa River were excluded from the analysis, the value of the risk loses its statistical significance.

The objective of this work was to reveal the relations between thyroid pathology prevalence and absorbed thyroid radiation dose from ¹³¹I in the individuals relocated into Ozyorsk from the radioactively contaminated areas of South Urals. The sources of data for statistical analysis were the electronic database “Thyroid” containing clinical and laboratory data, and electronic database “The man and the environment” containing dosimetry information on irradiated individuals. Thyroid diseases and individual thyroid doses from all sources of ionizing radiation were collate for 195 persons relocated into Ozyorsk from the villages of the Techa riverside and of the territory of the East Ural Radioactive Trace. Statistical analysis of the data was performed using a software package (Excel, Statistica 6.1). The prevalence of thyroid nodules increased in relocated female statistically significantly 1.7 times (p=0.03) in the range of thyroid doses of 1000-1499 mGy and 2 times (p=0.003) in the range of doses of 1500–1999 mGy compared to this parameter at the doses below 1000 mGy. The prevalence of all thyroid abnormalities has been increased 1.5 times (p=0.007) in the range of thyroid doses of 1500-1999 mGy. An increased prevalence of thyroid diseases by 1.6 times (p=0.02) relative to non-irradiated persons was noted for relocated female whose age at the time of the medical examination was less than 60 years only. A significant number of risk factors requires the use the multivariate statistical analysis to assess their contribution for the development of thyroid pathology in the individuals residing in childhood in radioactively contaminated areas.

In this work, the results of radon concentration measurements in samples of multi-storey apartment buildings in eight large cities of Russia are analyzed. Two samples, depending on the year of construction of the building – before and after 2000, were formed in each city on the basis of a quasi-random approach. Radon concentration measurements were performed using radon radiometers equipped with the CR-39 solid-state nuclear track detector. In the flats of multi-storey buildings, two radiometers were installed and flat’s average radon concentration was calculated. The exposure period for the radon radiometers was three months. To estimate the average annual radon concentration, seasonal coefficients calculated for the primary radon entry from building materials were used. In total, radon concentration measurements were carried out in 1032 flats. It was assumed that the combined sample for the cities of Ekaterinburg, Krasnodar, Nizhny Novgorod, Novosibirsk, Tyumen, and Chelyabinsk is representative for the multi-storey buildings in non-capital cities of Russia. The following arithmetic mean annual radon concentrations were obtained in samples of houses built up before and after 2000, respectively: Moscow – 17 and 21 Bq/m³; St. Petersburg – 15 and 25 Bq/ m³, the group of non-capital cities – 25 and 31 Bq/m³. Taking into account the contribution of each group of buildings to the general urban housing stock, the parameters characterizing the radon concentration in multi-storey multi-apartment urban buildings in Russia were calculated as follows: arithmetic mean 25 Bq/ m³; geometric mean 21 Bq/m³; the geometric standard deviation is 1.81. In general, exposure to indoor radon in multi-storey urban buildings in Russia is low both in terms of average value and range of concentrations. There is a tendency towards an increase in indoor radon exposure of the population in new buildings, which is associated with the introduction of construction technologies that increase the energy efficiency of buildings.

The aim of the study was to develop a methodology that allows taking into account the age and sex dependencies of the risk of radiogenic cancer and the age and sex distribution of the patients to evaluate the collective risk due to separate X-ray examinations and medical exposure in the Russian Federation as a whole. Methodology is based on the use of lifetime risk coefficients estimated for the Russian and Composite population and the results of the study of typical doses of patients for various X-ray examinations in the Russian Federation. It is shown that the assessment of the radiation risk of separate X-ray examinations calculated using lifetime age and sex risk coefficients, organ doses and age distributions of patients may differ up to order of magnitude from the risk assessment based on effective dose and nominal risk coefficients. The difference in estimating of the collective risk of total medical exposure in the Russian Federation by these two methods reached 2.5 times in 2018.

The scientific article is devoted to the actual problem of modern medicine – the exposure of the public during multislice spiral computed tomography in the Republic of Uzbekistan. For the period 2017-2020 the number of computed tomography procedures increased from 175000 to 375000 (by a factor of 2), there was an increase in the collective dose from computed tomography from 987,5 to 2482,6 man-Sv (2.5 times). During the study the patient effective doses were calculated and the risks were assessed. The research work was carried out in medical institutions on CT units from different vendors. The examination protocols of 1126 adult patients were analyzed. The patient effective doses during MSCT of various anatomical regions were calculated from the DLP value and their comparative assessment was carried out. The radiation risk assessment was carried out on the basis of the effective dose using the nominal ICRP risk coefficients adjusted for age-related radiosensitivity. According to the results of the studies, it was found that when examining the head area, the effective doses of patients ranged from 1.3 ± 0.3 to 1.9 ± 0.2 mSv, the neck area – from 1.3 ± 0.3 to 2.4 ±0.3 mSv, the chest area – from 5.3 ± 0.7 to 6.6 ± 1,9 mSv, abdomen – from 7.0 ± 1.0 to 8.8 ± 1.6 mSv, small pelvis – from 7.8 ± 1.0 to 10.8 ± 2.5 mSv. The lifetime risk of long-term stochastic effects for the health of a patient from 18 to 65 years old was in the range of 10^-4 – 10^-3. The results of the study showed that the effective doses differ significantly from each other depending on the anatomical area of study of the patients. A person receives the highest doses of radiation when examining the pelvic and abdominal area, and smaller ones when examining the head area. The difference in the values of effective doses in the study of the same anatomical parts of the human body mainly depended on the weight of the patients, the length of the studied anatomical area, the model of the computer tomograph.

The aim of the study is to assess the radioactive contamination of medicinal plants of economic types of meadow ecosystems of the Sozh River floodplain. The objects of the study were medicinal plants of the floodplain of the Sozh River. Soil samples and plant samples were taken for radiological analysis within the boundaries of the selected economic types of meadows. Determination of ¹³⁷Cs content in soil and plant samples was carried out on the Tennelec. Characteristics of the selected economic types of meadows. 12 species of medicinal plants were analyzed on each type of meadow. In the meadow large-sedimented type, the specific activity of soils in 2015 amounted to 1600 Bq/kg, and in 2020 – 1380 Bq/kg. Radiological analysis of the specific activity of aboveground phytomass in 2015 and 2020 showed that all plant samples did not exceed the republican permissible level of ¹³⁷Cs content in medicinal technical raw materials – 370 Bq/kg, with the exception of the pure Stahyis palustris swamp, the permissible level of which was 10 Bq/kg higher. In the turf type of meadows, the specific activity of soils in 2015 was 116 Bq/kg, and in 2020 – 970 Bq/kg. In this type of meadow, all plant samples did not exceed the permissible level of ¹³⁷Cs. In the meadow coarse-grained type, the specific activity of soils in 2015 was 1380 Bq/kg, and in 2020 – 1150 Bq/kg. In 2015 and in 2020 all plant samples corresponded to the permissible level of ¹³⁷Cs content, only in the meadow foxtail in 2015 the specific activity exceeded the permissible level by 155 Bq/kg. In the fine-grained type of meadows, the specific activity of soils in 2015 was 962 Bq/kg, and in 2020 – 704 Bq/kg. Both in 2015 and in 2020, the specific activity of all plant samples was below the permissible level. A comparative analysis of the specific activity of medicinal plants of the studied economic types of meadows shows that in 2020, compared to 2015, has decreased by an average of 1,3 – 1,4 times, the greatest specific activity of plant samples over the years of observation was observed in the meadow type with large leaves, which is 4 times more than in a fine-grained meadow. The decrease in radioactive contamination of medicinal plants occurred with a simultaneous decrease in the density of radioactive contamination of the soil.

After the publication of ICRP Publication 103 in 2007 and IAEA Basic Safety Standard “Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards. General safety requirements Part 3” in 2014, there is an ongoing process in the Russian Federation on the harmonization of the norms of the radiation safety and basic rules on the provision of the radiation safety with the international requirements. According to the Decree of the President of the Russian Federation № 585 “On the establishment of the basis of the governmental policy in the field of the provision of nuclear and radiation safety in the Russian Federation in the period up to 2025 and the future perspective” and the Plan of the execution of the “basis of the governmental policy…”, approved by the Decree of the Government of the Russian Federation №139-r, 02.02.2019, a work has been initiated on the development of the changes and additions into the Federal State Laws № 170-FZ “On the use of the nuclear energy” and № 3-FZ “On the radiation safety of the public”. For the successful execution of the mission it is necessary to develop joint inter-agency workgroups with the parallel development of the changes and additions to the № 170-FZ. №3-FZ, NRB and OSPORB.

A system of acquisition of information on indoor radon concentration was developed. The system is based on the transfer of devices for integral and/or quasi-integral measurements of radon concentration to the owner of the premises and the exchange of necessary information about the conditions and measurement results between the owner and the measuring laboratory using modern online technology. The information support system implemented on the website and the use of mobile communication technologies are designed to attract additional measurement participants and expand the range of objects available for surveys. At the same time, intermediaries between the measuring laboratory and the owner of the premises are excluded. The use of cloud technologies makes it possible to optimize the exchange of information between participants, and the use of QR codes on detectors eliminates errors associated with the identification of the detector and its coordinate reference to the measurement point. The software modules used in the system automate the process of entering this information. It is assumed that devices with a track detector will be used as the main ones. It is also possible to use carbon-adsorption samplers, but only for measurements in settlements, from which delivery to the processing laboratory is possible within no more than one day. Testing of the possibility of practical use of the system by persons who are not specialists in the field of radiation control was carried out on examples of a small and large settlement (the village of Kochubeyevskaya and the city of Pyatigorsk, Stavropol Krai). In general, the testing showed the operability of the system. As a result, changes were made to the system: the size of QR codes was increased and their color palette was changed, and the supporting system was supplemented with information on entering the editing mode without a QR code. From a social point of view, the system provides economically affordable services for most citizens to determine the level of radon exposure in the air of residential, public and other buildings. At the same time, in the future, significant savings are achieved in budget allocations required to create a potential radon risk map of the country.

At the 2018 FIFA World Cup held in our country, great attention was paid to ensuring radiation safety. When holding mass events, there are risks of terrorist attacks that need to be taken into account. Therefore, the use of radiation monitoring systems during this period is primarily aimed at countering radiation terrorism. This article reviews the equipment and personnel of the Rospotrebnadzor radiation control laboratories in the regions of the Russian Federation that participated in the 2018 FIFA World Cup for readiness to perform the task of responding to cases of activation of radiation control systems. In addition, a comparative description of the radiation monitoring systems used during the 2018 FIFA World Cup and the experience of their operation at pedestrian inspection points located on the border of the security perimeter of stadiums are provided.

As a part of administrative reform and “regulatory guillotine” in Russia in 2020-2021, several significant changes in the governmental regulation of dental care have occurred: implementation of new version of Order of provision of dental care and infrastructure of governmental dental facilities; approval of Rules of carrying of X-ray examinations; development of changes in the sanitary-epidemiological requirements to medical facilities. Meanwhile, the requirements on the radiation safety in the medical facilities remained the same. The lack of coordination during the development of new documents between the Ministry of Healthcare and Rospotrebnadzor resulted in preservation of the existing problems with the use of X-ray equipment in dentistry (for example, related to the allocation of dental X-ray units in residual and public buildings) and appearance of new problems (for example, removal of a requirement for the license in radiology for dentists). The study is focused on the analysis of the issues of regulation of the provision of radiation safety for dental care of public of the Russian Federation. It includes a review of the acting regulatory documents of the Ministry of Healthcare and Rospotrebnadzor, regulating the allocation of dental X-ray units and provision of dental X-ray examinations, with subsequent identification of the major issues and problems. The results of the study indicate that changes in the regulatory documents of the Ministry of Healthcare implemented in 2020-2021 contradict the acting requirements on radiation safety. It is necessary to further improve the legislative base regulating the dental care: harmonization of the acting requirements on the equipment of the dental rooms, orders and standards of dental care, training of staff. The harmonized base should result in a provision of qualitative dental care and radiation safety.

Today, the treatment of cancer with the use of radiopharmaceuticals is a developing method all over the world. The preparation of the radiopharmaceuticals and its quality control prior to its administration to the patient is one of the important elements of nuclear medicine procedures. The instability of the compound can lead to a change in the distribution of the radionuclide in the patient’s body, a decrease in the effectiveness of treatment, as well as to unjustified irradiation of healthy organs and tissues. The aim of this work was to estimate the absorbed doses in human organs and tissues during radionuclide therapy using ²²⁵Ac for the case of the ²²⁵Ac release. The absorbed doses were calculated for the model presented in ICRP Publication 141 for healthy people. This model consists of 18 cameras (blood, cortical volume, cortical surface, cortical red bone marrow, trabecular volume, trabecular surface, trabecular red bone marrow, kidneys (two chambers), bladder, liver (two chambers), gonads, contents of the small intestine, contents of the upper large intestine, soft tissues. Time-integrated activities were calculated using the specialized software SAAM II v2.3. The calculation of absorbed doses was performed using the IDAC-Dose 2.1 software. The highest absorbed doses were obtained for liver, testes, ovaries and red bone marrow, which leads to an increase in doses in these organs in comparison with doses from 225Ac-PSMA up to a factor of two. A change in the biodistribution of ²²⁵Ac in a patient’s body, associated with the release of a radionuclide from the radiopharmaceuticals, can lead to an increase in doses in healthy radiosensitive organs and tissues, as well as to a decrease in the effectiveness of treatment.