To date, the study of the effects of chronic exposure of the South Ural population has been carried out in two separate cohorts – in the Techa River Cohort and in the East Urals Radioactive Trace Cohort. In 2019, the Ural cohort of accidentally exposed population was formed. It included the population exposed in two radiation situations in the Southern Urals in the 1950s. The number of the combined cohort for the cancer incidence analysis was about 60 thousand people, the follow-up period was extended to 2017, the number of solid cancers was 4537, and the number of person-years was 1283267, which is 3 times more than when analyzing the effects of exposure in each of the two radiation situations separately. In the incidence analysis of all solid cancer types, we used the dose accumulated in the walls of the stomach, which corresponds to the dose accumulated in most organs and tissues with the exception of bone tissue and red bone marrow. The mean dose to the stomach accumulated over the entire follow-up period for cohort members was 38 mGy, the maximum -1.13 Gy. The paper presents the first results of solid cancer incidence risk analysis in the combined cohort, which show a statistically significant dose dependence of the incidence in case of chronic exposure in the range of low and medium doses. The sex and age-averaged excess relative risk value of 0.075/100 mGy (the 95% confidence interval is 0.039–0.113) is comparable to that obtained in the studies of the Japanese cohort of atomic bomb survivors. The statistically significant excess relative risk value of 0.047/100 mGy, obtained separately for men, is in good agreement with that in professional cohorts where men prevail – in the cohort of the Chernobyl NPP accident clean-up workers and in the cohort of professional workers in the three countries (UK, France, USA). The established cohort with a long follow-up period has a great potential for furthermore detailed studies of the effects of radiation and non-radiation factors on public health.

Colorectal cancer is one of the most common malignant neoplasms. Main causes inducing this type of cancer are factors related to the life style and occupational exposures to chemical agents. Some studies demonstrated an association of colorectal cancer incidence and mortality with ionizing radiation. The aim of the present study was to assess the trend in colorectal cancer incidence in a cohort of nuclear workers employed at the Mayak Production Association who had been exposed to ionizing radiation over prolonged periods. The cohort comprised 22,377 workers (25% of females) employed at one of the main plants (reactors, radiochemical and plutonium production plants) of the Mayak Production Association in 1948-1982 who had been externally exposed to gamma rays (cumulative absorbed colon doses were 0–5.85 Gy with the corresponding median dose of 0.16 Gy) and those who had inhaled aerosols containing plutonium particles had been also internally exposed to alpha radiation (cumulative absorbed colon doses were 0–0.18 Gy with the corresponding median dose of 0.0002 Gy). Over the period of 1948–2018, 239 colon cancers and 186 rectum cancers were diagnosed in the study cohort. The incidence of colorectal malignancies among workers of the study cohort was shown to increase with age above 50. Age-standardized incidence rates were higher in males than in females. The time trend analysis of age-standardized rates of colorectal malignancies among workers of the study cohort was performed using a spline regression. The trend of age-standardized rates of colorectal cancer incidence in the Mayak Production Association workers over the analyzed period was nonmonotonic. In general, the average annual percent change of incidence growth for colon cancer was less than 0.1% (for both sexes), while the corresponding estimates for rectum cancer were 1.1% in males and 30.3% in females. To assess the effect of occupational radiation exposure on the incidence of colorectal malignancies, a radiogenic risk analysis that would take into account non-radiation risk factors should be performed.

This paper is part of a research cycle focusing on studying the current levels of  ²⁴¹Am and ¹³⁷Cs in soils and local foodstuffs of populated areas neighboring the Chernobyl exclusion zone. Our objective was to estimate the maximum annual committed internal doses to individuals of the Bragin-area settlements from inhalation and consumption of locally produced foods. We updated the data on the levels of  ²⁴¹Am and ¹³⁷Сs in soils of 28 settlements of the district. Specific activity of  ²⁴¹Am in soils in two of the settlements were the highest of all; we took and analyzed samples of local-grown foodstuff.  ²⁴¹Am in food samples was measured via a radiochemical method with the use of selective chromatographic resins and alpha-spectrometry measurement. A gammaspectrometry technique was used to measure  ²⁴¹Am in soil and ¹³⁷Сs in soil and food samples. The most contaminated by  ²⁴¹Am and ¹³⁷Cs appeared the soils in the town of Bragin, the administrative center of the district where the respective levels were as high as 2.8 and 560 kBq/m2. Among the analyzed samples, the specific activities of  ²⁴¹Am in root and tuber crops were one-digit values, while the samples of leafy vegetables contained a few tens of mBq/kg of the same radionuclide. That said, however,  ²⁴¹Am concentrations in food samples were lower than those of ¹³⁷Сs by three orders of magnitude. The results showed an apparent difference between estimated annual committed internal doses to the Bragin residents due to  ²⁴¹Am intake and that resulting from ¹³⁷Сs with the respective 0.03 and 1.7 mSv/year. The maximum doses to population of the Bragin-district villages from inhalation of  ²⁴¹Am varied from 0.006 to 0.033 mSv/year exceeding the doses from inhaled ¹³⁷Сs – 0.0002-0.002 mSv/year – by one order of magnitude. The major contribution to the public internal exposure today is ¹³⁷Сs intake through consumption of contaminated food that produced locally; its contribution is about 93-99% of the total internal dose received by the Bragin-district residents.

The research results are presented as an analysis of long-term data on the effect of gas-aerosol emissions and liquid discharges of Beloyarsk NPP and the Institute of Reactor Materials on the content of artificial radionuclides in local foodstuffs. It was noted that the distance and directions from radiation-hazardous facilities do not significantly affect the accumulation of ⁹⁰Sr and ¹³⁷Cs in potatoes and milk. The investigation of a wide range of foodstuffs from the private households of 23 settlements, forests, rivers, and a reservoir of the 30-km zone of the Beloyarsk NPP influence showed that the operation of the BN-800 reactor since 2016 did not lead to a registered increase in the content of artificial radionuclides in agricultural and natural foodstuffs. The maximum specific activities of ⁹⁰Sr (0.84 Bq/kg) and ¹³⁷Cs (0.26 Bq/kg) in root vegetables, potatoes, melons and vegetables were noted before the start of operation of the new power unit and were 45 and 300 times, respectively, lower than the current SanPiN standards. The highest content of ⁹⁰Sr in milk (0.41 Bq/l) was 60 times lower than the requirements of SanPiN, ¹³⁷Cs (0.11 Bq/l) was 900 times less than the permissible levels. In poultry, the specific activity of ⁹⁰Sr (0.2-0.3 Bq/kg) and ¹³⁷Cs (0.13-0.16 Bq/kg) has remained stable low in recent years, and the standardised content of ¹³⁷Cs in beef (maximum 0.12 Bq/kg) more than 1.5 thousand times lower than the requirements of SanPiN. The highest concentration of ¹³⁷Cs in wild berries, found in strawberries (1.27 Bq/kg), was 125 times less than SanPiN standards. The content of ⁹⁰Sr in mushrooms was at the level of 0.1-2.5 Bq/kg, the content of ¹³⁷Cs is slightly higher than - 0.6-5.8 Bq/kg. The maximum recorded specific activity of ¹³⁷Cs in mushrooms was more than 80 times lower than the requirements of SanPiN. During the observation period, a decrease of up to 20% or more in the content of artificial radionuclides in samples of 5 fish species was noted; the maximum levels of ⁹⁰Sr and ¹³⁷Cs in it were 14 times lower than the strictest SanPiN standards (using fish for baby food). Selective radiation monitoring of foodstuffs of Beloyarsk NPP area aimed at ³H and ¹⁴C showed that the content of these radionuclides in foodstuffs was low, close to the background level. In agricultural products, ³H and ¹⁴C accumulated to a greater extent in potatoes and milk, and in natural products – in rough boletus and bream. There was noted a need to continue research on the accumulation of 3H and 14C in foodstuffs of Beloyarsk NPP vicinity.

An extensive radon survey was conducted in 2008-2011 in the framework of the Federal target program on the territory of 29 districts of Chelyabinsk Oblast. SSNTDs were used to measure indoor radon concentrations in public buildings, dwellings and industrial buildings. The results are stored in the database “Radon” owned by Research and Technical Center of Radiation-Chemical Safety and Hygiene of Federal Medical-Biological Agency. The paper presents the results of the analysis of spatial variability of indoor radon concentration and the relationship of this value with a set of geological predictors of radon potential of the territory integrated into a map of ecological and radiogeochemical zones. The results show that in all districts and the whole Chelyabinsk Oblast radon concentrations conform to a lognormal distribution, but in ten districts log-logistic distribution fits the data slightly better. Nevertheless, relative difference between the median values of indoor radon concentration calculated from the two fitted distributions yields zero. The results show that dose assessment based on the arithmetic means could lead to an overestimation of the doses from radon in 1.4 times on average compared to that based on the medians. The median value does not exceed 400 Bq/m³ in any of the surveyed territories and the 95th percentile lies between 96 and 1274 Bq/m³. The fraction of indoor radon concentrations above 400 Bq/m³ expected from the fitted distribution lies between less than 0.1 and 26.8%. The highest values of this fraction were obtained for the Sosnovsky, Kaslinsky, Bredinsky districts and the Miassky urban district (except for the city of Miass). A map of ecological and radiogeochemical zones in Chelyabinsk Oblast was released in 1993-1995 and it was based on a set of geological predictors of radon potential of the territory. We analyzed the relationship of these zones with the results of the radon survey. One-way ANOVA on ranks with the Bonferroni correction showed that there is no statistically significant difference at the 95% confidence level amongst the medians of indoor radon concentration on basement, ground and first floors in settlements, which are located on the territory of three of four of these zones and outside of the territory of all zones. In the fourth zone the median was even two times lower than outside of the zones. These results lead to the conclusion that the possibility of using this map as a map of radon-prone areas is very doubtful. Each datapoint stored in the “Radon” database has a number of additional properties, which allows analyzing other types of indoor radon concentration variability such as seasonal or floor-to-floor. It is expected that later this dataset could be used for estimating regional seasonal correction factors.

This study is aimed at the evaluation of the trends of the doses from internal exposure of the adult public of the Bryansk region due to the consumption of the main dose-forming food products in the remote period after the Chernobyl NPP accident and the methodical features of the assessment of the predicted doses form the internal exposure. A new methodical approach to the calculation of the predicted doses of the public from internal exposure is based on the single exponential model of the change of the dose with a time-dependent period of a half-decrease. Results of the study allowed increasing the precision of calculation of the predicted doses to the public of the Bryansk region up to 2056. A similar method (single exponential model) can be applied for the external exposure as well. That allowed calculating predicted doses of total (external + internal) exposure. As an example, the paper includes the distribution of all settlements in the Bryansk region referred to the zones of radioactive contamination by the predicted average annual effective dose to the public and critical groups in the different time periods after the accident.

The study is devoted to the assessment of dose parameters determine the probability of deterministic effects in the skin for patients undergoing high-dose interventional radiological examinations. Particular attention is paid to the analysis of the geometry of the absorbed dose distribution over the patient’s skin for the main types of interventional examinations. The aim of this study was to clarify the methodology for assessment of the maximum absorbed dose in the patients’ skin, taking into account new data. The data collection was carried out in nine city hospitals from Sankt-Petersburg; detailed information about more than 400 procedures was obtained. The data about operation technique for the main types of interventional examinations, physical, technical, geometric and dosimetric parameters for each procedure were registered. Based on the statistical data on distribution of geometric procedure parameters (fields size and projections) possible localizations and values of the absorbed dose in certain areas of the patients’ skin were determined. An updated methodology for skin dose assessment based on the recorded dosimetric value of dose area product considering the radiation fields size was presented. As an alternative, an estimation of the maximum skin dose based on the cumulative air kerma at the patient’s reference point – «representative» point for the patient’s skin considering the tube rotation was proposed. This method does not require the information on used field size. The conservative conversion coefficients from the measured dosimetric values to the peak skin dose and trigger values to prevent deterministic effects in the patients’ skin were calculated.

Starting from 2014, several cases of exceedance of the specific total alpha-activity of the natural radionuclides and specific activity of ²²²Rn were identified in the water of the underground wells in the eastern districts of the Orenburg region. Based on the results of the surveys, a number of settlements were equipped with the systems of aeration of water from underground wells prior to the distribution, but significant expenditures on the technical maintenance of the aeration units lead to their frequent malfunctions. Based on the results of the surveys of the drinking water in settlements of the Adamovskiy, Kvarkenskiy, Novoorkskiy, Dombarovsky, Svetlinsky districts and Yasnenskiy urban district, it was estimated that in some settlements specific activity of ²²²Rn in drinking water exceeded the intervention levels up to a factor of 10. No exceedances of intervention levels for ²²⁶Ra, ²²⁴Ra, ²²⁸Ra, ²¹⁰Pb, ²¹⁰Po and ²³⁸U were identified. Based on the results of experiments and analyses the authors performed the hygienic assessment of the indicators of the radiation safety of the drinking water from the underground water supply sources in several settlements in the eastern districts of the Orenburg region, performed the analysis of the effectiveness of the aeration systems, developed recommendations on the provision of the radiation safety of the public of the eastern parts of the Orenburg region for the use of the drinking water from the underground water supply sources and developed proposals on the improvement of the limitation of concentration of ²²²Ra in drinking water.

The article is devoted to the analysis of internal dosimetry in residents of Fukushima Prefecture due to the accident at the Fukushima-Daiichi NPP. On March 24-30, 2011, screening studies were conducted on measurements of  ¹³¹I content in thyroid gland of children in those municipalities where the Japanese program for assessing the radiological consequences of the radiation accident “SPEEDI” predicted doses in the thyroid of one-year children from 100 to 500 mSv. Among 1080 children measured, 55% had results below the background, and the maximum estimate of the equivalent dose in the thyroid was 43 mSv. Measurements of several dozen inhabitants with other instruments and methods confirmed low levels of  ¹³¹I in the thyroid. In total, the  ¹³¹I thyroid direct measurement database of Fukushima residents contains approximately 1300 individuals. 75% quartile of individual thyroid dose distributions was below 10 mSv, the median was from 0 to 3.7 mSv among children aged from 0 to 15 years in the five examined municipalities. The contribution of short-lived iodine radionuclides was estimated as 15% of the dose from  ¹³¹I for the main radioactive release on March 15. The effective dose of internal exposure to cesium radionuclides ( ¹³⁴Cs +  ¹³⁷Cs), estimated from 10 thousand whole body measurements for the first year after the accident, was below 0.1 mSv in 90% of the examined people. Whole body measurements of children 6-15 years old in the second year after the accident confirmed the values of the effective dose of internal exposure less than 0.1 mSv, while the estimates of the effective dose of external exposure in the same children with using individual dosimeters determined the median distribution as 0.66 mSv with a maximum value of 3.45 mSv . The measurement results do not provide any basis to expect a future increase in the incidence of thyroid cancer and other radiogenic diseases among the Fukushima residents. Preventive evacuation of the population before the radioactive release, stay in enclosed dwellings, strict radiation control of food products have effectively reduced the expected doses of internal exposure to residents. In the predictions of the radiological consequences of the accident, it is necessary to take into account the actually implemented measures to protect the population, and local characteristics of the style of life and living.

The purpose of this work is to investigative radiation protection of the female breast in different X-ray examinations, including radiography. It is actual, because Publication ICRP №103 takes female breast to maximum irradiating organs. Analysed: risk of ionizing radiation, FB cancer, volume and dynamics X-ray examinations, female breast organ dose and effective dose. In conformity with data of Publication ICRP №103, effective dose of patients at mammography increased in 2,4 time and reach 0,48 mSv for examination as compared with 0,20 mSv with data of Publication ICRP №60. It is shown, that among different cancer, female breast cancer takes first place and constancy increased. Quantity of mammograms for 10 years increased in 2 time and collective dose increased in 2 times at last 7 years. Female breast average organ dose in mammography is 0,96 mGy and effective dose 0,05 mSv. It is only a part of summary irradiation from all X-ray examinations. The average mean value female breast organ dose of all radiography is 1,84 mGy (anterio-posterior projection – 1,57 mGy, lateral – 2,91 mGy) and effective dose – 0,25 mSv (anterioposterior – 0,26 mSv, lateral – 0,17 mSv). Considerable female breast irradiation is caused by X-ray spine examinations (thorax and lumbar). It is necessary to ensure radiation protection of female breast in diagnostic radiology, including quality control and optimization. Also need to shut female breast by X-ray protection apron, particularly in the lateral projection.

Optimization of medical exposure by substantiating the reference level of patients during diagnostic medical procedures in domestic health care requires harmonization with international recommendations. The paper sets out the history of the question of developing a reference level based on materials from international and domestic regulatory documents, draws attention to the formation of a glossary, presents possible ways of collecting information about the measured levels of patient exposure during x-ray studies obtained at the local, regional and national levels.

The aim of the work was to characterize the radiation incidents that took place in the territory of the Voronezh region. Materials and methods. To prepare this article the stock data of the radiological laboratory of the Center for Hygiene and Epidemiology in the Voronezh Region for 2009-2018 was used. All measurements in the investigation of radiation incidents were carried out with the MKS-AT1117M dosimeter-radiometer which passed the state calibration. The equivalent dose rate of gamma radiation (μSv/h) was determined. Results. For the last 10 years, 8 radiation incidents were registered on the territory of the Voronezh region, which were related to domestic clocks - 4 (measurements according to citizens), the detection of orphan sources of ionizing findings - 2, scrap metal - 1 and a thermometer - 1 (during customs inspection). According to the classification of emergencies, the radiation incidents are local, i.e. do not go beyond the territory of the facility, according to the international scale of nuclear and radiological events, INES refer to the incident (anomalies) with the level 1 “minor problems with the safety of components, a radioactive source of low activity level”. All interactions in the investigation of radioactive incidents involving specialists from the radiological laboratory of the Center for Hygiene and Epidemiology in the Voronezh region with other services showed a good level of rapid response.