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The publication continues the series of research addressed to the dynamics of 137Cs concentrations in agricultural products after the Chernobyl accident. The purpose of the present paper was to analyze the data describing the changes of 137Cs concentrations in cow milk. The information on countermeasures in animal breeding is presented, the system of radiological monitoring of milk contamination is described. It is shown that the dynamics of 137Cs concentrations in milk was seriously affected by the implementation of agrotechnical and veterinary measures. Effective half-lives of 137Cs concentrations in milk in the first period after the accident (1987-1992) ranged from 1 to 2.0 years. In the subsequent period (1991-2015), the reduction of milk contamination slowed down and the half-lives ranged from 5 to 25 years depending on the scope of remediation works and 137Cs aging in the soil.

Computed tomography has become increasingly common for diagnosing socially significant diseases in recent years. In foreign practice, screening schemes for lung cancer in people belonging to risk categories have been developed and implemented. These schemes have been successfully used over the past 10 years. In this case, “low-dose” scanning protocols are used, which make it possible to perform examination with patient effective dose several times lower compared to standard protocols. Lung cancer screening methods using low-dose computed tomography are beginning to be introduced in the Russian Federation. To ensure the radiation safety of those individuals eligible for inclusion in screening programs or participating in biomedical research testing lung cancer screening, it is necessary to evaluate effective doses from low-dose computed tomography and compare these doses to established radiation dose limits. This study assessed the patients’ effective doses who underwent different types of low-dose computed tomography of chest at two medical organizations. The results of the study show that it is possible to achieve non-exceedance of the current annual effective dose limit of 1 mSv only for patients weighing less than 90 kg. For patients with higher body weight, the minimum effective dose will be in the range of 1.2 – 1.4 mSv. The results of the study indicate the need to make changes to the current regulatory and methodological documents of Rospotrebnadzor to ensure the possibility of using low-dose computed tomography as part of screening for all categories of people.

The results of studies of long-term effects of population exposure in the South Urals in the 1950s were based for a long time on studies of the effects of exposure in the Techa River cohort and later in the East Urals Radioactive Trace cohort. After the creation of the South Urals Population Exposed to Radiation cohort, combining all persons exposed in the South Urals in the period from January 1, 1950, to December 31, 1960 the size of the cohort doubled, follow-up period reached 71 years, and the number of person-years at risk increased to 1,964,333. The average dose to red bone marrow for all cohort members was 231mGy. Regression analysis using a simple parametric excess relative risk model was performed using the EPICURE statistical package. The analysis resulted in confirmation of a statistically significant (p

According to Rosstat statistics, in recent years there has been a tendency in the Russian Federation to increase the intensity of construction, while both the number of buildings put into operation and their total area are increasing. The assessment of the potential radon hazard of land plots for construction provides the possibility of timely inclusion of the necessary protective (preventive) measures against radon in the design of buildings. This is a legal requirement in cases where the density of radon flux from the ground surface within the building area exceeds the established hygienic standards (action levels). The paper presents a review of Russian and foreign approaches to assessing the potential radon hazard of land plots conducted within the framework of engineering and environmental surveys. The current regulatory requirements to radiation safety indicators of land plots for construction of residential, public and industrial buildings and facilities in the Russian Federation are analyzed. The main drawbacks of the algorithm for determining the potential radon hazard of land plots, used in the current guidelines MU 2.6.1.2398-08 approved at the federal level more than 15 years ago, are described. Critical remarks (the unsuitability of the value of density of radon flux from the ground surface for designing radon protective and mitigation (remedial) measures, lack of consideration of seasonal variations of radon flux density, etc.) accumulated over the years as a result of practical application of these guidelines are presented. Benefits and drawbacks of foreign approaches to assessing the potential radon hazard of the territory based on the results of measurements of radon concentration in soil gas, as well as the very possibility of a transition in Russian regulations from the density of radon flux from the ground surface to the radon concentration in soil gas, are analyzed. Some rational proposals of various Russian research teams on improving the algorithm for determining the potential radon hazard of land plots are considered.

Biological excretion from patients (urine) generated during radionuclide diagnostics enters directly into the hospital sewage system. The establishment of new clearance level according to Resolution of the Government of the Russian Federation No. 1069 of October 19, 2012 may entail amendments to regulatory documents for radionuclide diagnostics departments. One of these requirements is a mandatory dedicated sewage system. Establishment of the requirement may lead to an increase the cost of the radionuclide diagnostic examinations, and to a decrease the accessibility of radionuclide diagnostic. The aim of this study was to estimate the activity of radionuclides in patient urine after radionuclide diagnostic and activity concentration in sewage water in the hospital and in the transport tank of toilet for evaluation of paths of waste manage. Based on published literature data, models of biological excretion were constructed for the following radiopharmaceuticals: 99mTc-pyrophosphate, 64Cu-Labeled Monoclonal Antibody, 18F-FDG, 68Ga-PSMA-617. The activity of radionuclides in the patient waste in the hospital and in public transport during the patient transportation to home was calculated. Various scenarios of patient transportation were considered. The values of the excreted activity, activity concentration and dose rate at 1 m from the tank with sewage water for each type of transport were calculated. The calculated values of the radionuclide activity concentration in sewage water in transport tank of toilet for the majority scenarios exceed the clearance level (up to 180 times for 68Ga-PSMA-617 when traveling by bus). According the regulatory requirements, it is necessary to collect patient excretions after radionuclide diagnostic examinations and hold it for decay. However, estimated effective doses of individuals from the public from contact with biological patient waste do not exceed the acceptable value. This is due to the short half-life of diagnostic radionuclides. The paths of management system of biological patient waste were proposed.

The objective of the study is to analyze solid cancer mortality and estimate the risk value of solid cancer mortality in the offspring of parents irradiated in the Southern Urals, depending on the dose to the parents' gonads as well as to conduct a preliminary assessment of the mortality risk from cancer of individual locations depending on the gonadal dose. The issue of the transgenerational effects of the human gonad exposure is still very important. There exists conclusive evidence of the presence of such effects in experimental animals. However, there is no proof of the existence of these effects in humans despite a great number of research on this subject. International scientific community and international organizations, UNSCEAR and ICRP being among them, regard this issue as the one that has not been solved yet and requires further studies. Urals Cohort of offspring of the population exposed on the Techa River and on the territory of the East Ural radioactive trace was established in the Urals research Center for Radiation medicine in 2022. The key feature of the cohort is the exclusion of the offspring with postnatal exposure. The size of the cohort as of September 2023 is 31,154 persons. The number of person-years over the whole follow-up period from 1950 through 2020 is 1 226 380. Mean dose to the gonads of mothers of all the cohort members is 41 mGy, to those of the fathers' — 35 mGy, mean combined gonad dose is 76 mGy. Over the whole follow-up period 3,774 deaths from all causes including 284 deaths from solid cancers were registered in the cohort. The mean age of the cohort members at the end of the follow-up period was 42 years. The risk of death was analyzed using Poisson regression by the programs of the EPICURE statistical software package. Three models of dose dependence were tested: linear, quadratic, and linear-quadratic models of paternal gonadal dose, maternal gonadal dose, and total gonadal dose. Mortality risk analysis of all solid cancers in the offspring cohort showed no statistically significant effect with parental gonadal dose (we have obtained positive although statistically insignificant values of solid cancers mortality risk) which is consistent with the results of other studies in human populations. At the same time, the analysis for the first time obtained a statistically significant linear dependence of the solid cancer mortality risk in offspring with father's age over 45 years depending on the dose to the father's gonads. The excess relative risk of death was 8.09/Gy, (0.51-22.93), p < 0.05. Also, for the first time, evidence of dose dependence of the mortality risk of lung cancer in male offspring on maternal gonadal dose, paternal gonadal dose, and combined gonadal dose was obtained. The values of excess relative risk of lung cancer and 95% confidence intervals according to the linear model were 5.39/Gy (0.46; 15.56) from paternal gonad dose, 4.36/Gy (0.15; 13.48) from maternal gonad dose, and - 3.95/Gy (0.55; 12.14) from combined gonad dose. Point risk estimates of lung cancer at this stage are characterized by wide confidence intervals and require additional studies to assess the influence of possible effect modifiers, but with a high degree of probability indicate the presence of dose dependence of this effect. Increasing the follow-up period and attained age, will increase the number of cancers in the future and will reduce dose response uncertainties and provide more accurate estimates of the risk of death in the offspring cohort.

Sites of peaceful nuclear explosions pose a potential radiation hazard to the territories of the Russian Federation, primarily due to the possible release of radioactivity from the explosion cavity into aquifers and onto the earth's surface. Therefore, it is essential to conduct regular monitoring of anthropogenic radionuclides in drinking water sources in settlements located near the sites of peaceful nuclear explosions. Tritium serves as an indicator of the potential release of other anthropogenic radionuclides. Monitoring its levels in water bodies in regions where peaceful nuclear explosions were perfomed, and comparing this data with that from Roshydromet across the Russian Federation, allows for an assessment of the reliability of the engineering barriers between the central explosion zone and the environment with respect to preventing radionuclide migration into aquifers. One method for evaluating the reliability of these barriers is the assessment of tritium specific activity in drinking water sources. This article presents results of the study involving 220 water samples collected from drinking water sources (wells, boreholes, springs, central water supply systems) and surface waters within 167 settlements across 17 subjects of the Russian Federation, where 50 peaceful nuclear explosions were conducted between 1965 and 1988. The samples were collected between May and September 2024 in the settlements within a 30 km radius of a peaceful nuclear explosion site. Measurements of tritium specific activity were performed using the Quantulus 1220-003 alpha-beta spectrometric radiometer. The research revealed that the specific activity of tritium in underground water sources is significantly lower (Student's test p

The practical implementation of radiation protection principles in the medical exposure of patients often tends to fall into one of two extremes: either excessive simplification of the methodology for assessing radiation health detriment, or its excessive complexity. An example of an excessively simplified approach is the assessment of radiation risk to patients using effective dose and radiation damage coefficients (nominal risk coefficients) as presented in Norms of the Radiation Safety NRB-99/2009. An example of an unjustifiably complex approach can be considered Tables 1-2 in MR 2.6.1.0215-20 "Assessment of radiation risk to patients during X-ray diagnostic radiological examinations," which indicate "lifetime risk values of death taking into account harm from reduced quality of life due to cancer of various organs and tissues and genetic effects from medical examinations" for a wide range of medical diagnostic X-ray radiological examinations in five-year age groups of patients. The main shortcomings of the simplified approach can be considered the lack of differences in risk assessment between individuals of different sexes and ages, although the fact of higher radiosensitivity in children compared to adults and in women compared to men can be considered universally recognized. The risk assessment approach proposed in MR 2.6.1.0215-20 addresses these shortcomings. However, in the view of the authors of this study, it offers an unnecessarily detailed picture considering uncertainties inherent in risk assessments at low doses, as well as uncertainties in the method of interpopulation transfer of radiation risk proposed by the International Commission on Radiological Protection. The aim of this study was to develop and justify a simpler and more straightforward method of presenting information on radiation risks associated with medical X-ray radiological examinations, free from the main drawbacks of the two aforementioned methods. To achieve this goal, radiation risks were calculated using two methods (using effective dose and using the risk model of the International Commission on Radiological Protection). A comparative analysis of the calculation results was conducted with estimates presented in Tables 1-2 of MR 2.6.1.0215-20. As a result of the analysis, an original applied method for presenting qualitative characteristics of radiation risks was developed for use in prescribing X-ray radiological examinations and informing patients about potential health risks. The practical outcome of the study is the formation of a table of radiation risks associated with conducting studies on patients from the Russian population, using the developed method of presenting information on radiation risks.

The purpose of the study is to analyze the forest fire dangers of the Bryansk region forests, taking into account their radioactive contamination and potential risks for forestry workers involved in forest fires extinguishing. Significant areas of radioactive contamination of forests with a predominance of sites belonging to the classes of high and very high natural fire danger, restrictions on economic activity and a long fire-hazardous period contribute to the occurrence of radioactive forest fires. The analysis of the combined data on forest fires and radioactive contamination of forest areas showed that most forest fires occur outside the zones of radioactive contamination and are not radioactive. The largest number of fires occurs at the beginning of the fire season. Radioactive forest fires in most cases arise from the burning of dry grassy vegetation, as a result of the transition from lands of other categories and through the fault of the population. The average effective dose of additional radiation per a workday can be estimated at 1.96 μSv, and the maximum at ~ 15.4 μSv. Most fires are extinguished in the early stages and do not have time to cover large areas. It indicates the effective work of the forest fire service

A model of occupational exposure to gamma flaw detector operators working with portable flaw detectors in the field has been developed. The initial data for the development and verification of the model were the results of measurements of the characteristics of the gamma radiation field at the workplaces of flaw detectors and data from individual dosimetric monitoring. The relationships between the measured (H*(10), Hp(10)) and protection (effective dose) quantities (conversion coefficients) were determined using calculations and phantom experiments simulating three main operations of the full production cycle: transportation of the flaw detector to the place of X-raying of the product, installation of a flaw detector to perform x-raying and X-raying of the product. As a result of the study, it was found that more than 90% of the dose contribution to the readings of an individual dosimeter is due to the installation of the flaw detector in the working position and X-raying of the product. The values of the conversion coefficients for these operations in the form of the ratio of the effective dose values and the readings of dosimeters (Hp(10)) located on the worker's body at chest level (standard place) and abdominal level differ little for both positions of individual dosimeters. The use of maximum conversion coefficient value of 0.8 Sv/Sv corresponding to the operation of X-raying of the product will ensure conservatism in the assessment of the effective dose for the entire production cycle by no more than 15% and 25% for dosimeters located at the chest level and abdominal level, respectively.

Radiation events (accidents) appearance is an integral part of the use of ionizing radiation sources in medicine in general and nuclear medicine in particular. To minimize the negative impact on patients, workers, and public due to such events, it is necessary to have reliable information about real prevalence of the radiation events (accidents). The current work presents the analysis of the radiation accidents with medical ionizing radiation sources registered in the “Data bank of radiation accidents and incidents” of the Rospotrebnadzor Information and Analytical Centre for Radiation Safety and the results of workers questionnaires conducted in 25 nuclear medicine departments (about 30% of all nuclear medicine departments in the Russian Federation). The results of the analysis showed that the most common registered radiation accidents in the “Data bank of radiation accidents and incidents” are identification of passengers with high external dose rate as well as identification of waste contaminated by medical radionuclides. The results of the questionnaire showed that the most common radiation accidents (events) in nuclear medicine are contamination of work clothes or work surfaces with radionuclides, or patient fluids containing radionuclides; conducting examination without proper referral; extravasation of radiopharmaceutical. Existing systems of identification and registration of radiation accidents do not allow to identify radiation events (accidents) specific to nuclear medicine. The further research aimed at developing a classification of radiation events (accidents) in medicine and methods for responding to such events are feasible.

Diagnostic reference levels are one of the effective tools for optimizing patient radiation doses in diagnostic radiology. The staff of domestic radiology departments does not have an understanding of the development process and use of diagnostic reference levels during X-ray examinations, although this tool is a generally accepted in practice abroad. The article shows the experience of forming regional diagnostic reference levels based on measurements provided by the accredited testing laboratory of the Scientific and Practical Clinical Center for Diagnostics and Telemedicine Technologies of the Moscow Healthcare Department. The diagnostic reference levels for radiography in Moscow were developed for eight of the most common types of examinations based on the operation of 216 digital X-ray machines. The resulting levels, expressed in the dose-area product (cGy-cm2) and effective dose (mSv), were compared with the local diagnostic reference levels for the Ryazan region, Russia, and national diagnostic reference levels for other countries. The analysis showed continuity in the values. Some types of studies have been optimized. The developed diagnostic reference levels are the quality performance indicators foe diagnostic radiology departments and will be used to optimize a patient radiation dose during diagnostic studies in Moscow.

The paper provides an assessment of the probability and consequences of external events capable of leading to an incident with a breach of established safety barriers restricting the spread of radioactive substances along the coastline of the Techensky reservoir cascade. The initiating events for such an incident could be adverse meteorological conditions resulting in a decrease in the water level in the cascade water bodies below the specified design levels. Drying out the surface of previously inundated sections of the coastline will create an extensive source of atmospheric contamination by technogenic radionuclides during wind-induced resuspension. The probable area of the dried-out sections will be 0.02 — 0.08 kml for reservoir V-3, 0.06 — 0.28 kml for reservoir V-4, 0.19 — 0.90 kml for reservoir V-10, and 0.47 — 2.19 kml for reservoir V-11. The cumulative inventory of 137Cs and 90Sr in the specified area exceeds 105 Bq/ml. The activity released into the atmosphere within an hour will range from 3.69∙108 to 8.48∙1011 Bq for the wind speeds of 5 m/s and 20 m/s, respectively. The probabilities of joint occurrence of strong winds and drought conditions are 6.8∙10-7 per year for a wind speed of 20 m/s and 2.1∙10-3 per year for a wind speed of 5 m/s. The highest values of effective dose for the population of the nearest settlements, reaching 1-3 μSv in the first 10 days and over 200 μSv in the first year, are achieved under extreme wind loads with wind speeds of 20 m/s or more.

The article presents results of comparative study of 137Cs, 60Co, and 241Am activity concentrations in components of the soil samples collected in 2009 on the territory adjacent to the «Taiga» peaceful nuclear explosions site (the Perm region, Russia). The objective of the study was to identify differences between: 1) non fractionated native soil, 2) the soil passed through a sieve with a mesh size of 1.2 mm, and 3) the screened out coarse components. Measurements of the radionuclides activities in counting samples were performed using a semiconductor gamma spectrometer. Statistically significantly lower activity concentrations of 137Cs (factor of 1.2), 60Co (factor of 2.2) and 241Am (factor of 2.6) were found in the finely dispersed sieved fraction of soil compared to the native soil. On the opposite, in the solid radioactive inclusions selected from the screened out coarse fraction, the activity concentrations of 137Cs, 60Co and 241Am were significantly higher compared to those in the native soil. Especially large differences (up to a factor of 10 and more) between the native soil and radioactive inclusions were observed for the refractory and low-volatile 60Co and 241Am. Presumably, these radionuclides were concentrated predominantly in the glassy substance of the radioactive inclusions. For 137Cs, the unevenness in the contamination of different soil components was less pronounced. The results obtained will be used to standardize methods for assessing radioactive contamination of the territory at the sites of peaceful nuclear explosions

In the Russian Federation, there is a constant increase in the number of radiation medical installations with electron accelerators. Over the past 4 years, their number has increased 2.5 times. These installations contain pulsed electron accelerators that generate pulsed bremsstrahlung radiation with a maximum energy from 6 to 21 MeV. Currently, there are no devices designed for dosimetry of the pulsed photon radiation with energy of more than 10 MeV in the state register of measuring instruments of the Russian Federation. The most widely used radiation monitoring device for pulsed electron accelerators is the DKS-AT1123 X-ray and gamma radiation dosimeter designed for dosimetry of pulsed bremsstrahlung radiation with an energy of up to 10 MeV. The purpose of this work is to evaluate the possibility of using this device for dosimetry of pulsed bremsstrahlung radiation with a maximum energy of up to 20 MeV. The authors calculated the energy spectra of bremsstrahlung radiation for a point source with a maximum energy of 20 MeV behind flat concrete screens with a thickness of 1 m, 2 m and 3 m by the Monte Carlo method using the GEANT4 calculation program. The energy dependence of the registration efficiency of the DKS-AT1123 dosimeter was extrapolated to the energy range of 10–50 MeV in the kerma-approximation without taking into account the energy transfer by secondary electrons. It was assumed that it corresponds to the energy dependence of the total mass attenuation coefficient for the absorbed energy of gamma quanta in water. Using conversion coefficients for converting the fluence of monoenergetic photons into the effective dose rate at an anterior-posterior radiation incidence on the human body, real dose rates were calculated, and using the energy dependence of the dosimeter readings, the predicted results of measuring the unit dose rate with the DKS-AT1123 dosimeter behind a concrete protection with a thickness of 1, 2 and 3 m were obtained. It is shown that the maximum expected underestimation of the measurement results will not exceed 40% and practically does not depend on the thickness of the concrete shield in the thickness range from 1 to 3 m. To account for this underestimation, it is necessary to use the value of additional measurement error due to the energy dependence of the sensitivity of this device for the photon radiation energy of more than 10 MeV, equal to 70%. This makes it possible to use the measurement results obtained using this dosimeter to adequately characterize the state of radiation safety during operation of pulsed electron accelerators with a maximum energy of up to 20 MeV. It is possible to use a correction factor to the measurement results equal to 1.63 ±0.04 to compensate for this underestimation. The proposed approach can be used to create a methodology for using this dosimeter for radiation monitoring of medical electron accelerators with the energy of up to 20 MeV, if there are correction factors for radiation protection configurations and radiation energies encountered in practice.

Radiopharmaceutical therapy with 131I has been one of the most common types of radiopharmaceutical therapy for many years. Radiation safety of the public is ensured by limiting the patient contacts until the radiological parameters are reduced to the established criteria. To increase the availability of the radiopharmaceutical therapy with 131I, softer patient release criteria for 131I have been proposed. However, early patient release may increase exposure to the public, e.g. in transport. The aim of the work is to evaluate the radiation exposure from patients with 131I -MIBG and Na131I on the public in transport considering the generation of biological waste. In this work, 131I excretion from the body of patients in transport was evaluated for different scenarios of patient travel to the place of residence. As a result, it was found that mitigation of patient release criteria leads to an increase in the effective dose to the public in transport and an increase in the 131I activity excreted with patient waste. The specific activity in the tanks of biotoilets in transport, generated after the pas -sage of a patient with injected 131I -labeled radiopharmaceuticals, exceeds the limit value of classifying liquid waste as radioactive. To optimize radiation protection of the public, it is advisable to apply a differentiated approach to release patients after therapy with 131I: to group non-resident patients into a separate category retaining for them the established release criterion (without mitigation) to minimize the radiation impact on the public.

Colorectal cancer (colon, rectum, rectosigmoid and anus) is one of the most frequently registered cancer sites. Apart from main risk factors for the development of cancer of this localization (dietary disorders, obesity, alcohol and tobacco use, contact with certain chemicals), a number of authors have noted in their studies the effect of ionizing radiation. The objective of this study was to directly assess the excess relative risk of colorectal cancer in the population exposed to long-term chronic radiation mainly in the range of low-dose and low dose rates. These people are included in the Southern Urals Population Exposed to Radiation Cohort. Materials and methods: the analytical cohort included 47,282 people, the follow-up period was 63 years (from 1956 to 2018), and the number of person years at risk was 1,292,930. The incidence catchment area includes five Chelyabinsk Oblast raions, the cities of Chelyabinsk and Ozersk. For the period from 1956 to 2018, 462 cases of colon cancer were registered in the follow-up territory. The colon dose was used as a reference dose. The mean absorbed dose was 69 mGy, the maximum dose – 1,824 mGy. The analysis was performed using Epicure statistical package programs by Poisson regression method with a simple parametric model of excess relative risk. Significance of the results was assessed by the maximum likelihood method with 95% probability. Results: In SUPER members, baseline colorectal cancer incidence rates were found to be dependent on such factors as sex (p

The article presents results of the analysis of questionnaire survey data on preferences in the choice of cooking methods of different types of forest mushrooms by residents of the most contaminated south-western districts of the Bryansk region in the remote period after the Chernobyl accident. In the period from 2019 to 2022, the employees of Federal Budgetary Institution of Science «Saint-Petersburg Research Institute of Radiation Hygiene after Professor P.V. Ramzaev» conducted a face-to-face questionnaire survey of the adult population. In addition to general questions about the respondent, the questionnaires included questions about the species composition of the mushroom basket, the volume and proportion of consumption of each type of mushroom by the respondent and his family members (both in the current and last year), as well as methods of culinary processing of the mushrooms consumed. Based on the analysis of individual survey data, a group of 1 311 respondents, whose diet included various types of mushrooms, was selected. Analysis of the survey results showes that respondents prefer to process a large proportion of freshly picked forest mushrooms (59%) for long-term storage (pickling, freezing, drying, salting, etc.); 41% of mushrooms are consumed immediately. The most popular pretreatments of freshly picked mushrooms are washing and boiling (34 and 26%, respectively). When freezing, pickling and pickling up to 97% of respondents carry out pre-treatment (rinsing, soaking and / or boiling) of freshly picked mushrooms. Less popular methods of the mushroom preparation (from 2 to 4%) are pickling, drying and frying of fresh mushrooms with their subsequent preservation. Thus, the majority of respondents actively use various types of culinary processing with the use of preliminary stages of technological processing in the form of rinsing, soaking and (or) boiling. The use of the above methods of pre-cooking of freshly harvested mushrooms leads to a decrease in the 137Cs content in the consumed product.

The article proposes a new approach to assessing the effective doses of flaw detectorists performing flaw detection using portable radionuclide flaw detectors (gamma flaw detectors). The existing approach to assessing effective doses, based on the use of one individual dosimeter placed on work clothes in the chest area, is inadequate for the actual working conditions of exposure of flaw detectorists. Gamma flaw detectors contain a closed man-made source of ionizing radiation in their head, therefore, even in the non-working position, such flaw detectors pose a radiation hazard. When transporting and preparing gamma flaw detectors for work, the flaw detector operator is in close proximity to the radiation source. The irradiation geometry changing during the technological cycle when working with portable gamma flaw detectors at certain stages creates a sharply uneven irradiation of the flaw detectorist’s body. Therefore, after assessing the stages of the technological cycle, an option was proposed for a more conservative assessment of effective doses – to change the location of the individual dosimeter on the working clothes of the flaw detectorist, moving the individual dosimeter to the abdominal area. An anonymous study was carried out with the participation of 15 flaw detectorists; three individual dosimeters were displayed on their working clothes: two of them were experimental and were placed in the chest and abdomen; the third (a control dosimeter) was exposed for the quarter on the chest as part of constant individual dosimetric monitoring. In controlled anonymous measurements, the average effective dose, estimated from the readings of dosimeters exposed in the chest area, was equal to 0,95 mSv (median – 0,92 mSv, maximum value – 1,27 mSv). These values were compared with values obtained using dosimeters that were exposed to the abdomen, and the differences were significant (the average effective dose was 1,24 mSv (median – 1,22 mSv, maximum value – 1,78 mSv).

Cytogenetic Fluorescence In Situ Hybridization studies, that allow assessing the frequency of stable chromosome aberrations in circulating T lymphocytes, are commonly used in retrospective dosimetry in cases of uniform whole-body exposure. In the event of 89,90Sr exposure, interpretation of cytogenetic data is challenging, especially if blood sampling occurs long after the start of exposure. The weighted average dose to T-lymphocytes at the time of donor blood sampling in the long-term period after exposure to 89,90Sr does not coincide with the red bone marrow dose. Previously, we developed a model that allows us to estimate the weighted average doses to T-lymphocytes upon 89,90Sr ingress into the body of people belonging to various age groups. In this study, the modeling results were used to estimate the conversion factors from the frequency of translocations to the red bone marrow dose, which is important for assessing radiobiological effects associated with hematological diseases. The objective of our study is to estimate numerically the conversion factors (Brbm) from the dose to lymphocytes to the dose to red bone marrow for various scenarios of 89,90Sr ingestion depending on age, sex, and time after the start of exposure. The following scenarios are considered: single, uniform chronic for six months, uniform chronic for 1-5 years, non-uniform intake for 5 years (simulates the dynamics of intake in the Techa riverside settlements in 1950-1954). As a result, it has been found that the Brbm values significantly depend on the age at the time of 89,90Sr intake. The older the person is at the start of exposure, the more the cytogenetic dose differs (it is significantly lower) from the dose to the red bone marrow. We can say that the cytogenetic dose corresponds to the red bone marrow dose only in newborns and infants. This is due to the age-related dynamics of T-cell populations. Sex does not have a significant effect on Brbm. The effect of the 89,90Sr intake duration on Brbm is the most pronounced for 15-year-old adolescents. For them, the difference in Brbm values for a single and chronic 5-year ingress reaches 13%. Non-uniform intake of 90Sr over several years does not have a significant effect on Brbm and can be modelled by a uniform intake of the same duration.

In the paper, based on the analysis of scientific information regarding the parameters and characteris-tics of radiation fields for three dental X-ray procedures (intraoral radiographs, panoramic radiographs on orthopantomographs and computed tomography), the required thickness of stationary shields for rooms with different X-ray equipment is calculated. It has been shown that in most cases, in rooms where intraoral and panoramic radiographs are taken, conventional 20 mm thick plasterboard interior room partitions provide the necessary protection to comply with the dose limit for the population in the adjacent room. For the rooms where dental examinations are carried out using computed tomographs additional lead shield up to 1.5 mm thick is required depending on the conditions and the category of protected persons in the adjacent room.

The third article in a series of publications devoted to the results of studying the current radiation situation in the territories of the Bryansk region bordering the Republic of Belarus presents results of studies of the content of radionuclides (137Cs and 90Sr) in samples of agricultural food products produced in the personal subsidiary plots of the population. The regularities of changing 137Cs and 90Sr content in samples of cow’s milk and potatoes depending on the level of radioactive contamination of the territory were studied; the present values of the quantities characterizing the distribution of the ratio of the activity concentration of radionuclides in agricultural food products to the density of radioactive contamination of the soil of the territory were deter -mined. The ratios of average values of 137Cs activity concentration in milk from stalled and grazing periods for cattle were analyzed. The results of the study show that some dairy product samples (less than 1%) do not meet the radiological safety criterion. Exceedances of the hygienic standards were not found in the studied samples of potatoes, vegetables, and meat of farm animals.

Activities of gamma-emitting radionuclides were measured in glassy inclusions (particles) found in soil samples from the “Taiga” peaceful nuclear explosions site (the Perm region, Russia). The measurements were performed using a stationary semiconductor gamma spectrometer. Activity concentrations were determined for the following technogenic radionuclides: 60Co, 94Nb, 137Cs, 152Eu, 154Eu, 155Eu, and 241Am. The activity concentrations of 241Am in the glassy inclusions were one to two orders of magnitude higher compared to the level of minimum significant activity concentration (1 Bq/g for 241Am) established by the Russian Radiation Safety Standards “NRB-99/2009”. Earlier, exceeding this level for the 241Am activity concentration in the native (unfractionated) soil samples from the “Taiga” site was reported by other researchers. In accordance with current Russian legislative and regulatory provisions regarding use of nuclear charges for peaceful purposes, the soil and radioactive glassy inclusions found in the soil correspond to the category of special radioactive waste. Considering the long half-life of 241Am (432 years), radiologically significant contamination by this radionuclide will persist at the “Taiga” site for the foreseeable future.

The study assessed the acceptability of the currently existing approach to calculating shielding in computed tomography rooms and formulated proposals for its improvement, taking into account the parameters of research in domestic medical practice. It is proposed to use the dose-length product as the main measured parameter in the new approach to calculating shielding. Typical tomograph workload values of dose-length product, typical for examinations in the Russian Federation, were assessed. Using thermoluminescent detectors, the experimental assessment of the distribution of absorbed dose in the air in a computed tomography room was carried out. The experimental results showed that the distribution of of X-ray exposure in the central plane is not isotropic. Due to the attenuation of exposure by the gantry design, “shadow” zones are observed, where the absorbed dose reduction in the air reaches 10-13 times compared to its level in the direction of couch movement. Based on the results of measurements of the distribution of absorbed dose in air, the relative scatter coefficients were calculated. The workload was determined for 7 tomographs (1 in St. Petersburg and 6 in Moscow). For each tomograph, the average weekly number of head and body examinations and the values of dose-length product for these areas were assessed, taking into account the number of multiphase examinations. The obtained workload values turned out to be one or two orders of magnitude higher than those currently used in calculating shielding. Based on the results of the study and literature data, the work proposes a new approach to calculating shielding in computed tomography rooms, based on the value of measured dose-length product during the examination and allowing to take into account the specifics of the operation of the device.

The paper presents comments, remarks and opinions on the material presented in the publication “Radon regulation crisis in Russia: scale of the problem and proposals for remediation” by Tsapalov A., Miklyaev P., Petrova T., Kuvshinnikov S., published in the Russian peer-reviewed journal “ANRI” (“Radiation measurement equipment and news”), 2024, No. 1.

The Arctic zone is a strategically important territory of the Russian Federation from the point of view of socio-economic, scientific, and technological components, as well as in terms of planning the development of a system for ensuring national defense, state, and public security. Intensive exploration and development of Arctic territories, combined with a rapidly changing environment due to global climate change, carries a few risks for the environment. This determines the need to assess potential environmental damage and determine the significance of factors of potential negative impact on unique Arctic ecosystems now and in the future. The article presents current data from a radiation survey of the coastal zone of residential areas close to the site of the sinking of the nuclear submarine ‘K-159’ – Teriberka village and Kildin Island, Murmansk region, as well as the sea area to assess the primary levels of man-made and natural radionuclides before starting work on the potential lifting of the submerged object. This work was carried out as part of the implementation of the State Program of the Russian Federation ‘Health Development’ (approved by Decree of the Government of the Russian Federation dated December 26, 2017, No. 1640). The results of measuring the ambient dose equivalent rate of gamma radiation in open areas and determining the content of man-made and natural radionuclides in samples of environmental media (soil, aquatic vegetation, marine aquatic organisms) and food products of local origin and production (mushrooms, berries, fish, milk). The research results showed that the state of the study area is generally stable in terms of the radiation factor, the content of radionuclides is at the background level. As part of this work, electronic database modules have been developed based on the results of radiation monitoring in Teriberka village and on Kildin Island. Certificate No. 2022621890 was received on registration of a database with the results of the radiation situation of the above-mentioned territories.

The paper (in two parts) presents an overview of the new guidelines MR 2.6.1.0333-23 (approved on 01 December 2023) that supersede guidelines MU 2.6.1.2838-11, which were used for organizing radiation surveys of residential, public and industrial buildings and facilities and their sanitary assessment in terms of radiation safety indicators over the past 12 years. Due to a large number of critical comments on the document received during this period, a need for significant revision emerged. The scope of the revised document was expanded and now covers all stages of the life cycle of buildings and facilities: commissioning; operation period; overhaul and reconstruction; demolition. In the first part of the paper, the structure and legal status of the new guidelines are considered, as well as the main innovations in terms of measuring the ambient dose equivalent rate of gamma radiation, searching and identifying local radiation anomalies and sites of radioactive contamination, measuring surface contamination levels, and determining the minimum number of premises to be surveyed. The reasons for the introduction of certain changes are outlined. The issues of evaluation of measurement uncertainty, reporting of measurement results and registration of test reports are covered in detail. In the second part of the paper, numerous innovations will be considered in terms of estimating the indoor average annual equilibrium equivalent concentration of radon isotopes.

The paper presents the results of analysis of the Ivanovo Regional databank of radiation doses to the pub-lic from exposure to natural and technologically enhanced radiation background for 2008–2022. Despite the fact that the average individual annual effective dose of public exposure due to natural sources of radiation in the Ivanovo region calculated for the whole 15-year period (4.63 mSv/year) does not qualify as increased (i.e. does not exceed the level of 5 mSv/year), in some years of the period under review the average dose repeatedly exceeded this level, reaching 7.50 mSv/year. The analysis of the structure of the doses of public exposure due to natural sources of radiation in the Ivanovo region showed that the contribution of the dose from internal exposure to radon, thoron and progenies according to measurement results from 2008–2022 ranged from 65.98 to 81.47%. The paper provides examples of buildings of different types in settlements of the Ivanovo region, in which the indoor radon isotopes equilibrium equivalent concentrations are more than 1.5 times higher than the established action level for existing dwellings and public buildings (200 Bq/m3). Despite the significant amount of measurement data in the Regional databank, it is necessary to obtain additional information on the indoor radon levels in existing wooden and other low-rise dwellings and public buildings in the most radon-prone areas of the region. For this purpose, a radon survey is planned for 2024-2026 in the cities of Ivanovo and Kohma, Privolzhsky, Gavrilovo-Posadsky, Teykovsky and Zavolzhsky districts of the Ivanovo region within the framework of a joint project of Saint-Petersburg Research Institute of Radiation Hygiene after Professor P.V. Ramzaev, the Directorate of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing in the Ivanovo region, and the Center of Hygiene and Epidemiology in the Ivanovo region.

Evaluation of the low dose effect on population health is still a relevant issue. It requires further studies to improve our understanding of these effects. To solve this problem, it is important to conduct studies of the late effects of radiation exposure with direct risk estimation in the population that combines all strata of the society: people of different sex, age, initial health status, social and economic status. Moreover, this population should be sizeable and has been followed up for a long-term period. This manuscript is the first to present the findings of the analysis of the incidence risk of cancer of all the digestive organs, excluding intestines, and stomach cancer taken separately in members of the Southern Urals Population Exposed to Radiation Cohort depending on the dose accumulated in the stomach over the period from 1956 through 2018. This cohort is comprised of individuals exposed in the Southern Urals in two radiation accidents (on the Techa River and in the East-Urals Radioactive Trace) over the period from 01.01.1950 through 31.12.1960. The cohort also includes those who were born during this period; they could have additional in utero exposure or have exposed parents. The population was affected by long-term combined exposure (external and internal) at the low-to-medium soft tissue dose range (up to 1.1 Gy). The size of the incidence cohort was 47,282 people. Over the follow-up period 01.01.1956-31.12.2018, the number of person-years made up 1 292 930; mean dose to the stomach was 47 mGy, maximum – 1,132 mGy. Excess relative risk of the cancer incidence of the digestive organs was assessed using the Poisson regression analysis. Calculations were performed using the EPICURE Statistical software package. Excess relative risk for stomach cancer with a 2-year minimal, was 0.98/Gy (р=0.026), for all cancers of the digestive organs, excluding intestines, – 0.58/Gy, р=0.06. There was no significant modification of the effect by non-radiation factors. These values of excess relative risk do not disagree with the results of similar studies in the Japanese cohort of the atomic bomb survivors who were compatible in terms of age but had acute exposure at higher doses. No significant dose dependence of the cancer incidence of the oral cavity, esophagus, liver, or pancreas was detected at this stage.

Medical diagnostics procedures involving the use of ionising radiation is one of the most intensively developing areas in medical diagnostics. At the same time, medical exposure of patients has a number of fundamental differences from other routine situations of planned exposure. As a rule, medical exposure is acute, and radiation doses in some types of examinations exceed the level of natural and man-made exposure associated with normal operation of radiation facilities. In such a situation, risk differentiation is of great importance, taking into account the different radiosensitivity of individual sex and age groups of patients. Radiation risks should be taken into account both when prescribing examinations involving the use of ionising radiation and when analysing the benefit-harm ratio associated with their application to specific patients. Another reason why risk assessment is an urgent task is the need to inform patients and/or their legal representatives about the health risks associated with the carrying out of examinations, including radiation risks. Within the framework of the present work, the risks associated with fluoroscopic examinations were assessed. To characterise the risk we used the DALY indicator, which is more and more frequently used in risk assessment, reflecting the possible number of lost years of healthy life as a result of radiation exposure during the study. The aim of the work was to calculate DALY values for different sex and age groups of patients from the Russian population during fluoroscopic examinations. To achieve this aim, the method of estimating the number of healthy life years lost due to exposure to ionising radiation, which was developed in the course of the research work, was used. The paper presents the results of calculating DALY values for three types of fluoroscopic examinations. This work represents the next step in the direction of harmonisation of radiation risk assessment methodology with the methodologies of risk assessment of other nature. One of the directions of using the calculation results is the development of methodological approaches to the calculation of sex- and age-dependent risk coefficients associated with medical exposure of patients. The analysis of the obtained results showed that the contribution of oncological diseases to the total radiation harm in older men was significantly higher than in women.

The usage of modern positron emission tomography scanners, in particular with digital detectors, allows obtaining images with better quality, increases the detection of small pathological lesions, reduces scanning time and the activity administered to the patient which leads to a decrease of patient dose as well. However, the values of the quantitative image parameters shift upward, which can lead to significant differences with the quantitative assessment obtained on the previous generation device. In order to compare quantitative assessments obtained on different generations of PET/CT, it is necessary to harmonise quantitative image parameters and perform regular quality control. The aim of current work is the comparison of different methods for harmonization of quantitative image parameters on the example of harmonisation of two PET/CT: Biograph mCT 128 and Biograph Vision 600. NEMA IEC Body phantom filled with 18F solution was scanned in Listmode in two bed positions with overlap in the sphere area during five minutes per bed position. Recovery coefficient used for harmonisation was measured for each sphere of the phantom. Harmonisation between Vision and mCT was performed using two methods: choosing of harmonised reconstruction parameters and EQ.PET technology. The acceptable divergence range between the recovery coefficients for Vision and for mCT is ±10% (20% range). The recovery coefficients measured for reconstruction: 4 iterations and 5 subsets, ToF+PSF, Gaussian 7 mm, matrix 220x220 completely fit within the 20% range. The recovery coefficients measured using EQ = 6 mm (optimal value) fit within the 20% range except the spheres with a diameter of 10 and 13 mm. Both harmonisation methods allow to approximate the quantitative assessment/ However, EQ.PET has limitations for the small lesions. Choosing harmonised reconstruction parameters is the mostwidely used harmonisation method; the EQ.PET allows to harmonise quantitative assessment without the use of multiple reconstruction protocols and losses in visualization ability

We have tested applicability of the commercially available portable spectrometer-dosimeter MKS AT6101D (the manufacturer: ATOMTEX, Belarus) to measure the density of 137Cs soil contamination (inventory of 137Cs in soil) in situ. The study was performed in 2015–2020 at the territories of the Bryansk region of Russia contaminated due to the Chernobyl accident. The in situ measurements were performed in the 17 ground plots (7 grasslands and 10 kitchengargens) for which the 137Cs inventory and the mean migration depth of the radionuclide in soil was available from laboratory (ex situ) measurements of soil samples. It was found that the in situ data obtained with the method that was provided by the manufacturer of the instrument required additional correction on the vertical distribution of 137Cs in the soil. The correction procedure was developed; in 2020–2021, it has been successfully tested in 114 kitchengarden plots located at the settlements in the zones of radioactive contamination in the Bryansk region.

The article presents results of a study of the radiation environment on territories adjacent to the sites of the “Globus-4” and “Gorizont-1” peaceful nuclear explosions in the Komi Republic. Field survey was carried out in July 2021. The work provides an assessment of the radiation situation in terms of the main indicators: ambient dose equivalent rate, the content of anthropogenic radionuclides in soil, tritium in the water of water bodies and drinking water supply sources in the settlements nearest to the sites of the peaceful nuclear explosions. The values of gamma radiation ambient dose equivalent rate in all the surveyed territories are at the level of fluctuations of natural regional radiation background and amounted to 0.03 – 0.07 µSv/h in the territory of peaceful nuclear explosion “Globus-4”, 0.01 – 0.05 µSv/h in the territory of “Gorizont-1”. No contaminated soil areas with anthropogenicradionuclides were detected. Tritium activity concentration in water samples does not exceed 5 Bq/kg, which is typical for global levels of this radionuclide in water bodies. The study has shown that the radiation situation in the territory of peaceful nuclear explosions “Globus-4” and “Gorizont-1” meets the requirements of SanPiN 2.6.1.2819-10 “Ensuring radiation safety of the population living in the areas of (1965 – 1988) nuclear explosions for peaceful aims” and currently poses no threat to public health. A conservative dose estimate of additional anthropogenic exposure of individuals from the population from tritium intake with water from centralised water supply sources was 0.065 µSv/year. Longterm radiation safety of the researched territories requires organisation of radiation monitoring, determination of protected zone boundaries and installation of readable information signs warning about radiation hazard and prohibition of economic activities.

An open plot of virgin land is the reference location in the basic model used to date to estimate the effective dose of external exposure to the population living in a radioactively contaminated area. As our field observations in the Bryansk region of Russia have shown, at present it is very difficult to find truly reference plots of virgin land due to the fact that many virgin meadows were plowed or reclaimed for more than 30 years after the Chernobyl accident. Without special instrumental survey, such disturbed meadow areas can easily be confused with areas of virgin soil. Therefore, the situation with the use of open areas of virgin soil as the reference location has changed dramatically since the first years after the Chernobyl accident. It requires a change in the approach to choosing such a location for the model and/or some revision of the structure of the model itself. Firstly, we propose and justify the use of a permanently cultivated kitchengarden plot as the reference location. The second way to resolve the current difficult situation with the presence of a sufficient number of the virgin soil sites could be excluding the very concept of “reference location” from the model. In this case, when calculating the effective dose of external radiation, it is proposed to directly use the values of the gamma radiation dose rate in the air normalized to the 137Cs contamination density of soil. The values of the normalized dose rate should be experimentally determined in the required time period for each of the locations taken into account in the model.

In accordance with the fundamentals of state policy in the field of ensuring nuclear and radiation safety, State Corporation «Rosatom» carries out the remediation of JSC “AECC” nuclear legacy sites. The article presents the results of environmental impact assessment carried out in 2021-2023 in the vicinity of sublimation waste storage facilities that are being decommissioned. Health physics studies involved ambient dose rate measurements, sampling (soil, groundwater) and analysis of radiological and non radiological environmental pollutants. The external gamma dose rate, as well as content of natural and artificial radionuclides in soil, don’t exceed background levels. While uranium presence in groundwater is found to be 10 times and higher then background level. The data obtained indicate that the accumulated wastes of sludge sumps (bottom sediments, pulp) сome into contact with natural water. Flooded storage facilities form a plume of contamination spreading out in the direction of groundwater flow. Given the current situation optimization of the existing environmental monitoring programs in the JSC “AECC” health protection zone is recommended and reference levels of uranium proposed.

The objective of the current study is the direct assessment of the excess relative risk of solid cancer mortality in people affected by low dose-rate chronic exposure mainly in low-to medium dose range (up to 1 Gy) at the age of

A comprehensive radiation survey of settlements in six districts of the eastern part of the Orenburg region in terms of exposure to natural sources of ionizing radiation, carried out in 2019, revealed numerous exceedances of the hygienic norm (action level) for indoor radon concentration in residential and public buildings. It was found that among other studied factors, exhalation of radon from the ground under the buildings is the main source of high levels of public exposure. Due to the lack of funding for the continuation of the survey in 2020, specialists of St. Petersburg Research Institute of Radiation Hygiene after Professor P.V. Ramzaev, Directorate of Rospotrebnadzor in the Orenburg region and the Center of Hygiene and Epidemiology in the Orenburg region needed to develop new approaches to survey planning. These new approaches should provide maximum amount of measurement information necessary to ensure radiation safety of the region’s population, with minimal financial investments and labor costs. Indoor radon concentration in residential and public buildings was undoubtedly chosen as the studied factor, and the integrated measurement method using SSNTDs was chosen as the most suitable method for the objectives of the survey due to its scalability and ease of detectors deployment. Since exposure to radon and its progeny is the second leading cause of lung cancer after smoking, the selection of priority districts of the region for the radon survey was based on average standardized trachea, bronchi, and lung cancer morbidity rates in the districts of the Orenburg region for 2009-2018. The survey conducted in 2020-2023 revealed exceedances of the hygienic norm (action level) for indoor radon concentration in five of seven surveyed districts. By 2025 it is planned to conduct radon surveys in three more districts of the Orenburg region with increased respiratory systems cancer morbidity rates.

The need to study and evaluate the leading protective mechanisms of the respiratory system remains one of the key, but unresolved problems of modern medicine, concerning both radiation hygiene and toxicology, and pulmonology. The model of the respiratory tract presented by the ICRP only partially addresses them, significantly limiting the feasibility and possibilities of its use. The solution of this problem undoubtedly contributes to the improvement of methods of prevention and treatment from the effects of incorporative radionuclides entering by inhalation, as well as methods for diagnosing and treating respiratory diseases aimed at the earliest stages of their pathogenesis, given that the processes of deposition of inhaled substances and lung clearance directly depend both therapeutic and pathogenic effects. This is especially relevant when there is a danger of contamination with radioactive waste, when there is an urgent need to deal with highly pathogenic influence and its consequences. The most informative method for studying the processes of deposition inhalant and mucociliary clearance is radioaerosol. However, due to the circumstances, there are no radiopharmaceuticals that could be used for such a study since the 2000s, which prompted us to carry out this work. At the same time, albumin microspheres labeled with 99mTc are considered potentially suitable, but not studied radiopharmaceuticals in this regard. The aim of the work was to study the aerodynamic properties of albumin microspheres and evaluate the possibilities of their use for radioaerosol study of the processes of deposition of inhaled substances and mucociliary clearance. The aerodynamic properties of albumin micro[1]spheres were studied using optical and scanning electron microscopy by studying their dry dispersion, initial and obtained from its suspension in distilled water, generated by an ultrasonic inhaler according to the developed technology. The results indicated that the dispersible particles were characterized by sphericity, clear boundary differentiation and a relatively homogeneous distribution of particles with a relatively narrow size range (spread 1-2.5 µm) and little conglomeration, as well as a smooth surface. Conclusion. The investigated albumin microspheres are suitable for radioaerosol study of the processes of deposition of inhaled substances and mucociliary clearance.

Introduction of new methods of nuclear medicine, X-ray diagnostics and therapy using medical sources of ionizing radiation inevitably leads to an increase in the number and types of accidents (abnormal situations). In international practice in recent years, special attention has been paid to the prevention of radiation accidents and incidents from medical exposure. The main focus is put on accidental exposure (overexposure) of patients in X-ray and radionuclide diagnostics and therapy. These approaches are implemented in Russian regulatory and methodological documents in a limited and formal way. The main attention is paid to large-scale technogenic radiation accidents, and accidents (abnormal situations) from medical irradiation are undeservedly ignored. The aim of the work was to analyze the terminology and classification of radiation accidents and incidents from medical exposure in the Russian Federation and foreign countries to develop proposals to improve approaches to their classification within the framework of revision of existing regulatory and methodological documents. The results of the work indicate that it is necessary to actualize Russian approaches to the definition and classification of radiation accidents in medicine considering the specifics of medical exposure. For this purpose, it is advisable to introduce different levels of accidents (abnormal situations), differing from each other by the scale of impact and consequences for patients, workers and public. Considering the absence of elaborated scenarios of accidents (abnormal situations) in Russian regulatory and methodological documents, such gradation can be borrowed from international regulatory documents provided that it is adapted to the specifics and realities of the Russian health care system

In case of radiation accidents, one of the radical protective measures is the evacuation of residents from contaminated areas. Its purpose is to reduce the possible radiation effect to the population. At the same time, evacuation itself becomes a serious stressful factor that has a negative impact on a person’s health and mental status. The objective of this work is to assess the state of mental health of residents of the Muslyumovo settlement in the Chelyabinsk region (the territory exposed to radioactive contamination as a result of radioactive waste releases into the Techa River) who participated in the resettlement program in the period from 2006 to 2010. Mental health was assessed twice: primarily in 2008-2010 against the background of resettlement, and again in 2019-2020, 10 or more years after the resettlement. The study includes 2 groups formed by random selection. The main group consisted of 100 persons from among the participants of the resettlement program. The comparison group included 80 persons living in the territories exposed to radioactive contamination, but not participating in the resettlement program. According to the main socio-hygienic characteristics, the groups are homogeneous and comparable. The following methods were used: clinical, clinical and psychological, and the method of statistical processing of materials. As a result, it was found that both in the primary and in the repeated study, residents of the Muslyumovo settlement, Chelyabinsk region, participating in the resettlement program, were statistically significantly more likely (p

Computational phantoms are used to calculate the doses of internal exposure of active bone marrow. The computational phantoms of ICRP were created for a reference man with anatomical characteristics typical of an average individual. The doses calculated with such phantoms correspond to population-average values. Individual variability introduces a stochastic component of uncertainty into the dose estimation. The objective of this study is to assess the effect of individual variability of bone structure dimensions on the results of dosimetric modeling. The phantoms are represented by simple geometry figures filled with trabecular structures and bone marrow (spongiosa), covered externally with a cortical layer. The models of bone geometry are described by parameters characterizing the linear dimensions, the microarchitecture of the spongiosa (trabecular thickness, trabecular separation, bone volume fraction), as well as the cortical layer thickness. By varying these parameters, sets of phantoms were generated to simulate the individual variability of bone geometry. The mean absorbed dose rate in active bone marrow from a single decay of 90Sr/90Y was calculated assuming isotope distribution either in the volume of the trabecular or cortical bone. All estimates are on the example of the phantom of an adult male skeleton. The individual variability of the main parameters of segment computational phantoms depends on size and equal to: a) for linear dimensions – 12-15%; b) for bone volume fraction – 22-24%; c) for cortical thickness – 21-23%. This leads to uncertainties of dose rate estimation equal to 21% – 25%.

In cases of intake of higher levels of plutonium, a chelate diethylenetriaminepentaacetic acid is used to enhance the elimination and reduce deposition rate in the organs of major deposit in the form of calcium compound Ca-DTPA (pentacinum). To interpret the results of the nuclide measurements in excreta while estimating the doses of internal exposure to plutonium, the biokinetic and dosimetry models recommended by ICRP are applied; and in case of the actinide intake through damaged skin it is recommended to use the models of NCRP of the USA. Since the application of chelates significantly changes the picture of plutonium urinary excretion, special models of complex Pu-DTPA behavior are developed to describe the plutonium biokinetics in presence of chelates. The purpose of this work is to assess the suitability of a special model of plutonium behavior in presence of chelates elaborated by K. Konzen to describe the plutonium biokinetics in the body by the cases of wound intake of industrial plutonium compounds in the FSUE Mayak PA workers. This study used the measurements of plutonium activity in daily amount of urine for three cases with the actinide intake through damaged skin and Ca-DTPA treatment, the duration of pentacinum application and observation periods for workers depending on the levels of intake. For each case, the most likely type of an entered compound was selected using Akaike information criterion, then the daily urinary activity of plutonium was calculated by the model (estimated value) on the same days when it was determined actually (actual values). The analysis of the compliance of calculated data with actual data was conducted using the statistic tests of Foster-Stewart,Breusch-Godfrey, Mann-Whitney, Shapiro-Wilk, and the determination coefficient. It was found that for all cases considered, the adjusted determination coefficient and Foster-Stewart test indicated the compliance of actual data with calculated ones. The statistical analysis of the compliance of calculated data with actual measurements of plutonium urinary activity showed that the special model of plutonium behavior proposed by K. Konzen was able to predict the urinary activity of plutonium during both the radionuclide decorporation measures and the period of pentacinum aftereffect.

This paper describes the preconditions of creation and the process of development of the Automated System for Radiation Risk Analysis. Three main objectives for the development of an automated system for radiation risk analysis were identified: creation of a tool for the development and scientific justification of hygienic standards and other protective quantities in the field of ionizing radiation application; practical implementation of the principles of justification and optimization in radiation protection on the basis of monetary assessment of radiation health risks; and comparative analysis of risks of different nature on the basis of comparable indicators of population health. The Russian software platform 1C: Enterprise was chosen as the development platform for the Automatized System for Radiation Risk Analysis. The choice of this platform was related to simplification of integration with other computer systems being developed at the Research Institute of Radiation Hygiene after Prof. P.V. Ramzaev, such as the Automated System for Radiation Exposure Control of Rospotrebnadzor. Before the practical development of the system in accordance with the terms of reference, the main parameters in view of its interaction with the user were determined: arrangement of the user interface elements, main input parameters, primary calculated indicators and output calculation results, etc. The estimation of annual increase in the probability of radiation-induced malignant neoplasms depending on the organ dose, sex and age of the exposed person and other parameters according to the models of the UN Scientific Committee on the Effects of Atomic Radiation, the U.S. Environmental Protection Agency and Publications 103 and 152 of the International Commission on Radiological Protection was implemented in the system. The capabilities of the system include calculation of a number of modern lifetime radiation risk indicators used for risk characterization in various scientific publications over the last 35 years, including calculation of population risks based on national medical and demographic data of several dozen states published over the last 50 years.

This review provides information on the radiation situation in mining and energy production facilities. Mining activities are considered as one of the significant sources of radioactivity. Many radionuclides and metals that are transported by surface and ground waters, air flows over significant distances, contaminating soils, subsoil and bottom sediments of the adjacent territory, forming geochemically specific naturaltechnogenic areas. In this work is given an overview of radiation conditions in the territories of potassium phosphate, hydrocarbon and coal deposits. Developed potassium ores are the source of 40K emission into the environment. According to the results obtained, the migration of investigated radionuclides is limited to the zone of 2 km. Only an insignificant part of the investigated samples (8%) exceeds the world average activity of 40K for soils. In bottom sediments, the average activity of 40K does not exceed the values for other territories with anthropogenic impact. More than 30 million tonnes of phosphate fertilizers are consumed worldwide each year, and their use increases crop production. However, a possible negative effect of these fertilisers is the contamination of cultivated land with some natural radionuclides. Uranium concentrations in phosphate vary from 37 to 4900 Bq/kg for 238U and from 100 to 10 000 Bq/kg for 226Ra. The amount of radioactivity in oil, gas and formation water is estimated through determination of 40K, 226Ra, 232Th. According to the published data, increased radiation background is observed near wellheads, in the places of oil sludge accumulation, near the flares at oil and gas enterprises, as a result of bringing a number of natural and man-made radionuclides (226Ra, 232Th, 40K, 137Cs, 90Sr, etc.) to the day surface. Coal mines are sources of radioactive contamination. This results from the extraction of large amounts of natural radionuclides from the subsoil together with the coal. This paper presents the average natural radionuclides content in coals from some of the world’s coal mines. With the development of mining and fuel-energy complexes, there is an active export to the surface together with minerals of natural radionuclides 40K, 232Th, 226Ra, 238U, which leads to an increase in the radiation load on the environment. In this connection, the problems of ensuring radiation safety at the facilities of mining and fuel and energy industry require the closest attention.

Official data on radiation doses for flaw detectors do not take into account working conditions. In the reporting forms, there is no division between personnel performing flaw detection in stationary conditions and in situ, which roughly averages the values of effective doses towards underestimating the values for personnel working in site radiography. In this work, comparison of our own data on radiation doses of flaw detectors was performed. It has been shown that the difference in the mean and median values of effective doses reaches 10 times. When performing flaw detection in stationary conditions, the personnel are at a sufficient distance from the source of ionizing radiation and are well shielded by engineering protective equipment, so the exposure is fairly uniform. In such cases, one individual thermoluminescent dosimeter located at chest level is sufficient to estimate the effective dose. The average annual effective dose for personnel conducting flaw detection in stationary conditions is 0.87 mSv (median – 0.88 mSv, maximum value – 0.99 mSv). During individual radiation monitoring of personnel performing flaw detection in situ using portable roentgen flaw detectors, cases of neglect in the use of individual dosimeters were identified, which requires more stringent measures to comply with existing requirements for ensuring radiation safety and operating rules for individual dosimeters. The average annual effective dose for flaw detectors working with portable roentgen flaw detectors is 9.03 mSv (median – 8.85 mSv, maximum value – 12.37 mSv).

Significant temporal variations in radon are observed in any buildings, including unoccupied buildings with limited ventilation. This fact causes serious difficulties in radiation monitoring to assess the compliance of premises with the requirements of the normative, which limits the annual average level of radon in buildings. Therefore, neither at the national nor at the international level has yet been solved the problem of standardizing the indoor radon measurement if the test duration is less than a year. An analysis of approaches to radon measurement, including an assessment of the effectiveness of regulation, shows very significant differences between practices established in different countries. For example, in Russia, rapid (no more than 20 min) measurements are mainly used and mitigation measures to protect existing buildings from radon are practically not carried out. In European countries, mainly long-term (at least two months) measurements are used, while mitigation measures are still relatively rare, with the exception of the UK and Sweden. In the USA, short-term (2–7 days) measurements are widely used, which are not only carried out, but also paid for by residents themselves, including mitigation measures. However, despite the established approaches to indoor radon monitoring in Russia and the USA, there is a persistent distrust among specialists in the results of shortterm and, especially, rapid measurements. In this regard, a compromise approach is proposed to standardize radon measurements based on a rational criterion by applying fundamental ISO/IEC concepts such as “measurement uncertainty” and “conformity assessment”. The rational criterion for conformity assessment allows using measurements of different durations, providing a given reliability when making a decision. It also proposes a rationale for optimizing indoor radon monitoring through the participation of not only professional inspectors, but also the population itself due to the possibility of introducing simple methods and inexpensive radon devices within the rational criterion.

The purpose of the study is to identify differences in the content of 137Cs in the phytomass of coastal aquatic vegetation of the Vetka and Chechersk districts of the Gomel region for the period 2012–2022. The description and identification of ecological groups of coastal aquatic vegetation and the sampling of soil and plants to determine the content of radiocesium in the growing seasons of 2012 and 2022 were carried out according to generally accepted methods. It was found that the content of 137Cs in water samples from the objects of Vetka district did not exceed the normative value for drinking water (10 Bq/kg). The average specific activity of radiocesium in the soil for the studied objects was 807±125 and 586±84 Bq/kg in 2012 and 2022, respectively; and for soil was 549±85 and 395±46 Bq/kg respectively. Over time, there was a decrease in the amount of radiocesium in soil and in ground by 1.3–1.4 times. The average content of the isotope in the plants in 2012 and 2022 was 93–917 and 59–578 Bq/kg, respectively. The amplitude of variation in the average values of accumulation coefficient in the soil-plant system was 1.03 and 0.11 Bq/kg:Bq/kg in 2012 and 2022, respectively. In the ground-plant system it was 3.08 and 0.01 Bq/kg:Bq/kg, respectively. The specific activity of 137Cs in the water of objects in the Chechersk region did not exceed 3 Bq/l. The average content of 137Cs in the ground was 316 and 231 Bq/kg in 2012 and 2022, respectively. The same parameters for the soil were within the limits of 471 and 340 Bq/kg, respectively. The average content of 137Cs in phytomass varied from 149 to 483 Bq/kg in 2012. After 10 years, the amount of radionuclide was 115–288 Bq/kg. The average values of accumulation coefficient in the soil-plant system in 2012 and 2022 were 1.44 and 1.01 Bq/kg:Bq/kg, and in the soil-plant system were 1.70 and 1.10 Bq/kg:Bq/kg, respectively. As a result of the study, similar dominant groups of coastal aquatic plants were not identified in terms of the accumulation of radiocesium in the objects of the Vetka and Chechersk regions.

The designation of peaceful nuclear explosions as special radioactive waste imposes serious requirements to the territory of the explosion, its boundaries, and stakeholders informing about the prohibition of economic activities within these boundaries. The acting Sanitary Norms and Rules SanPiN 2.6.1.2819–10 “Ensuring radiation safety of the population living in areas where nuclear explosions were conducted (1965–1988) for peaceful purposes” do not define the size of the boundaries of protected zones. The aim of this paper is to analyze the scientific literature on the structure of deformation changes in the Earth’s interior due to peaceful nuclear explosions and to justify quantitative ratios on the basis of which the size of protected zones can be estimated. The quantitative ratios were selected on the basis of a comparative analysis of the literature data. Using the ratios values made it possible to calculate the radii of deformation changes (cavities, crushing zones, fracturing zones, and zones of residual deformations) in various rocks. It is shown that the maximum values of fracturing radii for peaceful nuclear explosions carried out on the territory of the Russian Federation in hard rocks and in plastic rocks do not exceed 200 m and 250 m, respectively.

We have summarized, analyzed and assessed data on radiation accidents and incidents that occurred on the territory of the Russian Federation for the period from 2010 to 2022. The data are presented in the Data bank of radiation accidents and incidents of the Information and Analytical Center of Rospotrebnadzor on radiation safety, in the form of federal statistical observation No. 18 “Information on the sanitary condition of the subject of the Russian Federation”, and in radiation-hygienic passports of territories. The objective of the study was to conduct a comparative analysis of information on radiation accidents for the period from 2010 to 2022 contained in the above-mentioned sources. The objective of the study was to perform a comparative analysis of information on radiation accidents for the period from 2010 to 2022 contained in the above-mentioned sources. Comparison of the number of radiation accidents in dynamics has shown the presence of discrepancies between the studied data sources, lack of systematicity of these discrepancies, and multidirectional trends in the number of radiation accidents. From 2010 to 2022, in the Data bank of radiation accidents and incidents of the Information and Analytical Center of Rospotrebnadzor on radiation safety were registered 2,690 cases of radiation accidents in 71 subjects of the Russian Federation, in Forms No. 18 – 2,469 cases in 67 subjects, in radiation-hygienic passports of territories – 2,457 cases in 76 subjects. Differences in the structure of data provision have been established: in the data bank and Form No. 18 radiation accidents are classified, but at the same time the principles of classification coincide partially; there is no classification in the radiation-hygienic passport of territories. The analysis showed that no information on radiation accidents was received from four regions during the study period. Among the subjects that provided information, only six regions have coincidence of data on all sources. Some regions were identified where information was provided to some data bases but not to others. In five regions, a range of more than 50 cases was detected; the coefficient of variation in the number of radiation accidents between sources exceeded 33% in 53 subjects. The identified discrepancies demonstrate the lack of a systematic approach to the procedure for providing information on radiation accidents, which may be related to the failure to fully comply with the requirements for providing information to Rospotrebnadzor and the St. Petersburg Research Institute of Radiation Hygiene after Prof. P.V. Ramzaev, contradictions in the list of information to be provided in Rospotrebnadzor’s offices, and difficulties in determining by Rospotrebnadzor’s offices in the subjects of the Russian Federation what information is to be reported in this or that form of statistical observation.