The objective of the study is to obtain risk estimates of lung cancer mortality for members of the Southern Urals Populations Exposed to Radiation Cohort. Materials and methods: The cohort, which unites individuals who were chronically exposed to radiation in the South Urals on the Techa River and in the East Urals Radioactive Trace, consists of 62,592 people. A regression analysis with a simple parametric model of the excess relative risk was used in the study. Results: Over the follow-up period from 1950 to 2020, 925 deaths from lung cancer were identified. The number of person-years at risk was 1964140. Mean accumulated lung dose calculated using the TRDS-2016 dosimetry system was 0.038 Gy and the maximum dose was 0.995 Gy. As a result of the analysis a statistically significant linear dose-dependence of the lung cancer mortality rate was obtained. The ERR/Gy for lung cancers with 2-year minimal latency period was 0.94/Gy, 95 % CI: 0.01–2.19; p < 0.05. Over the 71-year follow up period 3.5 % of lung cancer cases could be associated with radiation exposure in cohort. Analysis of baseline lung cancer mortality rates showed that smokers had 4 times higher mortality rates (p < 0.001). When analyzing the possible modification of the dose effect, a statistically significant relationship between risk and dose was obtained in women; in the group of Tatars and Bashkirs; in urban residents; in those who have cancers in first-degree relatives; in those exposed to radiation in the East Ural radioactive trace. Conclusion: Based on the findings of the accomplished study a statistically significant lung cancer mortality risk per 1 Gy has been established in the cohort of people affected by long-term radiation exposure in the low-to-medium dose range. The obtained results could serve as the basis to develop the program of preventive care for the population aggrieved.

This study compares standard radiation dose estimates for patients undergoing computed tomography (CT) of major anatomical regions at the A.I. Burnazyan Federal Medical Biophysical Center using three different statistical approaches. A total of 4,854 CT examinations performed in 2024 were analyzed. For most anatomical regions, the standard dose calculated using Method 1 (entire patient cohort with an average body weight of 76–85 kg) was significantly higher than that obtained using Method 2 (patients selected with a body weight of 70  ±  5 kg), with statistically significant differences (p < 0.001).Comparison of doses calculated by Method 1 and Method 3 (linear regression modeling based on the entire cohort to estimate the dose for a "standard" 70 kg patient) revealed similar values, reflecting the influence of the overall weight distribution on the final dose estimates. When comparing Method 2 and Method 3—both applied to estimate the dose for a “standard” patient—it was found that Method 2 yielded lower values, with differences ranging from 1.1 to 1.5 folds. For example, for the most extensive combined anatomical regions, the effective dose per a non-contrast study was 6.3 mSv (Method 2) and 9.34 mSv (Method 3), and for the contrast-enhanced CT of the abdominal and retroperitoneal organs, 18.8 mSv (Method 2) and 20.11 mSv (Method 3). Conclusion: The application of three statistical methods for assessing standard effective radiation doses in CT was analyzed. The accuracy and comparability of standard dose estimates for the purpose of exposure control depend on the consistency of methodological approaches used to determine the need for dose optimization.

The primary quantity used for monitoring exposure levels of the general population and personnel at radiation facilities is the individual effective dose. This metric accounts for variations in the radiosensitivity of specific organs and tissues by employing corresponding tissue weighting factors recommended by the ICRP. These factors were derived based on medico-demographic data from two artificially constructed populations: "Euro-American" and "Asian." Estimates of relative harm, calculated from risk assessments, served as the basis for establishing the recommended values of tissue weighting factors for organs and tissues. However, the use of effective dose as a risk measure in cases of non-uniform exposure within specific populations raises questions about the appropriateness of applying alternative tissue weighting factors in its calculation to more rigorously account for differences in relative radiosensitivity. The study aims to assess whether the recommended values of nominal risk coefficients and weighting factors for organs and tissues provide a comparable level of safety for the Russian population compared to that provided for the ICRP nominal population. Materials and Methods: The assessment of radiation-induced cancer risk was conducted using Russian medico-demographic data from 1993 to 2022, applying the interpopulation radiation risk transfer model from ICRP Publication 152. Results and Discussion: The calculations indicate that risk estimates for most organs and tissues in the Russian population have gradually increased for males over the 30- year period. However, with the exception of thyroid cancer risk in females, these estimates do not exceed the corresponding values used to establish the tissue weighting factors. Conclusion: The current system of risk indicators and dose limits provides an adequate level of protection for the Russian population and does not require revision until international approaches to radiation protection are updated.

The main effective radiation protection measures, in addition to decontamination measures and limiting the consumption of food products of local origin, include the evacuation and resettlement of residents. Nevertheless, forced changes in usual habitat of residents can have a negative impact on the quality of their life. The study of the impact of radiation and non-radiation factors on the health of the exposed population requires classifying for the studied cohort by the criterion of forced relocation (relocation due to implementation of radiation protection measure). However, the quality of retrospective information and the specifics of the implementation of this action do not always unambiguously allow to determine the moment of time when displacement of residents from radioactively contaminated territories actually began. The purpose of this study is to determine the actual term of relocation of settlements whose residents are included in the Ural cohort of accidentally irradiated population. Materials and methods: The main source of in-formation in this study was the medical-dosimetric database on exposed residents of radioactively contaminated territories due to two situations: discharges of liquid radioactive waste from a chemical plant in the late 1940s and early 1950s into the Techa River and the 1957 radiation accident at the same plant. The study cohort numbered approximately 63,000 people. Establishing criteria for forced relocation has been carried out using methods of demographic analysis of the collected data, and time frames of relocation has been determined using historical materials. Results and Discussion: The migration activity of residents between 1950 and 1960 has been studied for the two radiation situations. The net migration rate per year has been determined as a basic criterion (minus 100 ‰ for relatively large- and medium-sized settlements, minus 150 ‰ for small ones). The year of the beginning of the forced resettlement of residents and the year of the end of the resettlement have been determined for each resettled settlement. Conclusion: The study of migration processes allowed to define the criterion for forced relocation and determine actual time frames for the implementation of the protective action in relation to members of the cohort.

A wide range of tasks associated with organizing and conducting inspections has led to the development of a large number of models of beam inspection units differing in their scope of application and characteristics of the ionizing radiation sources included in their composition. According to the radiation and hygienic certification, 7,095 X-ray inspection units were used in the Russian Federation in 2023. The rich hardware fleet and the lack of a special regulatory and methodological document clarifying the issues of organizing and conducting individual dosimetric monitoring of personnel ensuring the operation of X-ray units for inspecting baggage and goods prompted a study to assess the adequacy of current approaches to assessing personnel doses. Materials and methods: Industrial radiation monitoring of operator workplaces of 11 X-ray units for inspecting baggage and goods of various models was carried out. The results of individual dosimetric monitoring of personnel ensuring the operation of X-ray units for inspecting baggage and goods using individual thermoluminescent dosimeters are presented. Results and Discussion: The presented models of X-ray units under normal operating conditions do not pose a significant radiation hazard to personnel and the population. The average value of the individual dose equivalent Hp(10) for operators of radiation inspection units practically corresponds to its value for the natural background dose component – the man-made component of the radiation dose is negligible. For all the considered models of X-ray units, the average value of the ambient dose equivalent rate of gamma radiation at the operators' workplaces was: 0.14 μSv/h and 0.13 μSv/h for operators of X-ray units for inspection of baggage and goods of types 1 and 2, respectively. Conclusion: Thus, based on the results of industrial radiation monitoring of the presented models of X-ray units and the results of individual dosimetric monitoring, it can be concluded that the conditions of radiation safety in the radiation field of these sources are properly observed by operators and persons not classified as personnel.

The aim of the current study was to create a new and easily reproducible method of modeling acute radiation syndrome, representing the features of the clinical flow of this disease. Materials and Methods: A series of experiments on Wistar rats, both genders (nursery “Rappolovo” (Leningrad region), weight 180–220 g), were performed. Rats were divided into groups and one time exposed at the investigated dose (range of 6–10 Gy) on Elekta Precise accelerator using Solid Water HE (Sun Nuclear) 30×30 cm2 phantom plates. The duration of animal observation was 30 days. Survival, mean lifespan, body weight dynamics, feed and water consumption, state of visible mucous membranes, hair coat and mobility were evaluated. Results and Discussion: The results showed that the proposed model of single exposure of laboratory rats demonstrates a good level of results reproducibility and complies with the basic requirements for experimental models. The lethality of rats within 30 days was 75% with a dose of 8 Gy, the 100% lethality of rats was with a dose of 10 Gy. The results are successfully reproduced in repeated experiments. Conclusion: The obtained data indicated that the proposed model is reliable and can be used for preclinical studies of radioprotectors without existing models’ problem of variability of results.

Modern radiation diagnostics, due to its rapid development and improvement of the methods and technologies used, requires constant monitoring, including in the context of patient irradiation levels. The choice of appropriate X-ray diagnostic equipment is one of the key aspects of ensuring radiation protection. Materials and Methods: The study analyzed X-ray diagnostic machines and digital fluorographs with different imaging technologies (detector types), using the example of lung surveys. The evaluation of the machines was carried out using a specially developed 5-point scale in relation to key parameters of quality and safety. Results and Discussion: The results of the study show that digital X-ray diagnostic machines with a U-arc stand and digital X-ray machines with a flat panel detector demonstrate higher image quality compared to other technologies at relatively low levels of patient irradiation. An additional advantage of such devices for city clinics, compared to "classic" fluorographs, is their versatility and the ability to conduct various X-ray examinations (not only lung examinations), which ensures the interchangeability of devices and the effective redirection of the patient flow during the repair of the device. Conclusion: The results of the study emphasize the importance of choosing the appropriate X-ray equipment to ensure high quality diagnostics and patient protection, taking into account the profile of the organization's medical care.

A review of epidemiological research of the effects of preconception (prior to conception) radiation exposure to a mother’s body was presented. The anatomical and physiological characteristics that affect radiosensitivity and radioresistance of female reproductive system were reported. Biological prerequisites accounting for different effects of radiation exposure to animals and humans were indicated. The results that were published in open access on epidemiological assessments of the effects of preconception exposure of mothers to the health of their offspring were described based on various cohorts as examples. Analysis of the research work was performed for the cohort of the offspring of atomic bomb survivors in Japan, among the offspring of the individuals affected by radiation accidents and nuclear weapon tests, among the population of the sites with high natural level of radiation. The results of research work among the offspring of female patients exposed to diagnostic and therapeutical radiation and of the offspring of the mothers who were in contact with ionizing radiation sources at workplaces were presented. A special attention was paid to specifics of standardization of occupational exposure of female personnel according to national and international approaches. Generally, it was demonstrated that despite a wide range of epidemiological research works there is still no clear understanding of the effects of preconception exposure of mothers to their offspring. The total results of the analysis of the effects of maternal exposure in preconception period are quite controversial and usually involve a range of uncertainties. In the course of such sort of epidemiological research the following difficulties are indicated: poor verification of medical outcomes, primary data based on questionnaire surveys, lack of detailed information on individual exposure parameters, low statistical power of research works and too short period of follow up of the cohort under research. For this reason, the necessity of further analysis of the effects of exposure of female body was indicated involving detailed risk coefficients of unfavorable reproductive outcomes. Prospective trends for epidemiological analysis of preconception exposure of mothers were indicated. Feasibility of assessment of long-term preconception radiation exposure was described based on the cohort of female workers of Mayak Production Association that is the leading atomic enterprise in the national history.

Data on dynamics in 137Cs concentration in muscles of farm animals obtained by the organizations of the Ministry of Agriculture of Russia in the areas of the Bryansk region affected after the Chernobyl accident have not been practically generalized so far. The aim of this study was to analyse the data of radioecological monitoring of 137Cs content in meat of farm animals in the south-western districts of the Bryansk region subjected to intensive contamination after the Chernobyl accident. Materials and Methods: The data on the 137Cs concentrations in 27519 samples of farm animal meat collected by the organizations of the Ministry of Agriculture of Russia in the period from 1986 to 2013 were analysed. Determination of 137Cs in samples was carried out by gamma-spectrometric method. Results and Discussion: The dynamics of 137Cs content in animal muscle tissue were largely determined by the specific protective measures implemented in agricultural production. In the initial year following the accident, the average half-life was 116 days for beef and 99 days for pork. Between 1987 and 1992, the effective half-life ranged from 1.5 to 1.6 years. After 1993, the decline in 137Cs levels in animal muscles slowed significantly, with half-lives extending to 9.8 years for beef and 16.1 years for pork. The rate of contamination decrease differed between meat produced in the public and private sectors, as well as between beef and pork.

The development of nuclear medicine has led to an increase in the use of open radionuclide sources and the associated processes of transporting ionising radiation sources and generating radioactive waste. This situation leads to focus on monitoring and accounting of ionising radiation sources in hospitals. The aim of the study was assessment of geographical distribution and structure of nuclear medicine centres in theRussian Federation. Material and Methods: The register of sanitary and epidemiological conclusions on the compliance (non-compliance) of activities (works, services) with the requirements of state sanitary and epidemiological rules and regulations were analyzed at the beginning of 2025. Results: 188 hospitals operated with radionuclide, are located in the Russian Federation in 2025, including 152 single photon diagnostic nuclear medicine departments (38 in Moscow and 20 in St. Petersburg); 81 positron emission tomography departments (26 in Moscow and 8 in St. Petersburg); 52 radiopharmaceutical therapy departments (12 departments in Moscow and 5 in St. Petersburg). According to the results of the study, all radiopharmaceutical therapy departments are based in diagnostic nuclear medicine centers. Conclusion: The current practice of organizing radiopharmaceutical therapy units based on diagnostic nuclear medicine units does not allow to consider the radiation safety issues separately for diagnostics and therapy. It is reasonable to have uniform requirements for nuclear medicine units

At present, the dose rate of gamma radiation from technogenic radionuclides in the territories contaminated as a result of the Chernobyl accident has significantly decreased and, in many cases, is comparable to the dose rate of gamma radiation from natural radionuclides. Therefore, when assessing the external doses to the population at these territories, it is important to correctly evaluate the contribution of natural radiation. The use of field gamma spectrometry (in situ measurements) allows solving this task directly on site without collection of environmental samples and subsequent analytical procedures in laboratory. For the in situ measurements, it is most convenient to use the gamma spectrometers that simultaneously measure both the dose rate in air and the effective activity concentration of natural radionuclides (226Ra, 232Th and 40K). The latter value is unambiguously related to the dose rate of gamma radiation from natural radionuclides when measurements are carried out in the 2π geometry. The possibility of using the results of measuring the effective activity concentration in conditions different from the 2π geometry, in particular, in an urban environment, requires justification. The aim of the study was to empirically determine the relationship between the ambient dose equivalent rate from natural radionuclides and the effective activity concentration of natural radionuclides in typical urban locations. Materials and methods. Simultaneous measurements (n = 170) of the total ambient dose equivalent rate and effective activity concentration were performed in the city of St. Petersburg (Russia) in the spring-autumn period in 2017–2024 using a portable gamma spectrometerdosimeter. The device was placed in a backpack on the operator's back. Main results. Based on results of the in situ measurements, the conversion coefficient from effective activity concentration to ambient dose equivalent rate ((nSv/h)/(Bq/kg)) was calculated. The mean ± standard deviation value of the conversion coefficient for the location “street”, “courtyard”, “square”, “embankment”, “bridge”, “park-lawn”, and “park-footpath” was 0.55 ± 0.02 (n = 70), 0.55 ± 0.01 (11), 0.55 ± 0.02 (10), 0.54 ± 0.01 (9), 0.54 ± 0.04 (16), 0.57 ± 0.02 (27), and 0.54 ± 0.01 (27), respectively. Conclusion. The obtained values of the conversion coefficient can be used when performing walk surveys of urban areas to determine contribution of natural sources to the total dose rate of gamma radiation in the case of radioactive contamination of the environment.

In order to ensure a high-quality and safe therapeutic process in radionuclide therapy, it is not sufficient to rely solely on safety monitoring within the framework of production control. Measures must be implemented within a quality assurance system as established in the quality assurance program. The purpose of this work is to define the requirements for quality assurance program in radionuclide therapy in terms of the ensuring radiation safety for patients, staff, the public, and the environment. The work discusses approaches to developing a quality assurance program in radionuclide therapy as a tool for optimizing radiation protection for patients, medical staff, and the public. The proposed structure of the quality assurance program covers all stages of radionuclide therapy – from patient identification and radiopharmaceutical quality control to the evaluation of therapeutic efficacy and safety at all levels. Particular attention is given to the need for equipment monitoring, imaging parameter control, management of biological waste, patient instruction upon discharge, as well as dosimetry-guided radionuclide therapy planning aimed at optimizing patient radiation protection. The quality assurance program in radionuclide therapy is proposed as a foundation for building a standardized, safe, and effective quality assurance system aligned with international practices, with a primary focus on personalized approaches to the planning and delivery of radionuclide therapy.

In modern clinical practice, multiple computed tomography examinations are increasingly common, which can lead to the accumulation of significant effective doses of patients. The aim of this study was to identify cases of high cumulative effective doses (more than 100 mSv) of adult patients undergoing computed tomography examinations in two departments of the Leningrad Regional Clinical Oncological Dispensary. Materials and Methods. The study is based on the analysis of patient effective dose data obtained from computed tomography examination logbooks for the periods 2020–2021 (Department No. 1) and 2019–2021 (Department No. 2). Effective doses were calculated based on dose-length product values using appropriate conversion coefficients in accordance with methodological guidelines MU 2.6.1.3584-19. Results. The study results showed that in Department No. 1, 1 % of patients (18 individuals) received cumulative doses exceeding 100 mSv, with a maximum value of 239 mSv. In Department No. 2, the corresponding figure was 0.3 % (9 individuals), with a maximum dose of 147 mSv. The dose accumulated over both extended periods (up to a year) and short intervals (less than a month). A comparison of the obtained results with international data showed that cumulative effective doses more than 100 mSv are often observed in non-oncological patients, including patients under the age of 40. In the study sample, most patients were over 40 years old. Justification and optimization of computed tomography examinations are the main tools for managing high cumulative effective doses in patients. It is important to emphasize the need to assess not only effective but also absorbed organ doses during multiple computed tomography examinations, especially when planning radiation therapy. Conclusions. Systematic monitoring of high cumulative effective doses in patients is necessary in the Russian Federation, particularly among younger patients.