Introduction: In natural ecosystems included in food chains with humans as the final link, high levels of ¹³⁷Cs were observed in the long-term period after the Chernobyl accident.

   The objective of this study was to describe current levels of ¹³⁷Cs in samples of foodstuffs from the Bryansk region settlements.

   Materials and Methods: An analysis of data on the ¹³⁷Cs concentration in 1837 samples of foodstuffs of wild origin from the Bryansk region settlements was taken. The ¹³⁷Cs concentration were measured using gamma spectrometry methods.

   Results of the Study and Discussion: Exceeding the permissible levels of ¹³⁷Cs concentration was found in all main categories of food products: mushrooms (40 % of the studied samples do not satisfy radiation safety requirements), wild berries (55 %), meat of game (50 %), and local fish (18 %). The total percentage of such kind of samples was 43 %.

   Conclusion: Foodstuffs of wild origin dominate internal exposure dose of residents at the present time. The main dose-forming foodstuff is wild mushrooms.

   Introduction: One of the most sensitive methods widely used to assess genotoxic effects on the human body in the early and long-term periods is the assessment of chromosomal aberrations. The study was focused on comparative analysis of the frequency of chromosomal aberrations in the blood lymphocytes of personnel (n = 20) of an atomic energy facility with a 15-year retrospective study.

   The aim of the study was to assess the dynamics of the frequency of chromosomal aberrations in the lymphocytes of the blood of atomic energy facility workers for 15 years.

   Materials and Methods: The assessment of the effects of ionizing radiation on the human body was performed by cytogenetic examination of the employees of the atomic energy facility (n = 20) exposed to ionizing radiation during their professional activities. The control group was composed of employees of the atomic energy facility, who underwent cytogenetic analysis in 2003. The study group was made up of the same employees of the atomic energy facility, who had been underwent a second cytogenetic study in 2018.

   Results and Discussion: A comparative analysis of the frequency of cytogenetic disorders in the blood lymphocytes of the atomic energy facility workers revealed differences between the studied groups in the frequency of dicentric chromosomes (p < 0.05). In the study group, compared with the control group, an increase in the frequency of dicentric chromosomes was revealed (p = 0.0017). The frequencies of the other chromosomal aberrations types studied (chromosomal fragments, chromatid fragments, and ring chromosomes) did not differ between the groups compared.

   Conclusion: The results of this work make it possible to supplement and trace the understanding of the mutation process in the somatic cells of individuals who are exposed to ionizing radiation during their professional activities. The revealed statistical differences in the frequency of dicentric chromosomes deserve special attention, since the presence of this type of chromosomal aberrations is a marker of radiation exposure and allows us to verify the fact of exposure.

   The purpose of the article is to analyze the radio protective and antioxidant properties of 3-hydroxypyridine fumarate in interaction with proton irradiation on a model test organism from the suborder Daphnia magna crustaceans in vivo.

   The salt of 3-hydroxypyridine fumarate synthesized by the authors was a white crystalline substance soluble in alcohol and water – a mixture of 2-ethyl-6-methyl-3-hydroxypyridine and fumaric acid in ethanol. Acute irradiation of the test organism was carried out on the Prometheus proton complex at the А. Tsyb Medical Radiological Research Center (Obninsk, Russia) with a scanning proton beam at a dose of 30 Gy (energy 150 MeV) in a distributed Bragg peak. The survival rate of D. magna was assessed in a 21-day experiment on a daily basis. The cytotoxicity of the studied factors was analyzed by changes in MTT and MDA parameters, the antioxidant properties of 3-hydroxypyridine fumarate were evaluated by changes in the activity of catalase, peroxidase and superoxide dismutase enzymes. The contribution of the analyzed factors to the observed effects was assessed using the Kruskal-Wallis test. Statistical processing of survival was carried out according to the χ² criterion, and other indicators – according to the Mann-Whitney criterion, adjusted for multiple comparisons. According to the data obtained, the survival rate of irradiated newborn animals decreased by 29.3 % by the age of 21 days (p = 0.03). When combined with 3-hydroxypyridine fumarate action, the death of animals decreased to 44.4 % (p = 8.8 x 10⁴). It was revealed that radiation contributed to the joint effect. An integral assessment of the level of oxidative stress showed that proton irradiation causes a cytotoxic effect in the cells of the test organism. 3-hydroxypyridine fumarate does not have radioprotective and antioxidant effects when D. magna is cultured in a solution of a substance with a concentration of 0.05 micrograms/ml after proton irradiation. The results obtained are consistent with the data on the absence of radioprotective properties of 3-hydroxypyridine fumarate after irradiation with heavy ions. The authors propose a unified mechanism of interaction between 3-hydroxypyridine fumarate and densely ionizing radiation of various types (protons, heavy ions, alpha particles), which does not exhibit radioprotective effects. It is necessary to continue the search for radioprotectors for proton therapy among substances of a different class.

   Introduction: The paper presents results of a radon survey conducted in 2021-2022 in existing dwellings and public buildings in 31 settlements of three districts of the western part of the Orenburg region (Buguruslanskiy, Buzulukskiy and Matveevskiy districts). Since exposure to radon and its progeny is the second leading cause of lung cancer after tobacco smoking, the selection of the districts for the survey was based on average standardized trachea, bronchi, and lung cancer morbidity rates in the districts of the Orenburg region for 2009–2018.

   Materials and Methods: The survey was conducted using solid-state nuclear track detectors in 31 settlements of the districts, where 83.5 % to 90.9 % of the population of each district live (9 settlements in Buguruslanskiy district, 9 in Buzulukskiy district, and 13 in Matveevskiy district). Results and Discussion:

   The results of measurements: taken in 51 dwellings and 45 public buildings in three districts showed that in 45 dwellings and 25 public buildings indoor radon concentrations do not exceed the established hygienic norm (action level) of 200 Bq/m3 (EEC) adopted in Russia for existing buildings. In six dwellings the action level is exceeded; in 20 public buildings with non-round-the-clock occupancy, additional measurements using instant or continuous methods during building operating hours are required. The highest values of annual average indoor radon EEC were obtained in the settlements of the Matveevskiy district: 745 Bq/m³ in Starokutlumbet'evo and 643 Bq/m³ in Kuz'kino. The largest number and percentage of exceedances of the established action level were also found in the settlements of the Matveevskiy district.

   Conclusion: The principle applied in the selection of districts for priority survey, based on the analysis of average standardized trachea, bronchi, and lung cancer morbidity rates, proved its effectiveness: the highest levels of indoor radon concentration were found in the district with the highest trachea, bronchi, and lung cancer morbidity rate in the Orenburg region.

   Patients undergoing radionuclide therapy with radiopharmaceuticals may become a radiation source of external exposure. Release of the patients requires strict abidance of radiation safety regulations to minimize exposure to individuals in contact with patient, especially children and pregnant women.

   The purpose of the current study was to determine precautions for patients after radionuclide therapy to limit the contact time with others and to develop guidelines to reduce doses to individuals in contact with patient.

   Two cases were considered for analysis: contact with young children and co-sleeping with partners. Determination of the necessary time limitations was performed using open-assessed publications and Monte Carlo calculations at different distances from the patient. The results showed that radionuclide therapy with 225Ac, 223Ra, 89Sr, and 90Y would not exceed the limit of 0.3 mSv to individuals in contact with patient after radionuclide therapy, even in the case of no precautions. However, for patients with 131I, 177Lu and 153Sm, precautions to limit the time of close contact with children and co-sleeping with partners are required. The suggested precautions ensure the radiation safety of individuals in contact with the patient after radionuclide therapy by limiting the exposure limits and allow patients to maintain social contacts, which is important for their rehabilitation.

   Based on the information regarding the parameters of routine radiographic procedures the values of the conversion coefficients to the effective dose in patients of different weights were calculated. The numerical values of the conversion coefficients correspond to the effective dose values during a given radiographic examination, which is completely determined by a set of technical, geometric, and dosimetric parameters normalized to the absorbed dose value in the air at a distance of 1 m from the tube focus (Ke, μSv/mGy)), or to the dose-area product value measured during the examination (Kd, μSv/(cGy cm2)). t is shown that the Ke factors have a greater relative spread of their values than the Kd factors. Within each weight group of patients, the Kd factor value for a patient of standard weight can be converted to the value for a patient of different weight. Furthermore, extrapolation of the calculated Kd values to infant weights well below 2.6 kg (down to 0.6 kg), i.e. for premature infants, yields satisfactory estimates of the Kd value.

   Introduction: In the long-term period after radiation exposure, the mental health status of the exposed persons becomes a significant problem. At the same time, there is still no clear understanding of the role of radiation and non-radiation factors in the development of mental illnesses and behavioral disorders in the exposed people.

   The objective of this study is to analyze the published data on the contribution of radiation and non-radiation factors to the development of mental disorders in exposed people in the long term period after radiation exposure.

   Materials and Methods: A generalization of the literature data and the results of our own research was observed.

   Results and Discussion: A generalization of the collected data have shown that changes in the state of mental health in irradiated individuals in dynamics ranged from a state of mental maladaptation to the development of persistent organic mental disorders and deviant behaviors. Currently, among the factors affecting the mental health of irradiated persons, it is possible to distinguish: 1) radiation exposure itself; 2) psychogenic factor, which naturally accompanies radiation accidents and incidents; 3) the use of protective measures and, above all, resettlement; 4) social changes in radioactively contaminated territories (insufficient development of social infrastructure facilities, lack of sufficient investments, outflow of socially active population); 5) information factor (accessibility to objective information); 6) premorbid personality traits that affect the perception of radiation risk and are one of the background factors for the formation of mental pathology.

   Conclusion: The complex influence of these factors contributes not only to the formation of mental pathology but also to the growth of socio-psychological tension of the population. The development of measures on interaction with the population of the territories exposed to radioactive contamination (local leaders, representatives of social movements), the provision of necessary medical and psychological assistance will minimize negative social effects and contribute to the formation of adequate perception of radiation risk and socially acceptable forms of behavior.

   Introduction: To successfully address the challenges of optimizing radiation protection during medical exposure, it is essential to have information on patient exposure levels and the structure of diagnostic radiology in medical organizations across the Russian Federation.

   Materials and Methods: The primary source of data on patient exposure levels and the structure of diagnostic radiology is the Form No. 3-DOZ, a part of the Unified state statistical monitoring system for controlling and recording individual radiation doses of citizens.

   The aim of this study was to comprehensively evaluate the results of completing Form No. 3-DOZ for 2023.
   The study utilized data from the Form No. 3-DOZ at the level of the constituent entities of the Russian Federation, obtained from the Federal Database on Individual Radiation Doses of Citizens during medical diagnostic X-ray radiological procedures.

   Results and Discussion: The collective dose from medical exposure among the adult population increased by 34 % in 2023 compared to 2022. The most significant increases in the collective doses were observed for radiographic (81 %), radionuclide (49 %), and interventional (57 %) procedures. For the first time in the past five years, the increase in collective doses for X-ray radiological procedures was not accompanied by a corresponding increase in the number of procedures, indicating a rise in average and individual effective doses for patients. The average effective dose per resident of the Russian Federation due to medical exposure in 2023 increased by more than one and a half times: 1.12 mSv compared to 0.86 mSv in 2022. The increase in collective doses for various types of diagnostic radiology is driven by the rise in average effective doses for different X-ray radiological procedures across regions of the Russian Federation. The greatest variations in average effective doses were observed for radiographic procedures (an increase of up to 2.5 times in 2023 compared to 2022).

   Conclusion: These changes in average effective doses may be attributed to errors in calculating effective doses and completing the Form No. 3-DOZ, as well as to objective changes in the equipment fleet and/or protocols for conducting X-ray procedures. At the same time, several regions of the Russian Federation reported anomalously low average effective doses. To identify the reasons for abnormally high and/or low effective doses during diagnostic radiology procedures, it is necessary to develop and test a methodology for verifying the data submitted in the Form No. 3-DOZ.

   Introduction: Monitoring the level of radioactive contamination, especially the tritium content in water sources, as an indicator of potential releases of man-made radionuclides from radioactive waste storage areas formed as a result of peaceful nuclear explosions, is crucial for ensuring radiation safety. It allows for a prompt response to emerging risks, minimizing negative consequences for the environment and public health.

   The purpose of this study was to assess the radiation-hygienic condition of the sites of peaceful nuclear explosions "Globus-3" and "Quartz-2" in the Komi Republic.

   Materials and Methods: In July-August 2021, field studies were conducted in the Komi Republic in the territories adjacent to the sites of peaceful nuclear explosions "Globus-3" and "Quartz-2". These studies included measuring the ambient dose equivalent rate, the content of anthropogenic radionuclides in soil, and the specific activity of tritium in water bodies and drinking water sources in the nearest settlements. The ambient dose equivalent rate was measured using an MKG-AT1321 spectrometer. Identification of gamma-emitting radionuclides on the ground was carried out using a scintillation portable gamma-spectrometer MKSP-01. The specific activity of tritium in water samples was determined using a liquid scintillation spectrometer "Quantulus-1220."

   Results and Discussion: The measured ambient dose equivalent rate of gamma radiation in all surveyed territories corresponded to the natural radiation background: in the territory of the peaceful nuclear explosion "Globus-3," the values ranged from 0.01 to 0.04 μSv/h, and in the territory "Quartz-2," from 0.01 to 0.06 μSv/h. No soil areas contaminated with anthropogenic radionuclides were detected in the investigated territories. The values of tritium specific activity in drinking water samples did not exceed 5.34 Bq/kg, which is significantly lower than the established hygienic standard (7,600 Bq/kg) and corresponded to background values. Additional anthropogenic exposure due to tritium intake with drinking water from centralized water supply systems did not exceed 0.05 µSv/year.

   Conclusion: The radiation situation in the areas of peaceful nuclear explosions "Globus-3" and "Quartz-2" meets the requirements of SanPiN 2.6.1.2819-10 and does not create health risks for the local population. However, the unsatisfactory sanitary condition of the protection zones of these facilities was noted. The presented results are of practical importance for future studies and may serve as a basis for bringing the protection zones into compliance with the requirements of paragraph 3.5 of Section 3 of SanPiN 2.6.1.2819-10.

   Introduction: The paper presents an overview of the new guidelines MR 2.6.1.0361-24 (approved on 24 December 2024) that supersede guidelines MU 2.6.1.2398-08, which were used for organizing radiation surveys of land plots for construction of residential buildings, public and industrial buildings and facilities, and their sanitary assessment in terms of radiation safety indicators over the past 16 years.

   Summary: The scope of the revised document was expanded and now covers not only construction sites, but also territories adjacent to buildings and structures, and public areas, as well as the soil located on the sites and intended for use as building materials. The conditions for compliance of radiation safety indicators with established standards have been adjusted to eliminate contradictions with the current formulations of sanitary requirements. A three-stage approach is proposed to assess the potential radon hazard of land plots. According to this approach, the customer has the opportunity to order a radiation survey at any stage and to complete it after any stage in case of non-compliance of the land plot with the established standards, skipping additional measurements and proceeding immediately to the design stage of radon protective measures.

   Conclusion: The changes made should make the procedure for conducting radiation survey of land plots and evaluating its results more understandable and transparent, as well as improve the quality of measurement information obtained by testing laboratories, without requiring them to significantly expand the measuring instruments fleet and the list of measurement methods used. Taken together, all this changes should contribute to an increase in the number of new radon-safe buildings where protective measures are implemented preventively.

   Introduction: A computer program was created to calculate intrauterine radiation doses, "FetusDose", in the frame of the dosimetric support of epidemiological studies conducted for the population of the Ural region.

   Summary: The paper presents the method and describes the principle of organization and functionality of the computer program. The software is designed to calculate trimester and total doses accumulated in the active marrow and extra-skeletal tissues of the fetus when it is irradiated with anthropogenic radionuclides that have accidentally contaminated the environment. When calculating doses, two radiation scenarios are considered: the external one from soil contaminated with gamma-emitters (⁹⁵Zr, ⁹⁵Nb, ¹⁴⁴Ce/¹⁴⁴Pr/¹⁴⁴mPr, ¹⁰⁶Ru/¹⁰⁶Rh, ⁹¹Y and ¹³⁷Cs/¹³⁷mBa) and the internal one from oral intake of radionuclides (⁹⁰Sr/⁹⁰Y, ⁸⁹Sr, ¹³⁷Cs/¹³⁷mBa and ¹⁴⁴Ce/¹⁴⁴Pr/¹⁴⁴mPr) into the mother's body with food and water.

   Conclusion: The software can be used both to study the consequences of radiation incidents that have already occurred, and to predict the radiation exposure from potential threats. The program will also be useful for educational purposes in the training of specialists in the field of radiobiology and dosimetry.

   The artilcle presents comments on the manuscript by A.S. Vasiliev et al. “A review of approaches to assessment of potential radon hazard of land plots”. The manuscript does not fully reflect some features of the existing regulations for assessment of potential radon hazard of territories. In addition, important results of modern research in the field have not been considered, and single science-based approach in Russia to assess the potential radon hazard of building sites, which has been implemented in practice and tested in the industry of engineering and environmental surveys, is ignored.

   Introduction: Assessment of the potential radiation detriment is one of the key elements in decision-making processes within the context of the practical implementation of radiation safety requirements. In the absence of more suitable indicators, the most universal approach is based on the evaluation of detriment in monetary terms. Although detailed calculations of such detriment are specific to each scenario involving the use of sources of ionizing radiation, a rough conservative monetary evaluation can be performed using the methodology outlined in the Norms of the Radiation Safety NRB-99/2009.

   The objective of this study was to assess the potential detriment associated with radiation exposure in the Russian Federation, expressed in monetary units.

   Summary: The work describes the limitations of this methodology and provides an evaluation of detriment for various sources of ionizing radiation.

   Conclusion: The results of this study can be used to justify and estimate the effectiveness of radiation protection measures in the Russian Federation.