The objective of the current research is to evaluate the contribution of the genetic factor to the risk of cancer development in the individuals affected by chronic low dose-rate exposure on the Techa River. Materials and Methods: The study of the relationship between the polymorphic loci of the genes regulating cell cycle and apoptosis with the risk of cancer development involved 922 members of the Southern Urals Population Exposed to Radiation cohort. Real-time PCR was used to perform the genotyping of polymorphic loci. Results and Discussion: A statistically significant relationship of the alleles rs2279744*С of the gene MDM2 and rs2279115*С of the gene BCL-2 with the increased risk of cancer development has been established (odds ratio = 1.75; confidence interval 95 % [1.15-2.65]; p=0.008 and odds ratio = 1.63; confidence interval 95 % [1.21-2.21]; p=0.001 respectively). Single nucleotide polymorphism that is associated with a decreased risk of cancer development has also been revealed: the allele rs1801270*А of the gene CDKN1A (odds ratio = 0.62; confidence interval 95 % [0.44-0.88]; p=0.007). The analysis of gene interaction factor and absorbed dose to the red bone marrow determined the most statistically significant model that includes the dose to the red bone marrow, NFkB rs28362491, ATM rs664677, BCL2 rs2279115, MDM2 rs2279744 (repeatability is 10 out of 10, accuracy 62 %; p=0.04). Polymorphism rs2279744 of the gene MDM2 is the greatest information contributor (2.43 %). Conclusion: Single nucleotide polymorphisms of the genes encoding cell cycle and cell death enzymes are capable of modifying cancer development risk.

The aim of the work was to estimate the radiation doses to the fetus during radionuclide diagnostic procedures in pregnant patients. Materials and Methods: The absorbed doses to the fetus due to the radiopharmaceutical administered to the mother during radionuclide diagnostic procedures were estimated for the most common procedures performed in the Russian Federation using the conversion factors from the administered activity of radionuclides in the radiopharmaceutical to the absorbed dose. Typical values of the administered activities of radionuclides for each radiopharmaceutical and the conversion factors taking into account the stage of pregnancy of the patient at which the study was conducted were used. For comparison, the absorbed doses to the mother's uterus, as the closest organ, were determined. For hybrid studies, the absorbed doses to the fetus from maternal CT scans at different stages of pregnancy were calculated in the FetalDose program for typical scanning protocols for adult patients. Results and Discussion: The absorbed doses to the fetus from the administered radiopharmaceutical for most studies do not exceed 20 mGy. In hybrid studies where the CT scan area includes the abdominal region, the CT dose is the largest contributor to the total dose, justifying a scan area limitation or low-dose protocols for whole-body scanning. An exception is the ⁶⁷Ga-citrate study, where the absorbed dose to the fetus may exceed 50 mGy, with the largest contribution to the dose coming from the maternally administered radiopharmaceutical. Conclusion: The results obtained indicate that for most nuclear medicine procedures, the risks of deterministic effects in the fetus or stochastic effects in the child from the maternal diagnostic examination are minimal. It is advisable to assess doses and risks for each individual patient, taking into account the clinical situation and radiographic history.

The objective is to study the incidence of malignant tumors of the central nervous system of the personnel of the Mayak production association. Material and Methods: The study used data from the medical and dosimetric personnel register of the “Mayak” production association personnel hired in 1948-2016 and the cancer population register of the city of Ozyorsk. An assessment of the standardized ratio of morbidity rates among the city's population and the staff of the Mayak production association was carried out. Results and Discussion: During the follow-up period from 1948 to 2017, 220 cases of malignant neoplasms of the central nervous system were registered in the city of Ozyorsk, of which 70 cases were among the Mayak production association workers included in the medical dosimetric register (57 cases among male staff, 13 among female employees). Malignant brain tumors prevailed in the structure of the studied lesions (87.1 %), the most common lesions affected several areas of the brain (28.5 %) and the temporal lobe (14.3 %). No cases of malignant tumors of the central nervous system were recorded among male staff until 1960, and until 1980 among female staff. The age-standardized ratio of the incidence of malignant tumors of the central nervous system among the staff of Mayak and the population of Ozyorsk in men was 1.00 (95 % CI: 0.76; 1.29), in women – 0.91 (95 % CI: 0.48; 1.56). The estimates obtained turned out to be statistically indistinguishable from the unit, which indicates that there are no differences in the incidence rates of the population of Ozyorsk as a whole and the staff of the Mayak production association as a part of it. Conclusion: The results of the study confirm the previously obtained data on the absence of the influence of the occupational radiation factor on the incidence of malignant neoplasms of the central nervous system of the population of the city of Ozyorsk, including the staff of Mayak production association.

In the middle of the 20th century residents of the Ural region were affected by chronic radiation exposure in a wide dose range due to the release of liquid radioactive waste into the Techa River. The objective of the study was to investigate the dynamics of the frequency of unstable chromosome exchanges in chronically exposed residents of the Techa riverside settlements. Materials and Methods: The study covers the period from 1970s through 2019. The analysis is based on the published research describing the results of cytogenetic examination, as well as on the retrospective study of the cytogenetic database data. Nine groups of examined individuals were formed by periods of examination: five groups of exposed people and four comparison groups. To obtain the preparations, T-lymphocytes were cultivated to the metaphase stage and hypotonically treated; the metaphase plates were fixed, and the chromosome preparations were prepared. Results and Discussion: Results of the assessment showed a decrease in frequency of dicentrics and unstable chromosome exchanges over the period from 1970 through 2019. Most significant decline in the number of chromosome aberrations was observed starting from 1993, i.e. 40–50 years after the onset of exposure. Dicentrics are statistically significantly more frequent in the group of exposed people relative to the comparison group in the periods 1970-1993 (23-43 years after the onset of exposure), and 1993-1996 (46-49 years after the onset of exposure), as well as in the period from 2012 through 2019 (65-72 years after the onset of exposure). Conclusion: At present, frequency of dicentrics in exposed people remains statistically significantly increased relative to the comparison group members. State-of-the-art equipment and use of special software packages in the work of cytogeneticists made it possible to increase the number of analyzed cells in more than 3 times. It increased considerably the probability of chromosome aberration detection both in exposed and unexposed individuals.

The analysis of trends in levels of radiation exposure of the public in the Russian Federation in recent years indicates a steady increase in patient doses from medical exposure. To maintain the necessary level of radiation protection of patients, the system of regulatory support of radiation safety for medical exposure in the Russian Federation needs to be updated and adapted to the current state of Russian X-ray diagnostics and therapy. The aim of this study was to substantiate the revision of the regulatory and legal framework in the field of radiation safety for medical exposure. For this purpose, international and Russian approaches to the provision of radiation safety for medical exposure were compared; the main problems were identified and proposals for their solution were formulated. Within the framework of this work, the analysis of international and national regulatory documents in the field of radiation safety, regulating the requirements for limitation, justification and optimization for medical exposure was performed. Based on the results of the analysis, the main directions of improvement of the national system of radiation safety for medical exposure were identified: establishment of interdepartmental interaction between Rospotrebnadzor, Ministry of Health and Roszdravnadzor to create an integrated approach to radiation safety for medical exposure; improvement of the system of registration and accounting of patient doses; improvement of approaches to assessment of radiation detriment (risk) for patients undergoing radiological procedures. A scheme for distribution of powers to ensure radiation protection of patients between Rospotrebnadzor, the Ministry of Health and Roszdravnadzor has been proposed. Some of the proposals were implemented in SanPiN 2.6.4115-25 “Sanitary and Epidemiological Requirements in the Field of Radiation Safety of the Population when Handling Sources of Ionizing Radiation.”

The article analyzes the data of the federal state statistical observation form No. 3-DOZ for 2022-2023, which revealed a significant increase in medical radiation doses to patients in the Russian Federation, especially in Khabarovsk Krai. The purpose of the examination was to develop a methodology for verification of these data at the regional level. Materials and Methods: The methods of calculation of the average effective dose and comparison with reference values of the Research Institute of Radiation Hygiene after Professor P.V. Ramzaev were used. Results and Discussion: The results showed that abnormally high average effective doses were recorded in medical organizations of Khabarovsk Krai, significantly affecting the collective dose of the region. An algorithm for detecting such anomalies to optimize radiation safety was proposed. Conclusion: It was found that the current format of Form No. 3-DOZ does not allow to accurately determine the causes of deviations due to the lack of data at the level of individual devices.

This publication describes the ongoing cycle of works aimed at the radiation survey in the Arctic zone of the Russian Federation, in order to assess the primary (background) levels of human-made radionuclides before starting work on lifting and disposing of flooded and sunken radiation facilities with spent nuclear fuel and radioactive waste based on the Action Plan for the implementation of the Strategy for the Development of the Arctic Zone of the Russian Federation and Assuring National Safety for the period up to 2035 approved by the Government Decree No. 645 dated 26 October, 2020. Materials and Methods: The radiation survey was carried out in the coastal zone of residential areas near the site of the flooding of the K-27 nuclear submarine and radiation facilities in the Kara Sea: the Amderma settlement, Nenets Autonomous Okrug, as well as its natural waters. The article includes results of measuring the ambient dose equivalent rate of gamma radiation in open areas by the pedestrian gamma survey method, and determining the content of human-made radionuclides in samples of environmental media (soil, bottom sediments, aquatic vegetation) and local foodstuffs by gamma spectrometric and radiometric methods with preliminary sampling in accordance with the established procedure provided by current regulatory documents and guidelines. Results and Discussion: the research results show that the state of the surveyed area is generally stable in terms of radiation factor; the content of radionuclides is at the background level characteristic of the Nenets Autonomous Okrug, not exceeding radiation safety standards. External and internal public radiation exposure was assessed. Conclusion: It was shown that the public radiation dose is formed mainly due to natural radiation sources. As part of this work, an electronic database module was developed based on the results of radiation monitoring in the Amderma settlement, which is part of the general database (registration certificate No. 2022621890).

Starting from September 1, 2025, SanPiN 2.6.4115-25 came into force. This is a comprehensive document that establishes requirements for ensuring radiation safety when working with a specific list of ionizing radiation sources, including those used in X-ray diagnostics and therapy. As a result, several regulatory legal acts in the field of radiation safety will be repealed, including SanPiN 2.6.1.1192-03 and SanPiN 2.6.1.2891-11. SanPiN 2.6.4115-25 introduces a number of new as well as revised and updated requirements for ensuring radiation safety in the operation of ionizing radiation-generating equipment used in medical practice. This paper presents analysis of the changes and additions introduced in SanPiN 2.6.4115-25 in comparison with the documents that should be repealed starting from September 1, 2025, which previously regulated radiation safety requirements for X-ray diagnostics and therapy. Conclusion: The work presents the background for revising the sanitary rules and standards and provides recommendations for improving the regulation of radiation protection in medical exposure.

The regulatory legal acts of Rospotrebnadzor that established requirements for ensuring radiation safety during radionuclide diagnostics and therapy procedures before September 1, 2025 are significantly outdated and do not reflect the technologies and radionuclides currently in use. The development of nuclear medicine technologies and the introduction of an increasingly wide range of therapeutic radiopharmaceutical drugs necessitate the updating of requirements for the conduct of procedures, patient discharge, and waste management during radionuclide therapy, as well as the consideration of modern practices in organizing radionuclide therapy units based on radionuclide diagnostics departments. This work presents an analysis of the changes and additions introduced in SanPiN 2.6.4115-25, aimed at establishing unified requirements for ensuring radiation safety for personnel, the public, and patients during nuclear medicine procedures. The requirements implemented in SanPiN 2.6.4115-25 for ensuring radiation safety during nuclear medicine procedures have addressed two important scientific and practical problems: accounting for the specifics of modern nuclear medicine methods and resolving a number of contradictions among the existing regulatory legal acts of Rospotrebnadzor. Conclusion: SanPiN 2.6.4115-25 is fully harmonized with international regulatory documents and comprehensively includes requirements for ensuring radiation safety in radionuclide therapy, with an emphasis on protecting the public from radiation exposure.

Relocation is a long-term radiation protection measure for the population of radioactively contaminated territories to prevent chronic exposure. The first experience of forced relocation of the population of radioactively contaminated territories took place in the USSR in the middle of the last century. The justification for such a radical protective measure is actively debated in the scientific literature. However, scientific research is more focused on the search for reasonable dose criteria and ways to optimise the resources needed to implement this protective measure. The question of the duration of measures for the resettlement of inhabitants from contaminated areas is poorly addressed. The aim of the study is to characterise the implementation of measures for the relocation of inhabitants of settlements of the Techa River basin and territories of East Ural Radioactive Trace. Materials and Methods: The main source of information on exposed inhabitants of radioactively contaminated territories of the Ural region is the medical-dosimetric database. Results and Discussion: For two radiation situations the conditions of relocation of settlements were analysed and compared. The implementation of measures for the relocation of the residents of the coastal settlements of the Techa River took eight years, and the actual relocation (excluding the preparatory period) of the residents lasted from two to four years. The agricultural settlement (Farm of Trust № 92) took longer to resettle of all the relocated settlements in the area. The relocation of the residents of the settlements located on the territory of the East Urals Radioactive Trace was carried out in a shorter period of time. At the same time, protective measures such as evacuation (lasted several days) and planned resettlement (lasted up to two years) were implemented. Conclusion: The implementation of the measures for the planned relocation of the population from the territory of the East Ural Radioactive Trace differed from the implementation of the measures for the relocation of the inhabitants of the settlements located on the Techa River - the duration of the actual relocation of the inhabitants from the contaminated territories of the East Ural Radioactive Trace did not exceed two years, and from the coastal territories of the Techa River - four years. The evacuation took several days.

The use of ionizing radiation is one of the most rapidly developing areas in medical diagnostics; it has led to a steady increase in both the number of examinations and the collective dose of medical exposure in recent years. In this regard, improving access to reliable scientific information on radiation risks associated with medical exposure is a relevant and timely objective. The aim of this study is to describe a mobile application developed for assessing radiation risk associated with medical X-ray radiological examinations for patients of different sexes and ages from the Russian population. Materials and Methods: To provide a comprehensive representation of radiation risks from diagnostic medical exposure, the mobile application incorporates results based on four different risk indicators: average individual effective dose; average number of disability-adjusted life years lost; average risk of developing malignant neoplasms adjusted for disease severity; and a qualitative risk scale supplemented with color-coded visual representation of risk magnitude. To build the database of radiation risk indicators, a total of 17,719 organ dose estimates were used. These were obtained for patients of various ages undergoing diagnostic medical examinations. Results and Discussion: The developed mobile application features a bilingual interface with the option to add additional language modules. Its minimalist design allows switching between three main screens: “Single Study”, “Study Series”, and “Saved Series”. Conclusion: The development of this mobile application for radiation risk assessment represents the first practical implementation of the risk assessment methodologies developed by the authors, with the goal of creating a simple tool to support information accessibility for patients, their legal representatives, healthcare professionals, and a wide range of interested users.

During expeditionary radiation-hygienic studies of territories, there is often a need to assess activity concentration of radionuclides in soil at depths greater than 20 cm. This is associated with certain methodological and technical difficulties in sampling. The aim of this study was to carry out a series of calibration measurements and evaluate the capabilities of a collimated scintillation detector for determining ¹³⁷Cs activity concentration in soil at different depths in boreholes in situ. Materials and Methods: A comprehensive calibration was carried out for the MKSP-01 RADEK gamma spectrometer with a LaBr₃(Ce) crystal, including a study of the axial sensitivity and detection efficiency for the ¹³⁷Cs radionuclide from both a point source and a volumetric soil source with known activity. This made it possible to determine the optimal measurement parameters, including the distances between collimators and calibration coefficients for accurate determination of activity concentration at different distances and with different sample volumes. Results and Discussion: This article presents the results of calibration of the detector based on a LaBr₃(Ce) crystal measuring ∅30х30 mm, designed to measure the intensity of ¹³⁷Cs gamma radiation in boreholes at depths of up to 1 m. The calibration measurements showed that the detector design allows measuring activity concentration of ¹³⁷Cs from 200 Bq/kg in boreholes with a diameter of 90 mm, with the ¹³⁷Cs peak detection efficiency of about 0.1% and a measurement time of 30 min. The detector ensures reliable detection of soil layers with ¹³⁷Cs activity above the minimum significant activity concentration. Conclusion: Collimators providing access of gamma radiation to the open part of the LaBr₃(Ce) crystal allow adjusting the thickness of the studied soil layer (horizon view width) during the measurement process. With a distance between the collimators of 1.5 cm, the detector allows studying the activity concentration horizons with a step of 5 cm, with an increase in the distance to 2 cm – 10 cm.

The subway (metro) is a popular form of public transportation system in many large cities. While in the subway territory (one of the locations in the city), a passenger is inevitably exposed to external irradiation from natural (terrigenous) sources of ionizing gamma radiation – ⁴⁰K, radionuclides of the ²³²Th and ²³⁸U series, which are present in the ground and building materials. The aim of this study was to estimate the external exposure for a metro passenger in St.-Petersburg (Russia). Materials and Methods: A portable gamma spectrometer-dosimeter, carried in a backpack by the operator, was used to measure the integral ambient dose equivalent rate and the effective activity concentration of natural radionuclides along 60 selected passenger routes in the metro. The effective dose rate of external exposure of a metro passenger was estimated using results of the measurements and the published conversion coefficient from ambient dose equivalent to the effective dose. Results and Discussion: The measured values of ambient dose equivalent rate varied from 65 to 214 nSv/h and averaged 92 nSv/h. Effective activity concentration of natural radionuclides ranged from 104 to 188 Bq/kg (average = 147 Bq/kg). The average ambient dose equivalent rate from natural radionuclides was 86 nSv/h (range from 61 to 107 nSv/h). The ratio of the ambient dose equivalent rate from natural radionuclides to the effective activity concentration varied slightly from 0.56 to 0.61 ((nSv/h)/(Bq/kg)) and averaged 0.58 ((nSv/h)/(Bq/kg)). The average effective dose rate of external exposure from natural radionuclides is conservatively estimated at 86 nSv/h for an adult passenger of the St. Petersburg metro. Conclusion: Comparison of the results of this work and literature data shows that the travel of a local resident or visitor in St. Petersburg using the metro, compared to walking on foot in surface urban locations, should not lead to additional external exposure from natural radionuclides present in the environment. In terms of ambient dose equivalent rate, the St.-Petersburg metro fully complies with modern sanitary and epidemiological requirements for public facilities.