In 1971 in the Perm region (the Russian Federation), three thermonuclear charges of the “Taiga” series were simultaneously detonated in order to test nuclear explosive technologies for creation of the Pechora-Kama canal. As a result of the underground explosions, long-lived technogenic radionuclides were released onto the surface of the earth along with soil and rock. Over time, a new forest ecosystem formed on the mound of the radioactively contaminated ground. The purpose of this study was to assess the ¹³⁷Cs accumulation by woody plants and edible mushrooms at the “Taiga” underground nuclear explosions site at a remote stage (38 years) after radioactive contamination of the environment. Content of ¹³⁷Cs was determined in organs of birch (Betula pubescens), spruce (Picea abies), aspen (Populus tremula), and pine (Pinus sylvestris), as well as in the fruiting bodies of mushrooms of the species Boletus edulis, Leccinum aurantiacum, Russula, and Suillus luteus. The activities of ¹³⁷Cs in the samples were measured by gamma-ray spectrometry using a HPGe detector. The values of ¹³⁷Cs activity concentration (on a dry weight basis) in the samples of wood, leaves/needles (1st year), and mushrooms were in the ranges of 0.5–6.8 Bq/kg, 54–112 Bq/kg, and 212-3260 Bq/kg, respectively. Aggregated transfer coefficients (kg/m²) for the radionuclide in the biota species were calculated using these results and previously reported data on the density of soil contamination by ¹³⁷Cs at the “Taiga” site. It has been found that the transfer coefficients of ¹³⁷Cs from soil to biota for all studied species at the “Taiga” site are abnormally low compared to those obtained by many authors for other places of radioactive contamination, in particular for the areas contaminated by ¹³⁷Cs as a result of the Chernobyl accident. Possible reasons for the low accumulation of ¹³⁷Cs in the biota at the “Taiga” site are discussed.

Sources of ionizing radiation are an integral part of modern healthcare and are widely used for diagnostic and therapeutic purposes. One of the key aspects of the safe use of ionizing radiation in medicine is the competence of medical professionals in the field of radiation protection. The aim of this study is to investigate the level of awareness and understanding of radiation protection among interventional radiologists in the Russian Federation. The research was conducted through an online survey. The link to the questionnaire was shared in communities of interventional radiologists in social networks. A total of 78 interventional radiologists participated in the survey. The questionnaire consisted of 26 questions, 11 of which focused on assessing knowledge of radiation protection. Each question addressed a fundamental aspect essential for understanding and application in medical practice. None of the respondents answered all radiation protection questions correctly. The average score among all participants was 6.1 out of a maximum of 11. The level of knowledge did not significantly depend on years of professional experience (p>0,05). The most challenging questions concerned the biological effects of ionizing radiation. Most participants assessed their knowledge of radiation safety as satisfactory (46,1%) or good (33,3%). Self-assessment of knowledge levels also did not significantly depend on professional experience (p>0,05). As preferred sources of information on radiation safety, interventional radiologists identified online resources, scientific conferences, educational materials, and training courses. Currently, no regularly updated, unified information online resource in Russian is available. Developing such a resource represents the most cost-effective approach to ensuring and improving the awareness of interventional radiologists regarding radiation protection. Simultaneously, efforts should be directed toward enhancing the quality of training courses on radiation protection.

The article presents results of a study on the tritium concentrations in seawater samples collected from September 2023 to June 2024 in coastal waters of the Far Eastern regions of the Russian Federation, including Primorsky, Kamchatka, and Khabarovsk Krais; Sakhalin and Magadan Oblasts; and the Chukotka Autonomous Okrug. The aim of the study is to determine the backgrounds values of tritium volume activity. The low-background liquid scintillation spectrometer-radiometer for alpha and beta radiation "Quantulus 1220” was used to determine the baseline tritium content in 185 seawater samples collected by specialists from the territorial bodies of Rospotrebnadzor in six subjects of the Far Eastern Federal District. The results indicate that the specific activity levels for the observation period from September 2023 to June 2024 were below 10.0 Bq/kg in samples collected from the coastal waters of the Far Eastern regions of the Russian Federation. The recorded tritium levels are significantly below the intervention level for drinking water (7600 Bq/L) as per NRB-99/2009, which applies to desalinated seawater.

With the active development and wide use of positron emission tomography, ensuring radiation safety in matters of irradiation of the skin of the hands of personnel, has become very important. Work with radiopharmaceuticals labeled with various radionuclides is characterized by fairly close contact with a source of ionizing radiation, during which the skin of the hands can be irradiated in significant doses. Thus, the effect of ionizing radiation on the skin of the hands is one of the main problems of radiation protection of personnel at nuclear medicine centers. The work of personnel at nuclear medicine centers, depending on the nature of the actions performed, can be divided into two types: predominantly manual processes (nurses – packaging and administration of drugs, analytical chemists – quality control) and predominantly automated processes (radiochemical engineers – synthesis, packaging into vials). The individual equivalent doses to the skin of the hands of nurses, analytical chemists and radiochemical engineers working with 18F-based radiopharmaceuticals were estimated using thermoluminescence dosimetry with individual dosimeters calibrated in terms of Hp(0.07). The maximum annual value obtained fo radiochemical engineers was 7.8 mSv, which is 1.56% of the dose limit, and for analytical chemists it was 171 mSv, which is 34% of the dose limit (mean value was 28 mSv, median was 8.8 mSv, minimum value was 4.6 mSv). At the same time, nurses, who are mainly engaged in the packaging and administration of radiopharmaceuticals, have higher values of annual doses in the skin of the hands (mean value – 114 mSv, median – 56 mSv, minimum value – 1.3 mSv). The maximum value of the annual dose in the skin of the hands, recorded during the work, for a nurse was 573 mSv, i.e. the dose limit of 500 mSv was exceeded. The results of the work indicate that specialists involved in manual processes when manipulating radiopharmaceuticals require special attention from the standpoint of individual dosimetric control of the irradiation dose to the skin of the hands and compliance with radiation safety requirements.

The pace of development of nuclear technologies is inextricably linked to the need to improve and update approaches to the preparedness of effective and adequate response to emergencies. The introduction of new solutions, which over the last few decades have significantly reduced the risks of severe consequences of major radiation accidents, cannot guarantee their absolute absence. Improvement of the systems of deep echelon radiation protection, radiation monitoring and control, the level of training of staff of radiation facilities cannot go separately from the development of a set of emergency preparedness and emergency response measures. The aim of the work is to review the systems of response to major radiation accidents recommended by ICRP and IAEA, and Russian federal laws and regulations. The results of the work have shown that when updating and revising sanitary norms and rules in the field of radiation safety, it is recommended to consider the need to supplement the current system of classification of radiation facilities by potential radiation hazard, with system criteria for categorisation of activities by the degree of emergency preparedness. These criteria would cover not only the operation of stationary radiation facilities for which a sanitary protection zone is established, but also operations with sources of ionising radiation outside stationary conditions, including transport of radioactive substances, operation of ships with nuclear propulsion systems, as well as radiation hazardous facilities located outside the country. The introduction of such categorisation creates a basis for determining emergency response zones and distances, which will make it possible to determine an effective set of radiation protection measures for the population planned by the authorities of the constituent entities of the Russian Federation together with the operating organisations and the authorities carrying out state regulation of safety in the field of the use of atomic energy.

In the previous study [1], we showed an increased risk of malignant neoplasms in carriers of the minor allele rs1052133*G of the hOGG1 gene who were affected by chronic radiation exposure at a wide range of doses (up to 3,507 mGy to the red bone marrow) at the Techa River (Southern Urals) contaminated due to the activities of the Mayak Production Association in the 1950s. The objective of the present study was to assess the contribution of radiation factor to the risk of malignant neoplasms development in persons chronically exposed at the Techa River. For this purpose, we analyzed the background level of genetically determined risk in the general population of unexposed people on the basis of meta-analysis of the world literature data on the search for the association of rs1052133 of the hOGG1 gene with the risk of malignant neoplasms development. At the final stage, the results of the meta-analysis were compared with data on exposed people. The study found that unexposed and exposed carriers of the rs1052133*G allele had a comparable increased risk of developing malignant neoplasms, odds ratio 1.20; 95% confidence interval [1.06–1.35], p=0.01 and odds ratio =1.38; 95% confidence interval [1.05–1.83], p=0.023, respectively.

The paper presents results of analysis of data accumulated during 2022–2024 in the Federal databank of radiation doses to the public from exposure to natural and technologically enhanced background radiation, which functions within the framework of the Unified State System for Monitoring and Accounting for Individual Doses of Radiation to the Citizens. The results of 598,604 measurements of ambient gamma dose rate in dwellings and public buildings and outdoors in various regions of the country, 155,249 measurements of indoor radon isotopes equilibrium equivalent concentration, 58,804 measurements of activity concentrations of natural radionuclides in drinking water were analyzed. Based on these data, a hygienic assessment of the radiation safety of the population of the Russian Federation due to exposure to natural sources of ionizing radiation in the period 2021–2023 was performed. The analysis of data on indoor radon isotopes equilibrium equivalent concentration showed that in a number of regions of Russia (the Altai Republic, the Republic of Sakha (Yakutia), the Republic of Tyva, Zabaykalsky Krai, Irkutsk Oblast, etc.), in the study period, hygienic norms (action levels) for dwellings and public buildings were exceeded. The analysis of data on activity concentrations of natural radionuclides in drinking water revealed significant (more than an order of magnitude) exceedances of the intervention level for radon in drinking water of certain sources of drinking water supply in Chelyabinsk Oblast and Zabaikalsky Krai. The assessment of public doses due to natural sources of ionizing radiation showed that in several regions of Russia (the Altai Republic, the Republic of Bashkortostan, the Republic of Tyva, Irkutsk Oblast, Stavropol Krai, etc.) public exposure to natural sources can be classified as “increased” (average annual effective dose is in the range 5–10 mSv), and in Zabaikalsky Krai public exposure can be classified as “high” (average annual effective dose exceeds 10 mSv/year) in 2021 and 2023.

Prediction of radon potential and justification of measures for reducing radon concentration in buildings necessitate the study of soil radon transport. The article presents an approach to estimating the geogenic radon potential of a site based on the study of the dependence of the radon flux from the soil on the pressure gradient. The efficacy of the method of radon flux density measurement with artificial activation of controlled advective air flow from the soil into the accumulation chamber was evaluated at an experimental site. The measuring installation consisted of a large-volume accumulation chamber (200 l), a system of pumps, flow meters, and a differential manometer. The results of measurements at 12 points on the experimental site yielded a number of values, including advective radon flux density as a function of pressure difference between the accumulation chamber and the atmosphere (in the range 4–20 Pa), radon concentration in soil air, and resistance to air flow in the soil-chamber system. The results demonstrate that at the investigated site, the potential advective radon flux density significantly exceeds the diffusive radon flux density: the corresponding radon flux density ranges are 23–870 mBq/(m² s) and 5.5–7.0 mBq/(m² s), respectively. The air flow resistance in the system of the soil measurement chamber varies depending on the meteorological conditions, with a range from 93 to 2400 kPa/(m³·s^-1). On average, under dry conditions, the resistance to airflow is 4.8 times lower than in rain. The radon concentration in the soil varies from 0.6 to 3.2 kBq/m³, with an arithmetic mean of 1.4 kBq/m³. The dependence of the advective radon flux density, normalized to a pressure difference of 1 Pa, on the air flow resistance follows the Darcy’s law. This dependence, taking into account the soil radon concentration, characterizes the geogenic radon potential at the site. The advantages and disadvantages of the method of geogenic radon potential estimation based on the artificial activation of the pressure gradient in the measurement system are discussed.

Currently, the most common methods to measure the activity of transuranium elements in biological samples are alpha radiometry and alpha spectrometry. Of these, alpha spectrometry is the most sensitive and selective method. However, this method is not sufficiently sensitive to control hardly soluble compounds of plutonium in the human body. For example, upon an intake of hardly soluble compounds of plutonium at the level of annual limit of intake, a year later, Pu in a daily urine sample is expected to be 0.4 mBq. Since the lower limit of measurement of alpha spectrometry is about 0.5 mBq, during the first 2 years as minimum, the workers who have contact with hardly soluble compounds of plutonium are not provided with a reliable monitoring of intakes. To solve this problem, a new technique of analysis was developed based on the plutonium activity measurement using the method of inductively coupled plasma mass spectrometry. This technique allows measuring plutonium by mass spectrometer in daily urine samples and blood samples after separation from interfering isotopes by anionic exchange chromatography. The method takes much less measurement time and is much more sensitive to long-lived isotopes. It enables reducing the lower limit of measurement by a factor of five compared to the alpha spectrometry method. Also, the technique for the first time allows to measure separately the activity of plutonium-239 isotopes and plutonium-240 isotopes, the energies of which are indistinguishable on alpha spectra. The plutonium activity was measured by the two methods in parallel in 88 daily urine samples collected from the personnel of the federal state unitary enterprise “Mayak Production Association” working primarily with hardly soluble compounds of plutonium. The analysis of the measurements of these samples demonstrated no statistically significant differences between the results obtained. Also, these results testify to better applicability of mass spectrometry for the activities below the lower limit of measurement of alpha spectrometry. The developed method of analysis can be applied to estimate the levels of current intake of hardly soluble compounds of plutonium, for retrospective dosimetry and as an express method to obtain the intake estimates by the plutonium activity in blood in non-routine situations.

Identification, prevention and response to events in medical exposure are an integral part of the radiation safety system in medicine. The existing approaches in the Russian Federation, presented in the current regulatory and methodological documents, need to be updated and harmonised with international practice. At the same time, it is advisable to focus on events related with patients, because of potential overexposure of workers and public is presented comprehensively. The study presents suggestions for amendments to terminology in medical exposure events of patients and development of classification of the events criteria as well. Schemes to identify and respond to events in medical exposure that related to overexposure of patients are defined. It is advisable to implement the results of the study into the section on radiation safety in medical exposure in the updated version of OSPORB-99/2010.

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 it covers all stages of the life cycle of buildings and facilities: commissioning; operation period; overhaul and reconstruction; demolition. In the second part of the paper, numerous innovations are considered in terms of estimating the indoor average annual equilibrium equivalent concentration of radon isotopes. The reasons for the introduction of certain changes are outlined. Based on the results of previous studies and the review of foreign recommendations, the procedures for measuring indoor radon concentrations have been improved in such a way as to balance the increase in the reliability of estimating the average annual equilibrium equivalent concentration of radon isotopes and the increase in time and labor costs for testing laboratories to conduct the survey. The revised document introduces separate procedures for measuring indoor radon concentrations in new buildings and existing buildings with round-the-clock and non-round-the-clock occupancy. Estimating a weighted average based on the results of two-season measurements will represent a significant step forward in assessing the actual average annual radon concentrations in operated buildings in Russia. At the same time, the case of radiation survey of the buildings within the framework of events with legally limited duration is considered separately in the revised document. Taken together, the changes should have a positive impact on the quality of measurement information obtained by testing laboratories and underlying decisions made by executive authorities.

The study presents summary, analysis, and hygienic assessment of data on the radiation accidents related to violations of the rules of gathering and recycling of ferrous and non-ferrous metal scrap within the Russian, based on data from the Radiation Accidents and Incidents Database of the Information and Analytical Center of Rospotrebnadzor on Radiation Safety. The aim of the study was to analyze information on radiation accidents associated with violations in the collection and handling of scrap metal occurring in the Russian Federation over period from 2010 to 2023. A total of 971 radiation accidents related to improper handling of scrap metal were recorded across 41 regions in Russia during the study period. The largest number of the accidents occurred in Vologda (206), Sverdlovsk (178), Khabarovsk (150), Saint Petersburg (116), and Orenburg (52) regions. A negative trend in the accident frequency was observed, with an average annual decline rate of 12%, indicating a steady decrease in occurrences over the last 14 years. The primary sources of radioactive contamination in scrap metal included fragments of various radiation-related equipment, pipes, and technological equipment from the oil and gas industry contaminated with natural radionuclides during use (primarily ²²⁶Ra and its salts), as well as devices containing permanent luminescent substances based on ²²⁶Ra salts. The identified sources were most commonly associated with the radionuclides ²²⁶Ra (63%), ¹³⁷Cs (12%), ⁶⁰Co (9%), ²³⁸U (9%), with occasional cases involving ²⁴¹Am, ²³²Th, and ⁹⁰Sr. In 66% of cases, the ambient gamma dose equivalent rate on the source surface exceeded 1 μSv/h; in 27% it exceeded 10 μSv/h, in 7% it exceeded 100 μSv/h, and in five cases were in range from 1 to 8.8 mSv/h. It was found that sources of ionizing radiation posing potential health risks to the public have been detected throughout the study period. In 14 cases, radioactive contamination was identified in scrap, indicating accidents of melting down radiation sources without investigation into the circumstances or assessment of potential adverse effects. In most (64%) of the registered radiation accidents, the batches of scrap metal were accompanied by radiation control certificates from accredited laboratories, confirming compliance with sanitary standards and regulations. The analysis of radiation accidents related to violations in the collection and handling of scrap metal revealed that the current domestic system for ensuring radiation safety during the procurement and sale of scrap metal remains effective and relevant. Recommendations for improving emergency response during investigations of such radiation accidents have been provided to the Rospotrebnadzor organizations.

Today in the Russian Federation, the existing method for assessing patients` effective doses during computed tomography in the form of conversion coefficients from the dose-length product provides for the area from the head to the upper third of the femur but does not consider the possibility of scanning the whole body including the lower extremities. In this case, for some nosologies, the lower extremities may be involved. The aim of the study was to develop conversion coefficients from the dose-length product to the effective dose for whole-body computed tomography scanning including the patient's lower extremities. The coefficients for whole-body computed tomography scans (including the lower extremities) were determined for a sample of computed tomography scanners that are part of positron emission tomography combined with computed tomography devices of different models for adults and children of different age groups. In NCICT 3.0 software absorbed organ doses were calculated taking into account the specific model of devices and scan length. Effective doses were determined in accordance with the methodology presented in Publication 60 of the International Commission on Radiological Protection and Radiation Safety Standards 99/2009. Separately, conversion coefficients were developed from the dose-length product to the absorbed dose in uterus to enable predictive assessment of doses in the fetus in pregnant women. The study presents the average values of the received effective doses, absorbed doses in uterus and conversion coefficients for all considered models of devices. Conversion coefficients for protocols with automatic tube current modulation were lower compared to those for protocols without automatic tube current modulation, especially for pediatric patients: for children with an average age of 0 years – 9 times, for children an average age of 1 year – 6 times, for children an average age of 5 years – 5 times, for children an average age of 10 years – 3 times, for children an average age of 15 years – 2 times; for adults the difference was 20%. Comparison of the conversion coefficients from the dose-length product to the effective dose for computed tomographic scanning of the whole body area limited to the upper third of the femur, presented in guidelines 2.6.1.3584-19, with the values obtained in this study for the whole body area with the lower extremities without automatic tube current modulation showed that for all age groups, with the exception of newborns, the conversion coefficients for the scanning area with the lower extremities are lower than those presented in the guidelines. Using the conversion coefficients from the Guideline 2.6.1.3584-19 for whole-body computed tomography scanning with the lower extremities will lead to a significant overestimation of patient doses. The calculated conversion coefficients from the dose-length product to the absorbed dose in uterus and from the dose-length product to the effective dose for computed tomography examination of the whole body with the lower extremities for different age groups of patients are suitable for assessing the effective doses of patients and for prognostic estimates of absorbed dose in the fetus in pregnant women.