Publication 134 of the International Commission on Radiological Protection introduces an updated biokinetic model for internal exposure to tritium, which highlights the need to transition to individualized dose assessment based on this model in dosimetric monitoring. The aim of the study was to validate ICRP Publication 134 for estimating inhalation intakes of tritium based on measurements of tritium activity concentration in urine and tritiated water concentration in workplace air. Materials and Methods. Five participants were involved in the study and stayed twice in a tritium work area at a 13-day interval; each stay lasted 6 h. The air temperature and humidity were measured, air condensate samples were collected using a Peltier element, and urine samples were obtained. Urine sampling continued on subsequent days after the exposure. The model validation was performed by comparing model-derived estimates with experimental values of tritium activity concentration in urine and condensate samples under identical HTO intake scenarios. Results and Discussion. The ICRP Publication 134 model provides estimates of HTO inhalation intake comparable to those obtained with the ICRP Publication 56 model; however, within the first 12 h after prolonged tritium intake, Publication 134 more accurately reflects the dynamics of uptake and elimination. For more accurate assessment of tritium intake based on urine samples collected one week or later after exposure, correction for the tritium effective half-life is required. It is easier to perform the correction using the Publication 56 model. The breathing rates assumed in the study for sedentary work (0.54 and 0.39 m[3] /h for men and women, respectively) led to underestimation of intake compared with estimates based on urine data, whereas breathing rates corresponding to light work resulted in intake estimates exceeding those derived from urine measurements. Conclusion: The validation results for the new ICRP tritium model showed that the new model has advantages over the old one only when interpreting urine concentration measurement results obtained in the first 12 hours after the onset of intake, which is extremely important for monitoring accidental intake.

Bone-seeking[89] Sr ingested to the body of Techa river residents and accumulated in bone tissue. It’s led to active red bone marrow exposure. The aim of this study: to calculate the dose coefficients converting activity from oral intake to the cumulative absorbed dose in red bone marrow for adult men and women. Materials and Methods: The Sr-AG biokinetic model was used to estimate the isotope concentration in the source tissue. After that, the absorbed dose rates in the target tissue were evaluated using dosimetric phantoms described the geometry of media in which radiation transfer is simulated. The result of this modeling is the dose factors converting the specific activity of[89] Sr in bone to the absorbed dose rate in red bone marrow. The phantoms are made according to the original method of stochastic parametric skeleton dosimetry modeling. Their parameters are based on a large number of published measurement results of the characteristics of skeletal bones. The perturbation of these parameters makes it possible to simulate the individual variability of bone morphology to calculate the corresponding uncertainties. Results and Discussion: The dose factors for strontium incorporated in the trabecular bone was 2.33 × 10[-7] and 2.23 × 10[ -7] G/s per Bq/kg for male and female respectively. For the cortical bone dose factors were 0.74 and 0.78 ( × 10[ -7] G/s per Bq/kg) for male and female, respectively. The estimated dose coefficients range from 1.81-4.38 ( × 10[ -9] Gy/Bq) for male and 2.30-5.55 ( × 10[ -9] Gy/Bq) for female. The relative standard dose coefficients uncertainties did not exceed 40 %. Conclusion: The values calculated in the framework of this work can be used to reconstruct doses in order to improve radiogenic risk assessments for the exposed population of the Ural region, as well as the risks associated with the use of radiopharmaceuticals such as strontium chloride.

Despite numerous studies, evidence regarding the impact of radiation exposure to parents’ gonads on the health of their offspring remains limited and contradictory. The accumulated data on radiation exposure among the population of the Southern Urals, resulting from the activities of the «Mayak» Industrial Association, provide an opportunity to study the long-term hereditary effects of radiation in humans. The aim of the study is to assess all-cause mortality rates and to obtain direct estimates of death risk in offspring included in the Urals Cohort of Exposed Population Offspring using doses to parental gonads. Materials and methods: The cohort includes 31154 offspring followed up from 1950 to 2020 in the Chelyabinsk and Kurgan ‑ regions. During the follow-up, 1093621 person years were accumulated and 3774 deaths were recorded. Parental gonadal doses were calculated using the TRDS-2016 (medians: mother 11 mGy, father 8 mGy, combined 34 mGy). Descriptive analysis and mortality risk estimation were conducted using of R and EPICURE software packages. Results and discussion: In the mortality structure, injuries and poisonings predominate, followed by circulatory and respiratory diseases. Male mortality is higher than female. Standardized rates did not exceed national data from the World Health Organization. A significant excess ‑ relative risk of all cause death was found for all doses, as well as for respiratory diseases from maternal ‑ gonadal dose. Modification of the dose dependence by non radiation factors was detected. Conclusion: The obtained estimates are preliminary. Extended follow-up is required to confirm the observed relationships.

Computed tomography is an important diagnostic tool in emergency conditions in pregnant women; however, its use is associated with fetal exposure to ionizing radiation, as the fetus exhibits heightened radiosensitivity. In the Russian Federation, the introduction of SanPiN 2.6.4115 ‑ 25 mandates that medical institutions maintain records of individual patient radiation doses, including pregnant women. Nevertheless, the requirement for mandatory assessment of fetal absorbed doses remains a matter of debate. Furthermore, there are no clear methodological guidelines for calculating such doses, and available data indicate substantial variation in scanning protocols even within the same institution. Therefore, the evaluation of fetal absorbed doses from computed tomography is a relevant task in radiation protection and clinical practice. Aim is to assess fetal absorbed doses from computed tomography examinations performed in pregnant women in a large medical center. Materials and Methods: A retrospective analysis of 40 computed tomography examinations performed on 35 pregnant patients between 2021 and 2025 was conducted. Fetal absorbed doses were calculated using the Fetal Dose Calculation online tool. Results and Discussion: Fetal absorbed doses ranged from 0 to 8.1 mGy. The lowest values (0–0.09 mGy) were observed for head and paranasal sinus; the maximum fetal absorbed dose (8.1 mGy) was found in a two-phase abdominal computed tomography performed in the third trimester. Elevated fetal doses (2.3–7.1 mGy) were associated with multiphase protocols and scanning of combined anatomical regions. In no case did the dose exceed the threshold values of 30, 50, or 100 mGy. Conclusion: Fetal absorbed doses from clinically indicated computed tomography examinations remained well below the established thresholds. The main dose-determining factors are scan region, scan length, number of phases, and gestational trimester. The results support the feasibility of performing computed tomography at any stage of pregnancy without exceeding the threshold for deterministic effects; however, further studies with larger sample sizes are required.

Reliable data on embryo/fetus exposure from the most common radiographic procedures are required to substantiate the justification and optimization of radiation protection of pregnant patients. The aim of the study was to estimate fetal absorbed doses and the corresponding radiation risks to the unborn child based on typical radiographic protocols used in medical facilities of St. Petersburg and the Leningrad Region. Materials and Methods: Fetal absorbed doses were modelled using the COnceptus Dose Estimation (CODE) software for standard chest, cervical spine, thoracic spine, lumbosacral spine, pelvic, and abdominal radiographic procedures in frontal and lateral projections. Input data were collected in 33 medical facilities in St. Petersburg and 18 in the Leningrad Region. Radiation risks were estimated based on the median fetal absorbed doses for each procedure and trimester. Results and Discussion: The highest median fetal absorbed doses were in the range of 1–3 mGy per single projection and corresponded to abdominal, pelvic, and lumbosacral spine radiography, i.e. procedures with uterus wholly or partly included in the irradiation field. Differences between minimum and maximum values reached up to two to three orders of magnitude, indicating considerable potential for optimization of radiation protection of pregnant patients. There were no scenarios with the fetal absorbed dose approaching 50 or 100 mGy. Radiation risks for chest and thoracic spine radiography were within the negligible-to-very-low range; for abdominal, lumbosacral spine, and pelvic radiography, risks were higher and corresponded to the low-risk category. Conclusion: The results of the study may be used to support justification of radiographic procedures for pregnant patients, for risk communication with patients and relatives, and for update of the national clinical guidelines.

Evaluation of patient doses for the establishment of diagnostic reference levels should be performed using dedicated dose surveys. Objective. To assess patient doses from common radiographic procedures in medical facilities in St-Petersburg and the Leningrad Region. Materials and Methods: Data on standard radiographic protocols were collected from 33 medical facilities in St-Petersburg and 18 medical facilities in the Leningrad Region, covering 137 digital X-ray units in St-Petersburg and 53 digital and 62 analogue X-ray units in the Leningrad Region in 2023-2025 and 2019-2021, respectively. Data were collected for radiography of the skull, chest, cervical, thoracic and lumbosacral spine, abdomen and pelvis in frontal and lateral projections. Effective dose, entrance surface dose and calculated dose-area product were determined for each protocol. Results and Discussion: For all radiographic procedures, differences between minimum and maximum patient doses were pronounced and reached up to two orders of magnitude. Statistically significant differences between regional patient-dose samples were observed only for individual procedures; no differences in effective dose were found between digital X-ray units in St-Petersburg and the Leningrad Region. When digital and analogue X-ray units in the Leningrad Region were compared, a significant difference was observed only for entrance surface dose in posteroanterior chest radiography. Standard patient doses in the present study differed significantly from the results of previous dose surveys, both upwards and downwards, indicating the need for detailed systematic assessment of patient doses. The data obtained may be used to justify numerical values of regional diagnostic reference levels. Conclusion: The study results showed that diagnostic reference levels should be established at the regional level, while pooling samples for digital and analogue X-ray units is acceptable.

In 2024–2026, a sample radon survey of operated residential and public buildings was organized in the settlements of the Ivanovo Region. Materials and methods. The survey was conducted using solid-state nuclear track detectors in the cities of Ivanovo and Kokhma, settlements of Gavrilovo-Posadsky, Privolzhsky and Zavolzhsky districts of the Ivanovo Region. The annual individual effective doses to the population from exposure to radon, the individual lifetime risks of death from radon-induced lung cancer, and the population risks expressed as the total number of disability-adjusted life years (DALY) were calculated. Results and discussion. Numerous facts of exceeding the action level (400 Bq/m[3] ) were found during the survey. In Ivanovo, the indoor radon concentration reached 3143 Bq/m[3] in public buildings and 1009 Bq/m[3] in residential buildings; in Kokhma 1618 Bq/m[3] and 1064 Bq/m[3] , respectively. In the public buildings of the Gavrilovo-Posadsky district, the maximum radon concentration was 934 Bq/m[3] , 720 Bq/m[3] in the Privolzhsky district, and 840 Bq/m[3] in the Zavolzhsky district. The largest number of exceedances were found in the cities of Ivanovo and Kokhma, which are home to more than 43 % of the total population of the region. Individual lifetime risks of death from radon-induced lung cancer for residents of all surveyed residential buildings in Kokhma were assessed as unacceptable neither for the public nor for the staff, and urgent measures to reduce them are required. The total effects of exposure of the population of the surveyed cities and districts to radon are estimated to range from 1,066 to 6,562 (on average, 3,066) DALYs. Conclusion. The results of the survey confirmed the correctness of information on elevated indoor radon levels from the Regional databank of radiation doses to the public from exposure to natural sources, and also highlighted the importance of the issue with insufficient measurement coverage of operated residential and public buildings.

The increasing number of computed tomography examinations is associated with growing collective medical radiation exposure and the number of unjustified imaging referrals, highlighting the importance of rapid automated tools for assessing patient radiation risks. Purpose is to analyze the capabilities of application programs for automated calculation of radiation doses and radiation risk during computed tomography. Materials and Methods: A comparative analysis of seven software programs designed to calculate the effective radiation dose during computed tomography was conducted. For each program, the input and output parameters, dose calculation algorithms, coefficients used, and ease of use were analyzed. A comparison of the calculated doses and radiation risk levels for computed tomography of the head, thorax and abdomen was performed. Results and Discusiion: Analyzed programs are grouped into three clusters: 1) determining only the effective dose; 2) calculating organ doses and the effective dose; 3) calculating the effective dose and radiation risks. Programs in cluster 1 estimate only the effective dose using coefficients for the selected anatomical region. Programs in cluster 2 provide a more accurate estimate of the effective dose, as the calculation is based on organ doses and takes into account scanning parameters. Programs in cluster 3 provide the most accurate results; they also calculate radiation risk levels and generate reports on series. The spread of effective dose values between different programs for the same anatomical regions is up to 30–40%, due to the use of different methods and standard coefficients. All of the programs reviewed take into account the doses accumulated during various medical diagnostic procedures, and not all of them provide recommendations on the use of radiation diagnostic methods for a specific patient. Conclusion: The use of automated calculation software facilitates the assessment of radiation doses during computed tomography scans and patient radiation risk levels. Existing solutions are limited by the lack of integration with radiation registries and the inability to account for the total radiation doses of patients employed at radiation facilities for diagnostic purposes and in professional settings, which remains a pressing issue in the field of radiation hygiene and radiation safety.

Ensuring radiation safety during international mass events is a complex state task that affects not only the health of participants, but also the reputation of the host country. An analysis of the literature confirms the continuing risks of radiation terrorism, the most likely scenario of which is the use of a dirty bomb. The purpose of the study is to systematize and classify the problems of radiation safety based on a comparative analysis of domestic and foreign experience. Materials and Methods: Official reports of the Olympic Games organizers (London, 2012; Sochi, 2014), the Pan American Games (2007), the Universiade (Kazan, 2013), the FIFA World Cup (2018), the IAEA guidelines and analytical publications. Results and Discussion: A classification of problems has been developed, including organizational and managerial (underestimation of requirements at the design stage), technical (false alarms of sensors) and interdepartmental (inconsistency of actions) categories. The positive dynamics of interagency cooperation in Russia has been revealed: from the scattered actions in Kazan to the multi-level security structures in Sochi and at the 2018 World Cup. It has been established that the main objects of operation of radiation monitoring systems are cargoes with natural radionuclides and patients after medical procedures, which requires different response algorithms. Conclusion: The proposed classification serves as a scientific and methodological basis for creating universal requirements for radiation monitoring at mass events. The research prospects are related to the development of standard control schemes for different facilities.

Transferring radiation risk models between populations remains a methodological challenge. Estimates of lifetime risk and radiation detriment depend not only on dose and model parameters, but also on the health and demographic characteristics of the population assessed. Objective: to analyse the influence of Russian population data on radiation risk estimates obtained using the International Commission on Radiological Protection methodology. Materials and Methods: The radiation detriment calculation procedure described in International Commission on Radiological Protection Publication 152 was analysed, including excess absolute and relative risk models, lifetime risk calculation using the cancer-free survival function, age and sex structure, and adjustment for severity. Calculations used cancer incidence, mortality, cancer-free survival, and lethality data for Russian and reference populations. Results and Discussion: Differences in baseline cancer incidence substantially affected estimates based on the relative risk model. Using the cancer-free survival function of a population with lower mortality increased the lifetime risk of radiation-induced bladder cancer in Russian males by approximately 1.5-fold, but did not eliminate the approximately twofold difference in baseline incidence at older ages. Baseline incidence and cancer-free survival may have opposing effects on betweenpopulation risk differences. Use of lethality data inconsistent with the population assessed substantially changes radiation detriment estimates. Conclusion: National health and demographic data increase the population specificity of expected radiation effect estimates; however, input data and interpretation should depend on the assessment purpose. For specific exposure situations, actual population, cohort, or clinical data should be used where appropriate. Population-specific risk estimates should not automatically justify relaxation of radiation protection requirements.

Field gamma spectrometry is a common method for determining activity concentration of natural radionuclides in soil in situ. However, the method requires comparison with laboratory methods. Aim of the study: Comparison of field and laboratory methods for measuring activity concentration of[226] Ra,[232] Th and 40K in soil in the presence of surface radioactive contamination with 137Cs. Materials and Methods: Field measurements and soil sampling were carried out simultaneously at 10 kitchen garden plots located in six settlements of radioactively contaminated ([137] Cs) zone of the Bryansk region of Russia. In situ measurements were performed using the MKS-AT6101D scintillation gamma spectrometer-dosimeter from ATOMTEX (Belarus). For the laboratory measurements, a semiconductor gamma spectrometer from ORTEC (USA) was used. Results and Discussion: No statistically significant differences were found between the two methods for determining activity concentration of the natural radionuclides in soil (Wilcoxon test, P > 0.05). The Spearman’s correlation coefficient was 0.87, 0.77, and 0.89 for[232] Th,[226] Ra, and[40] K, respectively. The maximum discrepancy between the laboratory and in situ results was 32 %; on average, the difference ranged from 2 to 8 %. The largest differences were found for[226] Ra. This is mainly due to the measurement uncertainty, which was highest for this radionuclide, compared to[232] Th and[40] K, in both field and laboratory measurements. Conclusion: The comparison study showed that the results obtained using field gamma spectrometry under conditions of contamination of the territory with the technogenic radionuclide[137] Cs were in good agreement with the results of laboratory measurements. There is no need to adjust the activity concentration values obtained using calibration, which was performed by the manufacturer of the portable gamma spectrometerdosimeter MKS-AT6101D.

The measurements were performed using TLD-100 thermoluminescent detectors, LiF:Mg, and Ti (Harshaw, USA). To estimate the average absorbed dose in an organ, 2 to 30 thermoluminescent detectors were placed within it. The total number of thermoluminescent detectors for one irradiation scenario was approximately 250. The phantom was irradiated with parallel (from the front, back, and left side) and diverging radiation beams from point sources located at distances of 20 cm, 50 cm, and 100 cm from the phantom surface. The results of absorbed dose measurements in organs for parallel radiation beams were normalized to the dose recorded by a personal dosimeter worn on the left side of the phantom's chest and to the exposure dose on the phantom's vertical axis at a height of 1 m 20 cm. The results of absorbed dose measurements in organs for divergent beams were expressed in terms of the dose rate (mGy/hour) from a source with an activity of 3.7 ∙ 10¹⁰ Bq (1 Curie). The absorbed dose measurements obtained in this study were compared with those performed by other authors. Results and Discussion: The relative discrepancies between the absorbed dose values in different organs measured by different authors did not exceed ± 15 %. Conclusion: The presented information can be used both for the verification of calculation programs and for the development of models for personnel and population exposure in situations of routine and emergency photon radiation exposure.

The aim of research: test new consumer grade radon monitors available in Russia to assess the possibility of their use in monitoring indoor radon activity. Materials and Methods: Three consumer grade AIKESI RM75 (China) monitors were exposed for 42 days together with professional measuring instruments AlphaGUARD PQ2000 PRO (reference monitor) and Radon Scout Professional in laboratory conditions. Results and Discussion: Statistical processing of time series of radon concentration was performed, and a comparison of measuring instruments was made. The relative error of readings from consumer grade monitors compared to the reference radon monitor does not exceed 12 % for long-term measurements and no more than 16 % for five-day measurements. The nonlinearity of the ratio of average radon concentration values based on readings from the tested and reference radon monitors for consumer grade radon monitors ranges from 3 to 7 %. A slight overestimation of readings was detected for all consumer monitors in the range of radon concentrations < 100 Bq/m³. According to the results of time series correlation analysis, consumer-grade radon monitors satisfactorily reproduce the dynamic of indoor radon activity. Conclusion: The satisfactory accuracy of radon activity measurements, operational characteristics, ease of data processing, and low cost of consumer radon monitors make them suitable for preliminary screening assessments of indoor radon activity. At the same time for research purposes and radiation dose estimations recalibration of consumer grade radon monitor using standard measuring instruments is required.

The operation of liquid radioactive waste collection and storage systems for patients undergoing radioiodine therapy is associated with several challenges that directly affect the throughput of nuclear medicine departments. Existing approaches to predicting Delay System performance do not adequately assess the consequences of different operational scenarios, as they fail to account for key physico-technical characteristics of the system and physiological factors governing activity excretion. Purpose if the study is to evaluate the results of predicting the operation of a liquid radioactive waste Delay System for patients undergoing radioiodine therapy. Materials and Methods: A dedicated mathematical model of liquid radioactive waste generation, collection, and storage processes was developed using the Monte Carlo method. The model incorporates patient hospitalization schedules, administered 131I activities, radiopharmaceutical pharmacokinetics, radioactive decay of[131] I, and various tank filling scenarios. Results and Discussion: The model was implemented as a computer program «RadIodineWasteSim 1.0». Simulation results are consistent with radiation monitoring data and operational logs of the Delay System at the Endocrinology Research Centre. The Pearson correlation coefficient between simulated and experimental data was 0.96. Conclusion: The high level of agreement between simulated and experimental results confirms the validity of the proposed modeling approach. The «RadIodineWasteSim 1.0» program can be used in the design and operation of nuclear medicine departments to assess the impact of organizational decisions on departmental throughput.