Effective Exposure Dose Research Articles

Influencing factors of occupational health of clinical nuclear medical staff

Objective: To analyze the characteristics and its influencing factors of occupational injury among clinical nuclear medicine staff, and to put forward suggestions for formulating relevant radiation protection intervention measures. Methods: In March 2022, a study was conducted involving 12 medical institutions engaged in nuclear medicine in Gansu Province. The occupational health examination data of 1451 clinical nuclear medicine staff were analyzed. The study subjects were divided into two groups based on the median annual effective dose of external exposure in 2022: Group A (annual effective dose ≤0.2 mSv, n=927) and group B (annual effective dose >0.2 mSv, n=524). The effects of annual effective dose, age, seniority, gender and occupational category on occupational health of clinical nuclear medicine staff were analyzed. Classification variables between groups were compared with Pearson χ(2) test. Multivariate logistic regression was used to analyze the influencing factors of the abnormal results. Results: The abnormal rates of white blood cell count (WBC), red blood cell count (RBC) and hemoglobin (HGB) in female clinical nuclear medical staff were higher than those in males, and the differences were statistically significant (P<0.001). The abnormal rates of WBC and HGB in clinical nuclear medicine staff of different occupational categories were statistically significant (P<0.05). The abnormal rates of RBC and HGB of clinical nuclear medicine staff in annual effective dose group B were higher than those in group A, and the differences were statistically significant (P<0.05). Multivariate logistic regression results showed that the abnormal risks of RBC in annual effective dose group B was 2.465 times of that in group A, the abnormal risks of RBC, WBC and HGB in females were 9.354, 2.939 and 6.760 times of those in males, respectively. The abnormal risk of WBC in the radiotherapy group was 2.334 times of that in general radiotherapy group. The abnormal risk of lens in nuclear medicine group was 2.459 times of that in general radiotherapy group. The abnormal risk of ECG and lens in ≥35 years old age group were 1.814 times and 1.969 times of those in <35 years old age group, respectively. The abnormal risk of lens of the ≥10 working years group was 1.899 times of that in the <10 working years group. The risk of lymphocyte micronucleus abnormality in the interventional group was 1.481 times of that in the general radiotherapy group, the risk of lymphocyte micronucleus abnormality in females was 2.215 times of that in males. The risk of lymphocyte micronucleus abnormality and lymphocyte chromosome aberration in ≥35 years old age group were 2.552 and 2.266 times of those in <35 years old age group, respectively. The risk of lymphocyte micronucleus abnormality in the group with≥10 working years was 1.443 times of that in<10 working years group (P<0.05) . Conclusion: Long-term low-dose ionizing radiation has a certain effect on the lens and genetic indexes of clinical nuclear medicine staff.

Assessment of the annual effective dose and lifetime cancer risks associated with tritium in groundwater within different age groups

Tritium is a radioactive isotope of hydrogen that emits low-energy radiation. When humans are exposed to tritium, the primary concern is internal exposure through inhalation, ingestion, or absorption through the skin. The severity of the adverse health effects depends on the duration, amount, and route of exposure. Therefore, estimating the tritium levels in groundwater and the corresponding health risks within different age groups is essential. The annual effective dose is determined by considering several factors, including the concentration of tritium, the volume of water consumed, and the duration of exposure. The calculated annual effective doses were then compared to the safety limit as directed by international organizations. The estimated tritium concentration in the searched groundwater samples was significantly low, ranging from 0.014 to 0.114 Bq/L. The annual effective dose of tritium exposure for infants, children, and adults varies from 0.028 to 0.605 μSv/y and is within the safe limit recommended by the World Health Organization (WHO) and other international organizations. The lifetime cancer risk (LTCR) for the consumer in the searched areas was estimated for males and females based on the average lifetime. Mortality and morbidity rates varied slightly between males and females across samples due to differences in activity concentrations and locations. However, the estimated LTCR values were below the radiological cancer risk limit. These findings will provide valuable insights to regulatory authorities, assisting them in developing strategies to ensure public safety against human exposure to tritium.

Analysis of data on levels of public exposure to natural sources of radiation in the Ivanovo region

The paper presents the results of analysis of the Ivanovo Regional databank of radiation doses to the pub-lic from exposure to natural and technologically enhanced radiation background for 2008–2022. Despite the fact that the average individual annual effective dose of public exposure due to natural sources of radiation in the Ivanovo region calculated for the whole 15-year period (4.63 mSv/year) does not qualify as increased (i.e. does not exceed the level of 5 mSv/year), in some years of the period under review the average dose repeatedly exceeded this level, reaching 7.50 mSv/year. The analysis of the structure of the doses of public exposure due to natural sources of radiation in the Ivanovo region showed that the contribution of the dose from internal exposure to radon, thoron and progenies according to measurement results from 2008–2022 ranged from 65.98 to 81.47%. The paper provides examples of buildings of different types in settlements of the Ivanovo region, in which the indoor radon isotopes equilibrium equivalent concentrations are more than 1.5 times higher than the established action level for existing dwellings and public buildings (200 Bq/m3). Despite the significant amount of measurement data in the Regional databank, it is necessary to obtain additional information on the indoor radon levels in existing wooden and other low-rise dwellings and public buildings in the most radon-prone areas of the region. For this purpose, a radon survey is planned for 2024-2026 in the cities of Ivanovo and Kohma, Privolzhsky, Gavrilovo-Posadsky, Teykovsky and Zavolzhsky districts of the Ivanovo region within the framework of a joint project of Saint-Petersburg Research Institute of Radiation Hygiene after Professor P.V. Ramzaev, the Directorate of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing in the Ivanovo region, and the Center of Hygiene and Epidemiology in the Ivanovo region.

DEVELOPMENT OF AN APPLICATION FOR ASSESSING PUBLIC RADIATION EXPOSURE WHEN LIVING AND CARRYING OUT ANY ACTIVITIES AT THE SEMIPALATINSK TEST SITE

The article presents an overview of capabilities of developed software ‘Assessment of public radiation exposure when living and carrying out any activities at the Semipalatinsk Test Site’ and quoted the algorithm to calculate public individual annual effective exposure doses from the major dose-forming man-made radionuclides at the test site (137Cs, 90Sr, 239+240Pu, 241Am, 3H). The software developed takes into account such behavior scenario as a farmer engaged in subsistence farming and living in the study area together with his family members. The software was developed for Windows operating system and implemented in the development framework of cross-platform applications Embarcadero Delphi XE7 Professional in the object-oriented programming language Object Pascal.

Current status of reference location in the basic model for assessment of external radiation doses to the population living in radioactively contaminated areas after the Chernobyl accident

An open plot of virgin land is the reference location in the basic model used to date to estimate the effective dose of external exposure to the population living in a radioactively contaminated area. As our field observations in the Bryansk region of Russia have shown, at present it is very difficult to find truly reference plots of virgin land due to the fact that many virgin meadows were plowed or reclaimed for more than 30 years after the Chernobyl accident. Without special instrumental survey, such disturbed meadow areas can easily be confused with areas of virgin soil. Therefore, the situation with the use of open areas of virgin soil as the reference location has changed dramatically since the first years after the Chernobyl accident. It requires a change in the approach to choosing such a location for the model and/or some revision of the structure of the model itself. Firstly, we propose and justify the use of a permanently cultivated kitchengarden plot as the reference location. The second way to resolve the current difficult situation with the presence of a sufficient number of the virgin soil sites could be excluding the very concept of “reference location” from the model. In this case, when calculating the effective dose of external radiation, it is proposed to directly use the values of the gamma radiation dose rate in the air normalized to the 137Cs contamination density of soil. The values of the normalized dose rate should be experimentally determined in the required time period for each of the locations taken into account in the model.

Ensuring radiation safety during dismantling, transportation and long-term storage of the SM-3 research reactor core

Described shortly here is a procedure of demounting, removal, transport and long-term storage of the SM-3 core, based on the previous experience of reactor refurbishment undertaken in 1991. Prior to performing refurbishment, computations and calculated data analysis were performed to prove radiation safety of this work, which included estimation of the activity level for activation products in the structural materials of the nuclear research reactor core and the radiation conditions at different stages of its handling. As evidenced by the calculated data, the activity of the main dose-forming radionuclide 60Co attains equilibrium in about 12 years of radiation exposure. Taking into account the fact that the time period between two refurbishments was longer than 12 years, the calculated values of the equivalent dose rate were normalized to the radiation monitoring data obtained during the previous refurbishment, taking into account the calculated activity of 60Co radionuclide. The normalization made it possible to confirm reliability of estimates. The obtained activity data of activation products and taking into account the time spent during the SM-3 refurbishment in 1991, the radiation impact on personnel was estimated. Calculated values of the anticipated effective radiation exposure doses to the personnel engaged in the refurbishment revealed that the main limits of the personnel radiation exposure established in accordance with NRB-99/2009 were not exceeded. Comparison of the results of calculating the equivalent dose rate with the results of radiation monitoring at various points allowed us to establish that during the calculation and analytical justification of the radiation safety of work, the assessment of reflected radiation was significantly underestimated. But the radiation monitoring data, personal radiation monitoring, as well as recorded data of automatic radiation monitoring system show that all work was performed in compliance with the requirements of regulatory documents in the field of radiation safety.

Глобальное загрязнение территории Южной Якутии Cs-137 и дозы облучения населения

The aim of the work is to estimate the radioactivity of Cs-137 in the soils of South Yakutia and to calculate the dose of internal irradiation of a critical group of people caused by the consumption of local foods containing radionuclide. An assessment of the radioactive contamination of the soil cover of South Yakutia showed that the radioactivity of Cs-137 in the soils of eluvial landscapes varies between 714 and 1,665 Bq/m2 and is commensurate with the radioactivity of Cs-137 in the soils of the Primorsky Krai, the Western Siberia and the Kola Peninsula. The present soil contamination levels of Cs-137, compared to the 2003 data, have been reduced on average by half due to radioactive decay of the radionuclide, the soil deepening and removal with surface water and vegetation. At present time there is no appreciable additional input of Cs-137 from the atmosphere to the soil cover of automorphic taiga landscapes in the South Yakutia. The specific activity of Cs-137 in watershed soils and river floodplains is low and corresponds to the background level of global pollution. The vertical distribution of Cs-137 over the soil profile of eluvial landscapes is realized on regressive-cumulative and eluvial-illuvial types. In soil profiles of hydromorphic landscapes Cs-137 is distributed, without any clear patterns, which is a consequence of the impact of alluvial processes. Calculations showed that at the current level of contamination of local foodstuffs, the annual effective dose of internal exposure of a critical population group from this radionuclide is 87 times less than the annual dose limit for the Russian population.

Targeted four-dimensional computerized tomography scans for elbow disorders: a literature review and refinement of existing technique with two exemplar cases

Background4D-CTs or motion CTs in elbow disorders have several potential advantages over conventional static imaging such as a reduction of misdiagnoses, a more targeted surgical approach, better patient understanding of their condition and potentially faster operative times. However, the radiation dose is higher than conventional static CT scans so this should be used judiciously. Our study reviews the current literature for 4D-CTs in dynamic elbow disorders and provides a technical note describing radiation-reduced targeted elbow 4D-CTs (te4D-CT) with two exemplar cases alongside our recommendations for when te4D-CTs are indicated. Methodste4D-CTs are performed in a lateral decubitus elbow above head position. Preliminary static source axial cut CT obtained with subsequent sagittal and axial planes reconstruction and 3D reconstruction obtained, followed by scan performed in motion and reconstructed to 4D Component. te4D-CTs are taken for either flexion and extension (FE) or pronation and supination (PS) motions depending on the clinical pathology suspected following thorough clinical examination. Resultste4D-CT for PS and FE protocol scans had an effective radiation exposure dose of 0.53 and 0.95mSv respectively compared to 1.13-1.83mSv in conventional elbow 4D-CTs. In addition, te4D-CTs have good diagnostic accuracy provided that the FE or PS pathology is identified carefully by the ordering physician. Conclusionte4D-CT using isolated pronation and supination, or flexion and extension protocols does come with a significantly reduced radiation dose and can be of equal clinical yield compared with 4D-CTs.

СРАВНЕНИЕ РАДИАЦИОННОЙ И ХИМИЧЕСКОЙ ТОКСИЧНОСТИ СОЕДИНЕНИЙ УРАНА НА ОСНОВЕ РАСЧЕТА ПО НОВЫМ БИОКИНЕТИЧЕСКИМ МОДЕЛЯМ МКРЗ

Purpose: Harmonization and improvement of the system for regulating the internal radiation exposure of workers and the basic requirements for ensuring radiation safety, taking into account the application of new international requirements and recommendations. Material and methods: The article presents a comparison of the radiation and chemical toxicity of uranium compounds, obtained on the basis of calculating the levels of inhalation intake and committed effective dose depending on the types of compounds F, M, F/M and M/S in the AMAD range from 0.3 to 20 μm for typical isotopic compositions of natural (NU), depleted (DU), low enriched (LEU) and highly enriched (HEU) uranium, which lead to the maximum permissible concentration of uranium in the kidneys. The calculations were carried out using new ICRP biokinetic models, which give more physiologically realistic representations of uptake and retention in organs and tissues, and excretion. Results: The dynamics of uranium activity in the kidneys was calculated for constant chronic inhalation intake over a 50-year period and for acute intake. It was shown that in case of chronic intake, the rate of accumulation of uranium in the kidneys, expressed in relative units, does not depend on the AMAD in the range from 0.3 to 20 μm and slightly depends on the types of compounds F, F/M, M and M/S, which include almost all chemical compounds of uranium. In case of acute intake, there is a rapid, within 1–3 days, an increase of uranium in the kidneys to a maximum value and then a gradual decrease to a value of 20 % of the maximum value in 20–60 days, depending on the type of compound F, M, F/M, M/S and AMAD in a wide range of values from 0.3 to 20 µm. To compare the radiation and chemical toxicity of uranium, the values of the committed effective dose were calculated, which is formed after intake of uranium aerosols of the types F, M, F/M and M/S and AMADs from 0.3 to 20 µm in an amount that creates the maximum concentration of uranium in the kidneys 0.3 µg/g for chronic intake and 3 µg/g for acute intake. The values of uranium intake per year in milligrams, which form the maximum concentration of uranium in the kidneys of 0.3 µg/g, in case of constant chronic intake of uranium aerosols, as well as the values of uranium intake in milligrams, which form the maximum concentration of uranium in the kidneys of 3 μg/g after a single intake of uranium aerosols in both case of the types F, M, F/M and M/S and AMAD in the range from 0.3 to 20 µm were calculated, which are evidently independent of the considered isotopic composition of the uranium. Conclusion: It is shown that chemical toxicity prevails over radiation toxicity for the types of uranium compounds F and F/M for all considered uranium isotopic composition, except for HEU; for the type of compound M it is the same for mixtures of NU and DU, and for the type M/S radiation toxicity prevails for all considered uranium isotopic composition. In case of chronic intake at committed effective dose exposure rate of several mSv per year, workers can suffer from the chemical toxicity of uranium when working with F and F/M compounds and isotope compositions of natural (NU), depleted (DU) and low enriched (LEU) uranium already after 1–2 years of work. In case of acute intake, the chemical toxicity of uranium should be taken as a criterion for limiting exposure for compounds F and F/M, and also partially M (for uranium isotope compositions of NU, DU and LEU), which can significantly, by tens and hundreds of times, reduce the permissible limit of uranium intake.

Radiation Dose Evaluation for Radiotherapy Workers at Unand Hospital Using Four-Element Thermoluminescence Dosimetry

Radiotherapy is a non-surgery therapy that employs ionizing radiation like X-ray or even radiation to cure cancer as a curative activity. Radiation dose rate analysis is required for the person who worked on radiotherapy to strengthen safety precautions for radiation protection, notably in oncology radiation. The research attempted to disclose time trends and radiation dose rate exposure variations among personnel in radiotherapy installation. Radiation dose examination utilizing four-elements TLD received from 16 respondents grouped into six groups (radiation oncologist, medical physicist, radiotherapist, electromedicine, nurse, and sculptor). The number of occupancy exposures rose 55.5% from 2018 to 2022. The most significant annual radiation dose rate for 900 patient workloads attained by medical physicists was 0.996 mSv. In addition, electronics receive the lowest annual radiation dose at Unand Hospital. Annual effective dose exposure by radiation is still safe, below national or international regulations. However, a protective improvement process is vital to limit radiation interaction, particularly for medical physicists, who are the most vulnerable to radiation exposure.

PEMANTAUAN DOSIS RADIASI PADA CT SCAN UNTUK MENGETAHUI PERSENTASE POTENSI KANKER DI RSUD DR. MOH SALEH PROBOLINGGO

CT Scan is a diagnostic tool that helps identify body disorders without surgery. It works by using X-ray radiation to create images of the body. However, X-rays can be harmful to the human body. This study aims to determine the amount of radiation exposure associated with a CT scan and the potential cancer risk from this exposure. The study analyzed 1396 scans, including 1046 scans of the head, 128 scans of the thorax, and 221 scans of the abdomen, using contrast and non-contrast techniques. The effective dose was calculated by multiplying the Dose Length Product (DLP) by the organ weight factor. The study found that the abdomen had the highest average effective dose of radiation exposure, at 18.78 mSv, followed by the thorax at 5.72 mSv and the head at 2.20 mSv. The study also found a positive, strong, and significant relationship (p=0.000) between effective dose and the potential risk of cancer, with a ratio of 0.9966. The highest risk of cancer was associated with exposure in the abdomen, at 0.094%. The effective dose information can help patients, healthcare workers, and families understand the potential risks associated with CT scans and can be used as a tool for education. Keywords: CT Scan, DLP, effective dose, radiation risk, cancer potential.

On the concentration of radon in a polluted city of the Middle East: An insight into its association with PM levels, air properties, and risk assessment

This study was conducted in Ahvaz city, where the concentrations of radon and airborne particles in 10, 2.5, and 1 micrometers, along with meteorological parameters were measured. The measurements were performed in three educational and therapeutic sampling points at both ground and underground levels during cold and hot seasons. The results showed that in 3.17% of the samples, the concentration of radon exceeded the permissible limit recommended by the Environmental Protection Agency (EPA). Factors affecting the increase of radon concentration in indoor air included cold season, underground sampling points, the number of doors and windows as air dilution factor and air exchange, air pressure, and air humidity. The concentration of particles in the air did not have any effect on radon in the indoor air. The annual effective dose of exposure to radon (DR), the annual effective dose of lung (DE), and the risk of lung cancer cases (LCC) during both cold and hot seasons and at ground and underground levels were lower than the permissible values recommended by the International Committee on Radiological Protection (ICRP). We concluded that the increase of particles is neither the cause nor the source of increased indoor air radon. The findings of the present investigation recommend controlling physical indoor air parameters particularly temperature and relative humidity by proper ventilation systems to mitigate the impact of radon exposure on inhabitants.

ОБОСНОВАНИЕ ПРЕДЛОЖЕНИЙ К НОВЫМ НОРМАМ РАДИАЦИОННОЙ БЕЗОПАСНОСТИ

The purpose of this work is to improve the Russian Radiation Safety Standards (NRB) in terms of the interpretation of the meaning of “the main limit of the annual effective dose” and the use of the concept of “emergency”. In [1], proposals were submitted to discuss the changing in new versions of NRB and the Main Health Rules for Radiation Safety (OSPORB) in terms of the interpretation of the concept of “the limit of the annual effective dose of man-caused occupational exposure” and health physics regulation of radionuclide contents in solid materials for free or limited use of these materials. The current NRB-99/2009 uses the term “radiation accident” and establishes the main limits of effective dose (Table 3.1.) for personnel and the public: ‒ for the personnel A group, the annual dose limit is 50 mSv under the mandatory condition of not exceeding the average annual value of 20 mSv for any consecutive 5 years; ‒ for the public, the annual dose limit is 5 mSv under the mandatory condition of not exceeding the average annual value of 1 mSv for any consecutive 5 years. However, in design documentation for the construction and reconstruction of nuclear facilities, in draft regulatory and methodological documents, there are periodically misinterpretations of the main dose limits for personnel and the public and an incorrect interpretation of the term “radiation accident”. In many cases, a dose of 20 mSv is called the annual dose limit for personnel, and a dose of 50 mSv/year is either not mentioned at all, or is considered only as permissible in a radiation accident. The term “radiation accident” is often treated as a synonym for “emergency”. The paper justifies the expediency of introducing relevant changes to the text of new NRB.

Occupational radiation exposure for dental radiation workers and diagnostic radiology workers in Albania

The development of dental radiology in Albania has been over a century. Medical imaging isessential to dental practice. X-rays examinations help dentists to diagnose, plan treatments and monitorboth treatments and lesion development. This study explored mainly the profile of dental radiation workerscomparing it with the diagnostic radiology workers and their occupational radiation exposure in Albaniafor the period 2016 to 2020. The assessment and analysis procedures of this study were carried out at thepersonal dosimetry laboratory, Institute of Applied Nuclear Physics. The total number of monitored dentalradiation workers increased from 39 in 2016 to 82 in 2020. The annual collective effective exposure dosefluctuated from 26.84man-Sv to 70.14man-Sv, and it showed an increasing trend. In addition, the averageannual effective exposure dose of total monitored dental radiation workers varied from 0.73mSv to0.87mSv. The total number of monitored diagnostic radiology workers increased from 196 in 2016 to 332in 2020. The annual collective effective exposure dose fluctuated from 240.99man-Sv to 358.03man-Sv,and it has showed an increasing trend. The average annual effective exposure dose of total monitoreddiagnostic radiology workers varied from 1.08 mSv to 1.40 mSv. The results of the measured annual dosewere well below the international recommended dose limit of 20 mSv.

Dual-energy computed tomography in reducing the effective radiation dose of computed tomography urography in patients with urinary calculi.

To evaluate the diagnostic performance of split-bolus single-phase dual-energy computed tomography (DECT) with virtual non-contrast computed tomography (VNCT) compared to three-phase computed tomography (CT) urography in patients with urinary calculi, and to examine the performance of split-bolus single-phase DECT when reducing the effective dose. A total of 48 patients with abdominal pain or hematuria suggestive of unilateral urinary calculi were enrolled and randomly divided into the experimental and control groups, with 24 cases in each group. Patients in the experimental group underwent split-bolus single-phase DECT to obtain a mixed nephrographic excretory phase. Patients in the control group accepted a single-bolus three-phase CT urography scan (non-contrast, nephrographic phase, and excretory phase). The CT values and the contrast-to-noise ratio (CNR) of 7 segments of the urinary tract were measured and compared between the two groups by using the Mann-Whitney U test. The dose-length product (DLP) and effective dose of each patient were compared between the two groups using an independent t-test. Among all 48 patients, 35 calculi were detected in the experimental group (n=24), and 47 calculi were detected in the control group (n=24). There was no significant difference between the two groups in both CT value measurements and the CNR. The mean DLP and mean effective dose of the experimental group were significantly lower than those of the control group, and the effective dose in the experimental group was decreased by 40% compared with the control group. The application of DECT combined with split-bolus nephrographic excretory phase CT urography can reveal the urinary calculi covered by a contrast medium and also reduce the effective dose exposure to patients.

Radiation exposure of personnel and public of radiation control areas of radiation hazardous facilities in the Russian Federation in 2021

The article presents analysis of exposure doses to the population of observation zones and personnel of radiation facilities of the Russian Federation in 2021. For the analysis , we used data received by the Federal Data Bank on Personnel Exposure Doses , which operates as part of the Unified System of Individual Dose Control of the Russian Federation citizens . Data received from 20 359 radiation facilities were used . Among them , there are 19 743 radiation hazardous facilities supervised by Rospotrebnadzor and 616 supervised by the FMBA of Russia. 15 883 (78%) radiation hazardous facilities are medical institutions . In total , in 2021, the Federal Data Bank on Personnel Exposure Doses received the results of measuring the annual individual effective doses of technogenic industrial exposure of 239 743 persons of group A personnel and 22 490 persons of group B personnel . 12 095 people of group A personnel who worked part-time at several radiation facilities were identified The average annual effective dose of technogenic occupational exposure of group A personnel in 2021 was 1.12 mSv , and for group B personnel , whose exposure doses were obtained according to instrumental control data – 0.61 mSv . The maximum values of the average annual effective dose of technogenic occupational exposure for group A personnel in 2021 took place in the Zabaykalsky Krai (2.81 mSv ), Perm Krai (2.60 mSv ), the Ulyanovsk region (2.03 mSv ), the Yamalo-Nenets Autonomous Okrug (1.93 mSv ) and the Republic of Buryatia (1.91 mSv ). The average individual annual effective dose of technogenic occupational exposure for part-time workers in 2021 was 1.92 mSv / year . It’s in 1.7 times higher compared to personnel A group . In 2021, two cases of exceeding the annual individual dose of 20 mSv and one case of exceeding the annual individual dose of 50 mSv for group A personnel and 12 cases of exceeding the annual individual dose of 5 mSv for group B personnel were identified . The annual individual dose of technogenic occupational exposure of 51.0 mSv ( exceeding the dose limit for group A personnel ) was registered in the Production association “ Sevmash ” in the Arkhangelsk region . In 2021, 1.54 million people lived in the radiation control areas of category I of potential hazard radiation facilities . The average annual effective dose of technogenic exposure to this category of the population due to the operation of radiation facilities was 0.018 mSv , which is only 1.8 times higher than the annual effective dose of 0.01 mSv , corresponding to a negligible radiation risk and 55 times less than the average annual dose limit for the population , equal to 1.0 mSv . In general , the radiation situation at the radiation facilities of the Russian Federation is quite stable and complies with safety requirements . Technogenic exposure of the population and personnel due to the normal operation of technogenic sources of ionizing radiation is the least significant radiation factor , both for individual exposure doses and for the collective exposure dose to the population of the Russian Federation. In 2021, only less than 24 thousand persons of group A personnel received annual effective dose of technogenic occupational exposure exceeding 2.0 mSv , which is comparable to the average annual effective dose of natural exposure (3.36 mSv ) received by the entire population of Russia. The collective annual effective dose to the population of the Russian Federation due to the operation of radiation facilities in 2021 was less than 0.1% of the dose from all sources .

Risk Assessment of Radon Exposure by Ingestion and Inhalation of Groundwater Within Different Age Groups

AbstractRadon and its short‐lived progeny are exposed to most human exposures as a natural source of radiation. Many studies have presumed that one of the most common incidences of lung cancer, colon cancer, and stomach cancer is caused by radon‐contaminated water. In this study, water was collected from different groundwater sources in the Hafr Al Batin area, Saudi Arabia, and the radon concentration was investigated using an electronic portable radon detector. The annual effective dose of radon exposure by ingestion and inhalation of water is calculated from that radon concentration for the different age groups to assess the risk of radon exposure. The calculated annual effective doses are then compared with the international standard of risk limit as directed by the international organizations. The estimated radon concentration for groundwater samples is found to be between 0.03 and 3.20 Bq/L with an average value of 1.16 Bq/L. These estimated values are below the safety limits set by the USEPA and EAEC and far below those recommended by the UNSCEAR, EC, and WHO standards. The calculated annual effective dose of radon exposure for the different age groups ranging from infant to adult is found to be in the range of 0.05 to 16.24 μSv/year, with a mean value of 5.89 μSv/year, which is in the safe limit recommended by the EC and WHO. The obtained results of this present study will support the authority and regulators who are responsible for controlling and strategizing to ensure public safety against radon exposure.

Оценки неопределённостей эффективных доз облучения населения в загрязнённых областях России после аварии на Чернобыльской АЭС

The study is aimed at investigation of the properties of distribution of effective dose convolutions for estimating parametric dependence on the ratio of geometric mean internal radiation doses to external radiation doses and standard geometric mean deviations of lognormal distributions. For research the average annual personal dosimetric information for the period from 1986 over 2022, kept in the database of the National Radiation Epidemiological Register (NRER) was used. Information on internal and external radiation doses received by each resident of 13,000 Russian settlements, the most contaminated with radioactive material from the destroyed Chernobyl NPP is kept in the NRER. The results of the study demonstrated the different values of ratio of geometric mean convolutions of annual radiation doses to effective doses. Their standard deviations are 1.05-1.28 and 2.2-2.8 respectively. The ratio of the arithmetic mean convolutions values to deterministic effective doses stored in the database included in the study is 1.0. With the account of uncertainties included in the estimates of the effective dose and doses of external and internal radiation exposure, the difference between probabilistic and deterministic estimates of effective doses received by the residents of the Russian settlements contaminated with Chernobyl radioactive releases is insignificant.

Дозы облучения населения Беларуси вследствие аварии на Чернобыльской атомной электростанции на 2021-2025 гг.

In accordance with the Laws of the Republic of Belarus «On the social protection of citizens affected by the accident at the Chernobyl NPP» dated January 6, 2009 and «On the legal regime of territories exposed to radioactive contamination due to the accident at the Chernobyl NPP» dated May 26, 2012, the value of the average annual effective dose of exposure to residents is one of the indicators of the radiation situation in settlements contaminated with radionuclides as a result of the Chernobyl accident. The objective: to update the method for assessing the exposure doses to the population in the situation of existing exposure after the Chernobyl accident and, on its basis, to assess the average annual effective exposure dose to residents of settlements of the Republic of Belarus due to the Chernobyl accident for the period 2021-2025. The method for estimating the average annual effective doses due to external and internal irradiation to residents of radioactively contaminated settlements of the Republic of Belarus has been improved taking into account international recommendations in the field of radiation protection, changes in the radiation situation in the long-time period after the Chernobyl accident and the new data on individual dosimetry of internal exposure to the population based on the results of whole-body counter (WBC) measurements. An assessment of the average annual effective exposure doses to the population of the Republic of Belarus residing in the territory of radioactive contamination was carried out, and based on its results, the Catalog of average annual effective exposure doses to residents of 2193 settlements for the period 2021-2025 was compiled. According to the compiled Catalog of average annual effective exposure doses to residents of settlements located on the territory of radioactive contamination of the Republic of Belarus, in 29 settlements out of 2193, the total effective exposure dose can exceed 1 mSv/year, in addition, it is about 1 mSv/year in 5 settlements. In none of the settlements, the average annual effective radiation dose can exceed 5 mSv/year. Valid for the period 2021-2025 Catalog of average annual effective exposure doses to the residents of settlements located on the territory of radioactive contamination of the Republic of Belarus, along with data on the density of contamination of the territories of the Republic of Belarus with long-lived radionuclides, was used to compile the List of settlements and objects located in the zones of radioactive contamination, and to adopt a Resolution of the Council of Ministers of the Republic Belarus on designation of settlements to the corresponding zones of radioactive contamination.

Numerical analysis for the optimization of multi-parameters stratum ventilation and the effect on radon dispersion

To reduce hazards due to the radon dispersion on occupants, careful consideration of multi-parameters of stratum ventilation is necessary, including air supply velocity, temperature, angle and air outlet position. In this study, the radon dispersion in a typical office with stratum ventilation was evaluated based on experimental measurements and computational fluid dynamics (CFD) modelling. Besides, the ventilation performance of each scheme was evaluated by using a technique of order preference by similarity to the ideal solution (TOPSIS) method. Results showed that the mentioned factors and their interactions could pose important impacts on the indoor environment. Combining with TOPSIS, the optimal operation of the stratum ventilation was determined. Compared with the worst ventilation scheme, the ventilation effectiveness was increased by 77.4%, the air distribution performance index (ADPI) was increased by 38.1% and the radon radiological effective dose rate was reduced by 63.4%. The findings may form an important mitigation control strategy to effectively minimize radioactive exposure in indoor environments. • Operation of stratum ventilation for cooling and reducing radon in a typical office is optimized. • Parameter impact on stratum ventilation performance for cooling is analyzed. • Compared with the worst ventilation scheme, the maximum ventilation effectiveness was increased by 77.4%, the air distribution performance index (ADPI) was increased by 38.1% and the annual effective dose of radon exposure was reduced by 63.4%.