Radionuclide therapy with ²²³Ra-dichloride is used to treat bone metastases and to improve the quality of life of patients with metastatic castration-resistant prostate cancer. At the present time there is no reliable data on the biodistribution of the ²²³Ra-dichloride in the patient body. The aim of this study was to assess absorbed, equivalent doses in radiosensitive organs and tissues and effective dose from internal exposure for patients with metastatic castration-resistant prostate cancer treated with ²²³Ra-dichloride. Internal doses from ²²³Ra-dichloride were calculated for a chamber model specific for patients with metastatic castration-resistant prostate cancer. This model consists of 8 chambers (blood plasma, two chambers describing bone tissue, small intestine, upper large intestine, lower large intestine, feces and the rest of the body). Time-integrated activities were calculated using the SAAM II v2.3 software. The IDAC-Dose 2.1 software was used to calculate the absorbed doses. The highest absorbed doses in organs and equivalent doses were determined for the bone surface and red bone marrow. The absorbed dose from a-radiation in the bone surface for a set of six therapeutic procedures with ²²³Ra-dichloride was estimated as 1 Gy; in the red bone marrow — 0.14 Gy. However, the approach used does not specifically consider accumulation of the radiopharmaceutical in metastases, which can lead to a significant overestimation of the absorbed dose in the healthy part of the bone surface and red bone marrow.

Uncertainties of radiation risk of late radiation exposure effects in humans are to a great extent determined by completeness and quality of epidemiological data. The registry of the studied cohort is of fundamental importance for the cohort studies. Particular difficulties appear in the course of development of the exposed population offspring registry as these people in contrast to their parents were not affected by radiation exposure. The formation of the cohort of the exposed population offspring has its peculiarities and requires evaluation of its completeness and quality. The objective of this research is to study the value of the sex ratio as a possible criterion to assess the completeness and quality of the registry of the Techa River Cohort offspring. The register of descendants of the irradiated population at the end of 2019 included information on 25930 persons. The formation of the register of descendants of the population irradiated on the Techa River was started in the mid-1950s. At the same time, various documents were used to confirm the fact of birth of a child in irradiated persons. In the Techa River population the proportion of offspring with exposed mother and unexposed father is 22.2%, those with exposed father and unexposed mother made up 13.9%; the proportion of in utero exposed offspring is 44.6%. In accordance to the widely accepted published data it was to be expected that the number of male 1st-generation offspring in the cohort would be lower. However, the results of the conducted research show no changes in the sex ratio among offspring relative to the population-based control. Moreover, it was stated that the sex ratio in the population of the 1st-generation offspring of the exposed residents of the Techa River settlements should not be viewed as secondary. The assumption about the influence of the pre-conceptional exposure of the parents as well as that of the in utero exposure on changes in the sex ratio was not confirmed. It is shown that the decrease in the value of the sex ratio is associated with misreporting of the male 1st -generation offspring who died in childhood and at young age. The value of the sex ratio in groups formed based on the character and dose of exposure, depended mainly on the source of information used in the course of the offspring registry development.

The paper analyzes the consistency of the input data of the radioecological model: the results of measurements of 137Cs and 131I concentrations in the atmosphere after the Chernobyl accident in Warsaw, the meteo-data on precipitation during the main radioactive fallout, the values of minimum 137Cs deposition densities on the territories of two dairy areas of Warsaw Area and Ostroleka Area in the central part of Mazovia. According to meteorological data in Warsaw Area during the period of radioactive fallout there were local rains. In Ostroleka Area, according to all weather stations, there was no rainfall during this period. In Warsaw Area, a minimum 137Cs deposition density of 1.3 kBq/m² with an error of less than 10% was found to be consistent with the “dry” deposition density of 137Cs (1.2 kBq/m²) reconstructed by a simulated agroclimatic model based on atmospheric 137Cs measurements. This agreement, taking into account the amount of precipitation recorded at weather stations during the period of radioactive fallout and the significant, more than 10 times, dispersion of 137Cs fallout densities across the Warsaw Area, suggests that a homogeneous cloud-uniform fallout model is preferable for this region in radio-ecological modeling. For the Ostroleka Area, the variation in deposition densities of 137Cs was relatively small, at 3.2, and the estimated dry deposition density of 137Cs was 2.0-2.7 times lower than the measured minimum deposition densities in districts and settlements. This discrepancy, given the absence of precipitation recorded by all weather stations during the deposition period, led to the assumption that the 137Cs and 131I atmospheric concentrations in Ostroleka Area were 2-2.7 times higher than those in Warsaw Area. The adjustment of the 137Cs and 131I atmospheric concentrations in the Ostroleka Area for this region will be verified by measuring the 131I specific activity in milk under the Warsaw scenario.

The ability to train the offspring of male rats irradiated at a dose of 0.5 Gy was studied. Cognitive (memorable) brain functions were evaluated by their ability to develop and reproduce a conditioned reflex of active avoidance. It is established that the initial state of cognitive functions of the brain of parents affects the development of these functions in the offspring. Taking into account this factor will allow to avoid methodological errors, consisting in the random formation of groups, unequal in the initial psychophysiological parameters. The expediency of such a previously not used approach is demonstrated on the model of irradiation in a small dose (0.5 Gy) of male germ cells. It is established that the intensity of the radiation effect on this criterion can vary significantly with different approaches to the formation of groups of parents.

The study represents the main types and technical characteristics of irradiation sources currently used for processing of foodstuffs. An absorbed irradiation dose is considered in the context of the technological goals of such treatment. The article discusses the standard dosimetry systems for irradiation treatment of foods, as well as the criteria for calibration and mapping of doses absorbed by a product. The article includes several references to international and Russian regulatory documents on dosimetry systems for food irradiation.

The recent years are associated with active development of the coastal areas of the Russian arctic regions including a construction of the facilities of the extraction and processing of the hydrocarbons, the civil and military facilities. The nuclear weapon tests, performed by the USSR and other nuclear countries in the second half of the XX century, lead to the global radioactive fallout, including the fallout on costal areas of the arctic regions of the USSR. Five most powerful nuclear munitions were tested on the Novaya Zemlya Test Site in the Arkhangelsk region. The Institute of Radiation Hygiene after professor P.V. Ramzaev (before 1994 — the Leningrad Scientific-Research Institute of Radiation Hygiene) has accumulated a 20-year experience of the radiation-hygienic surveys on the assessment of the consequences of the nuclear weapon tests for the Far-North of the USSR: from the development of the equipment and methods for the extraction, analysis and measurement of the low levels of the radioactive isotopes in humans and environment, to the wide-scale radiation-hygienic surveys of the links in the “northern food chain” — lichen, raindeers and native inhabitants. The obtained data allowed performing a complex assessment of the role of the radiation factor in the health of the public residing on the coastal areas of the Arctic Ocean.

The article considers the radiation situation in the Oryol region 33 years after the accident at the Chernobyl nuclear power plant. Since 1998, certification has made it possible to assess the main indicators of the radiation situation in the region and conduct a comparative analysis, evaluate the doses of the population from all the main sources and the effects of the radiation factor on public health, and determine the most significant directions for reducing the doses of the population. The contribution of man-made sources to the collective dose to the population of the Oryol region in 2017 was 0.73% according to radiation-hygienic certification, which is 3 times higher than in Russia (0.24%). This is primarily due to radioactive contamination of a part of the region after the Chernobyl accident. The Oryol region is one of fourteen oblasts of the Russian Federation affected by the accident at the Chernobyl nuclear power plant. As a result of this disaster, 22 out of 24 districts of the Oryol Oblast (about 40% of the oblast’s territory) were exposed to radioactive contamination to one degree or another. Differences in precipitation led to the formation of extremely spotted pollution in the Oryol region. 1243 people from the Oryol region took part in the liquidation of the Chernobyl accident. 43% of them became disabled 1, 2 and 3 groups, 115 people (9%) died within 14 years after these events. In the Oryol region, the radiation environment remains stable. The radiation background is between 0.12 and 0.19iSv/h, which corresponds to the values characteristic of the Oryol region before the Chernobyl accident. Comparison of radiation doses due to additional radiation for the 1st and 33rd years after the accident showed a 51-fold decrease due to the physical decay of long-lived radioisotopes and short-lived radionuclides, as well as their burial in the soil.

The aim of this work is to study the possibility of using an artificial neural network for identification and quantitative assessment of the content of individual radionuclides in the total beta spectrum. The neural network implemented by using of Matlab R2020b. A single-layer feedforward neural network with one invisible layer of 10 neurons and 3 outputs (according to the number of radionuclides) was used. To test and study the capabilities of the artificial neural network, 3 smooth model spectra were selected — ⁴⁰K, ¹³⁷Cs and ⁹⁰Sr, obtained on the liquid spectrometer Quantulus 1220. The results of the study showed that neural networks are an effective method for recognizing of the contribution of an individual radionuclide or establishing its presence in the total beta spectrum. The recognition accuracy depends on the smoothness of the spectrum and does not exceed 30% if the share of the radionuclide in the total spectrum is more than 10%, which is quite suitable for practical use. For statistically «noising» spectra, the method can be used to preliminary estimate the weight coefficients of individual radionuclides, the final value of which can be obtained by minimization methods with subsequent statistical criterial fitting of the total spectrum shape.

The article presents the results of the international radon in-field intercomparison study for passive radon measurement devices. The tests were organized by the environmental agency of the administrative region of Piemonte (Ivrea, Italy). Coverage of participants was 49 laboratories from 15 countries (Italy, Hungary, France, Great Britain, Lithuania, Russia, Sweden, Spain, Bulgaria, Argentina, Australia, Finland, Ireland, Greece and Slovenia). The certified radon passive devices included SSNTDs and electret detectors. SSNTDs are mostly represented by PADC plastic (CR-39) and nitrocellulose film (LR-115-2) detectors. Radon measuring devices were tested in long-term exposure modes at low and high radon levels (tests 1 and 2) and short-term exposure mode at the simultaneous presence of radon and thoron in the atmosphere (test 3). The intercomparison study was carried out in real conditions of operated buildings with different climatic conditions. The main purpose of this study was to evaluate the quality (accuracy and reliability) of the radon measurements under situations similar to the ones in which devices are normally exposed. In comparison with electrets, solid-state track detectors showed to have generally better reproducibility. For the electrets, the most «comfortable» radon measurement conditions were prolonged exposure at high radon levels. There was no significant fading effect of SSNTD at long-term exposure observed. The paper presents the results of the quality assessment of REI-4 passive device based on LR-115-2 widely used for radon monitoring studies in the Russian Federation.

The article describes a method for calibrating a gamma ray spectrometer using a three-dimensional simulation program for the transfer and registration of ionizing radiation. In the example of calibration of plane source counters (filter AFA-RMP20), this method allows one to determine the activity by using spectrometric equipment based on inorganic scintillation crystals. We proposed a method for parametric estimation of the identity of the calculated and experimental spectrum based on the Pearson agreement criterion. We then performed interlaboratory comparisons. The results demonstrate that the difference between measured values of the activity in the test samples of radionuclides using obtained calibration and values measured with a semiconductor based calibrated spectrometer do not exceed 20%.

In 2016—2019, comparison tests of different methods for quantitative determination of the content of the technogenic radionuclide ¹³⁷Cs in soil samples were performed. Soil samples were collected from areas with high and low ¹³⁷Cs contamination in Belarus. The intercomparison was performed as a part of an ongoing Russian—Swedish—Belarusian cooperation on the assessment of radioactive contamination of the environment. Three laboratories of the regular participants in the project and three laboratories from other facilities participated in the intercomparison that was focused on the samples of cultivated soil from the Gomel region (the first stage of comparisons, 3 samples) and the Grodno region (the second stage of comparisons, 4 samples). Results on activity concentrations in the samples presented by the participants were in satisfactory agreement with each other. The maximum deviation from the average value, that had been calculated for each sample based on the individual results from all laboratories, was 14%. Stage-averaged deviations from the inter-laboratory mean did not exceed 10%. Results of the comparison tests should be taken into consideration when comparing or merging experimental data from different laboratories participating in the Russian—Swedish—Belarusian cooperation project.

The article presents results of the analysis of information on the doses of technogenic exposure of personnel and the population due to the normal operation of radiation facilities, exposure of the population due to natural sources and technogenically altered radiation environment, and medical exposure of patients. The data were obtained using the Unified System of Individual Dose Control of the RF citizens for 2019. The analysis was carried out on the basis of the data contained in the forms of state statistical observation No. 1-DOZ (personnel individual doses), No. 2-DOZ (emergency doses), No. 3-DOZ (patients’ exposure doses) and No. 4-DOZ (population exposure doses from natural and technogenically impacted background) for 2019 submitted by the organizations and territories, the state sanitary and epidemiological supervision of which was carried out by Rospotrebnadzor and FMBA of Russia. The article used data obtained within the framework of Radiation-Hygiene passportization. In 2019, 18430 organizations dealing with technogenic sources of ionizing radiation submitted forms No. 1-DOZ with the information on the doses to personnel with a total number of 247934 people, of which 227723 people belonged to the personnel group A and 20211 person to the personnel group B. For these groups, the doses were assessed based on results of individual dosimetric control. In 2019, according to the Unified System of Individual Dose Control data, the average individual annual effective dose of technogenic exposure to the personnel group A was 1.19 mSv, and for the personnel group B it was 0.64 mSv. The total number of X-ray and radiological diagnostic procedures performed in the Russian Federation in 2019 exceeded 306.5 million, or 2.09 procedures per a citizen. The average annual effective dose of medical radiation exposure per one resident of Russia in 2019 was 0.62 mSv, and per procedure — 0.31 mSv. The submittedforms No. 4-DOZ of the constituent entities of the Russian Federation for 2019 contained results of the measurements of dose rate of gamma radiation in 9179 wooden houses, 11,307measurements in low-rise stone houses, 121323 measurements in multi-storey stone houses and 229342 measurements in open areas. These also contained results of 3930 measurements of radon levels in wooden houses, 5071 measurements in low-rise stone houses and 46896 measurements in multi-storey stone houses, as well as the results of 19444 analyses of the levels of natural radionuclides in drinking water. The average annual effective dose of radiation to residents of the Russian Federation from natural sources, according to all measurements for the period from 2001 to 2019, was 3.36 mSv. The article provides Appendices with the final forms of Unified System of Individual Dose Controlfor the Russian Federation for 2019. Data for the forms have been obtained on the basis of summarizing the information contained in the forms of state statistical observation No. 1-DOZ, 3-DOZ and 4-DOZ of the constituent entities of the Russian Federation.