The work was aimed to the study the Cs-137 and I-131 transport dynamics along the trophic chain, from the atmosphere to soil, vegetation, dairy cattle, milk, and the human body. This was done with the use of the radioecological simulation model based on instrumental data from the "Warsaw" scenario of the International Atomic Energy Agency's (IAEA) EMRAS project, which were collected after the Chernobyl nuclear accident. The created simulated radioecological model was used for reconstruction of the I-131 radioactivity in dairy cattle milk in the Warsaw and Ostroleka areas located in the central part of Mazovia, where the cattle dairy milk radiometry was performed in April-May 1986. The aim of the study was to verify the radioecological model, to assess the reliability and uncertainty of the milk block of the computed model. It was found that the successive account of discrepancies between computed and reconstructed instrumental data of I-131 radioactivity dynamics in green fodder on farms in Mazovia areas and the shortage of clean fodder stocks harvest lead to a successive improvement of the agreement between computed and instrumental data of 131I activity in the dairy milk. For all variants of accounting correction the ratio of computed data to instrumental data with recalculated I-131 activities in the atmosphere of the Ostroleka Area is on average 2.5-3 times closer to their ideal value of 1 than in calculations with instrumental data for a cloud. The prognostic properties of the computational model at the stage of reconstruction of the specific 131I activity in milk, estimated as the ratio of computed data to instrumental data, can be estimated as 1.05+/-2.0; the values of these ratios for correction of thyroid radiation doses to the population due to the contaminated milk consumption are estimated as 1.3+/-2.5.

Biological excretion from patients (urine) generated during radionuclide diagnostics enters directly into the hospital sewage system. The establishment of new clearance level according to Resolution of the Government of the Russian Federation No. 1069 of October 19, 2012 may entail amendments to regulatory documents for radionuclide diagnostics departments. One of these requirements is a mandatory dedicated sewage system. Establishment of the requirement may lead to an increase the cost of the radionuclide diagnostic examinations, and to a decrease the accessibility of radionuclide diagnostic. The aim of this study was to estimate the activity of radionuclides in patient urine after radionuclide diagnostic and activity concentration in sewage water in the hospital and in the transport tank of toilet for evaluation of paths of waste manage. Based on published literature data, models of biological excretion were constructed for the following radiopharmaceuticals: 99mTc-pyrophosphate, 64Cu-Labeled Monoclonal Antibody, 18F-FDG, 68Ga-PSMA-617. The activity of radionuclides in the patient waste in the hospital and in public transport during the patient transportation to home was calculated. Various scenarios of patient transportation were considered. The values of the excreted activity, activity concentration and dose rate at 1 m from the tank with sewage water for each type of transport were calculated. The calculated values of the radionuclide activity concentration in sewage water in transport tank of toilet for the majority scenarios exceed the clearance level (up to 180 times for 68Ga-PSMA-617 when traveling by bus). According the regulatory requirements, it is necessary to collect patient excretions after radionuclide diagnostic examinations and hold it for decay. However, estimated effective doses of individuals from the public from contact with biological patient waste do not exceed the acceptable value. This is due to the short half-life of diagnostic radionuclides. The paths of management system of biological patient waste were proposed.

Radiopharmaceutical therapy with 131I has been one of the most common types of radiopharmaceutical therapy for many years. Radiation safety of the public is ensured by limiting the patient contacts until the radiological parameters are reduced to the established criteria. To increase the availability of the radiopharmaceutical therapy with 131I, softer patient release criteria for 131I have been proposed. However, early patient release may increase exposure to the public, e.g. in transport. The aim of the work is to evaluate the radiation exposure from patients with 131I -MIBG and Na131I on the public in transport considering the generation of biological waste. In this work, 131I excretion from the body of patients in transport was evaluated for different scenarios of patient travel to the place of residence. As a result, it was found that mitigation of patient release criteria leads to an increase in the effective dose to the public in transport and an increase in the 131I activity excreted with patient waste. The specific activity in the tanks of biotoilets in transport, generated after the pas -sage of a patient with injected 131I -labeled radiopharmaceuticals, exceeds the limit value of classifying liquid waste as radioactive. To optimize radiation protection of the public, it is advisable to apply a differentiated approach to release patients after therapy with 131I: to group non-resident patients into a separate category retaining for them the established release criterion (without mitigation) to minimize the radiation impact on the public.

Development of radiopharmaceutical therapy treatment plans considering biokinetics of radiopharmaceuticals and individual features of patients is necessary for the provision of radiation safety of the patients and increase in the efficacy of treatment. Hence, it is necessary to assess the absorbed doses in lesions (targets). The current study presents the method for the assessment of the absorbed doses in lesions considering the biological effectiveness of exposure for the radiopharmaceutical therapy with 225Ac-PSMA-617 and 225Ac-DOTATATE. Assessment of the absorbed doses was performed based on the analysis of the PET images of patients. Results of the study indicate that the absorbed doses for 225Ac-PSMA-617 and 225Ac-DOTATATE were in the range of 90-190 Gy-eq. and 30-500 Gy-eq. correspondingly. The lack of radiotoxicity and accumulation of required absorbed dose per treatment course indicates the efficiency of radiopharmaceutical therapy with 225Ac-PSMA-617 and 225Ac-DOTATATE.

The federal forms of statistical reporting (3-DOZ form , form No. 30 of the Ministry of Health of the Russian Federation and radiation-hygienic passports of the subjects of the Russian Federation for 2015–2020) were analyzed in order to estimate the current status of nuclear medicine and assess the perspective and developing proposals for improving the national system of radiation protection in nuclear medicine . Over the past six years , the number of radionuclide examinations in the Russian Federation has been at the same level : on average 530 thousand per year . In 2020 the number of examinations decreased that was caused by the epidemic of coronavirus infection . The largest number of examinations in 2015-2020 were performed in Moscow (21%) and St. Petersburg (11%). Federal medical centers equipped with high-tech equipment are located in these cities , and patients from different regions are examined in these centers . The examination of bone is the most common examination in Russia: 40% from all of nuclear medicine examination ; there is a moderate increase of that examinations . There is a high number of renal examinations (17%). The next most frequent are examinations of myocardium , thyroid , liver and lungs ; the number of these examinations are decrease . Due to the development of modern diagnostic technologies , installation of new positron emission tomography departments and replacement of the old equipment with the new one ( decrease in the number of renographs and increase the number of positron emission tomographs ), the number of “ other ” examinations are increased with a factor of 3.7 since 2015 but the number of “ functional ” examinations is decreased . About two thousand studies per year were examined on a scanner ( renograph , gamma camera , single-photon emission tomography ), and about 0.6 thousand hybrid imaging examinations per year were performed on a single-photon emission tomography combined with computed tomography . The annual collective dose of radionuclide diagnosis in the country has increased from 1.2 to 3.7 thousand man-Sv since 2015. The main contribution to the collective dose in Russia was associated with “ other ” examinations , which include hybrid imaging and whole body positron emission tomography : 55% (39% in St. Petersburg , 60% in Moscow). Due to the limitations and heterogeneous content of the federal forms of statistical reporting it is difficult to assess the current state of nuclear medicine in the Russian Federation. The authors of the study were updated of the data collection system in the radionuclide diagnosis in 3-DOZ forms ; it is under approval . For detailed and reliable assessment of the nuclear medicine in the country , it is necessary to conduct a separate survey to determine the types of nuclear medicine examinations , the gender and age profile of patients and patient doses . That survey should be conducted in St. Petersburg or Moscow, as model subjects of the Russian Federation.

The development of nuclear medicine technologies in the Russian Federation contributes to the implementation of new diagnostic radiopharmaceuticals in practice . Theranostic pairs such as antibodies and peptides labeled diagnostic and therapeutic radionuclides are beginning to be commonly used . The use of radionuclides with a longer half-life in radionuclide diagnostics causes the updating of the approaches to management of liquid waste generated as a result of the patient’s metabolic activity during the time spent in the radionuclide diagnostics department . Management of liquid radioactive waste in radionuclide diagnostic department is regulated by guidelines MU 2.6.1.1892-04. The guidelines are not the regulatory document . These were developed about 20 years ago , and do not considering features of the modern methods in radionuclide diagnostics , promising radionuclides with half-life of several days , and new criteria for classifying as a radionuclide waste in accordance with Resolution of the Government of the Russian Federation No. 1069. The aim of the study was the assessment of the radionuclide activities excreted from patient after radiopharmaceutical injection in radionuclide diagnostics departments in order to define the waste management pathways . In a result , all diagnostic and therapeutic radiopharmaceuticals were divided into the categories : radiopharmaceuticals with ultrashort-lived radionuclides , which can be discharged into the hospital sewerage without any restrictions ; radiopharmaceuticals with 131 I, wh i ch n e ed t he spec i al sewer ag e ; t he ot h er radiopharmaceutic al s , wh i ch n e ed to ass e ss t he vol u me of dischar g ed radionucl i de activit i es dur i ng t he project i on of t he nucl e ar medic i ne departm ent . T he met h od of assessm e nt of t he radionucl i de activit i es enter i ng t he hospi t al sewer a ge is presen ted .

Current patient release criteria established in NRB-99/2009 relate to four radionuclides used in Russia that period of the document preparation. These criteria were calculated only considering the radionuclide decay. Thus, these criteria give conservative assessments which require the patient to stay in dedicated protected room (“hot” room) of the radiotherapy department for several days and do not allow to radionuclide therapy to be given in the outpatient hospital which certainly reduces the availability of this type of treatment. Consideration of the biological excretion of the radiopharmaceutical will be able to make the patient release criteria after radionuclide therapy significantly softer. Recently, new promising radionuclides and radiopharmaceuticals for therapy have appeared, the introduction of which into medical practice is obstructed by the lack of the patient release criteria. Current study is devoted to justification of improvement the approach to definition of patient release criteria after radionuclide therapy with promising and applied radiopharmaceuticals considering biological excretion of radiopharmaceutical. As examples, calculations of patient release criteria were performed for 177 Lu-PSMA, 177 Lu-DOTA-T A TE, 131 I-mIBG и Na 131 I. The dosimetric model used for calculation is based on the model which was used for definition of the current patient release criteria in NRB-99/2009. Additionally, the biological excretion of the radionuclide in radiopharmaceutical, which was assessed according to the published data, was considered. Two phases of biological excretion were evaluated for considered radiopharmaceuticals (fast and slow fractions). The main contribution of the radionuclide decrease in the patient’s body during the first hours after the injection is made by the fast-eliminated fraction. During 4-6 hours after the administration about 50% of these radiopharmaceuticals eliminated via urine. The calculation of patient release criteria were performed for slow-elimination fractions which characterize the decrease of radionuclide activity in the body after the patient release. The following effective half-lives were used: 177 Lu-PSM A – 60 hours, 177 Lu-DOTA-T A TE – 100 hours, 131 I-mIBG – 45 hours, Na 131 I – 7.5 days. The calculations demonstrate when planning a course of radionuclide therapy with four administrations of 177 Lu-PSMA, the release of a patient is allowed at the dose rate of 20 μSv/h from the patient at the distance of 1 m; in case of radionuclide therapy with 177 Lu-DOTA-T A TE, release of a patient is allowed at the dose rate of 12 μSv/h. Considering the fast-eliminated fraction in the first hours after the administration, it can be assumed that more patients with normal renal function can undergo radionuclide therapy with 177 Lu-PSM A in the outpatient hospital. Some patients after the 177 Lu-PSM A administration and patients in the therapy with 177 Lu-DOTA-T A TE may be held in the department in the “hot” rooms for 1-2 days until the dose rate decrease to the acceptable levels. The consideration of biological excretion of radiopharmaceutical makes it possible to soften patient release criterion for 131 I-mIBG by four times and for Na 131 I – by 10%. It will allow to release patients after radionuclide therapy earlier without reduce of radiation safety of people around the patient and will increase the capacity of radionuclide therapy department.

Over the recent period, the Russian healthcare system has been undertaking a nation-wide renewal of equipment for nuclear medicine, which, in turn, opens a gate to new diagnostic radiopharmaceuticals (DRPs) to routine practice. The market welcomed a new class of targeted DRPs. Dozens of PET centres and diagnostic rooms where DRPs with ultrashort-lived radionuclides are used for medical examination have been put into operation. All this dictates the need to modify the existing guidelines that govern this area. In 2021, there was an update in the procedural guidelines (PGs) MU 2.6.1.3700-21 “Assessment and registration of effective doses used in diagnostic nuclear medicine examinations”. The document presented the dose coefficients for new DRPs based on the latest data from the International Commission on Radiological Protection and the literature. This included calculation of the effective doses (using tissue weighting factors) from 1 MBq of radioactivity for approximately 280 DRPs used across five different age groups, as per ICRP Publication 60. These PGs apply to diagnostic nuclear medicine examinations performed using DRPs, scintigraphy, single-photon emission computed tomography (SPECT) and positron emission tomography (PET) alone or in combination with X-ray computed tomography (SPECT/CT; PET/CT). The guidelines do not apply to radionuclide therapies that involve DRP administration that require individual planning and assessment of the absorbed doses across the target regions, critical organs and other radiosensitive organs and tissues.

The paper presents the results estimation of uncertainties in doses to the thyroid, from external and internal exposure to radiation following the Chernobyl accident. For the estimation the data-base of radiometry activities of Cs-134+137 in the body and I-131 to the thyroid in 1986 for 28,311 residents of Kaluga region and 16,470 residents of Bryansk region. Whole body radiation spectrome-try measurements made for 167,325 residents of Bryansk region from 1990 through 1994 were used. The computational model for reassessment of I-131 activities into individual exposure doses is an analytical relationship that describes the relative dynamics of radionuclide activities in a chain consisting “vegetation”, “milk”, “thyroid” and “inside the human body”, that is the chain of successive single-chamber models with time-constant transition rates between chambers and depending on the age of a person after single deposition of radionuclides on vegetation. The dy-namics of specific activities of I-131, Cs-134+137 in the vegetation chamber is calculated according to the agroclimatic model, with account of the dynamics of precipitation, the growth of forage and food vegetation biomass according to the data of the annual variation of average daily air tem-peratures in the surface layer of the atmosphere. The official methodology was used to calculate external exposure doses and reassess whole body radiation spectrometry measurements into in-ternal exposure doses. Based on the results of the studies, uncertainty estimates were obtained in terms of standard geometric deviations in the year of the accident – for individual, average in populated areas and integral dose estimates: (minimum/average/maximum) doses of internal thyroid and whole body exposure, respectively (1.1/2,0/3.0), (1.2/1.5/2.3) and (1.3/2.9/3.3); for doses since 1987, respectively (1.2/1.9/4.0), (1.2/1.9/2.1) and (1.4/5.2/8.2). The uncertainty of the calculation model for internal doses since 1987 is estimated at 2.1 times; the uncertainties estimated from the data of individual dosimetry of external and internal exposure of the population with the allocation of critical groups are equal to 1.5 and (1.9-2.2) times, respectively.

Radioactive waste management is a modern-day issue in terms of radiation safety due to the development of radionuclide therapy, the emergence of new radiopharmaceuticals, radionuclides, and treatment methods, which allow for radionuclide therapy in a day hospital. According to the current domestic regulatory and methodological support biological wastes generated during the patient’s metabolic activity after injection of the radiopharmaceuticals for the therapy refer to the liquid radioactive waste. These wastes must be collected and kept for decay in hospitals to the safe levels before being spilled into the municipal sewerage. It requires additional expenses to the hospital for making the special sewerage. To increase the availability of radionuclide therapy, it is necessary to update the requirements of the liquid radioactive waste management in nuclear medicine departments, considering the volume activities of different diagnostic and therapeutic radionuclides in wastes generated after the injection of radiopharmaceuticals to the patients. On the basis of findings, it is possible to evaluate the feasibility of the binding requirement for the availability of special sewerage in the departments of the radionuclide therapy. In this work, excretion of the radiopharmaceuticals used in therapy: 89 Sr-dichloride, 223 Ra-dichloride, 131 I-MIBG, 177 Lu-PSMA, and 225 Ac-PSMA was studied based on published data to determine the activity levels of radionuclides in waste of patients. As a results of preliminary computations, some nuclear medicine procedure will not lead to generation of liquid radioactive waste from biological waste of patients in sewerage system in usual operating condition and special sewerage is not strictly necessary. For example, estimations of radionuclide activity in wastes showed the volume of current sewerage system in a small hospital with a limitation of 50 beds can be enough to reduce the level of specific activity of radionuclides in wastewater from one patient a day after radionuclide therapy with 89 Sr-chloride and 223 Ra-dichloride. In order to revision of requirements to special sewerage in each department of radionuclide therapy and to development of differentiated approach to the management of biological waste of patient in nuclear medicine departments, which ensure environment protection and radiation safety of people, it is necessary to continue the research including development and modeling of realistic scenario of staff and patient radiation exposure confirmed experimental results.

A review of methods for assessing doses in the thyroid gland, predictions of the long-term consequences of its irradiation and the actual incidence of thyroid cancer in residents of four regions of the Russian Federation with the most significant radioactive fallout after the Chernobyl accident are presented. The method for assessing doses in the thyroid gland is based on the results of monitoring in May-June 1986 of radioiodine in the environment, food and in the body of residents. Thyroid doses in the population were used to justify medical and social protection measures, as well as epidemiological studies. In addition, the authorities needed forecasts of the possible morbidity of the population in order to organize adequate medical care. Most of the thyroid cancer cases were predicted among the adult population, which was not confirmed by observations 35 years after the accident. The prognosis of the incidence of thyroid cancer in preschool children differed in different studies due to the use of different coefficients of reducing the biological effectiveness of 131I radiation in the thyroid gland and long-term external and internal irradiation of the whole body with a low dose rate compared to the effect of acute exposure. The increase in the incidence of thyroid cancer among children began five years after the accident at the Chernobyl nuclear power plant. Examples of the dynamics of the incidence for children in the Bryansk region of the Russian Federation are given. The 2018 UNSCEAR Report showed that for 1986-2015, among children and adolescents under 18 years of age on the day of the accident in Belarus, Ukraine and four regions of Russia, more than 19 thousand thyroid cancer cases were detected, of which the share of radiation-induced diseases was estimated at 25%. For four regions of Russia, this amounts to 460 cases with a range of possible estimates from 130 to 900 cases. The highest morbidity was manifested among younger children exposed at the age of 0-4 years. In older children and adolescents, the proportion of radiation-induced diseases has significantly decreased 30 years after the accident. In general, early forecasts of radiation-induced thyroid cancer incidence in children in four regions of the Russian Federation with high levels of radioactive fallout are consistent with the data of subsequent 30-year epidemiological observations within an order of magnitude. With regard to thyroid cancer in adults, such a comparison is difficult, since no radiogenic increase in the incidence has been detected.

The article is devoted to the analysis of internal dosimetry in residents of Fukushima Prefecture due to the accident at the Fukushima-Daiichi NPP. On March 24-30, 2011, screening studies were conducted on measurements of 131I content in thyroid gland of children in those municipalities where the Japanese program for assessing the radiological consequences of the radiation accident “SPEEDI” predicted doses in the thyroid of one-year children from 100 to 500 mSv. Among 1080 children measured, 55% had results below the background, and the maximum estimate of the equivalent dose in the thyroid was 43 mSv. Measurements of several dozen inhabitants with other instruments and methods confirmed low levels of 131I in the thyroid. In total, the 131I thyroid direct measurement database of Fukushima residents contains approximately 1300 individuals. 75% quartile of individual thyroid dose distributions was below 10 mSv, the median was from 0 to 3.7 mSv among children aged from 0 to 15 years in the five examined municipalities. The contribution of short-lived iodine radionuclides was estimated as 15% of the dose from 131I for the main radioactive release on March 15. The effective dose of internal exposure to cesium radionuclides (134Cs + 137Cs), estimated from 10 thousand whole body measurements for the first year after the accident, was below 0.1 mSv in 90% of the examined people. Whole body measurements of children 6-15 years old in the second year after the accident confirmed the values of the effective dose of internal exposure less than 0.1 mSv, while the estimates of the effective dose of external exposure in the same children with using individual dosimeters determined the median distribution as 0.66 mSv with a maximum value of 3.45 mSv . The measurement results do not provide any basis to expect a future increase in the incidence of thyroid cancer and other radiogenic diseases among the Fukushima residents. Preventive evacuation of the population before the radioactive release, stay in enclosed dwellings, strict radiation control of food products have effectively reduced the expected doses of internal exposure to residents. In the predictions of the radiological consequences of the accident, it is necessary to take into account the actually implemented measures to protect the population, and local characteristics of the style of life and living.

The analysis of instrumental data of “Prague” and “Warsaw” scenarios on the dynamics of 131I specific activities in the grass is carried out. Reconstruction of the 131I the specific activities dynamics in the grass in the Mazovia and Bohemia localities is performed in three models: direct calculation the input data of the “Prague” and “Warsaw” scenarios, homogeneous cloud, heterogeneous rain and heterogeneous cloudhomogeneousrain. The actual 137Cs fallout densities in the grass sampling sites in average more than 2.9 times for Prague and 2 times for Warsaw. Effective rain during the main fallout at the grass sampling sites, reconstructed on the model of a homogeneous cloud is 3–4 times more than at the nearest weather stations during this time. A realistic scenario of the input data leading to the optimal agreement of the calculated and instrumental data is revealed. It is shown that direct calculations and the homogeneous cloud model give almost identical results and lead to a significantly better agreement with the instrumental data than the an inhomogeneous cloud model. The calculated and instrumental data show a significant decrease in the 131I specific activity in the grass after the end of the main fallout due to its flushing from the grass surface by strong prolonged rain 13 and 19 days after the accident in Mazovia and 30 and 35 days in Bohemia. Uncertainties in the results of reconstruction of the dynamics of 131I and 137Cs activities in vegetation are estimated. The meangeometric values and standard mean-geometric deviations of the calculation/ 8instrumental data ratios are: 0.8–1.1 and 1.8–1.9 for grass.

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 article describes the main areas of scientific and administrative activities of professor P.V. Ramzaev during his work in the Research Institute of Radiation Hygiene. In particular, the results of a study of global radioactive fallout in the Far North of the USSR, as well as a study of the radiation situation and an assessment of the doses to the public after the accident at the Chernobyl NPP, are presented in a systematic way. The leading role of P.V. Ramzaev in the development of hygienic regulation and in the development of the theory of health is shown. The activities of P.V. Ramzaev in the International Commission on Radiological Protection are discussed in detail. The role of P.V. Ramzaev in the development of the law «On Radiation Safety of the Population» is shown.

Создание и верификация взаимосогласованной базы входной информации имитационной модели транспорта радионуклидов 137 Cs и 131 I по пищевой цепочке на инструментальных радиоэкологических данных (по материалам «Пражского» и «Варшавского» сценариев проекта МАГАТЭ EMRAS) Власов О.К. 1 , Краевский П. 2 , Бартускова М. 3 , Малатова И. 4 , Щукина Н.В. 1 , Чекин С.Ю. 1 , Туманов К.А. 1 , Звонова И.А.5  1 МРНЦ им.А.Ф.Цыба -филиал «НМИЦ радиологии» Минздрава России, Обнинск; 2 Центральная лаборатория радиологической защиты, Варшава, Польша; 3 Филиал Национального института радиационной защиты, Острава, Чехия; 4 Национальный институт радиационной защиты, Прага, Чехия; 5 ФБУН НИИРГ им.П.В.Рамзаева, Санкт-Петербург Излагается технология создания взаимосогласованной базы входных данных имитационной радиоэкологической модели после радиационной аварии с выбросом продуктов в атмосферу.В набор данных для объектов исследования (населённые пункты или их ареалы) входят средние за период основных выпадений или временные зависимости удельных объёмных активностей 137 Cs в атмосфере, осадки в период выпадений, плотности выпадения 137Cs. Данные плотностей выпадения 137 Cs на территориях центральных частей регионов Мазовии (Польша) и Богемии (Чехия) после аварии на ЧАЭС, метеоданные об осадках и инструментальные данные о динамике активностей 131 I и 137 Cs в атмосфере указывают на их слабую пространственную вариабельность, что свидетельствует о сравнительно однородной структуре параметров радиоактивного загрязнения атмосферы и слабых локальных осадках в период основных радиоактивных выпадений в этих регионах.Максимальные значения удельных объёмных активностей 131 I и 137 Cs атмосфере в период первого пика выпадений в Богемии и Мазовии практически совпадают.В Мазовии в период с 11 по 13 сутки после аварии, в отличие от Богемии, наблюдался второй пик активностей 131 I и 137 Cs в атмосфере с их максимальными значениями приблизительно на порядок меньшими, чем в первом пике.Интегралы удельных объёмных активностей 131 I и 137 Cs в кБк/м 3 сут составили в Мазовии 0,39 и 0,023 соответственно; в Богемии -0,2 и 0,03 соответственно.Среднее за период основных выпадений значение отношения удельных объёмных активностей 131 I к 137 Cs в атмосфере Мазовии было равно 17,2, что в 2,3 раза больше, чем в Богемии, равном 7,1.Несогласование базы входных данных проявляется в существенных различиях в инструментальных плотностях выпадения 137 Cs в населённых пунктах и реконструированных по модели прямого расчёта: активность 137 Cs в атмосфере -метеоданные об осадках.Для согласования входных данных используются модели однородного облака -неоднородных осадков и неоднородного облака -однородных осадков.В целом для населённых пунктов прямой расчёт плотностей выпадения 137 Cs по модели несогласованных данных (однородное облако -метеоданные об осадках) даёт существенное отличие как от инструментальных данных, так и от моделей согласованных данных (однородное облако -неоднородные эффективные осадки) и (неоднородное облако -однородные осадки по метеоданным).Причём тем большее, чем больше плотность выпадения 137 Cs.При существовавшей динамике параметров активностей радионуклидов в атмосфере влияние осадков на плотности выпадения 131 I и 137 Cs и удельные активности 131 I и 137 Cs в растительности начинает проявляться только при их величинах, больших 0,2 мм.Для травы оно заканчивается при осадках, больших 1-2 мм.Для 131 I это влияние меньше, чем для 137 Cs.Существовавшие в регионах различия в динамике активностей 137 Cs и 131 I в атмосфере привели к тому, что плотности «сухих» выпадений 131 I и его выпадений с осадками 10 мм на растительность были в 1,8 и 2,1 раз больше, чем в Богемии, а для 137 Cs -меньше соответственно в 1,8 и в 1,4 раза.Фактически это означает, что в таком же соотношении были и дозы внутреннего облучения щитовидной железы и доз на всё тело населения Мазовии и Богемии.Использование взаимосогласованных данных, в первую очередь осадков в период выпадений и параметров загрязнения атмосферы, приводит к адекватному воспроизведению инструментальных данных о плотностях выпадений 137 Cs на местность, к существенному уменьшению неопределённостей транспорта 137 Cs и 131 I по пищевой цепочке и, как следствие, более точной реконструкции доз внутреннего облучения населения загрязнённых территорий.Ключевые слова: авария на ЧАЭС, имитационная модель в радиоэкологических исследованиях, проект МАГАТЭ EMRAS, активность 137 Cs и

The article describes the main areas of scientific and administrative activities of professor P.V. Ramzaev during his work in the Research Institute of Radiation Hygiene. In particular, the results of a study of global radioactive fallout in the Far North of the USSR, as well as a study of the radiation situation and an assessment of the doses to the public after the accident at the Chernobyl NPP, are presented in a systematic way. The leading role of P.V. Ramzaev in the development of hygienic regulation and in the development of the theory of health is shown. The activities of P.V. Ramzaev in the International Commission on Radiological Protection are discussed in detail. The role of P.V. Ramzaev in the development of the law «On Radiation Safety of the Population» is shown.

In the current study we evaluated the structure of positron emission tomography combined with computed tomography (PET/CT) diagnostics in the Russian Federation. Patient effective doses, organ doses and corresponding radiation risks for the most common PET/CT examinations were evaluated. Data was collected in 12 regions of the Russian Federation in the period 2012-2017 in 19 facilities (26 PET/CT scanners, corresponding to more than 60 % of the scanners in the country). Typical administered activities and DLP values for the CT protocols were estimated with the subsequent calculation of typical organ and effective doses from external and internal exposure. Lifetime radiation detriment-adjusted risks were calculated based on both the effective dose and organ absorbed doses considering the gender of the patient. The results of the dose survey indicate that the most common PET/CT examinations are whole body and brain examinations with 18F-FDG (performed in 26 and 8 surveyed departments respectively). Other PET/CT examinations are significantly less common. The highest patient doses were calculated for whole body PET/CT examinations - about 20 mSv. The doses increase up to 35-40 mSv if multiphase CT scan was performed, the CT scan composed up to 70-90 % of the total effective dose. Lifetime detriment-adjusted risk was estimated for PET/CT examinations of the brain as 2.10(-4); for pelvic as 5.10(-4), and may reach up to 10(-3) for whole body PET/CT examinations. Comparison of risks assessed by two approaches indicated that the simplified risk assessment based on effective dose overestimated the risk for PET/CT examinations of the brain (both genders) and for whole body and pelvic examinations (males only). Overall, differences in male and female patients can reach up to the 30 %.

The paper presents methodology of the internal dose reconstruction from I-131 and caesium radionuclides received by population of Russia after the Chernobyl accident. The direct measurements of radionuclides content in a human body were the most relevant data for internal dose reconstruction. Assessment of radionuclides intake with food products was considered as the second priority and application of radioecological models as the third priority when measurement data were absent.