Vol 68, No 6 (2023)

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Purpose: To study the role of binding of corticosteroids to blood plasma proteins in the mechanism of influence of the radioprotector RS-11 on the function of the adrenal cortex in irradiated animals.

Material and methods: The experiments were carried out on 30 male chinchilla rabbits weighing 2.5–3.0 kg. The first series of experiments is aimed at studying the reaction of the adrenal cortex and the processes of protein-steroid interaction after the administration of PC-11 to intact animals; in the second series – the same indicators in animals irradiated during the prophylactic administration of RS-11. The total content of 11-hydroxycorticosteroids (11-OKS) in blood plasma was determined by the fluorometric method of Guillemin et al in the author’s modification. The amount of free corticosteroids was determined by the difference in their content in whole plasma and in its protein fraction after separation on Sephadex G-25. Binding capacity of corticosteroid binding globulin (CSBG) was determined by gel filtration De Moor at al. in the author’s modification. Statistical analysis of the study results was carried out using the Student–Fisher method.

Results: In the group of intact rabbits under conditions of administration of PC-11, the reaction of the adrenal cortex after 2.5–3 hours was significantly higher compared to control animals. The increase in the free fraction of the hormone with the introduction of the radioprotector RS-11 during this period is associated with an increase in the total level of 11-OKS, since the binding ability of CSBG did not change. In the group of irradiated rabbits, 2.5–3 hours after irradiation, the administration of PC-11 also led to a significant increase in the total content of 11-OKS in the blood compared to the initial data. At the height of radiation sickness on the 4th day, RS-11 protected rabbits showed a significantly smaller decrease in the binding capacity of CSBG than control animals, and the total content of 11-OKS was higher than in the control. The level of free hormone on the 4th day was sharply reduced (8 % of the total 11-OKS content versus 41 % in the control). On the 8th day of radiation sickness, free 11-OKS in protected RS-11 and control rabbits was practically absent, however, in protected animals, the binding capacity of CSBG was 2 times higher than in control animals.

Conclusions: The influence of the radioprotector RS-11 leads in the first hours to an increase in the total concentration of 11-OX in the blood plasma and to an increase in the amount of free hormone in intact animals. The binding capacity does not change. Prophylactic administration of RS-11 inhibits, at the height of radiation sickness, the decrease in the binding capacity of CSBG in the blood plasma, and as a result, the increase in the level of free physiologically active hormone at a higher overall level of hormones in the blood. In the mechanism for reducing post-radiation hypercortisolism under conditions of protection with the drug RS-11, the main significance is the lesser degree of disruption of the binding ability of CSBG, and not a change in the overall level of hormones in the blood.

A great amount of scientific information on the effect of radiation on the human body in various fields of knowledge from genetics and molecular biology to radiation epidemiology has been accumulated over a long-term period of activity of the URCRM of the FMBA of Russia.

To get the best out of the use of numerous registers and databases maintained in the URCRM and to make interdisciplinary research possible, a Unified Information System was created, which consists of two parts: information complex REGISTR and complex Storage.

The creation of the Storage complex makes it possible to ensure the safety of scientific data obtained in the departments of the URCRM, as well as methods/techniques elaborated to obtain them. The development of the REGISTR complex, the creation of new functionality in it, have significantly increased the use of information resources, which allows for strategic planning of new research.

The paper describes in detail the basic functionality of the Unified Information System. The technical aspect of the usage of the REGISTR complex is presented. An example of the use of the Selections Constructor for planning of the study performed in the Laboratory of Molecular and Cellular Radiobiology of the URCRM of the FMBA of Russia is given.

Radiation diagnostics methods are widely used not only for the diagnosis of adult patients, but also in pediatrics. Children are the most radiosensitive group of the population, with a higher risk of developing long-term effects of ionizing radiation than adults. Therefore, control of exposure levels of pediatric patients is a priority. Nowadays, many publications have been devoted to the issues of radiation safety of children in foreign countries. There is no reliable information of diagnostic exposure levels of children in the Russian Federation. In domestic publications, these issues are considered insufficiently. Foreign and domestic publications of children exposure levels during X-ray, interventional and computed tomography examinations (CT-examinations) were analyzed. First of all, publications containing a quantitative characteristic of exposure levels in terms of effective dose (ED) were considered. Effective doses presented in the publications were recalculated in accordance with the division of age groups adopted in the Russian Federation for the convenience of comparing the values with each other: 0‒0.5; 0.5‒3; 3‒8; 8‒13; 13–18 years old. This study presents the average of weighted effective doses for children of all age groups for different types of radiography, interventional and CT-examinations. According to publications the average weighted effective doses of children on average for all types of X-ray diagnostics are lower in the Russian Federation than in foreign countries. To ensure the radiation protection of children in the Russian Federation during radiography, interventional and CT-examinations, it is necessary to increase the reliability of information of children exposure levels, by improving the systems for collecting data, monitoring and accounting of individual patient doses, and raising the level of awareness of specialists.

Purpose: Study the repertoire of the T-cell receptor in persons chronically exposed to radiation in the long-term period.

Material and methods: The study involved 48 people, who were divided into two groups: a group of exposed persons – 31 individuals with the average accumulated dose to red bone marrow (RBM) of 981±130 mGy, and a comparison group – 17 individuals, the average accumulated dose to RBM was 25.3±5.91 mGy. The study groups did not differ significantly in age, gender and ethnicity. The repertoire of Vβ-segments of the T-cell receptor of the peripheral blood T-lymphocytes of exposed persons was analyzed by flow cytometry method. 24 Vβ-segments of the T-cell receptor were studied. Statistical processing of the obtained data was carried out using the Wilcoxon signed-rank test, and a direct description of Vβ-segment repertoire of the T-cell receptor was performed using the Lorenz curve and the Gini-TCR index.

Results: The study revealed a statistically significant increase in the number of Vβ3 and Vβ5.2 T-cell receptor segments in exposed individuals relative to the comparison group (p=0.03 and p=0.003, respectively). It was also shown that the distribution of the Vβ-segments of the T-cell receptor is uneven in both study groups. However, there was no significant difference between the repertoires of the T-cell receptor of the studied groups by the Gini-TCR index (p=0.14).

Summary: Investigation purposes Diabetes mellitus (DM) occupies the largest share in the structure of endocrine system diseases, nutritional disorders and metabolic disorders, which is currently one of the important priorities of national health systems. Research on certain groups of the population with their own harmful occupational risk factors is relevant. Analysis of the incidence of diabetes mellitus of the second type - T2DM (ICD 10: E11-E11.9) of liquidators of the consequences of the Chernobyl accident ‒ workers of nuclear industry enterprises for 30 years of observation and assessment of the radiation risk of its occurrence.

Material and methods: The study includes data from the Industry register of persons exposed to radiation as a result of the Chernobyl accident over a thirty-year period, having a verified dose of external radiation received during work in the 30 km zone of the Chernobyl nuclear power plant, men – 12663 people, 1327, of whom have data on the dose of occupational irradiation. The Poisson process with an intensity parameter was chosen as a statistical model of morbidity.

Results: The incidence of T2DM in liquidators of the consequences of the Chernobyl accident was estimated by age and sex groups. On the basis of the obtained file of individual unstratified data, an analytical likelihood function for the Poisson process was constructed and the value of the excess relative risk (ERR) of T2DM incidence was calculated and the nature of the dose dependence of RR was investigated. A cohort epidemiological study of a group of liquidators in 1986–1990 was carried out. over a thirty-year period, depending on the dose, both received during the liquidation of the consequences of the Chernobyl accident, and during professional work with radioactive substances (RS) and sources of ionizing radiation (IRS). Direct estimates of the radiogenic risk of diabetes mellitus are given. Different values ​​of risk were noted when using doses from different types of radiation. There was no significant increase in the risk of disease per dose unit (ERR / Sv).

Conclusion: With the aging of the cohort of liquidators, an increase in the incidence of T2DM was noted in both men and women. The results obtained on the assessment of the radiation risk of T2DM at this stage are taken as preliminary, since the use of radiation risk in the development of radiation safety regulations requires a total dose from all types of exposure (professional, emergency, medical, natural).

Despite the widespread introduction of CT into clinical practice, the diagnosis of cryptogenic organizing pneumonia is still an urgent task of modern radiology. Radiological diagnosticians and clinicians have significant difficulties in diagnosis due to rather low frequency of this disease and nonspecific clinical manifestations. Cryptogenic organizing pneumonia is a disease which sharply worsens the quality of life in case of untimely diagnosis and belongs to the group of idiopathic interstitial pneumonias. The article is devoted to the clinical case of a patient with verified cryptogenic organizing pneumonia. CT of the chest organs, along with clinical data, plays a key role in the accurate diagnosis of organizing pneumonia.

Aim: To evaluate the possibilities of absolute and relative values of the apparent diffusion coefficient (ADC) in the diagnosis of metastatic lesions of skeletal bones.

Material and methods: The study included 12 patients with metastatic bone lesions, before any treatment was applied. The age of the patients ranged from 38 to 73 years, 3 men, 9 women. Among the morphological forms of tumors were presented: cancers of the breast (3), prostate (1) glands, colon (1), lung (2), body (1) and cervix (1) uterus, thyroid (1) and pancreas (2). The detected changes were classified on the basis of Bone scan, SPECT/CT and standard MRI. The ADC values of unchanged bone marrow (n=360), divided by anatomical zones, metastatic foci (n=117), as well as benign changes of various nature (n=19) were analyzed. The ratio of the ADC values of each of the metastatic and benign focal formations to the normal values for each of the localizations was calculated.

Results: Unchanged bone marrow, depending on anatomical localization (cervical, thoracic, lumbar spine, pelvic bones, shoulder blades, collarbones, sternum, ribs, proximal humerus and femur bones) from the point of view of ADC, showed statistically significant heterogeneity. Statistical analysis has shown that there is no connection between the groups of ADC indicators in the foci of metastatic lesions, combined depending on the anatomical localization. With a similar comparison, but by belonging to the primary tumor, an even greater intergroup difference was found. ADC values in the foci of metastatic lesions turned out to be dependent on the morphological type of the primary tumor and significantly differ both from metastases of other morphological affiliation and from normal red bone marrow parameters. The use of relative values allowed to increase the specificity from 15 to 19 %.

Conclusion: This study showed that knowledge of the range of reference ADC values for unchanged red bone marrow and anomalies of various genesis is important in differential diagnosis. The differentiation of the skeleton into separate anatomical zones probably makes it possible to increase the effectiveness of the isolated application of the technique when it comes to absolute values. The morphological affiliation of metastatic foci is important in the formation of ADC values, rather than the bone marrow microenvironment, which is also supported by the low efficiency of the use of relative values.

The purpose: To evaluate the efficiency of combined treatment of patients with salivary gland cancer using neutron therapy.

Material and methods: The study included 130 patients with salivary gland cancer who underwent combined treatment with adjuvant neutron or standard photon radiotherapy. Neutron therapy was performed on a cyclotron U-120. The average energy of fast neutrons was 6.3 MeV.

Results: There was observed a significant decrease in the frequency of relapses in the group of patients who received a postoperative course of NT compared with the control group (21.1 % vs. 45 %, p<0.05). The five-year overall survival in the study group was 73.8±9.5 %, in the control group ‒ 43.2±9.4% (p<0.05). The value of five-year relapse-free survival in the study group was 65.6±7.5 %, in the control group ‒ 34.8±9.1 % (p<0.05). Erythema of the skin in the irradiation area (grade I) was the most frequent type of local acute radiation reaction and was observed in 60 % of patients in the study group and in 25 % of patients in the control group. The most frequent late complication in both groups of patients was skin atrophy and subcutaneous fibrosis (grade I on the RTOG/EORTC scale). In the study group, this indicator was 34.4 %, in the control group ‒ 20 % (p>0.05).

Conclusion: Thus, the study confirmed the high effectiveness of fast neutron therapy against malignant tumors of the salivary glands. Neutron therapy does not cause serious complications, encourages to increase of patients life expectancy and to decrease the number of relapses after combined treatment in comparison with standard methods of treatment.

Purpose: To conduct a search and generalization of literature data to assess the relevance and prospects for the development of brachytherapy in the treatment of cervical cancer.

Material and methods: Scientific sources were searched in PubMed / Medline for the following key words: «cervical cancer», «radiotherapy», «brachytherapy». The time horizon covered 2016–2023. Using a time filter, the most relevant and innovative research papers on cervical cancer brachytherapy were selected.

Results: Modern radiology provides specialists with a wide range of methods, one of which is brachytherapy (BT). Brachytherapy is a promising direction in the treatment of cervical cancer, however, its use is largely limited and continues to gradually progressively decline around the world. The reasons associated with this are different: the complex technical component of this technique, the high requirements for the training of BT specialists, the high cost of treatment, and others.

However, it should be noted that most of the current data demonstrate the high efficacy of BT in the complex therapy of cervical cancer. Therefore, research is ongoing to increase the involvement of BT in the treatment strategy for cervical cancer.

Thus, many authors emphasize that the rates of primary complete remission and 5-year cancer-specific survival were significantly higher in patients treated with BT than in those who were treated with EBRT instead of BT (92.5 % versus 73.3 % and 68. 5 % versus 35.4 % respectively).

Modern technical developments in the field of BT are also interesting, for example, the use of 3D printing methods. New applicators make it possible to increase the conformity of the conducted BT. The presented methodology also provides an opportunity for better training of specialists in the field of BT.

An important aspect of the spread of BT and radiological treatment in general, and along with it the dynamics of the main indicators of survival, is still the socioeconomic factor. Thus, there are direct correlations between the total income of a country and the degree of prevalence of BT in it. Some countries are almost completely deprived of the possibility of using BT methods in health care.

In general, brachytherapy is actively developing, opening up new horizons in the treatment of malignant neoplasms of cervical cancer.

Purpose: To develop a software package Virtual examination of brain perfusion by the method of SPECT/CT with ^99mTc-HMPAO (Teoxime) and its practical application to study the conditions for achieving the best image quality in clinical studies of patients.

Material and methods: The studies were performed using clinical data and the method of computer simulation. Clinical data of single-photon emission computed tomography combined with X-ray computed tomography (SPECT/CT) with ^99mTc-hexamethylpropyleneamine oxime (^99mTc-Teoxime, produced by DIAMED LLC) of a patient with an ischemic stroke of the right frontal cortex were obtained on a two-detector gamma-camera NM/CT 670 DR GE Discovery (USA) using high-resolution low-energy collimators (LEHR). The measured data were processed using specialized software Q.Brain and Q.Volumetrix MI on a Xeleris 4.0 DR workstation from GE Healthcare (USA) to obtain reconstructed axial tomographic slices. To carry out simulation computer simulation of the procedure of examination of perfusion of GM by the method of SPECT/CT has developed a software package that includes a mathematical Hoffman phantom with the ability to simulate clinical cases of hypoperfusion of different localization and size (Virtual Patient), modeling the collection of “raw” projection data and an image reconstruction program based on the OSEM algorithm (Ordered Subset Expectation Maximization). An important advantage of the mathematical modeling method is the ability to assess the quality of the reconstructed image by calculating the root-mean-square error when compared with a given phantom. In numerical experiments, the dependence of the reconstruction error on the parameters of the OSEM algorithm (on the number of subgroups – subsets, and on the number of iterations) was investigated in order to determine the conditions for achieving the best image quality. A statistical stop criterion was developed and tested.

Results: For the first time, a software package was developed and tested that allows us to investigate errors in the reconstruction algorithm, which is a great difficulty when using clinical research methods. A criterion for stopping iterations is proposed when using the OSEM reconstruction algorithm – minimizing the functional deviation of the chi-square function from the target value, while the detector pixels with non-zero values are combined into blocks according to the 2×2 scheme.

There is a reliable good correlation between the proposed stop criterion and the minimum of the root-mean-square error of image reconstruction. This makes it possible to introduce this criterion into the clinical practice of using computational tools for reconstructing sections of the SPECT to obtain the best image.

The simulation results demonstrated the possibility of reducing the time of data recording, during which the patient must remain motionless, at least twice.

Conclusion: The method of computer simulation developed in this work is a practically useful technology that helps optimize the use of SPECT to achieve the best possible results of brain imaging in patients.

Purpose: Using the example of reviewing and discussing the results of comparison tests of dosimetric systems of gamma and neutron radiation used in organizations of the State Corporation “Rosatom”, to assess the current state of reliability of monitoring the planned exposure of workers in fields of mixed gamma-neutron radiation using the considered dosimetric systems in order to produce recommendations for corrective actions to ensure a unified approach to conduct individual dosimetric control of external exposure.

Results: All measuring instruments for individual dose equivalent of photon and neutron radiation, presented in comparison tests, comply with up-to-date requirements for individual dosimetric control systems. All measuring instruments confirmed their measuring capabilities, showed satisfactory quality of measurement results and the absence of a systematic bias in the measurement results. Analysis of the results of measuring the individual dose equivalent of neutron radiation showed that problems affecting the quality of the results obtained were identified in the considered instruments of measuring personal dose equivalent. The following factors might be the sources of problems:

lack of knowledge about the real characteristics of radiation fields (spectral characteristics, radiation direction, etc.) at workplaces;

insufficient research of the method used for measuring neutron radiation under real conditions (technical and metrological characteristics and features of the individual dosimeters used);

failure to take into account the weighing coefficients for neutrons of various energies when measuring instruments are calibrated and when real measurements are conducted.

Conclusion: It is necessary to organize and conduct investigations of the metrological characteristics of the measuring instrument that are used under conditions typical for a specific radiation object. After finishing these experimental studies, it is recommended to test the methodology with an analysis of the compliance of the accuracy indicators with the requirements of the relevant guidelines. In order to solve the problem of a lack of knowledge about the real characteristics of radiation fields, radiation safety services of organizations are recommended to organize and conduct research aimed at studying such characteristics using radiometric and spectrometric methods, experimental modeling of the process of personnel exposure using anthropomorphic phantoms and determining correction factors for the individual dosimeters used.