Том 70, № 1 (2025)

Relevance: Due to the high chemical toxicity of effective radioprotectors and the low radioprotective effect of low-toxic compounds, the use of several substances as part of a single therapeutic regimen for the treatment of radiation sickness seems promising.

Purpose: Evaluate the radioprotective effect of several therapeutic regimens using different substances on a number of physiological parameters in male ICR (CD-1) mice acutely exposed to X-ray radiation at a dose of 6.5 Gy.

Material and methods: The regimens studied included the use of riboxin (inosine), phenylephrine, glutathione, copper chlorophyllin, two forms of vitamin E (tocopherol, trolox), ascorbic acid and granulocyte stimulating factor (G-CSF) in the form of pegfilgrastim. Efficacy was assessed based on hematological parameters, the content of thiobarbiturate-reactive products in the liver, changes in the weight of the liver, thymus and spleen 4 days or 7 days after irradiation.

Results: Among the parameters assessed, the most striking picture was given by the level of leukocytes in the blood of mice 4 and 7 days after irradiation. None of the schemes used returned this indicator to the vivar control level. The most pronounced increase in the content of leukocytes, compared with the irradiated control group, was observed in mice that were administered phenylephrine before irradiation, 30 minutes after irradiation – glutathione, the next day – tocopherol and G-CSF, followed by daily administrations of G-CSF. At the same time, in the case of joint administration of copper chlorophyllin with G-CSF, the protective effect completely disappeared, and the general condition of the mice became worse than in the irradiated control group. That is, G-CSF is not compatible with copper chlorophyllin. The result also occurred in the group that received tocopherol, glutathione and ascorbic acid on the day of irradiation, a day later – only glutathione, and after 2, 3 and 4 days – copper chlorophyllin. Only in this group was there a correction of thrombocytopenia, which occurred one week after irradiation. The deterioration of the condition of the mice, up to the death of some animals in the group, was caused by intragastric administration of riboxin 1, 2, 3 and 4 days after irradiation.

Сonclusions: The results of the work update research into the possibility of treating radiation sickness using several substances with a mandatory study of the effects of their pharmacological interactions. Growth factors and low molecular weight compounds with sulfhydryl groups seem to us to be the most promising.

Purpose: To review the literature on the use of heavy ion beam mutagenesis for selecting various microorganisms, including bacteria, fungi, yeast, and microalgae, for biotechnological purposes.

Material and methods: Data have been collected over the past 15 years on the metabolic effects of mutants exposed to heavy ions, biotechnologically significant microbiological objects (bacteria, fungi, algae).

Results and discussion: The biotechnological and genetic significance, as well as the morphological and other aspects of the detected changes in mutant microbiological objects, are discussed. Currently, heavy ion irradiation-induced mutagenesis with high linear energy transfer and biological efficiency is recognized as a powerful new method for creating microbial strains with previously unknown properties. We believe that targeted breeding using heavy ion mutagenesis will make a significant contribution to the development of industrial producer strains for biotechnology.

Conclusion: The studies discussed in this review indicate that the use of ion beam mutagenesis for microorganisms can be beneficial for both fundamental science and applied research.

Purpose: To analyze the frequency and structure of computed tomography (CT) and magnetic resonance imaging (MRI) studies at the A.I. Burnazyan Federal Medical Biophysical Center from 2020 to 2023 by major anatomical regions, to assess the potential for reducing radiation exposure in CT.

Material and methods: The number and structure of CT and MRI studies performed at a multidisciplinary medical institution from 2020 to 2023 were analyzed. During this period, a total of 62,340 CT studies were conducted on three multispiral CT scanners, and 29,942 MRI studies were conducted on four high-field MRI scanners. The primary areas of study, as per form No. 30 approved by Rosstat Order No. 681 dated December 25, 2023, include the head, neck, chest, heart and blood vessels, abdominal cavity, retroperitoneal space, pelvis, spine and spinal cord, bones, soft tissues and mammary glands. The number of studies in these areas, both with and without administration of intravenous contrast, was evaluated.

Results: An increase of 1.2 times in the total number of CT studies and 1.5 times in the total number of MRI studies was established in 2023 compared to 2020. At the same time, in 2023, the number of CT studies was 2.2 times higher than the number of MRI studies. In the structure of CT studies for the entire period from 2020 to 2023, the main share fell on the abdominal and retroperitoneal space (35.2–53. %) and chest (33.4–42.9 %), in the structure of MRI during this period, head studies prevailed (28.9–36.6 %), bones and MT (14.3–21.1 %), and spine (20.1–27.5 %). When assessing the ratio of CT and MRI frequencies, a significant predominance of CT over MRI was established for the abdominal and retroperitoneal space (in 2023 – 7.5 times). In the areas of head, neck, pelvis, spine, bones and MT, the prevalence of MRI studies over CT was found to be from 1.1 to 13.9 times.

Conclusion: A growth in the number of CT and MRI studies was recorded at the A.I. Burnazyan Federal Medical Biophysical Center during the period from 2020 to 2023 in 2 time, which aligns with the data from the State Report “On the State of Sanitary and Epidemiological Well-being of the Population in the Russian Federation in 2022”. The area of abdominal and retroperitoneal space studies can be considered as the primary potential for increasing the share of MRI studies, following an additional assessment of indication optimization, to reduce patient radiation exposure.

Aim: To map the potential radon hazard of territories based on the results of sample measurements of radon equivalent equilibrium concentration (EEC) in the premises of public buildings in connection with the analysis of geological information reflected in the state geological maps at the scale of 1:200 000, supported by the results of reconnaissance measurements of the content of natural radionuclides in soil samples, using Pyatigorsk as an example.

Material and methods: The results of measurements of radon EEC in the premises of Pyatigorsk were used, which were carried out mainly in kindergartens, schools and higher educational institutions of the city separately in summer and winter periods with the help of the track method using the equipment set TREC-REI_1M (LR-115-2 detectors placed in REI-4 exposimeters). A total of 2851 measurements of radon EEC in 97 buildings were analysed. Measurements of the specific activity of natural radionuclides in 20 soil samples were carried out using the gamma spectrometer NaI(Tl) with ‘Progress-2000’ software.

Results: The territory of Pyatigorsk was mapped according to the degree of potential radon hazard. It was found that potentially radon-hazardous areas are those composed of cover loams and clays with specific activity of ²²⁶Ra 30–64 Bq/kg. The arithmetic mean value of radon EEC in buildings in these areas is 125 and 109 Bq/m³, and the proportion of EEC values exceeding the permissible level of 200 Bq/m³ is 18 and 13 %, respectively. Areas consisting of relatively low radioactive alluvial sediments and marls are characterised by a relatively low radium content in the soil (11–32 Bq/kg) and low radon EEC values in buildings (on average 50–70 Bq/m³); the proportion of radon EEC values exceeding the permitted level of 200 Bq/m³ in these areas does not exceed 5 %. Maps of both preQuaternary bedrocks and Quaternary sediments were used to correctly delineate areas characterised by different soil types. In some cases, the resolution and detail of the 1:200,000 scale proved to be insufficient, requiring additional geological investigations to clarify the position of geological boundaries on the ground. In the future it is planned to carry out more detailed studies of the specific activity of radionuclides in soils and to supplement the available data with the results of surface radon flux density measurements. The experience gained in zoning can be used in the development of theoretical bases for the mapping of potentially radon-hazardous areas.

Purpose: To study the possibilities of using for early diagnosis of acute radiation bone marrow syndrome (ARBMS) combined mechanical injuries (CRMI) symptoms of the primary reaction to radiation (time of onset of nausea and vomiting, the multiplicity of the vomiting), as well as to assess the depth of absolute lymphopenia during the first week after radiation exposure.

Material and methods: 1. Comparative analysis of the literature data on the early symptoms of traumatic brain injury (TBI) and previously published own data on the primary reaction to radiation exposure in acute radiation syndrome (ARS) of varying severity in 134 victims on 04/26/1986 in the Chernobyl accident. 2. Comparative analysis of the dynamics of the absolute number of peripheral blood lymphocytes in 36 patients with mechanical polytrauma (average age – 40.24 ± 4.07 years) and 11 ARS I patients (comparison group 1, average age – 30.00 ± 2.01 years), as well as 15 ARS II patients (comparison group 2, average age – 28.47 ± 2.03 years). Statistical processing of the material is the IBM SPSS Statistics.23 software package, the Kraskal‒Wallis criteria and the Mann‒Whitney U-criterion for independent samples. The results obtained were considered statistically reliable at p <0.05.

Results: 1. Upon admission of a patient with suspected TBI within the framework of CRMI, who has nausea and vomiting, is unconscious and has damage to the skin of the head, dyspeptic syndrome cannot be considered only as a manifestation of the primary reaction to radiation. In the absence of suspicion of TBI, with clear consciousness and intact skin, nausea and vomiting can be used to predict the severity of developing ARBMS. 2. Analysis of the dynamics of peripheral blood lymphocytes in 15 (41.7 %) patients with polytrauma revealed absolute lymphopenia during the first week after mechanical exposure. At the same time, the depth of absolute lymphopenia in trauma without exposure to ionizing radiation at the time when it is usually examined and the severity of ARBMS is determined in individual patients corresponds to the indicators characteristic of ARS I and ARS II (can reach 0.3 × 10⁹/l).

Conclusions: The use of methods for early diagnosis of the severity of ARBMS will have some features in CRMI. The use of criteria for the primary reaction to radiation to diagnose the severity of developing ARBMS can be recommended only if the patient has no obvious signs of TBI: consciousness is preserved, there are no signs of mechanical trauma in the head area (hematomas, abrasions, open wounds, bone fractures). In 42 % of patients with mechanical polytrauma, posttraumatic fever may be detected during the first week of follow-up post-traumatic absolute lymphopenia in combination with post-traumatic absolute lymphopenia can lead to an overestimation of the severity of developing ARBMS. The final decision on the prognosis of the severity of ARBMS, as well as CRMI in general and patient management tactics should be made only after evaluating the absorbed dose by cytogenetic method.

Purpose: To show that connective tissue forming the inner surfaces of blood vessels can act as a concentrator of an external electric field.

Material and methods: Previously, when studying the effects of electromagnetic fields and radiation on the human body, the SAR calculation method and the experimental method of tissue-equivalent phantom dummies were used. Their implementation usually assumed that the absorbing medium is homophase. At the same time, the effects associated with the fact that biological tissue is a mixture of components whose permittivities differ by tens of times, and the particle sizes of the phase components, as a rule, do not exceed one millimeter, were not taken into account. The article presents the results of developing a computer model that allows analyzing the uneven distribution of the electric field in such an object. Computational experiments were performed using the author’s program based on the finite element method.

Results: The structure of tissue containing blood capillaries was simulated by matrix systems containing cylindrical inclusions, the cross-sections of which were characterized by round and rectangular shapes. Computer experiments were conducted to calculate the patterns of spatial distributions of the electric field strength. The values ​​of the permittivity of the matrix and inclusions, the relative sizes and mutual positions of the inclusions were varied. The processes were considered stationary and axisymmetric. It was found that if the external electric field is directed along the axis of the cylindrical capillary, the field strengths inside the capillary and in the surrounding tissue are close to each other. If the external field is directed perpendicular to the capillary axis, a significant (tens of times) concentration of tension occurs in the connective tissue surrounding the capillary. The results obtained can be used to analyze the effects of stationary electromagnetic fields on the human body, as well as electromagnetic waves whose length significantly exceeds the size of blood capillaries. It is noted that the endothelium, which performs a number of important physiological functions, falls into the area of ​​concentration of electric field intensity and heat generation power.

Conclusion: The data obtained indicate that when analyzing the mechanisms of occurrence of pathological changes created by an electric field in living tissue, it is necessary to take into account that the internal surfaces of blood vessels are characterized primarily by an increased risk. Particular attention should be paid to areas in which vessels converge with each other. Further development of specialized computer programs and their implementation in clinical research practice is expected.

Purpose: To modernize software for calculation and optimization of isoeffective and absorbed dose distributions in a homogeneous media when planning fast neutron therapy for malignant tumours.

Material and Methods: The updated absorbed dose calculation system was applied to patients with two localisations, breast cancer (BC) and head and neck cancer (HNC). The study included data from 12 patients, of which 7 were patients with primary locally advanced breast cancer and 5 patients with head and neck cancer. In patients with BC, comprehensive treatment was performed. Patients with malignant tumours of the head and neck region underwent neutron and neutron-photon radiation therapy both in terms of combined treatment and as an independent type of treatment. Breast cancer was irradiated in fractionation mode with 4 fractions of 1.6 Gy each. Field docking was used. Patients diagnosed with head and neck cancer were irradiated in the mode of 3 fractions with a single dose of 2.4 Gy with the duration of the full course of treatment of 8 days. Irradiation took place on the therapeutic channel of the U-120 cyclotron located at Tomsk Polytechnic University.

Results: The planning results showed that the dose to the skin in the irradiation zone was 3.190 Gy and 3.143 Gy for beams 1 and 2, respectively. In the tumour centre, the dose was 3.253 Gy (isoeffective dose 7.980 isoGy). For critical sites (heart), the maximum doses ranged from 0.507 Gy to 1.943 Gy. ). The duration of exposure from each beam was 4 minutes and 26 seconds. For five patients with cancer in the head and neck region, planning was performed using 2 fields separated by an angle of 90 degrees (irradiation angles of 45 and 315 degrees). The fractionation regime included: 3 sessions with tumour dose 2.4 Gy, total dose 7.2 Gy per treatment course. The full course of neutron therapy was carried out in 8 days. TDF in the tumour zone was 55.4 units, with the maximum permissible value of 130 units. As a result, the dose to the skin was from 5.8 to 7.5 Gy. The dose to the tumour centre ranged from 7.1 to 7.23 Gy (taking into account RBE = 2.686 isoeffective dose ranged from 37.9 to 38.4 isoGy). Total treatment time per fraction was from 12.3 to 13.5 minutes.

Purpose: To systematize the data on the possibilities of head and neck cancer visualization in patients with dental metal constructions using radial diagnostic methods and to choose the most informative one.

Introduction

Somatostatin receptor imaging capabilities

Radiopharmaceuticals based on somatostatin receptors agonists and technetium-99m

Radiopharmaceuticals based on somatostatin receptors antagonists and technetium-99m

Conclusion

Gastrin releasing peptide receptor (GRPR) is overexpressed in prostate cancer (PC). Currently, radiopharmaceuticals (RP) for visualization of GPRP based on bombesin antagonists are developed. The aim of the present work was to conduct a phase I clinical trial of the GRPR antagonist [^99mTc]Tc-RM26 and to study the possibility of its use for PC SPECT imaging. Thirteen patients diagnosed with PC were included in the study. Patients received [^99mTc]Tc-RM26 intravenous bolus at a dose of 640±165 MBq (40 μg/injection). Six patients underwent whole-body planar imaging and SPECT/CT at 2, 4, 6, and 24 h after injection. Seven patients had SPECT/CT alone performed 2 h after RFP injection. The study showed that a single intravenous injection of [^99mTc]Tc-RM26 is safe and well tolerated. Critical organs for RFP are the gallbladder, small intestine, upper colon and kidney. The dose burden per patient associated with the administration of [^99mTc]Tc-RM26 RFP is 3–6 mSv per study. The studied RP allows to visualize primary prostate malignant tumors, as well as its metastases to lymph nodes and bones. It is reasonable to conduct further clinical studies of [^99mTc]Tc-RM26 to evaluate the sensitivity and specificity of SPECT/CT with this RP for diagnostics and staging of prostate cancer.

Purpose: To quantitatively evaluate reconstruction software algorithms in combination with algorithm O-MAR for correcting metal artifacts in CT-images and explore the potential of using O-MAR for radiation therapy planning tasks.

Material and methods: A quantitative assessment of the O-MAR algorithm on CT scans of a 20 cm diameter cylindrical phantom with a hip joint implant in the center was performed. Test tubes with different concentrations of potassium hydrogen phosphate (K₂HO₄×3H₂O) were placed around the implant. The evaluation parameters used standard deviation (SD) of the region of interest (ROI) density in HU units and the calculation of the degree of susceptibility to artifacts (P).The calculation of absorbed dose in the phantom was performed on the Eclipse 17.0 planning station, using the AAA (Analytical Anisotropic Algorithm) calculation algorithm.

Results: Calculations of the degree of artifact susceptibility showed that the minimum mean noise value was observed for the iMR series in combination with O-MAR (31.6 ± 45.5 HU) and the maximum for FBP (16) without O-MAR (77.0 ± 31.1 HU). As a result of comparison of CT studies with/without O-MAR, the average calculated difference in absorbed dose for all control points is 0.33±1.68 % and 0.42±1.38 % in the presence of implant for FBP and iMR modes, respectively. However, for both modes the difference was 3.22 % for the artifact zone (dark spot).

Conclusion: It is shown that the use of the O-MAR algorithm reduces the distorted values of X-ray density that arose as a result of the presence of an implant in CT studies. The calculation of the absorbed dose for the artifact zone (dark spot) shows a decrease in the uncertainty of the dose calculation in O-MAR-corrected studies.