卷 69, 编号 2 (2024)

Purpose: Simulate radiation-pasteurellosis lesions in the body.

Material and methods: Modeling of radiation and pasteurellosis lesions caused by the action of physical and biological factors on the organism Modeling of acute radiation disease (ARD) of animals was carried out by gamma-irradiation at the “Puma” facility with an exposure dose rate of 2.36×10^-5 A/kg. Pasteurella multocida, the causative agent of pasteurellosis, as one of the most frequently occurring pathogenic agents, was used as a model biological agent to reproduce the experimental biological lesion. Modeling of radiation-pasteurellosis lesion was carried out on rabbits and on white mice with live weight of 2.8‒3.4 kg and 18‒20 g, respectively.

Results: In experiments on white mice to determine the optimal doses of the affecting agents it was found that the minimum doses of gamma rays and the causative agent of pasteurellosis are 6.0 Gy and 4.5×10³ microbial cells per kg (m.k./kg), 3.9 Gy and 9.0×10³ m.k./kg, which leads to the development of pasteurellosis infection and radiation sickness in acute form with death of all animals, mainly on the first and second days after exposure to the affecting agents. k./kg, which leads to the development of pasteurellosis infection and radiation disease in acute form with death of all animals, mainly on the first and second days after combined exposure to the affecting agents. It was found that gamma-irradiation of rabbits at a dose of 8.0 Gy, followed by infection with Pasteurella at a dose of 4.5×10³ m.k./kg, aggravated the course of the pasteurellosis process, contributed to its generalization and accelerated the death of animals.

Conclusion: Radiation-pasteurellosis affection proceeded rapidly. Animals died on 2‒13 days after the onset of the disease with an average life expectancy of 6.3 days. Exposure of rabbits to non-lethal doses of the studied agents at the indicated doses led to aggravation of the course of radiation sickness and pasteurellosis infection, causing death of all animals from radiation-pasteurellosis pathology. At autopsy of corpses of animals, which died from acute course of radiation-pasteurellosis pathology, swelling of subcutaneous tissue in the area of pharynx and intermandibular space of neck, hyperemia and enlargement of lymph nodes, numerous hemorrhages on serous and mucous membranes and in tissues of parenchymatous organs ‒ serous or serous-fibrinous exudate in thoracic and abdominal areas, pulmonary edema were found.

Relevance: Due to the high chemical toxicity of all known effective radioprotectors, studies of the radioprotective properties of safer drugs are very relevant. A sufficient number of works are devoted to the radioprotective properties of ribonucleoside riboxin (inosine). However, studies comparing the direct radioprotective properties of riboxin and a recognized radioprotector, for example, indralin, using a survival test in irradiated animals have not yet been carried out.

Purpose: Conduct a comparative assessment of the radioprotective properties of riboxin and indralin using a survival test in mice exposed to external X-ray radiation.

Material and methods: The experiment was carried out on 200 male ICR (CD-1) mice of the SPF category in duplicate. In each experiment, the animals were divided into the following groups, separated by body weight, 10 animals each: vivar control, not exposed to drugs and radiation, radiation control, with preliminary intraperitoneal administration of sterile water and exposed to external X-ray radiation in doses of 6.0, 6.5 and 6.75 Gy, experimental groups exposed to irradiation in the indicated doses with preliminary intraperitoneal administration of riboxin at a dosage of 100 ml/kg body weight or indralin at a dosage of 100 ml/kg. Survival was assessed for 30 days after irradiation. The dose change factor was determined using probit analysis as the ratio of the radiation dose causing the death of half of the irradiated animals that received the drug to the radiation dose causing the death of half of the irradiated animals without administration of the drug.

Results: The use of indralin before X-ray irradiation in doses of 6.0 Gy, 6.5 Gy and 6.75 Gy led to a statistically significant increase in the survival of animals compared to the group receiving Riboxin and control irradiation (р<0,05, log-rank test). Using equations derived from Phinney probit analysis, LD₅₀ doses were calculated for indralin and riboxin, from which dose change factors were calculated to be 1.8 and 1.07, respectively.

Conclusion: Since riboxin has not demonstrated radioprotective properties, its preventive use with intraperitoneal administration under the conditions described in this paper, for leveling the effects of radiation can be considered ineffective.

Purpose: To justify the main areas of Russian legacy framework in the field of radiation safety assurance as a basis for improvement of the current standards and regulations.

Material and methods: The article analyses international documents and Russian federal laws regulating different aspects of human safety and highlights the most important approaches and procedures of safety assurance proven in practice.

Results: The necessity of developing new federal law “On Radiation Safety in Russian Federation” is substantiated.

The article shows that internationally recognized principles of radiation safety assurance should be applied in Russia: those are the preservation principle, the responsibility principle, the continuous control principle and, in particular, the permission principle. The last principle means that what is not permitted is forbidden when it comes to handling ionizing radiation sources.

The article describes the main provisions and elements of new law and details some considerations that need to be articulated and enhanced in new federal law based on positive experience of their implementation in the current federal laws on different safety aspects.

Conclusion: New federal Law “On Radiation Safety in Russian Federation” should incorporate all positive experience of applying the current Federal Law of 09.01.1996 N 3-FL “On Radiation Safety of the Public” and other Russian laws regulating different aspects of human safety assurance in various fields.

New law should be based on unconditional priority of protection of human life and health, present and future generations and the environment from possible radiation exposure. New law should enable interaction of the facilities whose activities are related to handling ionizing radiation sources and facilities of the infrastructure for radiation safety assurance, as well as provide connection to other regulations that set specific norms and requirements in the field of radiation safety assurance.

Based on the maintained database (source database) on effects in nuclear workers (NW), a selection of major studies of the relationship between mortality from diseases of the circulatory system (CVD; codes 390–459 according to ICD-9 and I00–I99 according to ICD-10) and external radiation dose. The sample included 30 papers and covered cohorts from 6 countries plus an NW cohort from 15 countries. For the sample, in most cases based on published standardized mortality rates (SMR), the relative risks (RR) of mortality from CVD were calculated for the selected dose groups with subsequent processing of the material for outliers. Initial: n = 207; final sample: n = 199; covers very low (0–10 mSv; 15.8 % of the sample), low (>10–100 mSv; 45.8 %) and moderate (>100–1000 mSv; 36.4 %) doses; data for high doses (>1000 mSv; n = 4; 2 % of the sample), due to dubiousness, were excluded.

A systematic review and pooled analysis of the RR for mortality from CVD depending on the dose on an ordinal scale was performed on the final sample. For the entire dose range (0–1000 mSv) and for moderate doses, statistically significant trends in increasing RR were found when expressed in five types of regressions (except for the logarithmic one for the entire range). Although the r values were small (0.230–0.293), the effect was clear. The ERR per 1 Gy (Sv) calculated for moderate doses using linear regression was 0.54. This value is higher than those obtained previously in meta-analyses, but should be considered as the most adequate.

No dose relationship was found for the very low + low dose range (0–100 mGy); the r coefficients for the regressions were either negligible or negative at statistical insignificance. For the subthreshold dose range for CVD mortality after exposure (according to UNSCEAR and ICRP: 500 mSv), only a weak trend towards an increase in RR was found, statistically insignificant, despite the large sample size (n = 191), while for the dose range 500–1000 mSv, the highest tendency among the pooled analyzes was revealed to increase the risk depending on the level of exposure (r = 0.297–0.423; statistically insignificant due to the small sample size: n = 8).

It is concluded that for mortality from CVD after irradiation, the threshold value of 0.5 Gy established by UNSCEAR and ICRP and confirmed in the present pooled analysis should be strictly adhered to. Due to the lack of effects of low doses, it is inappropriate to raise the issue of low dose effects in the context of these pathologies.

Purpose: Demonstrate a clinical observation in which to establish a diagnosis it was necessary to use eight methods for diagnosing coronary pathology, four of which are radiation.

Material and methods: To establish a diagnosis in a cardiac patient with suspected coronary heart disease (CHD), post-infarction cardiosclerosis, echocardiography (ECG), Holter monitoring (HM), bicycle ergometry (VE), X-ray computed tomography (X-ray computed tomography) to determine calcification of the coronary arteries, single-photon selective computer tomography (SPECT), magnetic resonance computed tomography (MRI), positron emission computed tomography (PET), coronary angiography (CAG).

Results: The sequential use of eight diagnostic methods, four from radiation, was established when observing cardiosclerosis with coronary heart disease, cardiosclerosis in the 4, 5, 10, and 11 segments of the heart, complicated by a left ventricular aneurysm in the lower and lateral walls with minor ischemia at the height of physical activity. The need to use SPECT/CT in the complex diagnosis of coronary heart disease consists of using hybrid tomography and sequentially performing two studies in one diagnostic procedure (X-ray computed tomography and SPECT with ^99m Tc-technetril) it seems possible to obtain 26 study indicators (with X-ray computed tomography – 4 indicators assessing calcification of the coronary arteries, with SPECT – 11 indicators of perfusion and 11 indicators of myocardial function).

Conclusion: A clinical observation of the diagnosis of coronary artery disease with post-infarction cardiosclerosis and left ventricular aneurysm was demonstrated in which eight diagnostic technologies were used (ECG, CM, VE, CT, SPECT, MRI, PET, and CAG), four of which relate to radiation diagnostics (X-ray CT, SPECT, PET, and KAG). A feature of sequential hybrid tomography (X-ray CT and SPECT with ^99mTc-technitrile) is that this technology allows you to obtain 26 research indicators.

Purpose: Medical elementology and its subsection nuclear physics medical elementology, as the most important areas of biomedical science, are still insufficiently included in the arsenal of medical radiology as a fundamental basis for the development and use of new methods for diagnosing and treating various diseases, including oncological ones. For the successful establishment of nuclear physics medical elementology as a new scientific discipline, it is necessary to develop a clear methodology for its further development.

Results: The definition of the subject of research and the main postulates of medical elementology is given. The close interrelation of knowledge about the content and metabolism of chemical elements, as well as their radioactive and stable isotopes, with the needs of medical radiology is shown. The following areas of research are considered: 1) The use of chemical elements, as well as their radioactive and stable isotopes in medicine; 2) Visualization of organs and tissues, as well as in vivo determination of the content of chemical elements in them; 3) Nuclear physical methods for determining chemical elements in samples of tissues and fluids of the human body in solving oncological problems; 4) The role of chemical elements in calculating absorbed doses during radiotherapy; 5) The use of nuclear physical methods in the formation of groups at increased risk of cancer. A range of modern nuclear physics analytical methods acceptable in clinical practice and as an adequate research tool is outlined. The need for the integrated use of nuclear physics analytical technologies to obtain reference values ​​for the content of chemical elements in various organs, tissues and fluids of the human body in normal and various pathological conditions, as well as to organize the strictest quality control of measurements and unify methodological approaches is demonstrated. The modern possibilities of using the achievements of nuclear physics medical elementology in solving the problems of medical radiology are determined and the priorities for the future are outlined.

Conclusion: The steady development of nuclear physical methods of chemical elements analysis and their implementation in medicine is constantly expanding the scope of possibilities of medical elementology. The development of this area will certainly make a significant contribution to the future successes of medical radiology.

Introduction

1. Tritium and reference radiation

1.1 Tritium isotope and its energy spectrum

1.2 Reference radiation

2. Methods for determining the quality of radiation and RBE

2.1 Radiation quality in microdosimetry

2.2 RBE by the number of DNA double-strand breaks

2.3 RBE by fraction of secondary low-energy electrons

3. Analysis of calculations of radiation quality and tritium RBE

3.1 Estimation of tritium emission quality factors

3.2 Evaluation of the RBE of tritium radiation during its action on DNA

3.3 Estimation of the RBE of tritium from the fraction of secondary low-energy electrons

3.4 Quality factors and RBE of tritium with respect to reference emissions

Conclusion