To optimize the radiation processing planning process, the software ‘‘DosePreview by IRT’’ has been developed, which calculates depth dose distributions based on the specified energy spectrum of the electron beam. This software is built on a database of depth dose distributions from monoenergetic electrons, covering energy levels from 0.1 to 20 MeV and calculated using the Geant4 simulation toolkit. The created tool can make the planning of radiation processing easier and faster. This will help to make the use of electron beam technology for food processing more accessible and contribute to food security.

MRI is widely used in radiation therapy planning, particularly in stereotactic radiosurgery for brain metastases. The article addresses the geometric distortion of MRI images, which can lead to errors in radiation therapy planning. A series of experiments with a simple phantom were conducted on two MRI scanners with 0.5 and 1.5 T magnetic fields. Deviations in the positions of the phantom objects from their actual locations were observed. The detected deviations can reach up to 5 mm. A theoretical dependence of the magnetic field gradient on the distance to the center of homogeneity was calculated, which agrees well with the approximation of experimental data. An assessment was made of the dependence of the image area distortion of objects located at the center of the field homogeneity on their actual sizes. It was found that the area deviation can reach up to 20 % .

Currently, persons with higher professional (non-medical) education and no work experience as medical workers or who have less than five years of work experience as medical workers must undergo primary specialized accreditation. In order to accredit medical physicists to work in radiation therapy departments on the basis of the Department of Accelerator Physics and Radiation Medicine, Faculty of Physics, Moscow State University named after M.V. Lomonosov developed a bank of 2000 questions. In 2023, the tasks of the simulation stage were updated and approved. To test the practical skills of medical physicists as part of accreditation, domestic developers from the companies RT 7 LLC and Gradation LLC provided specially designed training modules based on their software, which is currently used, including in radiation therapy departments. Despite the fact that a lot of work has been done, at present only the starting point has been formed for the launch of primary specialized accreditation in Russia. In the future, constant cooperation between higher educational institutions, accreditation centers and leading cancer centers in our country is necessary to regularly update and improve assessment tools for the accreditation of specialists in the field of medical physics.

The study suggests an algorithm for estimating the depth dose distribution in the material irradiated with an accelerated electron beam, based on the absorbed dose distribution data in the reference material, such as aluminum or water. It was shown that a margin of error in the measured absorbed dose distributions as well as the choice of the materials have an impact on the accuracy of reconstruction of the dose distributions in the materials.

Radiation treatment of food products carried out to increase their shelf life can result in chemical transformations initiated by free radicals. Volatile compounds (alcohols, aldehydes, ketones, etc.) formed, in particular, as a result of lipid oxidation, impair the organoleptic properties of products. Method of gas chromatography-mass spectrometry (GC-MS) makes it possible to identify the fact of food processing by detection of volatile marker compounds: in the case of meat products, the existing standard brings under regulation detection of 2-alkylcyclobutanones, however, the products with a reduced fat content, such as turkey and chicken, require an alternative marker. The results of GC-MS study revealed the dependence of microbiological parameters and the content of various volatile organic substances in chilled turkey meat on the dose of electron radiation. It is shown that the total amount of alcohols, ketones and aldehydes (11 compounds) decreases exponentially with an increase in the absorbed dose. An increase in the radiation dose leads to a higher content of carbonyl compounds (aldehydes and acetone), which results in a specific taste and smell of the irradiated products. At the same time, the acetone concentration increases linearly with the absorbed dose, which makes it possible to use acetone as a potential marker of the degree of irradiation of low-fat meat products. Irradiation in the “working” doses (0.5–1 kGy) significantly suppresses the pathogenic microflora and keeps the organoleptic properties of the product.

The research explores a wide range of applications for electron accelerators in industrial irradiation processing. It also compares the physical properties of electron beams, dose ranges, and methods used for irradiation of polymers, medical items, transplantology objects, pharmaceuticals, and foods. Moreover, the study discusses the depth dose non-uniformity in objects irradiated with accelerated electrons. The research also highlights the dependency of geometry, density, and chemical composition of the object on the dose distribution. Another focus of the study is computer simulation of electron irradiation method, encompassing all physical and technical parameters to assess the dose distribution throughout the irradiated objects, since without knowing the precise electron beam spectrum, it is impossible to accurately reconstruct the dose distribution throughout the objects. Considering that the beam spectrum cannot always be identified, especially for industrial accelerators, the study presents algorithm for reconstructing the dose distribution in irradiated objects. The final part of the research provides methods for increasing the dose uniformity throughout objects irradiated with electron beams.

A method of modifying the absorbed dose distributions over the volume of objects has been proposed based on the alternating placement of aluminum absorbers of different thicknesses between the exit window of the electron accelerator and the irradiated object. It is demonstrated that the use of a limited set of plates (nine different ones) with thicknesses of 5.5–9.5 mm makes it possible to increase the radiation treatment uniformity up to 98

This paper describes a method of electron beam modification with the use of aluminium modifier plates of different thickness which enables a higher dose uniformity for the objects treated with accelerated electrons with the energy of up 10 MeV. Values obtained during experiments at two types of industrial electron accelerators are included to prove the validity of the proposed method.

The impact of aluminum beam modifier plates on the uniformity of the absorbed dose distribution over the depth of objects is studied using computer simulation of the treatment of objects by monoenergetic accelerated electrons with energies from 4 to 10 MeV. It has been found that the method for modifying the electron beam using modifier plates makes it possible to increase the uniformity of the dose distribution over the volume of the treated object by 15–20%.

The purpose of this work was to compare the effect of electron and X-ray irradiation on microbiological content and volatile organic compounds in chilled turkey meat. Dose ranges which significantly suppress the pathogenic microflora while maintaining the organoleptic properties of the turkey meat are different for electron and X-ray irradiation. According to the study it is recommended to treat chilled turkey using X-ray irradiation with the dose ranging from 0.5 to 0.75 kGy, while in electron irradiation permissible doses should be within 0.25–1 kGy. Three main groups of volatile compounds: alcohols, ketones, and aldehydes—were found in irradiated and non-irradiated samples of turkey meat. It was found that the total amount of aldehydes, which are responsible for the formation of a specific odor of irradiated meat products, increases exponentially with the increase in the absorbed dose for both types of irradiation. It was established that acetone can be used as a potential marker of the fact of exposure of low-fat meat products to ionizing radiation.

The study presents analytical dependencies that describe the electron spectrum and depth dose distribution in the object with an accelerated electron beam with having an initial energy of 1–10 MeV after passing through aluminum plates with a thickness of 0.5–5 mm. The mathematical model we developed allows to determine the spectrum of an electron beam after passing through plates with an error margin of no more than 10 $$\%$$ and the depth dose distributions with a margin of error of no more 5 $$\%$$ .

The authors determined the beam energy spectrum of the industrial electron accelerator by the depth dose distributions in aluminum using different parameters of Tikhonov regularization method. The impact of the measurement errors, found in depth dose distributions, on the determined spectra was estimated.

Anna A. Oleshkevich, Specific features of change in enzymate activity in

Представлены результаты исследования зависимостей характеристик дозовых распределений в биообъектах от их толщины, плотности и энергии пучков электронов, применяемых при радиационной обработке пищевой продукции.

This study provides the results of the experimental research involving 1 MeV electron treatment of chilled turkey meat with the dose rates of 1 Gy/sec, 10 Gy/sec and 100 Gy/sec. It was found that the doses exceeding 2 kGy decrease bacterial content in turkey meat at least 100 times with the dose rate ranging from 1 Gy/sec to 100 Gy/sec. Irradiation with the dose rates 1 Gy/sec and 10 Gy/sec significantly reduces the number of pathogens with doses up to 1 kGy to compare with treatment using 100 Gy/sec. Microbiological parameters of the samples irradiated with 2 kGy coincide within statistical margin of error at all dose rates. Electron treatment with dose rate 100 Gy/sec shows a more considerable reduction in bacterial content at the doses exceeding 3 kGy. Thus, the study shows the nonlinear dependence of viable cells in chilled turkey irradiated with low-energy accelerated electrons in the range from 0.25 kGy to 3 kGy on the dose rate.