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13PHYSICS AND MATHEMATICS
DETERMINATION OF OPTIMAL IRRADIATION DOSE OF MEDICAL PRODUCTS
Razmukhamedov D.,
Tashkent Chemical-Technological institute, senior lecturer Senior lecturer on faculty of chemical technology of fuel organic compounds
Xudayberdiyeva A.,
Tashkent Chemical-Technological institute, head of department, assistant professor Assistant professor on faculty of chemical technology of fuel organic compounds
Fernando Jonathan, Ural Federal university, bachelor course student Third year bachelor course student of faculty biomedical engineering
Ali Alzuabi,
Ural Federal university, bachelor course student Fourth year bachelor course student of faculty biomedical engineering
Bizimana Jean Damascene
Ural Federal university, master degree student Second year master course student of faculty nuclear physics and technology
Abstract
The presented below results were determined during a train-the-trainees course in Ural Federal University in the Centre of Radiation and Sterilization of medical products under the support of Rosatom Technical Academy. A group of researchers were collect metrological data on electron beam accelerator during the radiation sterilization processes of medical surgical gloves packed in the standard box. Determination of optimal irradiation dose through the electron beam accelerator of the standard boxes with surgical gloves and made a conclusion of dose mapping.
Keywords: radiation sterilization, international sterilization standards, safety regulations, medical devices, dose, electron beam accelerator.
Nowadays the food and medical industries become more variety and the quality of the products should be checked by the international standards. Moreover the process of sterilization of food and medical products is a process that leads to ensure the complete death of all microorganisms and their spores. Day to day the methods of sterilization become simpler and more safety, but the main methods that we can faced daily and have used in many laboratories is the Electron Beam processing systems [1]. The idea of e-beam is penetrate medical devices and pharmaceutical products in their final shipping container. The process involves accelerating a beam of electrons to near light speed where it passes through a scan chamber and then transitions into a curtain of electrons. Materials moving through the chamber on a conveyor system are showed with these high-energy electrons, which penetrate the material with a precise, predermined dose.
The first accelerators were invented and used to study nuclear physics at university research centers, which later influenced the use of these devices more efficiently. Today in the world there are more than 12,000 accelerators, and only about 1,200 of them are research accelerators, and they serve not only physics, but also chemistry, biology, medicine, and materials science. About 6000 accelerators work in the semiconductor industry, fifteen hundred in other high-tech industries, about 4500 in oncology clinics, and about two hundred are used to obtain radioactive isotopes. So the bulk of such installations work in medicine [2]. Nevertheless, the largest accelerators (there are only a dozen of them)
now, as before, serve to penetrate the secrets of the micro world.
As the analysis of the literature data shows, the scientific application of accelerators is primarily associated with the study of the structure of the atomic nucleus, the structure and properties of elementary particles and their interactions. The accelerator in this case is essentially a "microscope" that allows you to see the structure of particles and follow the properties of their interactions on a very small scale. But such studies require intense particle beams with enormous energies. The charged particle accelerators used for these purposes are very complex and very large electro-physical devices that create strong magnetic fields and impart high energies to various particles (electrons, protons, ions), which are necessary to study the smallest structural elements of matter and energy in nature.
As it is known, technological processes using accelerators can be reproduced at low energies, but with a large current of accelerated particles and a sufficiently large beam size. Irradiation of various types of materials is used to increase their melting point, tensile strength, and durability. As for the bombardment of the surfaces of materials with various ions, this method of implanting ions to the posterior depth is one of the most effective. This scientific article also describes the technological application of accelerators, sterilization of medical devices, such as disposable syringes, medicines. The need to use radiation sterilization is due to the beginning of mass production of medical devices made of plastics and polymeric materials, which, as a rule, had a one-time use, which required sterilization on
an industrial scale. The possibility of using radiation sterilization is due to the high rates of development of the atomic industry and nuclear medicine, the beginning of the commissioning of powerful irradiation facilities based on radionuclide sources and electron accelerators suitable for carrying out radiation sterilization on an industrial scale. The main advantages of the radiation method for sterilizing medical devices are the low temperature of the process, the relative cheapness, and the absence of toxic by-substances.
In this research work, an electron accelerator was used, with the radiation dose when using EL sterilization higher - from 15 to 50 kGy and largely depended on the operating mode of the accelerator. The sterilization mechanism in this type consists in the transfer of energy to the valence electrons of the irradiated material, followed by their emission, which causes breaks in the DNA and RNA molecules of microbial cells, producing oxygen compounds, which in turn damage important cellular components.
The results presented in this research paper are taken in the laboratory in Ural Federal University on the train-the-train course. Main research that was done by a group of students were in the Multipurpose Irradiation centre in UrFU that is working with radiation sterilization of the medical equipment such as hospital gloves, stringers, needles and etc. through irradiation using electron beam accelerator.
Radiation sterilization of medical devices is necessary in the modern world since the spread of infection viruses through various types of materials affects the human body, which can subsequently lead to various types of infectious diseases. Devices delivered in a sterile state shall be designed, manufactured and packaged in accordance with placed on the market and that, unless the packaging which is intended to maintain their
Figures 1,2. Fillers with written dose
It should be pointed that a continuous supply of the sterilized product to the irradiation zone and optimization of the speed of the conveyor device must also be ensured. Fundamental research carried out in the researched area shows that the principle of operation is based on irradiation of packaged medical devices using
sterile condition is damaged, they remain sterile, under the transport and storage conditions specified by the manufacturer, until that packaging is opened at the point of use. It shall be ensured that the integrity of that packaging is clearly evident to the final user [3].
It should be pointed that firstly, devices labeled as sterile shall be processed, manufactured, packaged and sterilized by means of appropriate, validated methods and secondly, devices intended to be sterilized shall be manufactured and packaged in appropriate and controlled conditions and facilities.
In this presented research there were list of tasks presented below:
1. Put fillers into the calorimeter 36.6P and put it on the conveyor to irradiate them
2. Dose fillers were 1-10 kGy
3. Energy was 10 MeV
4. Speed of the conveyor was 1 m/min
5. Determination the initial resistance before the irradiation (R=2.102 kOhm)
6. Determination the initial resistance after the irradiation (R=1.675kOhm)
7. Open the irradiated box with samples
8. Take our marked samples that are with films on the surface
9. Determination the dose (D=8 kGy)
10. Determination the dose on each films on the samples
Based on the tasks presented, the following basic requirements were taken into account in the radiation sterilization center, namely:
- The radiation source (linear electron accelerator) must be simple in design, reliable in operation, and the energy of the supplied electrons must be sufficient for the full penetration of electrons to the entire thickness of the irradiated object.
W
o
8 kGy that were put into calorimeter
a linear accelerator, moving under a beam of accelerated electrons deployed in a strip across the movement of the conveyor. The technological line includes: a linear electron accelerator, an irradiation chamber, a transport device, an automation and safety interlock system, a control panel and control.
Figures 3, 4. Box with irradiated samples with measuring bands (1-10 kGy)
Analysis of literature data asserts that the sterilizing dose of radiation of medical devices is determined on the basis of data on the initial contamination of products and data on the radio sensitivity of microorganisms [4]. With a high initial abundance of microbes, it will take more time or a higher dose of radiation to reduce the number of surviving microbes to a certain level than when there were initially few. This once again confirms the fact that compliance with sanitary standards in production affects the reliability of subsequent sterilization.
The given box had a dimension: Length = 50 cm Width = 40 cm
After the irradiation the first step was to determine the optical density and then calculate the dose. With the obtained information we draw the dose map follow by the coordinates of the fillers.
The distance between the irradiated samples was: From 1^2 was equal 10 cm From2^3 was equal 12.5 cm From 3^4 was equal 10.5 cm From 4^5 was equal 9.5 cm The packages selected for the irradiations were located in the middle, the corners and between the middle and the corners, like can be partly observed in the figure 3. At every package were attached 15 measuring bands in 3 columns and 5 rows along the package, as can be seen at the figure 4. These measuring films are designed to change its color when they are irradiated. With the change of color, they change its optical density. Which is necessary to determinate the irradiation dose. With that distribution of the measuring bands and the packages was obtained a completed distribution map of the irradiation dose inside the box.
1.1= 1.2= 1.3=
2.1= 2.2= 2.3=
3.1= 3.2= 3.3=
4.1= 4.2= 4.3=
5.1= 5.2= 5.3=
Figure 5. Determination of dose of 5 samples depends on the coordinates. The given figure is only one sample.
Overall, we had 5 samples.
After the irradiation, the optical density of every measuring marked was measured on the spectropho-tometer ПЭ-5400 BH. With these measurements, were
made 5 matrixes with the doses of each package on its corresponding coordinate like on the figure 5.
Figures 6,7. Spectrophotometer with a wavelength X=512 nm
Figure 8. The chamber of spectrophotometer and the red one is film with irradiation dose of 8 kGy
To calculate the irradiation dose from the optical density, was used the formula given below. Were calculated the dose in every measuring band. Then, with the calculated values, were constructed again 5 matrixes with the scheme of figure 5.
Using the coefficient of 0.155 (which depends on the measuring bands and is given by their manufacturer),
For the first sample we got these numbers:
1.1=20.60 1.2=18.62 2.1=21.45 2.2=22.73
3.1=21.13 3.2=21.02
4.1=20.70 4.2=21.61
5.1=20.60 5.2=22.57
D= (A - 0.155) * 8,0998 A-optical density.
After the process of calculating the irradiation dose we got the table with numbers given below for 5 samples.
1.3=21.93 2.3=21.07 3.3=22.09 4.3=23.90 5.3=21.82
For the second sample we got these numbers:
1.1=24.43 1.2=19.63
2.1=25.50 2.2=20.70
3.1=23.31 3.2=23.24
4.1=22.99 4.2=21.82
5.1=19.37 5.2=20.60
1.3=21.23 2.3=20.17 3.3=21.55 4.3=21.40 5.3=21.15
For the third sample we got these numbers:
1.1=22.94 1.2=22.03
2.1=22.46 2.2=19.63
3.1=24.17 3.2=22.14
4.1=24.01 4.2=21.61
5.1=26.84 5.2=21.18
1.3=20.81 2.3=22.09 3.3=21.98 4.3=20.97 5.3=19.37
For the fourth sample we got these numbers:
1.1=22.03 1.2=20.81
2.1=23.26 2.2=23.05
3.1=22.51 3.2=20.75
4.1=21.34 4.2=22.67
5.1=22.83 5.2=21.45
1.3=19.90 2.3=22.14 3.3=21.50 4.3=22.25
5.3=
For the fifth sample we got these numbers:
1.1=19.20 1.2=17.76 1.3=19.31
2.1=18.8 2.2=17.28 2.3=20.27
3.1=20.17 3.2=17.66 3.3=20.17
4.1=20.22 4.2=18.40 4.3=20.06
5.1=19.52 5.2=18.14 5.3=21.29
As we can see the irradiation dose of the fifth sample (the one in the right corner) is low compare to other samples. After discussion and evaluating possible causes, was concluded that this happened because the box wasn't set at the center. Instead, it was shifted right, causing this abnormality in the dose distribution inside the box.
In this presented work, a linear accelerator (produced in Russia) was used to fulfill the conditions of radiation sterilization. When creating such powerful radiation installations, some basic requirements for them must be taken into account, namely:
- The radiation source (linear electron accelerator) must be simple in design, reliable in operation, and the energy of the incident electrons must be sufficient for the full penetration of electrons to the entire thickness of the irradiated object.
- Continuous supply of sterilized products to the
The principle of operation is based on irradiation with a linear electron accelerator (name and number if you want, not important) of packaged medical products moving under a beam of accelerated electrons deployed in a strip across the movement of the conveyor.
The speed of the mesh of the belt conveyor in this study was 1 m / min.
Based on the data obtained, it follows that the energy of electrons in the range from 3-10 x 106 electric volts (MeV) with a beam power in the range from 1-10 kW is sufficient to penetrate into the product, hermetically packed in a finished container. When electrons scan a product, they pass through a variety of secondary particles, including ions and free radicals. Secondary particles break the DNA chains of microorganisms both on the inner surface of the package and inside the product, thus blocking their further multiplication. Microorganisms are destroyed, and as a result, the product is
irradiation zone and stabilization of the speed of the sterilized. transport device must be ensured.
30 20 10 0
fifth package
□ 20-30
□ 10-20
0-10
30 20 10 0
package
5
Figure 9. Dose surface distribution in the researched box with surgical gloves
After the research made it can be concluded that:
• The dose distribution in the researched box was considerably affected by the correct position of the box in the line.
• The dose absorbed by every item depends on its position inside the paper box. Additionally, the items at the centre are more irradiated compare with the sides.
On the basis of the lectures, seminars and practical classes, an exhaustive educational-methodological and scientific-practical material was obtained for further fundamental and applied research in the field of nuclear physics. Including, for the effective practical implementation of the results of the research work carried out during the internship and the implementation of the main provisions set out in the Decree of the President of the Republic of Uzbekistan dated October 8, 2019 "On approval of the Concept for the development of the higher education system of the Republic of Uzbekistan until 2030 year "on the phased implementation of the concept" University 3.0 ", which provides for a close relationship of education, science, innovation and activities to commercialize the results of scientific research in higher educational institutions, the experience
gained in the scientific and technical laboratory at the Center for Radiation Sterilization, will be applied at the Tashkent Chemical Institute of Technology, in part concerning this direction in the bachelor's degree course "Electrical Engineering" at the department «Physics and Electrical Engineering».
References
1. Basic sanitary rules of radiation safety (OSPORB-99). Moscow: The Ministry of Health of the Russian Federation, 2000. 97 pages
2. Kalashnikov V.V., Gordeyev A.V., Pavlov E.P., Bushmanov A.Y. Разработка и применение метода радиационной стерилизации в федеральном медицинском биофизическом центре им. А.И.Бур-назяна // Саратовский научно-медицинский журнал. 2014.№4 С.844-849.
3. Radiation Safety Standards NRB-99. НРБ-99. Moscow: The Ministry of Health of the Russian Federation, 2000. 115 pages.
4. Sevalnev, Anatoliy I., and Nikolay P.Grebnyak. The fundamental of radiation safety provision: study guide. Zaporizhzhia: Zaporizhzhia State Medical University, 2015. 108 pages.
