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Design of CNT-based electron microbeam cell irradiation system
for low-dose radiobiology research
c,d
Hanna Lee , Jinho Choi , Amar Prasad Gupta , Jaeik Jung , Jaekyu Jang ,
b
d
d
a
Kyung-Sik Yoon *, Jehwang Ryu *
e
f
a Department of Age Service-Tech Convergence, College of Medicine, Kyung Hee University, Seoul 02447, Korea
b Department of Radiation Oncology, College of Medicine, Kyung Hee University, Seoul 02447, Korea
c Department of Physics, Kyung Hee University, Seoul 02447, Korea
d CAT Beam Tech Co. Ltd., Seoul 02455, Korea
e Department of Biochemistry and Molecular Biology, College of Medicine, Kyung Hee University, Seoul 02447, Korea
f Department of Radiology, College of Medicine, Kyung Hee University, Seoul 02447, Korea
Abstract
Radiation research is mostly aimed at improving the use of radiation such as radiation therapy and materials. Although the effect of high-dose
radiation in cells has been studied a lot, the effect of low-dose radiation still needs a lot of scientific evidence. Therefore, we study the cellular
response to low-dose radiation from the development of carbon nanotubes(CNT) cold cathode microbeam cell irradiator.
Introduction Results
◈ Previously developed microbeam system (A) x 1,000 (B) • (A) SEM image of
• Devices to study intracellular and pointed emitter,
intercellular mechanisms • (B) Field emission
• Previous microbeam cell irradiator; 50 ㎛ characteristics of CNTs
Thermionic cathode, Particle accelerator on point emitter e-gun.
※ Problems J Imaging Syst Technol. 2021;1–8
- High operating temperatures CNTs were not aligned vertically, but rather looked like spaghetti
- Short life randomly grown on a point metal substrate. The current-voltage (I-
- Huge size and high cost
Nucl Instrum Methods Phys Res B. V) characteristics of CNT field emitters will be measured.
2011, 269(18): 1992–1996 - Difficulty in immediate operation
• Particle simulation for
◈ Carbon nanotubes (CNT) (A) 0 kV (B) e-beam irradiation;
(A) Electron trajectories;
sectional view of YZ
plane, (B) Electron field;
Graphene SWCNT MWCNT
30 kV sectional view of XY
RSC Adv., 2020, 10, 43704-43732
• In 1991, Iijima discovered CNTs plane.
• Cylinder-shaped structure in which single or multiple layers of Simulation results showed that a high-energy, focused electron
graphene are rolled up beam was focused on a very small area of the window surface.
• Different mechanical, electrical and chemical properties
depending on shape and structure (A) (B)
→ Various fields of application • (A) An actual image of
part of irradiator
(Semiconductor, X-ray source, sensor, etc.) • (B) An actual image of
Electron transport Electron-gun
◈ Why did we use CNTs for the electron source? vacuum chamber electron-gun.
• High thermal and mechanical stability
• Low operating temperature → Increase the life of device Z-motion An open microbeam source was used, and the
• Digital control possible microbeam was directed upward. The distance
• Flexibility and miniaturization of cathode design between the cathode and the window could be
adjusted using Z-motion. Cells were designed to
◈ Cellular responses in high-dose radiation be placed directly above the window.

Conclusion
◈ Additional studies
① Check the dose Irradiated to the cell ② Cell viability
Signal Transduct. Target. Ther.(2020) 5:60 Cells, 2019, 8, 1105
• Compared to high-dose radiation, studies on the biological
effects of low-dose radiation have not been much conducted.
• Direct damage: DNA ionization, ionization of water molecules
bound to DNA, etc. Rev. Sci. Instrum. 2008, 79, 125102 Int J Mol Sci. 2017, 18(7): 1460
• Indirect damage: Radical, secondary species (cations, anions, ③ Cell response to dose ④ Cell's internal reaction
secondary electrons) interact with DNA, etc.

Methods

◈ Microbeam Cell irradiator
• CNTs were grown by CVD method. Eur Biophys J (2009) 38:721–728 Eur Biophys J (2009) 38:721–728
• Composition; By irradiating the cells with the developed microbeam cell irradiator
- Electron-gun in the future, it will be possible to understand the microscopic
phenomena that low-dose radiation has on the cells. If the precision
- Electron transport vacuum chamber
and completeness of the irradiator are subsequently improved, it is
- Cell irradiation and control stage expected that the scope of application of low-dose irradiation to lesion
- Image acquisition cells will be expanded.