Browsing by Author "Cho, I. C."

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A compact biological cell irradiation system with a Van de Graaff accelerator
(2013-11-15)
Cho, I. C.
;
Niu, H.
;
Chen, C. H.
;
Chou, W. T.
;
Yu, Y. C.
This report describes the development of a compact microcell irradiation system in the 3 MV MN Van de Graaff accelerator in the Accelerator Laboratory of National Tsing Hua University (NTHU). The main feature of this system is backscattering, a technique whereby a 100 nm gold scattering foil is placed in the center of a scattering chamber, instead of a 90 bending magnet. The incident particles produced by the accelerator bombard the scattering foil and scatter isotropically. A set of micro pinholes was installed above the scattering foil and directed the 90 scattering particles to irradiate the cell target. This innovation simplifies the system design and massively reduces the cost and space requirements for system construction. (C) 2013 Elsevier B.V. All rights reserved.
A Novel Cell Irradiation System Using 90 degrees-Scattering Technique
(2011-02-01)
Cho, I. C.
;
Weng, M. F.
;
Wu, J. M.
;
Chiang, S. Y.
;
Chou, W. T.
A novel cell irradiation system was developed for use with the HVEE Van de Graaff accelerator at the National Tsing Hua University. A 90 degrees-scattering technique using an Au foil was designed, in which charged particles were directed from horizontal to vertical irradiation. Beam performance was tested with a silicon detector and a CR-39 nuclear track detector. The HeLa cells were irradiated with 2-MeV alpha particles and the formation of giant cells was observed. The result showed that this system provides a convenient way of generating a vertical particle beam and a cell-supporting chamber, thereby allowing a suitable cell growth condition during irradiation. Furthermore, establishment of such a system is more convenient and economical than the alternatives.
A Novel Cell Irradiation System Using Backscattering Technique
(2009-01-01)
Cho, I. C.
;
Chen, C. H.
;
Weng, M. F.
;
Chiang, S. Y.
;
Chou, W. T.
In this paper, we report a novel cell irradiation system at the HVEE Van de Graaff accelerator at National Tsing Hua University. The significant change of system design is use the backscattering technique to replace the 900 magnet which was widely used to derive beam direction from horizontal to vertical. A silicon barrier detector was used to measure the scattered particle energy. Meanwhile, nuclear track detector CR-39 was also applying in this study to assess the particle distribution at beam nozzle. The preliminary experiment performed by using 2 MeV alpha particle to irradiate the HeLa cell. The result showed, this system can provide an efficiently vertical particle beam irradiation and a standard growth condition during the period of irradiation. Furthermore, it's more economical and easier to set up than others.
DNA double-strand breaks induced along the trajectory of particles
(2011-12-15)
Cho, I. C.
;
Niu, H.
;
Chen, C. H.
;
Yu, Y. C.
;
Hsu, C. H.
It is well-known that the DNA damage caused by charged particles considerably differs from damage due to electromagnetic radiation. In the case of irradiation by charged particles the DNA lesions are more complex and clustered. Such clustered damage is presumed difficult to be repaired, and is potentially lethal. In this study, we utilize a 90 degrees-scattering system and related imaging techniques to investigate the accumulation of gamma-H2AX along the trajectory of charged particles. By immunostaining the gamma-H2AX protein, optical images of corresponding double strand breaks were observed using a high resolution confocal microscope. We demonstrate the difference in the accumulation of gamma-H2AX from irradiation by 1 MeV protons and that of 150 key X-rays. The acquired images were arranged and reconstructed into a 3D image using ImageJ software. We discovered that the gamma-H2AX foci, following irradiation by protons, have a tendency to extend in the beam direction, while those from X-ray irradiation tend to be smaller and more randomly distributed. These results can be explained by the physical model of energy deposition. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.