| Project/Area Number |
14208069
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
環境影響評価(含放射線生物学)
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| Research Institution | High Energy Accelerator Research Organization (2004)
The High Energy Accelerator Research Organization (2002-2003) |
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Principal Investigator |
KOBAYASHI Katsumi High Energy Accelerator Research Organization, Institute of Materials Structure Science, Associate Professor, 物質構造科学研究所, 助教授 (20114077)
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| Co-Investigator(Kenkyū-buntansha) |
USAMI Noriko High Energy Accelerator Research Organization, Institute of Materials Structure Science, Research Associate, 物質構造科学研究所, 助手 (60232807)
MAEZAWA Hiroshi Tokushima Univ., Medical School, Professor, 医学部, 教授 (00138653)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥52,780,000 (Direct Cost: ¥40,600,000、Indirect Cost: ¥12,180,000)
Fiscal Year 2004: ¥7,280,000 (Direct Cost: ¥5,600,000、Indirect Cost: ¥1,680,000)
Fiscal Year 2003: ¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000)
Fiscal Year 2002: ¥39,260,000 (Direct Cost: ¥30,200,000、Indirect Cost: ¥9,060,000)
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| Keywords | biological responses to low dose radiation / synchrotron monochromatic x-ray / microbeam / bystander effects / irradiation system for individual cell / adaptive response |
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| Research Abstract |
Risk evaluation of low dose or low dose rate irradiation has been great concern for human societies utilizing modern technologies. In order to study biological effect of low level of radiation such as bystander effects, we have developed a new irradiation system with which radiation can be delivered to each cell individually using monochromatic synchrotron X-rays.
Developed system is composed of three parts. The first part is to produce X-ray microbeam, either by a Kirkpatrick Baez (K-B) mirror system to focus the X-ray beam or a high-precision slit system to cut out the beam. The second is an epi-fluorescent microscope equipped with a precise motorized stage, on which the sample dish is fixed and irradiated with X-ray microbeam. The third is a fluorescence image analyzer (computer) with a sensitive CCD camera, which recognizes the target cells and their positions. It also controls irradiation of X-ray beam to the target cells, one by one, automatically. The system has been installed at BL-27B in the Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan. Minimum beam size of 5 μm square is now routinely exploited. Intensity of diffracted X-ray beam at the sample position is about 40 R/sec (ca. 10^4 photons/s in 10 μm square). Positioning accuracy of the targets, coordinates of which are automatically analyzed, are about 1 μm. Preliminary results of biological experiments are summarized as below.
1. Corresponding to the size of the microbeam used, localization of γ-H2AX and other response proteins was observed in the nuclei of irradiated mammalian cells.
2. Survival fractions of the microbeam-irradiated cells could successfully be obtained. By using the nucleus-averaged dose, the dose survival curve appears to be comparable with the case of wide beam experiments.
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