量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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When cells were irradiated with ionizing radiation, non-irradiated cells around irradiated cells showed same biological effect, for example apoptosis, DNA damage, chromosomal aberration, and this phenomenon is called bystander effect. Bystander effect is caused by two major pathways. One is a gap junction signalling and the other is a medium-mediated signalling. The correlation of these pathways with bystander effect, and some transmission agents of this effect were reported in many papers. But the existence of the particle number-, dose or LET-dependency of this effect is still a matter of debate. In this experiment, we demonstrated that the dependency of bystander effect was observed in AG01522 cells exposed to photon or heavy-ion (carbon (120 keV/µm), neon (430 keV/µm) or argon (1260 keV/µm)) micro-beam, respectively. The bystander effect was estimated by the micronucleus (MN) formation which is a kind of a chromosome aberration. As the results, Ne- and Ar-ion beam with high-LET beams showed the bystander effects by only one particle irradiation, however the dose-dependency was not observed. C-ion beam with middle-LET showed the significant dose-dependency of bystander effect. On the other hand, X-ray micro-beam did not show the bystander effect as well as the dose-dependency. In summary, the bystander effect must have dose and LET dependency, however it is considered to be greatly dependent on some conditions, such as dose range, biological end point, radiation quality, and a kind of cells.
会議概要（会議名, 開催地, 会期, 主催者等）
Micros 2013 16th International Symposium of Microdosimetry
Dose and LET Dependency of Bystander-Induced Micronucleation in Normal Human Fibroblasts
