| Project/Area Number |
15K12204
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Risk sciences of radiation and chemicals
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| Research Institution | Osaka University |
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Principal Investigator |
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| Research Collaborator |
BANDO Masako
WADA Takahiro
TOKI Hiroshi
NAKAJIMA Hiroo
TSUNOYAMA Yuichi
KUNUGAWA Tetsuhiro
TOKITA Miwako
SUZUKI Kazuyo
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| Project Period (FY) |
2015-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2017: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2016: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2015: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
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| Keywords | 放射線 / 線量率 / 定量評価 / 低線量・低線量率放射線 / 突然変異 / 数理モデル / 低線量放射線 / 放射線防護 / 生物影響 / 線量・線量率 / 生体影響 |
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| Outline of Final Research Achievements |
Since we considered exposure time as an important variable to construct a mathematical model to counter LNT hypothesis using the total dose as a parameter, we built a time-dependent differential equation. Currently, people are most interested in cancer risk, so we have tried to build mathematical models from the occurrence of mutations, to the occurrence of cancer through multiple mutation stages, and to the stage of cancer growth and death. As a result, we reconfirmed the validity of our model for mutations. With respect to the hypothesis that cancer occurs due to the occurrence of multistep mutations, differential equations in which mutations occur in multiple steps were constructed. As a result, we confirmed that the data of retinoblastoma can be almost reproduced by our mathematical model. We also created a mathematical model of shortening the life span by radiation-induced cancer. As a result, it was confirmed that the data was almost reproducible.
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| Academic Significance and Societal Importance of the Research Achievements |
時間依存性を考慮した数理モデルを作成することで、物理過程としての生体の構成要素の破壊だけではなく、生物過程としての回復を自然に考慮することが可能となる。今回、突然変異の発生から、多段階突然変異によってがんが発生し、がんによって個体が死ぬまでの過程の数理モデルを構築できる見込みが立ったことにより、現状のLNT仮説に替わる、放射線のリスクの定量評価の可能性を示せた。今後、生物種の違いを反映させることが可能になれば、放射線の正確なリスク評価が可能となり、放射線、原子力の利用がより適切に行われるようになり医療が変革される。更に、原子力従事者の作業指針、大規模原子力災害の帰還指針が変わる可能性を示した。
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