| Project/Area Number |
62580166
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
放射線5生物学
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| Research Institution | Hiroshima University |
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Principal Investigator |
SHIGETA Chiharu Hiroshima Univ., Res.Inst.Nuclear Med. & Biol., Research Associate, 原爆放射能医学研究所, 助手 (10034654)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Kimio Hiroshima Univ., Res.Inst.Nuclear Med. & Biol., Research Associate, 原爆放射能医学研究所, 助手 (70116622)
OGUMA Nobuo Hiroshima Univ., Res.Inst.Nuclear Med. & Biol., Associate Professor, 原爆放射能医学研究所, 助教授 (10034646)
KAMADA Nanao Hiroshima Univ., Res.Inst.Nuclear Med. & Biol., Professor, 原爆放射能医学研究所, 教授 (00034629)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1989: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1988: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1987: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Human LD50 dose / Breast cancer / Atomic bomb survivors / Chromosome abnormality / 乳癌 |
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| Research Abstract |
Many attempts have been made to estimate the dose at which 50% of the individuals cause death. We studied a group of girl students who had a history of exposure to Atomic bomb in Hiroshima and were exposed at the same place, in order to investigated the 50% lethal dose for human. Ninety girl students were 14-15 years old when they were exposed to the atomic bomb and working at the Central Telephone Office in Hiroshima located 550 meters from the hypocenter. Of 90 students, 31 died on the day explosion and another 29 within 2 months. The remaining 30 students have been alive in 1946 and been followed thereafter. Of a total 59 students, 53 were exposed on the 2nd floor and 6 on the 1st floor. Thus the mortality rate was estimate to be 50.9 % (27/53:2nd floor) and 33.7 % (2/6:1st floor), respectively. Therefore, this group have been identified to estimation of LD50 for human. Using T lymphocyte from another group of atomic bomb survivors, the relation between radiation dose and chromosome
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abnormality had been calculated, based on T65D dose estimation. Peripheral lymphocyte from 9 students, including 2 exposed on the 1st floor, were analyzed cytogenetically. Chromosome analyses showed that students exposed on the 2nd and the 1st floor seemed to have been exposed to around 6 Gy and 1.5 Gy (T65D), respectively. Six Gy of T65D dose is equivalent to about 4 Gy in the neW dosimetry system (DS86). These data indicate LD50 for human is around 4 Gy. Of the 30 surviving students, one was missing, one died colon cancer, 6 have developed breast cancer and one had masthopaty. The incidence of breast cancer was calculated for the students and compared with a non exposed persons (control group) in the fixed population established by RERF. For the control group and the present study group, the incidence per 1,000 person-years is 0.52 and 11.90, respectively. Thus the relative risk is 23.1 with 95 % confidence limits of 12.9 to 42.2. This incidence may be contributed to the age of the girls at the time of the bombing. Less
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