1988 Fiscal Year Final Research Report Summary
Studies on accumulation of strontium-90 in human third molar.
| Project/Area Number |
61480425
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
小児・社会系歯学
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| Research Institution | 国立予防衛生研究所 |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
MAEKAWA Hideaki NIH, 技術部, 放射能室室長 (60100096)
IMAI Susumu NIH, 歯科衛生部, 主任研究官 (80072958)
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| Project Period (FY) |
1986 – 1988
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| Keywords | Strontium-90 / human third molar / 経年推移 / 安定Sr |
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| Research Abstract |
For the esitimation of strontium-90 in human teeth, 752 of third molars were analysed. Half of them were collected in the Kanto area and others were from all parts of Japan. Donnor's year of birth was ranged from 1900 to 1967 and ages when teeth were extracted were 20-29(684 teeth) and 40-69(68 theeth).
The collected teeth were divided into 27 experimental groups including 18 to 30 teeth based on the donnor's year of birth and the age when extracted.
Samples was heated at 500 C in the electric furnace for 8 hours and pulverized into the fine powder less than 53 m. Radiochemical analyses was performed using 10g of the ashed teeth by the method recommended by science and technology lnstitute.
The strontium -90 content of the third molar began to increase from 1940-1942 and reached maximam (3,02pCi/g Ca) in 1953 of donnor's birth year. The strontium-90 was rapidly decreased linearly after 1953 extending over 1967 to 1pCi/g Ca. Only the trace amout of strontium-90 was found before 1925.
The present study strongly suggests that the third molar could be an important indicator substance to examine the past environmental pollution by strontium -90.
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