1990 Fiscal Year Final Research Report Summary
A Study of the Tooth as a Lifetime Dosimeter
| Project/Area Number |
62440078
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
外科・放射線系歯学
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| Research Institution | Ohu University |
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Principal Investigator |
SHIMANO Tatsuya Ohu University School of Dentistry, Dental Radiology, Professor, 歯学部・歯科放射線学講座, 教授 (20083462)
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| Co-Investigator(Kenkyū-buntansha) |
IWASAKI Midori Ohu University School of Dentistry, Dental Radiology, Assistant, 歯学部・歯科放射線学講座, 助手 (30168182)
MIYAZAWA Chyuzo Ohu University School of Dentistry, Preventive Dentistry, Assistant-Prof., 歯学部・口腔衛生学講座, 助教授 (70083441)
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| Project Period (FY) |
1987 – 1990
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| Keywords | E S R / Tooth enamel / Dosimetry / Signal Intensity |
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| Research Abstract |
Only tooth enamel is used for the ESR dosimetry and the enamel must be crushed for the measurement. The size of the crushed particles of enamel must be from 250 micrometers to 2 millimeters. An unexpected signal is detected on the enamel of a human tooth in the ESR measurement. After the investigation for the cause of the unexpected signal, it is clear that the unexpected signal is due to the tube that an extracted tooth is put into.
If a tooth can be used as a personal dosimeter to estimate the received exposure during a lifetime, it is necessary to separate out the contribution of dental x-ray dose from the cumulative dose. The method of dividing into two portions (the labial part and the lingual part) on the enamel of a tooth is useful, even if the dental X-ray photographs are not always taken from the same direction. We have tried to apply this method for practical cases and obtained satisfactory results. In general, the actual dose received by an individual is too low to make the co_3^<3-> signal. In addition, the ESR spectrum of enamel is an overlapping of two ESR signals (the CO_3^<3-> signal and organic signal). In case of a low dose, the apparent intensity of CO_3^<3-> signal has the effect of overestimation on the dose estimate. Hence, it is necessary to process the ESR spectrum by computer in order to make a correct estimate.
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