| Project/Area Number |
17390503
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Pathobiological dentistry/Dental radiology
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| Research Institution | Showa University |
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Principal Investigator |
OKANO Tomohiro Showa University, School of Dentistry, Professor, 歯学部, 教授 (20124688)
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| Co-Investigator(Kenkyū-buntansha) |
HARATA Yasuo Showa University, School of Dentistry, Associate Professor, 歯学部, 助教授 (30119250)
ARAKI Kazuyuki Showa University, School of Dentistry, Associate Professor, 歯学部, 助教授 (50184271)
SATO Kenji Nippon Dental University, Associate Professor, 歯学部, 助教授 (50130670)
KATO Tsuguhisa Tokyo Metropolitan University, Associate Professor, 健康福祉学部, 准教授 (70095107)
SASAKI Takehito Showa University, School of Dentistry, Visiting Professor, 歯学部, 兼任講師 (90013896)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥15,000,000 (Direct Cost: ¥15,000,000)
Fiscal Year 2006: ¥5,300,000 (Direct Cost: ¥5,300,000)
Fiscal Year 2005: ¥9,700,000 (Direct Cost: ¥9,700,000)
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| Keywords | dentistry / radiology / dental radiography / quality assurance program / diagnostic reference level / radiation protection / optimization / patient dose / 歯科X線装置 |
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| Research Abstract |
The objectives of this research were to establish diagnostic reference levels (DRLs) for dentomaxillofacial radiography in Japan in order to promote optimization of radiological protection for patients and to manage patient doses in routine X-ray examinations. For evaluation of these DRLs we studied the radiation quantities and methods of radiation measurement, and then surveyed the quantities and patient doses in university dental hospitals and in dental clinics.
Transportable dosimeters coupled with X-ray films were used for the regional area survey and ionization chambers were used for the local area survey, which were calibrated by the Japanese Quality Assurance Organization. The ionization chambers were compared with the transportable dosimeters which were composed by an optically stimulate luminescence dosimeter for intraoral radiography and a thermoluminescent dosimeter array for panoramic radiography.
From the results of the survey the DRLs were determined as a third quartile of the dose distributions for standard adults as follows : (1)intraoral radiography : patient entrance dose, PED=2.1 mGy and dose-area product, DAP=59 mGy cm^2 ; but a double of PED or DAP for D-speed films and the DAP should be calculated from the product of PED by the area of a rectangular field ; (2)panoramic radiography : dose-width product, DWP=65 mGy mm and DAP=113 mGy cm^2 ; (3)cephalometric radiography : entrance surface air kerma, ESAK=0.4 mGy, but DAP was not proposed because of the usage of wedge filters and radiation fields of wedge shapes ; (4)computed tomography (CT) for planning of dental implantation surgery of both jaws : weighted CT dose index, CTDI_w=35 mGy and dose-length product, DLP=360 mGy cm, but a half of DLP for each jaw.
These DRLs, which are almost the same as those proposed in Europe, should be achieved in Japan to maintain adequate tube potentials, beam filtrations, and high sensitivity image receptor systems in dental radiographic examinations.
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