アブストラクト（15巻2号：神奈川歯学）

神奈川歯学

Japanese

Title　： 歯科X線撮影における被曝線量の評価に関する研究 - 口内撮影法について -
Subtitle　： 原著
Authors　： 杉本康樹
Authors（kana）　：
Organization　： 神奈川歯科大学放射線学教室
Journal　： 神奈川歯学
Volume　： 15
Number　： 2
Page　： 230-249
Year/Month　： 1980 / 9
Article　： 原著
Publisher　： 神奈川歯科大学学会
Abstract　： 「抄録」 最近, 医療被曝は, 撮影フィルム枚数の激増に伴って社会問題として大きい関心がもたれている. そこで今回, 歯科の口内撮影法(成人では全顎10枚法, 小児では全顎6枚法)に伴う放射線の被曝線量を, 頭頸部ファントームを用いてTLD素子およびフィルム法で測定した. そして, 皮膚, 眼(水晶体), 甲状腺, 骨髄の線量を測定し, 白血病および甲状腺がん発生のリスクについて考察を加え, つぎのようにまとめることができた. (1)神奈川歯科大学附属病院(1978年)における全顎X線撮影をした患者数は総計1,099人であった. この内, 男子は382人(フィルム枚数3,804枚), 女子は717人(フィルム枚数7,138枚)であった. また, X線撮影したものは男女とも8～14才の年齢層のものが最も多かった. (2)神奈川歯科大学附属病院(1978年)における, 口内撮影法(全顎10枚法)に伴う白血病誘発にかかわる集合線量は, 約6.0radであった. これは, 年間およそ8, 000分の1の白血病発生のリスクに相当するということになる. (3)同様に, 甲状腺の集合線量は, 約13radであり, これは, 年間およそ15,000分の1の致死的甲状腺がん発生のリスクに相当するということになる. 以上, 神奈川歯科大学附属病院における歯科診療上の放射線被曝は, 全体として, 放射線障害の発生が懸念されるような水準を十分に下まわっている. しかし, この線量の評価値を全国レベルで考えるとき, 歯科診療に伴う放射線被曝のリスクをひきつづき低減する努力が必要であることを示唆した.
Practice　： 歯科学
Keywords　：

English

Title　： A Study on the Evaluation of Radiation Doses in Dental Radiography - Doses and Risks due to Dental Full Mouth Examination
Subtitle　：
Authors　： Koju Sugimoto
Authors（kana）　：
Organization　： Department of Radiology, Kanagawa Dental College
Journal　： Kanagawa Shigaku
Volume　： 15
Number　： 2
Page　： 230-249
Year/Month　： 1980 / 9
Article　： Original article
Publisher　： Kanagawa Odontological Society
Abstract　： Radiation doses and possible biological risks due to dental full mouth examination (adult : 10-film technique, child : 6-film technique) were evaluated based on preliminary experiments and statistical surveillance of patients' records. Dosimetrical studies were performed by using head and neck phantoms and a dental X-ray tube. Radiation doses were measured by X-ray films and thermoluminescence dosimeters. For the obtained doses of skin, eyes, thyroid gland and bone marrow, the biological risk of leukemia and thyroid cancer was discussed on the statistical basis of patients at Kanagawa Dental College Hospital. The major findings were as follows : (1) Absorbed doses (DA) measured by thermoluminescence dosimeters at various positions in the head and neck phantom were able to be estimated from the film densities (d) measured at the corresponding positions by the equation : log DA=0.0244d3-0.2123d-1-0.0038d-3+2.5401 (2) The skin doses due to full mouth 10-film examination ranged from 300 to 600 mrad. (3) Absorbed dose of the eyes due to full mouth 10-film examination was approximately 15.2 mrad. (4) Absorbed dose of the thyroid gland due to full mouth 10-film examination was approximately 11.6 mrad. (5) The dose of the bone marrow due to full mouth 10-film examination of adult was 5.8 mrad and that due to full mouth 6-film examination of child was 3.0 mrad. (6) The total number of patients who recieved full mouth X-ray examination at Kanagawa Dental College Hospital in 1978 was 1,099. The number of mate patients was 382 (3,804 films) and that of female patients was 717 (7,138 films). In both sexes, the number of patients was the greatest in the group of 8-14 years of age. (7) The collective doses of bone marrow due to full mouth 10-film examination performed at Kanagawa Dental College Hospital in 1978 were approximately 6.0 rad, which could induce leukemia with a probability of 1/8,000. (8) The collective doses of thyroid gland were approximately 13 rad, which could induce lethal thyroid cancer with a probability of 1/15,000. The radiation dose due to the dental radiography for examination at Kanagawa Dental College Hospital was proved to be apparently below the level that could actually induce radiation injuries. But the collective radiation doses due to dental examination in Japan as a whole were approximately 8,000 times greater than that in Kanagawa Dental College Hospital. For this reason author would recommend that further efforts should be made to minimize the radiation exposure in dental examination.
Practice　： Dentistry
Keywords　：