摘要
目的测定拍摄全口牙片时人体不同器官吸收的辐射剂量，为相应的防护措施提供客观依据。方法应用具有完整骨骼的仿真体模详细测定了拍摄全口１４张牙片时脑垂体、眼晶体、腮腺、颌下腺、舌下腺、甲状腺、乳腺、卵巢及睾丸等器官和各牙位照射野中心的皮肤辐射剂量。结果吸收的辐射剂量：眼晶体为２４９μＧｙ，甲状腺为１２５μＧｙ，垂体为１１２μＧｙ，腮腺为１５３μＧｙ，颌下腺为６２９μＧｙ，舌下腺为１９００μＧｙ，乳腺为１２μＧｙ，性腺吸收剂量极低。结论目前拍摄根尖片时患者吸收辐射剂量较少，全口牙片检查较安全。垂体的吸收剂量中两侧上颌磨牙片约占一半。眼睛吸收剂量的６０％来自于同侧磨牙和前磨牙牙片。腮腺吸收剂量的５７％来源于对侧磨牙、前磨牙牙片。若将遮线筒长度加至２０ｃｍ，Ｘ线机总滤过加至２ｍｍ，则患者的辐射剂量可以减少９０％。如果将目前的１４片法改为１０片法，则辐射剂量还可能再减少２０％。
Objective A few studies were reported in China on radiological risk of dental radiography. The aim of this study is to evaluate the absorbed doses of patients from the full mouth radiographs, and to find out the contribution from each projection to the total absorbed dose of the organs.Methods Absorbed doses to critical organs were measured from 14 film complete dental radiography. The organs included pituitary, optical lens, parotid glands, submandibular glands, sublingual glands, thyroid, breasts, ovary, testes and the skin in center field of each projection were studied. A radiation analog dosimetry system (RANDO) phantom with thermoluminescent dosimeters (ILD200) was used for the study. All of the exposure parameters were fixed. The total filtration was 2 mm Al equivalent. The column collaboration was 6 cm in diameter and 20 cm in length. The absorbed doses of organs were measured three times in each projection of the full mouth series (FMS) exposures.Results The absorbed dose of lenses in FMS (249 μGy) in present study was much less (10%) than the doses (2 630 μGy) reported in 1976. The doses absorbed of other organs in the present study were thyroid gland (125 μGy), pituitary gland (112 μGy), parotid gland (153 μGy), submandibular gland (629 μGy), sublingual gland (1 900 μGy),and breast gland (12 μGy).The doses of the ovary and testis were too small to further analysis. Conclusion All of the results show that the radiation risk to patients in intraoral radiograph has been reduced significantly. In the pituitary, half of the dose is from both sides of the maxillary molar projection. For the lenses, the largest contribultions of radiation (60%) come from the ipsilateral molar and premolar projection of maxilla. In parotid gland, up to 57% of the dose is from the contralateral molar, pre molar and canine of maxilla. It could be derived that about 90% of the absorbed doses could be avoided in FMS if the column collimator is 20 cm long and the filter is 2.0 mm thick. If we use the 10 film complete mouth radiograph instead of the 14 film series, more 20% of the doses would be reduced.
出处
《中华口腔医学杂志》
CAS
CSCD
北大核心
1999年第1期5-8,共4页
Chinese Journal of Stomatology
