口腔医学影像检查中甲状腺和晶状体的辐射防护研究

Study on the radiation protection of thyroid and lens in the examination of oral medical imaging

目的:探究口腔医学影像检查中口腔牙片摄影(DP)、口腔颌面计算机曲面断层扫描(COPT)和口腔锥形束立体断层扫描(CBCT)3种口腔影像技术对甲状腺和晶状体的辐射防护价值,指导临床口腔检查时的合理辐射防护。方法:采用仿真成年人头颈体模(简称头颈体模),分别依次在口腔DP、COPT和CBCT检查中对甲状腺和晶状体测试点进行无辐射防护和有辐射防护测试,将无辐射防护测试纳入对照组,有辐射防护测试纳入观察组,采用热释光剂量计(TLD)72支放置于头颈体模的体表的24个测试点(每个点位3支)对两组进行辐射剂量测试,并读出相应测试点入射体表剂量,每个点位3支TLD测试取平均值转换为有效剂量,比较头颈体模的相应测试点的辐射剂量。结果:两组口腔DP、COPT和CBCT检查头颈体模左侧、右侧甲状腺体表各测试点比较,差异有统计学意义(t_(口腔DP)=86.646,t=135.345;t_(口腔COPT)=1164.732,t=1109.619;t_(口腔CBCT)=74.083,t=28.416,P<0.001)。对照组口腔DP、COPT和CBCT检查左侧、右侧眼部体表测试点辐射剂量高于观察组,其差异有统计学意义(t_(口腔DP)=58.788,t=58.788;t_(口腔COPT)=662.587,t=789.500;t_(口腔CBCT)=135.001,t=147.309;P<0.05)。结论:临床中进行口腔DP、COPT和CBCT影像检查时,应对受检者口腔邻近的敏感腺体眼晶状体和甲状腺进行专业性辐射防护。

Objective:To explore the value of radiation protection for thyroid and lens in the examination of oral medical imaging of three kinds of oral imaging techniques included oral dental photography(DP),computed orthopantomography(COPT)and cone beam computed tomography(CBCT),and to guide the rational radiation protection in clinically oral examination.Methods:The simulated head and neck phantom of human(Abbreviation:head and neck phantom)was adopted in this research.The tests with and without radiation protection were respectively conducted on the thyroid and lens in the oral DP,COPT and CBCT examinations.The test without radiation protection was included in the control group,and the test with radiation protection was included in the observation group.A total of 72 thermoluminescent dosimeters(TLDs)were placed at 24 test sites(3 TLDs per site)on the body surface of head and neck phantom to test the radiation dose of two groups.And then,the incident dose of body surface of corresponding test site was respectively read,and the tested mean value of 3 TLDs of each site was converted to effective dose.At last,the radiation doses of corresponding test sites of head and neck phantom were compared between two groups.Results:There were significant differences in the radiation doses of each test site of the surfaces of the thyroids of the left and right sides of head and neck phantom of oral DP,COPT and CBCT examinations between two groups(t_(oral DP)=86.646,t=135.345,t_(oral COPT)=1164.732,t=1109.619,t_(oral CBCT)=74.083,t=28.416,P<0.05).The radiation doses of test sites of the surfaces of the left and right sides of the eyes of oral DP,COPT and CBCT examinations of control group were significantly higher than those of observation group(t_(oral DP)=58.788,t=58.788,t_(oral COPT)=662.587,t=789.500,t_(oral CBCT)=135.001,t=147.309,P<0.05).Conclusion:The lens and thyroid of sensitive glands adjacent to the subject’s oral cavity should be professionally protected from radiation when the oral DP,COPT and CBCT imaging examination are conducted in clinical application.