江苏省CT扫描检查中受检者剂量调查与分析

Investigation and analysis of radiation dose levels of patients in CT scanning in Jiangsu province

目的了解江苏省CT诊断放射剂量现状,探讨CT扫描的诊断参考水平(diagnostic reference level,DRL)。方法在江苏省7个设区市抽取13家医疗机构的13台CT扫描设备,调查设备扫描病例时剂量水平。每台CT收集头部、胸部、腹部和腰椎4个检查部位,将CT受检者分为<1、1~<5、5~<10、10~≤15、>15岁5个年龄组,每个部位每个年龄组收集不少于10个随机病例。以容积CT剂量指数(CTDIvol)和剂量长度乘积(DLP)为研究指标,计算其P75为CT诊断参考水平推荐值。结果共收集1 460例受检者剂量数据,其中头部、胸部、腹部、腰椎CTDIvolP75分别为55、15、15、20 mGy,DLP P75分别为690、350、460、480mGy·cm。头部、胸部、腹部、腰椎CTDIvol均值分别为45、8.9、11、20mGy,DLP均值分别为565、246、372、346mGy·cm,不同部位间差异均有统计学意义(F值分别为1 341.4、182.2,P值均<0.05);Tamhane法两两比较结果显示,CTDIvol指标各组间差异均有统计学意义(P值均<0.05);DLP指标除腹部和腰椎外,其他组间差异均有统计学意义(P值均<0.05)。CTDIvol、DLP指标头颅扫描辐射剂量均高于其他部位。结论江苏省CT剂量分布有自身特点,需根据实际建立省CT扫描诊断参考水平。

Objective To study current CT dose levels in Jiangsu province;to discuss the diagnostic reference level for CT scanning.Methods A total of 13 CT scanning devices were selected from 13 hospitals in 7 cities which were subjected to investigate scanning dose levels for patients.The data of each device for 4 scanning parts such as head,chest,abdomen and lumbar spine were collected,the patients were divided into 5 groups at ages of<1,1 to 5 years,5 to 10 years,10 to 15 years and more than 15 years;at least 10 patients were enrolled in every age group.The volume CT Dose Index(CTDIvol)and Dose Length Product(DLP)were used as investigated parameters,the P75 values were calculated and set as recommendation level of DRL.Results A total of 1 460 dose values of patients were collected.The P75 values of CTDIvolfor head,chest,abdomen,lumbar spine were 55,15,15 and 20 mGy,respectively;the P75 values of DLP were 690,350,460 and 480 mGy·cm,respectively.The average CTDIvolwere 45,8.9,11 and 20 mGy for head,chest,abdomen,lumbar spine,respectively;while corresponding average DLP were 565,246,372 and 346 mGy·cm,respectively;all with statistical difference(F=1 341.4 and 182.2,all P<0.05).The results of Tamhane analysis method showed that there were significant differences in CTDIvol indexes among different groups(all P<0.05).There were significant differences in DLP indexes except for abdomen and lumbar spine(all P<0.05).Conclusion The distribution of CT doses in Jiangsu province has its own characteristics;it is necessary to establish the reference level of CT scanning diagnosis in Jiangsu province based on actual condition.