体型特异性剂量估算值在儿童胸部CT诊断参考水平中的应用  

Application of size-specific dose estimate in diagnostic reference levels of pediatrics chest CT examination

作　　者：张见 杨凤 张晓军 ZHANG Jian;YANG Feng;ZHANG Xiaojun(Department of Radiology,the Children’s Hospital of Nanjing Medical University,Nanjing 210008,China)

机构地区：[1]南京医科大学附属儿童医院放射科,江苏南京210008

出　　处：《实用放射学杂志》2024年第6期986-989,1036,共5页Journal of Practical Radiology

摘　　要：目的统计由容积CT剂量指数(CTDI_(vol))、基于水当量直径的体型特异性剂量估算值(SSDE_(DW))及剂量长度乘积(DLP)衡量的本医疗机构诊断参考水平(DRLs),探讨SSDE_(DW)在DRLs中的应用价值。方法回顾性选取行胸部检查患儿1386例,记录其年龄、CTDI_(vol)、DLP,测量最中间图像前后径(AP)、左右径(LAT)、感兴趣区面积(A_(ROI))及感兴趣区平均CT值(CT_(ROI)),按照美国医学物理学家协会(AAPM)方法计算有效直径(ED)及DW,并计算SSDE_(DW);将患儿按照年龄及ED进行分组,统计各组患儿的CTDI_(vol)、DLP和SSDE_(DW)50%位数及75%位数,并将75%位数作为DRLs;比较CTDI_(vol)、SSDE_(DW)在衡量辐射剂量上的差异及回归分析CTDI_(vol)、SSDE_(DW)与年龄、ED之间的相关性。结果按年龄分为<1岁组、1~<5岁组、5~<10岁组、10~<15岁组、≥15岁组,以CTDI_(vol)为衡量指标的DRLs分别为1.80 mGy、2.10 mGy、3.10 mGy、4.20 mGy、4.45 mGy;以SSDE_(DW)为衡量指标的DRLs分别为4.23 mGy、4.55 mGy、6.00 mGy、6.75 mGy、6.86 mGy;以DLP为衡量指标的DRLs分别为40.80 mGy·cm、55.80 mGy·cm、95.60 mGy·cm、154.90 mGy·cm、185.60 mGy·cm。按ED分为<15 cm组、15~<20 cm组、20~<25 cm组、25~<30 cm组,以CTDI_(vol)为衡量指标的DRLs分别为1.80 mGy、2.70 mGy、3.70 mGy、4.60 mGy;以SSDE_(DW)为衡量指标的DRLs分别为4.22 mGy、5.49 mGy、6.50 mGy、6.95 mGy;以DLP为衡量指标的DRLs分别为42.20 mGy·cm、76.90 mGy·cm、134.53 mGy·cm、179.93 mGy·cm。各组内CTDI_(vol)与SSDE_(DW)间差异均有统计学意义(P<0.01),各组内CTDI_(vol)均小于SSDE_(DW);CTDI_(vol)、SSDE_(DW)和DLP均随着年龄及ED的增加而增加。结论本医疗机构DRLs与其他国家或地区的辐射剂量值相比,DRLs处于合理水平;SSDE_(DW)较CTDI_(vol)更能准确反映辐射剂量。Objective To calculate the diagnostic reference levels(DRLs)based on volume CT dose index(CTDI_(vol)),size-specific dose estimate based on water equivalent diameter(SSDE_(DW))and dose length product(DLP),and to discuss the application value of SSDE_(DW)in DRLs.Methods A total of 1386 children who underwent chest examinations were retrospectively selected,the age,CTDI_(vol),and DLP were recorded,while anteroposterior(AP),lateral(LAT),area of region of interest(A_(ROI))and CT_(ROI)of the middle image were measured.The effective diameter(ED),DW and SSDE_(DW)were calculated according to the American Association of Physicists in Medicine(AAPM)method.The cases were grouped according to age and ED,the 50%and 75%percentile of CTDI_(vol),DLP and SSDE_(DW)in each group were counted,and the 75%percentile was taken as DRLs.The differences between CTDI_(vol)and SSDE_(DW)in measured radiation dose were compared,and regression analysis of the relationships between CTDI_(vol),SSDE_(DW)and age,ED were applied.Results According to age,the DRLs of<1 year group,1-<5 years group,5-<10 years group,10-<15 years group and≥15 years group with CTDI_(vol)as the measurement index were 1.80 mGy,2.10 mGy,3.10 mGy,4.20 mGy and 4.45 mGy respectively;the DRLs measured by SSDE_(DW)were 4.23 mGy,4.55 mGy,6.00 mGy,6.75 mGy and 6.86 mGy respectively;the DRLs measured by DLP were 40.80 mGy·cm,55.80 mGy·cm,95.60 mGy·cm,154.90 mGy·cm and 185.60 mGy·cm respectively.According to ED,the DRLs of<15 cm group,15-<20 cm group,20-<25 cm group,25-<30 cm group with CTDI_(vol)as the measurement index were 1.80 mGy,2.70 mGy,3.70 mGy and 4.60 mGy respectively;the DRLs measured by SSDE_(DW)were 4.22 mGy,5.49 mGy,6.50 mGy and 6.95 mGy respectively;the DRLs measured by DLP were 42.20 mGy·cm,76.90 mGy·cm,134.53 mGy·cm and 179.93 mGy·cm respectively.There were statistically significant differences between CTDI_(vol)and SSDE_(DW)within the group(P<0.01),and CTDI_(vol)within the group was less than SSDE_(DW).CTDI_(vol),SSDE_(DW)and DLP increased with the increa

关 键 词：儿童 胸部 计算机体层成像 体型特异性剂量估算值 诊断参考水平 

分 类 号：R339.31[医药卫生—人体生理学] R826.63[医药卫生—基础医学] R814.42