儿童胸部CT辐射剂量指标比较及扫描前剂量预算回归模型的建立  

Comparisons of chest CT radiation dose indexes in children and establishment of the regression models for prescaned radiation dose calculation

作　　者：张见 刘杰[1] 张朋[1] 张晓军 ZHANG Jian;LIU Jie;ZHANG Peng;ZHANG Xiaojun(Department of Radiology,Children′s Hospital of Nanjing Medical University,Nanjing 210000,China)

机构地区：[1]南京医科大学附属儿童医院放射科,江苏南京210000

出　　处：《西部医学》2024年第4期565-569,共5页Medical Journal of West China

基　　金：江苏省政府留学基金项目(JS-2018-137);江苏省妇幼保健课题(FYX201816);南京市医学科技发展基金项目(QRX17169)。

摘　　要：目的比较容积CT剂量指数(CTDI_(VOL))与基于水当量直径(DW)的体型特异性剂量估算值(SSDE_(DW))在辐射剂量衡量上的差异,分析CTDI_(VOL)、SSDE_(DW)、剂量长度乘积(DLP)与儿童年龄(Age)、胸围(CC)的相关性,建立快速计算CTDI_(VOL)、SSDE_(DW)、DLP的回归模型。方法回顾性分析2021年1月—12月我院748例儿童胸部影像学资料,根据年龄分为<5岁、5~≤10岁及10~≤15岁3个年龄组。手动测量最中间横断面图像的兴趣区面积(A_(ROI))及CT值(CT_(ROI)),计算基于DW的SSDE_(DW),使用t检验比较不同年龄段CTDI_(VOL)与SSDE_(DW)间差异。Pearson分析CTDI_(VOL)、SSDE_(DW)、DLP与Age、CC间相关性,建立基于Age、CC计算CTDI_(VOL)、SSDE_(DW)、DLP的回归模型并对其准确性进行分析。结果所有患儿CTDI_(VOL)为(3.05±0.72)mGy;SSDE_(DW)为(5.69±0.87)mGy;CTDI_(VOL)较SSDE_(DW)低46.40%,二者间比较差异有统计学意义(t=-241.95,P<0.001)。基于Age的回归模型:CTDI_(VOL):y=1.78exp(0.06 x)(x=Age,R^(2)=0.64);SSDE_(DW):y=4.16exp(0.03 x)(x=Age,R^(2)=0.51);DLP:y=40.10exp(0.09 x)(x=Age,R^(2)=0.81);基于CC的回归模型:CTDI_(VOL):y=-0.76+0.06x(x=CC,R^(2)=0.84);SSDE_(DW):y=0.06x+1.99(x=CC,R^(2)=0.55);DLP:y=-84.26+2.96x(x=CC,R^(2)=0.81)。基于变量Age、CC计算CTDI_(VOL)其误差分别为(0.13±0.10)、(0.09±0.06);基于变量Age、CC计算SSDE_(DW)其误差分别为(0.10±0.06)、(0.09±0.07);基于变量Age、CC计算DLP其误差分别为(0.13±0.09)、(0.13±0.10);基于CC计算的辐射剂量指标其误差值较Age小。结论在儿童胸部CT辐射剂量衡量上,CTDI_(VOL)较SSDE_(DW)低估其辐射剂量,使用SSDE_(DW)更为精确;使用年龄、胸围作为水当量直径的替代指征来预计算患儿的辐射剂量指标,可以在检查前快速预算其辐射,对于辐射剂量更好的控制具有重要作用。Objective To compare the difference between the volume CT dose index(CTDI_(VOL))and the size-specific dose estimate(SSDE_(DW))based on the water equivalent diameter(DW)in the measurement of radiation dose,and analyze the correlations of CTDI_(VOL),SSDE_(DW) and dose length production(DLP)with age and,chest circumference(CC)and establish a regression model for rapid calculation of CTDI_(VOL),SSDE_(DW) and DLP.Methods The imaging data of 748 children of chest were retrospectively analyzed.According to age,they were divided into three groups:<5 years old,5~≤10 years old and 10~≤15 years old.We manually measured the area of interest(A_(ROI))and CT value(CT_(ROI))on the representative central cross-sectional image,calculated the SSDE_(DW) based on DW,and compared the differences between CTDI_(VOL) and SSDE_(DW) at different age groups using t-test.Pearson analysis was performed to test the correlations of CTDI_(VOL),SSDE_(DW) and DLP with age and CC.Consequently,we established regression models based on age and CC to calculate CTDI_(VOL),SSDE_(DW) and DLP,and analyzed the accuracy of the models.Results CTDI_(VOL) of all children was(3.05±0.72)mGy,SSDE_(DW) was(5.69±0.87)mGy,CTDI_(VOL) was 46.40%lower than SSDE_(DW),and the difference was statistically significant(t=-241.95,P<0.001).Age-based regression models were developed as follows:CTDI_(VOL):y=1.78exp(0.06 x)(x=Age,R^(2)=0.64);SSDE_(DW):y=4.16exp(0.03 x)(x=Age,R^(2)=0.51);DLP:y=40.10exp(0.09 x)(x=Age,R^(2)=0.81).Regression models based on CC were also established:CTDI_(VOL):y=-0.76+0.06x(x=CC,R^(2)=0.84);SSDE_(DW):y=0.06x+1.99(x=CC,R^(2)=0.55);DLP:y=-84.26+2.96x(x=CC,R^(2)=0.81).The errors of CTDI_(VOL) calculated based on the variables including age and CC were(0.13±0.10)and(0.09±0.06),respectively,and there was no statistically significant difference between them(t=11.92,P<0.001);the errors of SSDE_(DW) calculated based on age and CC were(0.10±0.06)and(0.09±0.07),respectively,and there was no significant difference between them(t=-17.41,P<0.001);the er

关 键 词：儿童 胸部 体层摄影术 X射线计算机 辐射剂量 回归模型 

分 类 号：R814.2[医药卫生—影像医学与核医学]