基于管电流自动调制模式的儿童头颅CT体型特异性剂量的快速估算  

Rapid Estimation of Size-Specific Dose of Head CT in Children Based on Automatic Tube Current Modulation Mode

作　　者：张见 刘鹏[1] 张晓军 ZHANG Jian;LIU Peng;ZHANG Xiaojun(Department of Radiology,Children’s Hospital of Nanjing Medical University,Nanjing Jiangsu 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：《中国医疗设备》2023年第10期73-78,共6页China Medical Devices

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

摘　　要：目的比较容积CT剂量指数(Volume CT Dose Index,CTDIvol)与基于水当量直径(Water Equivalent Diameter,WED)的体型特异性剂量估算值(Size-SpecificDoseEstimate,SSDE),即SSDE_(WED),在衡量儿童头颅CT辐射剂量方面的差异,探讨快速计算SSDE_(WED)的方法。方法回顾性分析2021年1-12月1136例儿童的CT影像学资料,依据年龄依次分为A、B、C、D共4组,比较4组患儿CTDIvol与SSDEWED的差异;分析SSDE_(WED)与管电流、WED,WED、转换因子(Conversion Factor,f)与年龄间的相关性。结果1136例患儿头颅平均CTDIvol为(9.52±1.32)mGy,SSDE_(WED)为(8.30±0.67)mGy,二者间差异有统计学意义(P<0.001)。A组CTDI_(vol)<SSDE_(WED),其余分组均CTDI_(vol)>SSDE_(WED),各分组内CTDIvol的变异系数、全范围及四分位间距均大于SSDE_(WED)。SSDE_(WED)与管电流有较强的正相关性(100 kVp:r=0.95,P<0.001;120 kVp:r=0.91,P<0.001);SSDE_(WED)与WED在100 kVp管电压条件下具有较强的正相关性(r=0.82,P<0.001),在120 kVp管电压条件下具有中等强度的相关性(r=0.61,P<0.001);f随着年龄的增加而减小。结论SSDE_(WED)可以更准确地衡量儿童头颅CT检查辐射剂量,通过建立f与年龄间的回归模型,可以更快速地计算SSDEWED。Objective To compare the difference between volume CT dose index(CTDIvol)and size-specific dose estimate(SSDE)based on water equivalent diameter(WED)(that is SSDE_(WED))in measuring radiation dose on head CT in children and to explore a fast method for calculating SSDE_(WED).Methods The CT imaging data of 1136 children from January to December 2021 were analyzed retrospectively,they were divided into 4 groups including A,B,C,D group according to their ages.The differences between CTDIvol and SSDE_(WED) in 4 groups were compared.The correlation between SSDE_(WED) and tube current,WED,and also the correlation between WED,conversion factor(f)and age were analyzed.Results The mean CTDIvol was(9.52±1.32)mGy and the mean SSDEWED was(8.30±0.67)mGy in 1136 cases,and the difference was statistically significant(P<0.001).The CTDIvol was smaller than SSDE_(WED) in group A,the CTDIvol was larger than SSDE_(WED) in the other groups,and the coefficient of variation,full range,and inter quartile range of CTDIvol were larger than those of SSDE_(WED) in all groups.There was a strong positive correlation between SSDE_(WED) and tube current(100 kVp:r=0.95,P<0.001;120 kVp:r=0.91,P<0.001).There was a strong positive correlation between SSDE_(WED) and WED at 100 kVp(r=0.82,P<0.001),the correlation was moderate at 120 kVp(r=0.61,P<0.001),and f decreased with age.Conclusion SSDE_(WED) allows a more accurate and reliable measurement of radiation dose on head CT examination in children,allows a more rapid calculation of SSDEWED by establishing a regression model between f and age.

关 键 词：儿童 头颅CT 容积CT剂量指数 水当量直径 体型特异性剂量估算值 

分 类 号：R816.1[医药卫生—放射医学]