剂量指数结合全模型迭代重建技术在降低儿童胸部CT扫描辐射剂量中的应用研究  

Application of DoseRight index combined with iterative model reconstruction in reducing radiation dose of children's chest CT scan

作　　者：王梅[1] 边传振 张见[1] 刘鹏[1] WANG Mei;BIAN Chuan-zhen;ZHANG Jian;LIU Peng(Children's Hospital Affiliated to Nanjing Medical University,Nanjing 210008,China)

机构地区：[1]南京医科大学附属儿童医院,南京210008

出　　处：《医疗卫生装备》2020年第7期59-63,共5页Chinese Medical Equipment Journal

基　　金：江苏省妇幼保健协会科研项目(FYX201918);南京医科大学科技发展基金项目(NMUB2018076)。

摘　　要：目的:探讨各年龄段儿童胸部CT扫描时剂量指数(DoseRight index,DRI)的临界值,并对比分析全模型迭代重建(iterative model reconstruction,IMR)技术和混合迭代重建(iDose4)技术在低DRI条件下对图像质量的改善能力。方法:将行胸部CT扫描的临床预实验组(341例)和临床实验组(137例)共478例6~16岁患儿均按年龄分为6~9岁组、10~13岁组和14~16岁组,采用飞利浦128排Brilliance iCT进行数据采集(管电压100 kV,自动曝光控制技术)。临床预实验组预设6组不同的DRI(分别为18、16、14、12、10、8)进行扫描,图像采用iDose4技术进行重建,然后对图像质量和辐射剂量进行对比分析,得到DRI临界值;采用DRI临界值扫描条件对临床实验组进行扫描,图像分别采用iDose4技术和IMR技术进行重建,并对比分析其图像质量。结果:临床预实验组中6~9岁患儿DRI的临界值是10,10~13岁患儿DRI的临界值是12,14~16岁患儿DRI的临界值是14;3组患儿的信噪比(signal-to-noise ratio,SNR)在胸大肌处及主动脉处均随着DRI的增加而增加(P<0.01);3组患儿的容积CT剂量指数(volume CT dose index,CTDIvol)及剂量长度乘积(dose length product,DLP)均随DRI的减小而降低(P<0.01)。临床实验组3组患儿的IMR图像均优于iDose4图像(P<0.05)。结论:合适的DRI结合IMR重建技术能够降低儿童胸部CT检查的辐射剂量并保证图像质量。Objective To explore the critical value of DoseRight index(DRI)in chest CT scan of children at different ages,and to compare the ability of iterative model reconstruction(IMR)and iDose4 in improving the image quality under the condition of low DRI.Methods Totally 478 children aged from 6 to 16 who underwent chest CT scan were divided into a clinical pre-experimental group and a clinical experimental group,and in the two groups the children were re-grouped into three subgroups respectively aging from 6 to 9,from 10 to 13 and from 14 to 16.Philips Brilliance 128iCT with 100 kV tube voltage and automatic exposure technology was used for data acquisition.Scans were executed with 6 sets of preset DRI(18,16,14,12,10 and 8)in the pre-experimental group,and image reconstruction was performed with iDose4,then the comparison analysis was carried out over image quality and radiation dose to determine DRI critical values;scans were executed in the experimental group with the acquired DRI critical values,then the images were reconstructed with iDose4 and IMR technologies,and the image quality was compared and analyzed.Results In the pre-experimental group,the critical value was 10 in the subgroup aging from 6 to 9,12 in the subgroup aging from 10 to 13 and 14 in the subgroup aging from 14 to 16;the SNR rose with the increase of DRI at pectoralis major muscle and aorta(P<0.01),while the CTDIvol and DLP lowered with the decrease of DRI(P<0.01).In the experimental group,all the IMR images of the three subgroups gained advantages over the iDose4 images(P<0.05).Conclusion Appropriate DRI combined with IMR technology can reduce the radiation dose of children's chest CT examination and ensure the image quality.

关 键 词：胸部CT 辐射剂量 剂量指数 容积CT剂量指数 剂量长度乘积 

分 类 号：R318[医药卫生—生物医学工程] R814.42[医药卫生—基础医学]