迭代重建技术与自动毫安控制相结合降低肝脏平扫辐射剂量的效果研究  

Effect of iterative reconstruction algorithm combined with CARE dose 4D on reducing radiation dose in liver CT

作　　者：赵君禄[1] 刘冲[1] 郑立冬[1] 任庆云[1] 王猛[1] 

机构地区：[1]河北医科大学第一医院放射科,石家庄市050031

出　　处：《河北医药》2015年第7期968-971,共4页Hebei Medical Journal

基　　金：河北省医学科学研究重点课题(编号:ZD20140296)

摘　　要：目的：研究IRIS迭代重建技术与CARE dose 4D自动毫安控制相结合在肝脏平扫中对提高图像质量、降低辐射剂量的影响。方法（1）尸体标本研究：采用130 kV，mAs为250～30（每次递减20）的扫描参数对尸体标本上腹部进行扫描，对扫描后的原始数据分别进行IRIS与FBP重建，经测量分析后选择低剂量扫描IRIS重建后图像的噪声与常规剂量扫描FBP重建噪声相等的扫描条件进行临床研究。（2）临床研究：120例进行肝脏CT平扫的患者随机分为A、B 2组，每组60例。 A组采用130 kV、图像质量控制参考毫安秒150 mAs自动毫安控制进行扫描，分别进行IRIS与FBP重建；B组采用130 kV、250 mAs进行扫描，分别进行IRIS与FBP重建。记录2组患者CT容积剂量指数（CTDIvol）及剂量长度乘积（DLP）。由3名医师采用盲法对4组图像进行噪声测量、对比噪声计算等客观评价及主观图像质量评价。结果尸体标本研究得到规律：低剂量扫描IRIS重建后图像的噪声与常规剂量扫描FBP重建噪声相等时mAs可降低至150 mAs。将其应用到临床，临床研究扫描剂量为：A 组CTDIvol 为2．35～16．3 mGy；DLP为63．4～287．5 mGycm。 B组CTDIvol为25．7 mGy；DLP为523．8～586．6 mGycm。 A组较B组降低了50％～70％。 A1、B1、B23组图像质量均满足临床诊断要求。 B1图像质量高于B2图像质量，A1图像质量与B2差异无统计学意义（ P＞0．05），A2图像质量最差，不能满足诊断需要。结论迭代技术与自动毫安控制相结合相同剂量条件下可以提高图像质量，在保证图像质量条件下可以降低肝脏平扫的辐射剂量，值得临床推广。Objective To investigate the influence of iterative reconstruction algorithm （ IRIS） combined with CARE dose 4D on reducing radiation dose and improving image quality in liver CT .Methods （1） Human cadaver study ：human cadaver was scanned for twelve times by emotion 16-slice CT scanner with same tube voltage 130 kV and different tube currents from 30mAs to 250mAs with increment of 20mAs.The images were reconstructed with IRIS and FBP respectively ,and the data were analyzed before clinical study .（2）Clinical study：120 patients were randomly divided into two groups ,group A and group B,with 60 patients in each group.The patients in group A received liver CT （130kV,CARE dose 4D and reference mAs of 150）,and images were reconstructed with IRIS and FBP ,redpectively.The patients in group B were scanned by CT （130kV, reference mAs of 250）,and images were reconstructed with IRIS and FBP respectively .CT dose index volumes （CTDIvol）, dose length product （ DLP） were recorded .The image quality was evaluated by three radiologists blindly with objective methods （noise measurement and CNR calculating etc ） as well as subjective methods.Results CTDIvol and DLP were 2.35 ~16.3mGy and 63.4~287.5mGycm,respectively,in group A,however,which were 25.7mGy and 523.8~586.6mGycm in group B,respectively,which in group A were decreased by 50%~70%.Image quality in both group A1,group B1,group B2 met diagnostic requirements .The image quality in group B1 was better than that of group B2,however,there was no significant difference in image quality between group A1 and group B2 （ P 〉0.05）.The image quality in group A2 was the worst,which could not meet diagnostic requirements .Conclusion IRIS combined CARE dose 4D can improve the image quality under the condition of the same dose , which can reduce the radiation dose of liver CT under the condition of guaranteeing the image quality,so it is worthy of clinical spreading application .

关 键 词：计算机体层摄影 图像域迭代重建 自动毫安控制 辐射剂量 肝脏平扫 个性化 

分 类 号：R814.42[医药卫生—影像医学与核医学]