数字化X线摄影曝光条件对影像质量的影响  

Effects of exposure conditions on image quality in digital radiography

作　　者：曲良勇 苑翠红 赵洪波[2] 钮建武 徐亮 钱爱君[3] 蒋笑欢 唐伶奇 高林峰[3] 

机构地区：[1]上海中冶医院放射科,上海200941 [2]上海长征医院影像科 [3]上海市疾病预防控制中心 [4]上海市闸北彭浦新村街道卫生服务中心 [5]宝钢卫生处医院

出　　处：《实用放射学杂志》2011年第10期1574-1577,1587,共5页Journal of Practical Radiology

基　　金：上海市卫生局科研项目（编号：2007177）;上海市公共卫生优秀青年项目（编号：08GWQ16）.

摘　　要：目的研究数字X线摄影曝光条件对影像质量的影响。方法确认数字x线摄影处于良好状态，用CDRAD2．0体模，测试kV、mAs、过滤等曝光条件对影像质量及剂量学参数的影响。结果影像质量存在随管电压的增加而降低的趋势，在70kV和90kV时影像质量最好，IQFinv分别为6．27和6．10，而在110kV时影像质量最差，IQFinv为4．27。从60～80kV，图像的像素值下降13%；而80～130kV，图像的像素值在很小范围内波动，变化率仅在2％左右。随着kV数的增加，图像噪声呈逐渐增高趋势，与60kV时相比，90kV、120kV时的噪声值分别上升了9．6％和16．9％。在70kV、90kV和110kV条件下，分别在32mAs、6．4mAs和3．2mAs时影像质量最佳。图像的像素值随mAs增加而升高，而图像的噪声总体上随mAs的增加而降低。IQFinv与剂量与面积之积之间呈明显正相关（P〈0．05），与kV呈负相关，而与mAs呈正相关，但这种相关性统计学意义不显著（P〉0．05）。结论对于数字化X线摄影，合适的管电压和mAs为曝光参数可以获得较好图像质量，并有效控制受检者辐射剂量。Objective To study the effects of exposure conditions on image quality in digital radiography （DR）. Methods Quality assurance （QA） was performed with Barracuda system to make sure DR X-ray machine was in good condition. On condition that CDRAD 2.0 phantom was used, dosimetric and image quality parameters were recorded when the exposure conditions including kV, mAs and filter changed. Results Image quality was decreased with increasing of tube voltage,and it was best at 70 kV and 90 kV, with IQFinv 6.27 and 6.10 respectively,worst at 110 kV, with IQFinv 4.27 respectively. The values of pixels were decreased of 13% when tube voltage was increased from 60 kV to 90 kV, but only changed 2% when tube voltage was increased from 80 kV to 130 kV. Pattern noise was increased with tube voltage. Comparing with that of 60 kV, pattern noise was separately increased 9.6 % and 16.9% at 90 kVand 120 kV. At the condition of 70 kV, 90kVand 110 kV, image quality was best at 32 mAs, 6.4 mAsand3.2 mAs. The value of pixels was increased with increasing mAs, and pattern noise was decreased with increasing mAs. Significant positive correlation was observed between IQFinv and DAP （P〈0.05）. IQFinv had negative correlation to kV,and positive correlation to mAs,but there were no statistic significance （P〉0.05）between them. Conclusion For DR,the better image quality at proper tube voltage and mAs can be obtained,and can effectively control exposure dose of examinees.

关 键 词：数字 X线摄影 曝光条件 影像质量 

分 类 号：R814.41[医药卫生—影像医学与核医学] R814.49[医药卫生—放射医学]