摘要目的 观察数字X线摄影(DR)系统不同曝光量与影像质量的关系.方法 选择摄影管电压90 kV、曝光量从0.5～16.0 mAs变化时,使用X线摄影系统对Cdrad 2.0对比度细节体模进行曝光,观察者对显示器的影像进行阅读,计算其影像质量因子(IQF).统计方法采用随机区组设计的方差分析(ANOVA),对8名检查者不同曝光量下测得IQF均值进行F检验,P＜0.05为差异有统计学意义.结果 (1)管电压90 kV,曝光量从0.5～8.0 mAs变化时,随着曝光量的增大,观察者在显示器上观察到IQF逐渐减小,最小为38.54±2.82,曝光量从8.0～16.0 mAs变化时,IQF逐渐增大,最大为44.33±2.35.(2)不同曝光条件下,IQF差异有统计学意义(F=60.35,P＜0.01).结论 随着X线摄影曝光量的增大,显示器图像分辨能力逐渐提高,摄影曝光量为8.0 mAs,影像质量最佳,曝光量＞8.0 mAs,显示器对图像细节的显示能力开始下降.

abstractsObjective To explore the relationship between image quality and different exposure intensity of digital radiography(DR).Methods Using a contrast-detail phantom Cdrad 2.0,observers evaluated images on the monitots when exposure parameters were 90 kV and mAs ranged from 0.5 to 16.0 mAs.Then calculate image quality figure(IQF),and ANOVA was used to analyze the difference of IQF under different radiation dose in 8 subjects.Results (1)When exposure parameters were 90 kV and mAs altered from 0.5 to 8.0 mAs.the IQF observed on the monitor was reduced,and the minimal value was 38.54±2.82.When mAs changing from 8.0 to 16.0 mAs.IQF observed on the monitor was increased,and the maximum was 44.33±2.35.(2)Under the different exposure condition,the difference of IQF values were statistically significant(F=60.35,P＜0.01).Conclusions With the increased exposure intensity,the image quality on monitor increased.When mAs was 8.0 mAs,image quality was the optimum When mAs was more than 8.0 mAs,the image quality on monitor reduced.