两种平板探测器X线摄影系统的成像剂量与成像质量的比较研究

目的 定量分析、比较非晶硅平板探测器X射线摄影系统与非晶硒平板探测器X射线摄影系统在不同成像剂量条件下成像质量的差别。方法 以非晶硅平板探测器系统和非晶硒平板探测器系统分别摄取对比度-细节体模CDRAD2.0在相近曝光剂量条件下的X射线影像,由4位独立观察者分别阅读影像,并计算所对应的曝光剂量下图像质量因子（image quality figure,IQF）,应用ANOVA分析两成像系统对比度及细节检测能力。使用X射线摄影统计学体模（TRG）测量两系统在不同曝光剂量条件下操作者特性曲线（receive operating characteristics,ROC）,应用Wilcoxon检验分析、比较两种成像技术的影像信息检测能力的差别。结果 在低曝光剂量条件下,两系统CDRAD体模影像IQF值及ROC曲线AZ值差别有显著意义,在对比度、组织细节检测能力上非晶硅平板探测器系统优于非晶硒平板探测器系统。在高曝光剂量条件下,两系统差异无统计学意义。结论 在低曝光剂量条件下,成像质量非晶硅平板探测器系统优于非晶硒系统。在获得相同的影像质量的前提下,使用前者进行X射线摄影可以降低被检者受照剂量。

Comparison of two kind of flat panel detector radiography system:imaging quality versus exposure dose

ObjectiveTo compare the imaging quality at different exposure settings for amorphous Silicon (a:Si) Cesium Iodide (CsI) flat panel detector digital radiography system with amorphous Selenium (a:Se) flat panel detector digital radiography system. Methods The images of contrast-detail phantom (CDRAD 2.0) were taken at different exposure settings for two digital radiography systems. Four independent observers read the images and calculated the IQF for different dose settings. The detectability of two system for contrast and detail was analysed using ANOVA. A ROC analysis was performed with TRG phantom in different exposure settings. The statistical significance was evaluated using the Wilcoxon test. Results There was a significant difference of IQF and Az values of ROC between the two systems at lower dose exposure, which ensured a better image quality concerning contrast and detail detectability. Higher dose exposure provided similar results for both systems. ConclusionThe a:Si flat panel digital radiography system proved to be superior to a:Se flat panel digital radiography system at low dose settings. Without the image quality lost, the patient dose might be reduced if an a:Si system was used.