数字X线摄影辐射剂量与图像质量相关性的实验研究  

The experimental study of correlation between the radiation dose and image quality in digital radiography

作　　者：曾勇明[1] 吴富荣 张志伟[1] 罗天友[1] 欧阳羽[1] 

机构地区：[1]重庆医科大学附属第一医院放射科,重庆400016 [2]重庆市疾病预防与控制中心,重庆400015

出　　处：《重庆医科大学学报》2009年第11期1517-1520,共4页Journal of Chongqing Medical University

基　　金：重庆市卫生局科研基金项目(编号:05-2-198)

摘　　要：目的:前瞻性研究不同X线辐射剂量与图像质量的相关性,以探索数字X线摄影(Digital radiography,DR)最适宜曝光量。方法:在仿真胸部体模中放置模拟网状、线状和结节病变结构。用125 kVp不同mAs,对体模及分辨率测试卡进行DR成像。4位放射医师分别对所有图像进行阅片评分,同时测量入射体表剂量(Entrance surface dose,ESD)、均方根(Root meansquar,RMS)和空间分辨率。结果:ESD随着mAs的增加会增加,而RMS随着mAs的增加会降低;ESD增加至一定量时,空间分辨率达到极限值。曝光指数(Exposure index,EI)值1 800以下的图像模拟微小结节显示不清,EI值2000以上的图像对模拟病变的检出高。结论:在保证DR图像质量的前提下,最优化的曝光剂量可以有效地减少辐射损伤。Objective：To prospectively research the correlation between the radiation dose and image quality in order to explore the optimization of exposure dose for digital radiography （DR）. Methods： Simulated reticular, linear, and nodular structures were located in an anthropomorphic chest phantom.The phantom and resolution wedge were exposed by DR system with the same kilovohage values （125 kVp） and different mAs sets.Four radiologists assessed all of the images.In addition,the entrance surface dose （ESD）,root mean squar （RMS） and resolution were measured. Results：ESD was increasing along with mAs＇s enhancement, but RMS was decreasing when mAs was increasing. As long as the ESD increased to a certain degree, spatial resolution would go up to the limit. Images obtained with lower dose （EI〈 1 800）were obscure at the tiny nodular structure.Images of 2 000 EI value could show clearly the Simulated lesion. Conclusion： The optimization of exposure dose for DR imaging may effectively decrease radiation injuries under the precondition of DR image quality to be guaranteed.

关 键 词：数字X线摄影 仿真体模 模拟病变 辐射剂量 

分 类 号：R814.42[医药卫生—影像医学与核医学]