斜射线摄影对直接数字化X线摄影系统影像质量的影响评价  

Effect of oblique ray on image quality of direct digitized radiography system

作　　者：宋玉全[1] 何志诚 伍筱梅[1] 邓宇[1] 于兹喜[3] 何建勋[1] 肖少屏[1] 

机构地区：[1]广州医学院第一附属医院放射科,510120 [2]广州市第六人民医院放射科 [3]泰山医学院放射系

出　　处：《中华放射学杂志》2005年第10期1084-1087,共4页Chinese Journal of Radiology

摘　　要：目的探讨斜射线摄影对直接数字化X线摄影(DDR)系统影像质量的影响。方法(1)实验组使用DDR系统对直径5.5cm钢质球体进行重复摄影,X线入射角度分别为垂直(0°)、15°、30°、45°,并将影像打印出激光胶片。(2)对照组用屏-片系统替换DDR系统的平板探测器,摄影条件与实验组相同,得出传统照片。(3)分别对实验组和对照组的球体影像边缘进行微密度测量,评价2种成像方法所得影像边缘模糊值随入射X线角度而变化的情况。结果(1)实验组和对照组的影像边缘模糊值随着X线入射角度的增加而增大,角度越大,增幅越明显,在大角度时实验组增幅更加明显,当入射角度为45°时,实验组的边缘模糊值(y2值)达到(0.9240±0.0033)mm,而对照组的y2值为(0.4840±0.0033)mm。(2)X线管倾斜15°投照时,DDR系统和屏-片系统的影像边缘模糊值变化幅度差异无统计学意义,(15°x)t=0.989,P=0.336;(15°y1)t=0.039,P=0.969。X线管倾斜30°和45°投照时,两系统的影像边缘模糊值变化幅度差异有统计学意义,(30°x)t=18.439,P=0.001;(30°y1)t=10.308,P=0.001;(30°y2)t=21.811,P=0.001;(45°x)t=31.315,P=0.001;(45°y1)t=107.727,P=0.001;(45°y2)t=160.863,P=0.001。结论(1)DDR系统在垂直和小角度倾斜X线管时,影像边缘模糊值与值屏-片系统差异不大,成像质量较好。(2)DDR系统在X线管倾斜角度较大时,影像边缘模糊增幅明显大于屏-片系统,成像质量受到影响。Objective To evaluate the effec on image quality of DDR system caused by oblique ray. Methods （1）Experiment group： A sphere was taken radiographes repeatedly using DDR system, the respective incidence were vertical （0°）, 15°, 30° ,45°, and all images were printed into laser films. （2） Comparison group ： By way of self comparing, conventional films were radiograpbed under all conditions as in experiment group with screen-film system instead of flat-panel detector. （3）To evaluate the edge fog of sphere image, micro-density of image edge. Both groups were measured separately. Results （ 1 ） The image edge fog in both experiment group and comparison group increased along with increase of X-ray incidence, the more large angle was, the more amplitude of image fog was. And the amplitude of experiment group was more distinct while with large incidence. When incidence was 45°, the edge fog value of experiment group went up to（0. 9240 ±0. 0033）ram, while only （0. 4840 ±0. 0033）ram of comparison group contrarily. （2） When projecting with 15° inclination of tube, the amplitude of variation of image edge fog in both DDR system and screen-film system had no distinct difference （P 〉 0. 05 ） ; when the lean angle were 30°and 45°, it had distinct difference （ P 〈 0. 05 ）. Conclusion （ 1 ） The image edge fog of DDR system has no distinctly difference from screen-film system and better image gotten while the inclination of tube is vertical or small angle, （2）The amplitude of variation of image edge fog have distinctly difference that it of DDR system is visibly over screen-film system, when the inclination of tube is big, the imaging quality will be affected.

关 键 词：放射摄影术 质量控制 评价研究 直接数字化X线摄影系统 影像质量 射线摄影 边缘模糊 DR系统 成像质量 实验组 

分 类 号：R814.4[医药卫生—影像医学与核医学]