X线射野内偏离中心线距离与极限分辨率变化的关系研究

Research on relationship of different situation in radiographic area and resolution limit's value

目的:使用星形测试卡分别测试X射线照射野内中心线入射点及其他多点的极限分辨率值,分析其变化规律。方法:以X射线中心线为零点,分别沿X射线管长轴、短轴等间距标记6个位点,将星形测试卡圆心依次置于各位点测试焦点的极限分辨率值,统计其数据并描绘成曲线。结果:①X射线管长轴各位点上的焦点宽的极限分辨率值相等,而焦点长方向上的极限分辨率值有明显变化;②X射线管短轴各位点上焦点宽和长的极限分辨率值基本相等。结论:在照射野内X射线管长轴方向上位置不同,对焦点长的极限分辨率值有一定影响。

Objective：To test the resolution limit of center-ray point and other points in X-ray radiographic area by using star test pattern, analyze the rule of resolution limit. Methods： To mark six other points respectively along long axis and short axis of the X-ray tube by taking center-ray point as zero. Place star test pattern on every marked point and test resolution limit of X-ray tube focus, finally gain statistic data and made curve of resolution limit. Results：1.The resolution limits of the focus’ width about all points in X-ray tube’s long axis are almost equal but those data of the focus’ length about each point in X-ray tube’s long axis are different. 2.The resolution limit of the focus’ width and length about each points in X-ray tube’s short axis are almost equal. Conclusion： In radiographic area, only these resolution limits of the focus’ length about all points in X-ray tube’s long axis are different.