基层医疗单位使用的床旁Ｘ线机多为Ｆ３０型等单焦点小型Ｘ线机。其均无中心线指示灯装置。如自行在球管上安装带有指示灯的遮线器，多因机型限制，安装复杂及资金问题等因素，有一定困难。所以在床旁摄片时，Ｘ线中心线无明确标志，不能准确定位，致使摄影位置出现偏差，从而 The bedside X-ray machines used by primary care units are mostly single-focus X-ray machines such as the F30 type. There are no center line indicator devices. Such as the installation of the indicator with a lamp on the ball tube, due to the limitations of the model, the installation of complex and financial issues and other factors, there are certain difficulties. Therefore, when photographing at the bedside, there is no clear mark on the centerline of the X-ray and it cannot be accurately positioned, resulting in deviation of the photography position.