该欧洲标准规定了一种通过针孔照相机射线照相法测量X射线系统直到并包括500 kV管电压的焦点尺寸大于0.2mm的方法。用于该测量的电压限于200kV用于视觉膜评估。 X射线图像的图像质量和分辨率高度依赖于焦点的特征，特别是尺寸和二维强度分布。 对于商业X射线管型（即广告或贸易）的表征，使用表A.1的具体值

This European Standard specifies a method for the measurement of focal spot dimensions above 0,2 mm of X-ray systems up to and including 500 kV tube voltage by means of the pinhole camera radiographic method. The voltage applied for this measurement is restricted to 200 kV for visual film evaluation. The image quality and the resolution of X-ray images depend highly on the characteristics of the focal spot, in particular the size and the two dimensional intensity distribution. For the characterisation of commercial X-ray tube types (i.e. for advertising or trade) the specific values of Table A.1 are used.