该欧洲标准规定了通过狭缝摄影机X射线照相法测量直到并包括500kV管电压的X射线系统的0.1mm以上的焦点尺寸的方法。用于该测量的电压限制在200kV。 X射线图像的图像质量和分辨率高度依赖于焦点的特性，特别是物体平面中的尺寸和二维强度分布

This European Standard specifies a method for the measurement of focal spot dimensions above 0,1 mm of X-ray systems up to and including 500 kV tube voltage by means of the slit camera radiographic method. The voltage applied for this measurement is restricted to 200 kV. 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 in the object plane.