The focalspot sizes can immediately influence picture definition when X-ray machine carry through clairvoyance and photography.
焦点的尺寸大小及聚焦质量直接影响X射线机透视、摄影图像的清晰度；
2
The Modulation Transfer Function(MTF) of X-ray tube focalsPOt and its size are the main parameters, which can be used to describe the photo function of X-ray tube focal spots.