Doi K, Rossmann K
Radiology. 1975 Feb;114(2):435-41. doi: 10.1148/114.2.435.
From a computer simulation study of blood vessel imaging with uniform, triangular, gaussian, and twin gaussian line spread functions (LSF) corresponding to various focal spot distributions, it is found that vessel images magnified less than 6 times are not strongly dependent upon the focal spot distributions when the size of the focal spot is equal to or smaller than the vessel diameter. When the focal spot is larger than the vessel, image distributions vary appreciably with focal spot distributions, except at low magnification. It is concluded that, in many practical cases, the focal spot distribution does not seriously affect magnified image distributions of blood vessels.
通过对与各种焦点分布相对应的均匀、三角形、高斯和双高斯线扩展函数（LSF）进行血管成像的计算机模拟研究发现，当焦点尺寸等于或小于血管直径时，放大倍数小于6倍的血管图像对焦点分布的依赖性不强。当焦点大于血管时，除了低放大倍数外，图像分布会随焦点分布而明显变化。得出的结论是，在许多实际情况下，焦点分布不会严重影响血管放大图像的分布。
