Barnes G T
Med Phys. 1982 Sep-Oct;9(5):656-67. doi: 10.1118/1.595126.
A comprehensive theory of radiographic density fluctuations is developed. The theory incorporates film granularity, quantum mottle, the absorbed x-ray photon energy distribution, fluctuations in phosphor light photon yield, and phosphor coating weight variations. The resulting expressions allow one to calculate the density fluctuations or, alternatively, the Wiener spectrum that will be obtained with a radiographic screen/film system from the physical parameters of the system. Reasonable agreement is obtained between experimental results and calculated values for three typical screen/film systems. An expression is also derived for the detective quantum efficiency (DQE) of screen/film systems, and the results of DQE calculations are presented for a commonly used screen/film combination as a function of density and of object size.
本文建立了一个关于射线照相密度涨落的综合理论。该理论纳入了胶片颗粒度、量子斑点、吸收的X射线光子能量分布、磷光光子产额的涨落以及磷光体涂层重量变化。所得表达式使人们能够根据系统的物理参数计算密度涨落，或者计算用射线照相屏/片系统获得的维纳频谱。对于三种典型的屏/片系统，实验结果与计算值之间取得了合理的一致性。还推导了屏/片系统的探测量子效率（DQE）的表达式，并给出了一种常用屏/片组合的DQE计算结果，作为密度和物体尺寸的函数。
