Modulation Transfer Function of Radiographic Systems Using Fluorescent Screens*

When radiographic film is exposed with fluorescent intensifying screens, the spatial x-ray quantum fluctuations are recorded on the film in the form of density fluctuations (“quantum mottle”). The x-ray quantum fluctuations can be regarded as the input and the quantum mottle as the output of the image-forming system. The Wiener spectrum of the quantum mottle has been used to determine the relative modulation transfer function of two radiographic systems.