1. A method comprising: radiographically scanning an object containing first type material and second type material using a phase contrast imaging (PCI) system; generating a plurality of radiographic images in response to the step of scanning, including generating a first image of the object that represents levels of absorption of radiographic radiation by the object and generating a second image that represents phase shifts of the radiographic radiation caused by the object; and calculating a proportional amount of the first type material in the object and calculating a proportional amount of the second type material in the object based on both a function of the absorption of radiographic radiation by the object per unit of length of the object and of the phase shifts of radiographic radiation caused by the object per unit of length of the object.