A medical imaging system includes an X-ray imaging apparatus and an image processor. The X-ray imaging apparatus is provided with a Talbot or Talbot-Lau interferometer and includes an X-ray source, an X-ray detector, and a subject table. The image processor generates a differential phase image, and optionally, one or both of an X-ray absorption image and a small-angle scattering image of the subject on the basis of the image signal of the subject. The image processor specifies a location of an edge of a bone in the joint on the basis of at least one of the generated images； and detects an edge of a cartilage in the joint in the differential phase image on the basis of the specified location of the bone edge to quantitatively measure a feature of the cartilage.
