BONE TRABECULAE INDEX FOR X-RAY DARK-FIELD RADIOGRAPHY

A method (200) and system (20) for expressing signals in a dark field X-ray image of bone (34; 44) in units of a trabecular quantity are disclosed, in which an X-ray dark field image of a bone having a trabecular network is acquired (204) at an image resolution that is not capable of resolving the trabecular network (41) of the bone. Information about the positioning of the scan bone relative to the X-ray dark field imaging apparatus used for acquisition is determined. Signals in the X-ray dark field image of the bone are converted (206) into a corresponding trabecular quantity, wherein the conversion accounts for the determined information about the positioning of the bone and depends on a plurality of generated X-ray dark field image signal normalization values, generated for a sample bone.