1. A method for mapping radiological image data from a source imaging system to a different target imaging system, executed at least in part by a computer, comprising: obtaining sensitometric response data for both the source and the target imaging systems; identifying an anchor point that relates a specified source signal value to a specified target signal value; applying a transform to map a range of source signal values the image data to a corresponding range of target signal values, wherein the transform is defined according to the sensitometric response data obtained for both the source and the target imaging systems and according to the identified anchor point; and using the transformed target signal values of the image data for display and/or analysis.