We mentally distinguish between two image types, radiographs and photographs. However in many ways there is really no difference as far as the computer is concerned. Just as a 35mm color slide and an x-ray transparency are different versions of the same photographic technology a digital color image and a digital x-ray are different versions of the same digital technology. The primary difference is the wavelength of the EM energy and in how the image is acquired. Yet once it is digitized the computer software needed to work with either an x-ray or visible light image is really the same.