A method is proposed for the spatially-resolved determination of the concentration
of n elements and/or element combinations in an object to be examined that includes
these elements and/or element combinations. In the method, use is made of an X-ray
installation to record a number of digital X-ray images of at least one region
of the object to be examined with the aid of mn different spectral distributions
of the X-radiation S(E) and/or of the detector sensitivity D(E), in order to obtain
m attenuation values for each pixel representing the same location in the X-ray
images. The concentrations of the n elements and/or element combinations are then
calculated for at least one pixel from the respective m attenuation values while
taking account of known spectral absorption spectra of the n elements and/or element
combinations and of the m different spectral distributions of the X-radiation and/or
of the detector sensitivity.