1. A method for detecting a particular material in an object via electromagnetic radiation, in which intensities of unabsorbed radiation from at least three radiation planes are measured and evaluated in associated detector devices, the method comprising: measuring intensities of the unabsorbed radiation of the object by each of the at least three radiation planes; producing a two-dimensional image from the measured intensities of the unabsorbed radiation; identifying areas of the two-dimensional image of the object using the produced two-dimensional image based on the measured intensities of the unabsorbed radiation of the object; from the identified areas, determining an area of the object with an approximately constant intensity of the unabsorbed radiation of the object and an area of the object with varying intensity of the unabsorbed radiation; reconstructing a three-dimensional image of the object using the two-dimensional image of the object produced by each of the at least three radiation planes; and selecting the area of the object with the approximately constant intensity of the unabsorbed radiation and detecting a material of the object in said selected area of the object with the approximately constant intensity of the unabsorbed radiation by an estimation of an attenuation coefficient, wherein the approximately constant intensity is of an intensity with only a slight change or no change at all.