beam direction and denoted by the subscript j they have the following meanings f j mean gray scale value in voxel j corresponding to the mean linear attenuation coefficient of the voxel v j k f j u03b1 k f j gt t wk 0 f j u2264 t wk u2062 u2062 and u2062 ue891 u2062 v j w f j u03b1 w t aw u2264 f j u2264 t wk 0 f j lt t aw u2062 u2062 oder u2062 u2062 f j gt t wk where u03b1 w or u03b1 k denote the mass attenuation coefficient in cm 2 g in the case of a specific reference energy of the radiation that is to be advantageously selected the soft part coverage and bone coverage in g cm 2 required for the hardening correction and the scattered radiation correction then results in the vector u03bb generally represents a combination of three vectors v w v k l where a single scalar variable can moreover be formed for example in the following way and is capable of at least sweepingly taking account of the dependency of the distribution of bone along the measuring beam relative to the distribution of soft tissue in the scattered radiation correction the following variables are used for this purpose the voxel coordinates of the centre of the voxel j along the measuring beam where j 1 for designating the first voxel which belongs to the object or of which the hu value corresponds to soft tissue or bone focal points of the u201c soft part voxel u201d or u201c bone voxel u201d along the measuring beam the following scalar variable u03bb which lies between u2212 u00bd and u00bd estimates the relative asymmetry.