This paper presents a tomographical reconstruction approach to quantify planar damage in plate‐like structures. By adopting the Mindlin plate theory, theoretical solutions are derived for the scattering or diffraction wave fields due to a damage represented by an inhomogeneity. The relative simplicity of Mindlin’s plate theory as opposed to the exact Rayleigh‐Lamb solution in describing both the symmetric and anti‐symmetric guided waves in plate‐like structures makes it possible to derive analytical solutions, by appealing to the first order Born approximation. The diffraction tomographic algorithm forms the basis for reconstructing the image of a structural damage, thus providing quantitative information on structural health. © 2003 American Institute of Physics