The Bethe-Rohrlich approximation for small angle Delbruck scattering, which is valid for photon energies of some l00MeV, can be easily modified so as to be also applicable at low energies of a few MeV. This allows to calculate the real and imaginary part of the scattering amplitude at low energies and scattering angles not larger than some 10 mrad. There the real part is found to be in general at most equal in magnitude to the imaginary part. Since only the real part gives evidence for the existence of the polarization of the vacuum, the possibility of its observation in experiments at a few MeV and small scattering angles is discussed.