  A rigorous evaluation of the Landau-Pomeranchuk-Migdal effect for finite-size
targets is performed within the path integral approach previously developed in
ref. [4]. The bremsstrahlung rate in QED is expressed through a solution of a
two-dimensional Schr\"odinger equation with an imaginary potential. The
boundary condition for this solution is formulated in terms of a product of the
light-cone electron--photon wave function and the dipole cross section for
scattering of $e^{+}e^{-}$ pair off an atom. Numerical calculations are
performed for homogeneous and structured targets. Our predictions for the
homogeneous target agree well with the photon spectrum measured recently at
SLAC with 25 GeV electrons. The spectra obtained for the structured two segment
targets exhibit the interference minima and maxima.
