  A theoretical description of photon-pair production in polarized
positron-electron annihilation is presented. Complete one-loop electroweak
radiative corrections are calculated taking into account the exact dependence
on the electron mass. Analytical results are derived with the help of the
SANC~system. The relevant contributions to the cross section are calculated
analytically using the helicity amplitude approach. The cases of unpolarized
and longitudinally polarized fermions in the initial state are investigated.
Calculations are realized in the Monte Carlo integrator MCSANCee and generator
ReneSANCe which allow one the implementation of any experimental cuts used in
the analysis of $e^+e^-$ annihilation data of both low and high energies.
