  The differential cross section for scattering of the astrophysically
important X-ray emission lines by a helium atom is calculated with an accuracy
sufficient for astrophysical applications. For a helium atom an energy ``gap''
(due to the structure of the energy levels) is twice larger than for a hydrogen
atom and the ``compton profile'' (due to broader distribution of an electron
momentum) is significantly shallower. This opens principle possibility to
distinguish helium and hydrogen contributions, observing scattered spectra of
X-ray emission lines. With the appearance of a new generation of X-ray
telescopes, combining a large effective area and an excellent energy resolution
it may be possible to measure helium abundance in the molecular clouds in the
Galactic Center region, in the vicinity of AGNs or on the surface of cold
flaring stars.
