Three-dimensional tomographic reconstruction of the extended solar
corona, constructed from H I Lyman alpha and O VI 1032 Angstrom
emission observations made by UVCS and EUV images of the coronal
base from the Extreme Ultraviolet Imaging Telescope in August and
September 1996 (the first Whole Sun Month Campaign).
 
Emission lines measured by UVCS sample the optically thin plasma
along an extended region, effectively integrating along the
line of sight.  Assuming a time-steady corotating system, these
measurements can be used to reconstruct the full 3D structure of
the coronal emissivity.

(Panasyuk 1999, J. Geophys. Res., 104 (A5), 9721)