  The comparison of COMPTEL 1.8 MeV gamma-ray line data to an extended data
base of tracer maps revealed an extremely close correlation between 1.8 MeV
gamma-ray line emission on the one side and 53 GHz microwave free-free emission
and 158 um far-infrared line emission on the other side (Knodlseder et al.,
these proceedings). We demonstrate that the two tracer maps are correlated to
the extreme Population I, tracing the distribution of very massive stars in the
Galaxy. This strongly suggests that these stars are also the dominant source of
galactic 26Al, making Wolf-Rayet stars and/or core collapse supernovae the
primary candidates.
