  Recent observations of the diffuse Galactic gamma-ray glow at 1.809 MeV,
attributed to the radioactive decay of 26Al, point towards a massive star
origin of this radioactive isotope. Wolf Rayet stars and core-collapse
supernovae appear to dominate the production of this isotope. Massive stars are
commonly located in clusters and OB associations, regions of recent star
formation. We thus discuss the temporal evolution of 26Al, and 60Fe within
evolving OB associations. The goal of this study is to utilize the associated
gamma-ray lines as a diagnostic tool for the study of correlated star
formation, and also to provide more detailed models for the interpretation of
data obtained with COMPTEL on the Compton Observatory. We investigate the
effects of possible aluminum yield enhancements, predicted for some massive
close binary systems. In addition to the ejection of chemically processed
matter, massive stars also drive strong stellar winds and emit large fluxes of
ionizing radiation. This energy and radiation input into the interstellar
medium (ISM) is crucial for the dynamical evolution of the gas and subsequent
star forming activity in the galactic disk. We discuss population synthesis
models for a variety of star formation histories, and compare the predicted
gamma-ray line lightcurves to COMPTEL measurements in the Cygnus region.
Radioactive tracers such as 26Al and 60Fe provide a unique gamma-ray tracer of
Galactic star formation activity, complementary to other methods using spectral
information in the radio, IR or optical bands.
