  The medium-induced one-gluon radiation spectrum off a massive quark-antiquark
($q {\bar q}$) antenna traversing a colored QCD medium is calculated in this
contribution. The gluon spectrum off the antenna computed at first order in the
opacity expansion is collinear finite but infrared divergent, which is
different from the result obtained from an independent emitter which is both
infrared and collinear finite. The interference between emitters dominates the
soft gluon radiation when the antenna opening angle is small and the emitted
gluon is soft, whereas the antenna behaves like a superposition of independent
emitters when the opening angle is large and the radiated gluon is hard. As a
phenomenological consequence, we investigate the energy lost by the projectiles
due to the radiation. In general, the size of the mass effects is similar in
both cases.
