In this talk, we consider inverse source problems arising in bioluminescence tomography (BLT). Mathematically, BLT is an under-determined inverse source problem which leads to no solution uniqueness. Particularly, one cannot distinguish between a strong source over a small region and a weak source over a large region. Therefore, it is particularly important to know the support $\Omega_s$ of the underlining light source $p_*$ so that its strength could be reconstructed accurately. In the literature, $\Omega_s$ is assumed to be given in advance. Practically, we only get an approximation $\Omega_a$ of it, known from some a priori information. The accuracy of $\Omega_a$ affects largely the one in approximate solutions of $p_*$. Therefore, in this talk, a new time-dependent coupled model is proposed motivated by the solution uniqueness. Some theoretical and numerical results are reported for the verification of the new model and methods.