An important issue in tissue optics and Optical Tomography is to have an efficient forward solver. In this work, a new numerical algorithm was developed for solving light propagation with the radiative transport equation within a three-dimensional absorbing and a highly forward-scattering medium such as a biological tissue subjected to an incident beam. Both elastically scattered light and fluorescence light were studied. Two steady state problems used to assess the performance and accuracy of the proposed algorithm are presented. We show that it is possible to obtain a good level of accuracy with a deterministic numerical method: relative differences less than 1.7% and 4.5% were obtained when compared against Monte Carlo solutions for problems of elastically scattered light and fluorescence light, respectively.