Parallel-beam computed tomography aims at reconstructing the 3D volume of an object from its 2D projection measurements. As most rays used in CT imaging (x-rays, electron-rays, etc.) are harmful for the object being imaged, an important issue is to maximally reduce the radiation dose necessary for high-quality 3D reconstructions. In this project, we will study, through 2D and 3D simulations, the impact of two dose-reduction approaches (i.e., reducing the number of tilt views Vs reducing the dose per view) on the quality of the reconstructed image, at different levels of gaussian noise. This shall be done for two distinct types of reconstruction algorithms: filter-back projection (FBP) algorithms and more advanced iterative algorithms.