In X-ray computed tomography (CT) the X rays are used to obtain the projection data needed to generate an image of the inside of an object. The image can be generated with different techniques. Algebraic methods are more suitable for the reconstruction of images with high contrast and precision in noisy conditions and from a small number of projections. Their use may be important in portable scanners for their functionality in emergency situations. However, in practice, these methods are not widely used due to the high computational cost of their implementation. In this work we analyze and propose the usage of the PETSc library for the optimal usage of a system in the parallel reconstruction of images. Also, the quality comparison of the images reconstructed with both methods, analytical Filtered Back projection (FBP) and iterative LSQR, has been performed. © 2011 IEEE.