  In Single Photon Emission Computed Tomography (SPECT), 3D images usually
reconstructed by performing a set of bidimensional (2D) analytical or iterative
reconstructions can also be reconstructed using an iterative reconstruction
algorithm involving a 3D projector. Accurate Monte Carlo (MC) simulations
modeling all the physical effects that affect the imaging process can be used
to estimate this projector. However, the accuracy of the projector is affected
by the stochastic nature of MC simulations. In this paper, we study the
accuracy of the reconstructed images with respect to the number of simulated
histories used to estimate the MC projector. Furthermore, we study the impact
of applying the bootstrapping technique when estimating the projector
