  Simulated annealing tomography (SAT) is a simple iterative image
reconstruction technique which can yield a superior reconstruction compared
with filtered back-projection (FBP). However, the very high computational cost
of iteratively calculating discrete Radon transform (DRT) has limited the
feasibility of this technique. In this paper, we propose an approach based on
the pre-calculated intersection lengths array (PILA) which helps to remove the
step of computing DRT in the simulated annealing procedure and speed up SAT by
over 300 times. The enhancement of convergence speed of the reconstruction
process using the best of multiple-estimate (BoME) strategy is introduced. The
performance of SAT under different conditions and in comparison with other
methods is demonstrated by numerical experiments.
