Abstract—Image reconstruction from its projections is a necessity in many applications such as medical (CT), security, inspection, and others. This paper extends the 2-D Fan-beam method in [2] to 3-D. The algorithm, called Pyramid Beam (PB), is based upon the parallel reconstruction algorithm in [1]. It allows fast capturing of the scanned data, and in 3-D, the reconstructions are based upon the discrete X-ray transform [1]. The PB geometries are reordered to fit parallel projection geometry. The underlying idea is to use the algorithm in [1] by porting the proposed PB geometries to fit the algorithm in [1]. The complexity of the algorithm is comparable with the 3-D FFT. The results show excellent reconstruction qualities while being simple for practical use.