Comparison between phantom data and reconstruction. Slices 44, 54, 64, 74, and 84 of every volume are shown. Reconstructions were performed on noisy projections of a phantom (range: -50° to +50°, every 1°, vertical tilt axis). A: Original phantom. B: Reconstruction using the ART with 10 iterations and a relaxation coefficient of 0.01. C: Reconstruction using WBP. D: Reconstruction using the SIRT with 10 iterations and a relaxation coefficient of 1.