Figure 2: Test images. (a) Thorax phantom data acquired at 120 kVp, 150 mA. (b) A phantom data produced by Matlab. (c) Modified Shepp-Logan head phantom whose size is . (d) A CT image of an abdomen of a 58-year-old man with 120 kVp, 150 mAs. (e) A CT image of a chest of a 62-year-old woman with 120 kVp, 150 mAs.