Tissue phantom imaging with a virtual point detector. (a) to (d) Images reconstructed using the BP method with 240, 120, 80, and 60 tomographic angles. (e) to (h) Images reconstructed using the CS method with 240, 120, 80, and 60 tomographic angles. (i) to (l) Images reconstructed using the traditional iterative reconstruction method with 240, 120, 80, and 60 tomographic angles. (m) Lines extracted from (a), (d), (h), and (l). (n) Comparison of the mean square errors of the three reconstruction methods.