This research studied the advantages of using multi-energy bin when reconstructing the Compton and photoelectric images compared to the switched dual-energy bin. Weighting method from Bouman et al. was also employed to improve reconstruction accuracy . The results show that the multi-energy bin can improve the image quality compared to dual-energy bin. Combined with the weighting method our approach can significantly increase the Peak Signal to Noise Ratio (PSNR). The improvement is more evident when larger inclusions with high attenuation are in the phantom. We also apply Cramer-Rao lower bound to compare the signal-to-noise ratio (SNR) between dual and multiple bins reconstruction methods, which shows a larger upper bound for SNR when using multi-energy bin.
 Sauer, Ken, and Charles Bouman. "A local update strategy for iterative reconstruction from projections." IEEE Transactions on Signal Processing 41.2 (1993): 534-548.