@article{chen2007automatic,
  title={Automatic 3D-to-2D registration for CT and dual-energy digital radiography for calcification detection},
  author={Chen, Xiang and Gilkeson, Robert C and Fei, Baowei},
  journal={Medical physics},
  volume={34},
  number={12},
  pages={4934--4943},
  year={2007},
  publisher={Wiley Online Library}
}