Dual-Energy CT Principles and Applications.

X-ray spectra consist of high- and low-energy components that interact differently with atomic components of tissues and materials in the human body. Dual-energy computed tomography (CT) uses these differences to produce detailed anatomic and functional images not possible with traditional single-energy CT. Dual-energy CT can digitally subtract materials and tissues from images and enhance iodine contrast without the added image noise typical with low-energy settings. Techniques such as iterative reconstruction with postprocessing algorithms can improve image quality and provide more information without increasing overall radiation dose and can lower dose in some cases.