Dual-energy CT

Dual-energy is a CT imaging approach aimed at generating and extracting additional information beyond material density from image slices. The additional information, a second material property, is known as the effective atomic number, Zeff. Although the X-ray attenuation coefficient is proportional to a material s density p, it is also a function (i) of the atomic number Z of each of the material s 

Dual-energy CT capability, providing measurement of a second, independent material quantity Zgfr of candidate threat objects, is expected to aid significantly in reducing false alarm rates and thereby to improve performance over single-energy CT systems. 

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A preliminary feasibility exptl study indicated that simulated expls in a test box (cast DNT and an Amm Nitrate, sugar and water mixt) could be readily distinguished from the other items in the box (shaving cream, cologne, book, wood, aluminum, water) by dual-energy CT techniques... 

Raptoponlos, V., KareBas, A., Bernstein, J., Reale, F.R., Constantinou, C., Zawackl, J.K. Value of dual-energy CT in differentiating focal fatty infiltration of the hver from low-density masses. Amer. J. Roentgenol. 1991 157 721-725... 

With the development of Dual Source CT, simultaneously acquired Dual Energy CT has become feasible in a clinical setting. Running both x-ray tubes at different potentials, different x-ray spectra can be obtained. Thus, elements with a strongly energy dependent absorption such as iodine or xenon gas can be differentiated from other materials. A three material decomposition algorithm is apphed to map the distribution of such a substance in a CT image. 

In summary, dual-energy CT offers the possibility to exploit spectral information for diagnostic purposes in routine chnical examinations. The mapping of iodine distribution in the lung, liver or kidneys and the bone removal from angiography datasets can be regarded as very promising applications. The differentiation of kidney stones represents another clinically useful implementation. 

Cann CE, Gamsu G, Birnberg FA, Webb WR (1982) Quantification of calcimn in solitary pulmonary nodules using single- and dual-energy CT. Radiology 145 493-496... 

Goldberg HI, Cann CE, Moss AA, Ohto M, Brito A, Federle M (1982) Noninvasive quantitation of liver iron in dogs with hemochromatosis using dual-energy CT scanning. Invest Radiol 17 375-380... 

Keicz F, Joseph PM, Hilal SK (1979) Noise considerations in dual energy CT scanning. Med Phys 6 418-425... 

Wang B, Gao Z, Zou Q, Li L (2003) Quantitative diagnosis of fatty liver with dual-energy CT. An experimental study in rabbits. Acta Radiol 44 92-97... 

Johnson TR, Krauss B, Sedlmair M, Grasruck M, Bruder H, Morhard D, Fink C, Weckbach S, Lenhard M, Schmidt B, Flohr T, Reiser MF, Becker CR (2007) Material differentiation by dual energy CT initial experience. Eur Radiol 17(6) 1510-1517... 

SCT single-slice scanner, DECT dual-energy CT E.g., Sensation 16, Siemens AG, Forchheim, Germany... 

Dual Energy CT Initial Description of Clinical Applications in the Abdomen... 

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