Dual-Energy CT with Fast-kVp Switching and Its Applications in Orthopedics

Dual-Energy Multidetector CT for the Characterization of Incidental Adrenal Nodules: Diagnostic Performance of Contrast-enhanced Material Density Analysis

“…Data reconstruction.-In each patient, conventional nonenhanced and material decomposition images with fat-iodine, iodine-fat, fat-water, and water-fat material basis pairs were reconstructed by using 5-mm section collimation with both a filtered back-projection and a projection-based material-decomposition algorithm, respectively. Material density images were obtained by using a two-material decomposition algorithm, which works by first establishing a basis pair and the associated attenuation characteristics of each material in the basis pair (26)(27)(28)(29). Then, each voxel is decomposed proportionally into the two-material basis pair according to the attenuation characteristics of that voxel as measured at each energy level (80 and 140 kVp).…”

“…Then, each voxel is decomposed proportionally into the two-material basis pair according to the attenuation characteristics of that voxel as measured at each energy level (80 and 140 kVp). Material density images represent the relative densities in a given material basis pair that are needed to produce the observed projections at the high and low energies (26)(27)(28)(29). Therefore, the values obtained on material density images do not represent absolute density measurements; rather, they reflect the true proportion or relative quantity of material under investigation (26)(27)(28)(29).…”

“…Material density images represent the relative densities in a given material basis pair that are needed to produce the observed projections at the high and low energies (26)(27)(28)(29). Therefore, the values obtained on material density images do not represent absolute density measurements; rather, they reflect the true proportion or relative quantity of material under investigation (26)(27)(28)(29). As an example, for a material basis pair composed of fat and iodine, the effective fat density image is represented by the fat-iodine data set, whereas the effective iodine density image is represented by the iodine-fat data set.…”

“…A region of interest (ROI) measurement obtained from a fat-iodine image data set represents the relative effective density of fat without the iodine contribution. Similarly, an ROI measurement drawn on an iodine-fat image depicts the relative effective density of iodine without fat, within a given target area (26)(27)(28)(29).…”

High Bandwidth Non-Resonant High Voltage Generator for X-Ray Systems

“…A different approach is to use a single tube (single source) which is switched between two voltage levels, requiring rise-and fall times of less than 100 μs [4]. Besides eliminating one tube single source dual energy CT also reduces the patient dose [5]. Although recent achievements in SiC semiconductor technology offer diode break-down voltages up to 35 kV [6], [7], the secondary side of the high-voltage DC-DC converter is typically involving multiple diode rectifier stages connected in series in order to reduce the winding capacitance.…”