ABSTRACT
This chapter aims to provide the basic physics and principles of dual energy computed tomography (DECT) imaging and describe the different technologies for implementation of DECT available in modern computed tomography (CT) systems. DECT data are acquired consecutively using either sequential (axial) or helical acquisition mode. Consecutive DECT acquisition requires minimal hardware effort, but suffers from the apparent limitation regarding the considerable temporal difference between high- and low-energy projection data acquisition. Rapid tube voltage switching DECT acquisition enables raw data-based production of DECT images, which allows generation of images free from beam hardening artifacts. Rapid tube voltage switching DECT systems are single-source systems having the ability to operate also in constant tube voltage mode. The apparent advantage of the dual-layer detector DECT approach is the ability to simultaneously collect low- and high-energy projection data. Also, the dual-layer DECT approach requires increased hardware effort, due to the sophisticated detector-readout channels implementation, which considerably elevates the cost of purchase.
