Fig. 1
From: Detector-based spectral CT with a novel dual-layer technology: principles and applications
Spectral technology. (a) Illustration depicting the configuration of the dual-layer detector-based spectral CT. The top layer is made up of an yttrium-based garnet scintillator, which absorbs the low-energy photons and the bottom layer is made up of gadolinium-oxysulphide, which absorbs the high-energy photons. Attached to each layer, there is a thin front-illuminated photodiode (FIP), which converts the light photons to an electrical signal and an application-specific integrated circuit (ASIC) for analogue to digital conversion (not shown here). (b) Diagram showing the technique of image generation from the SDCT scanner. Data from the two layers is utilised to generate photoelectric and Compton scatter basis pairs. Linear combination gives virtual monoenergetic images, while material decomposition gives iodine-density, virtual non-contrast and effective atomic number-based images