TABLE OF CONTENTS Within this chapter we will discuss most of the requirements on X-ray detectors which are specific to Computed Tomography (CT) scanners. In order to facilitate a detailed understanding of the special properties a detector should provide for CT measurement, we will give a short introduction into the basics of CT measurement, the standard configuration of modern clinical CT systems and some typical performance parameters of a typical CT scanner. This will include the mechanical and geometrical set-up, special alignment features, the X-ray source, filtration and collimation. In the following, the physical detector principles and properties and their influence on image quality are discussed. Wherever necessary we will take into account modern concepts for multi-row detectors which are state of the art with the latest generation of modern clinical CT scanning units. Special fields of medical CT such as >dimensional (3D) angiography or non-destructive material testing with Micre-CT will be addressed in the outlook. Although there is very interesting work going on in these fields, we will not treat these topics in great detail, but rather focus this contribution on modern clinical CT systems for standard radiological applications.
To be able to compute an image in acceptable quality following Radon's theory, a sufficiently high number of attenuation integrals or projection values have to be recorded. It is necessary to carry out measurements in all directions,...
