Aspects of Semiconductor Current Mode Detectors for X-Ray Computed Tomography

For all types of X-ray CT-scanners the basic problem is quantitative measurement of X-ray attenuation with high accuracy. Quantum noise should be the limiting factor for spatial and contrast resolution to avoid unnecessary radiation hazards to the patient. Together with short exposure times and the required dynamic range this results in a number of serious demands to CT-detectors. After illustrating the fundamental aspects of semiconductor current mode detector operation, candidates for CT application are discussed in detail. Principally there are chances for the use of semiconductor detectors in CT, but the detector materials and the preparation technique have to be considerably improved.