Imaging X-ray projections can be acquired via a multiplicity of medical devices for X-ray imaging, for example computed tomography systems, C-arm angiography systems, radiography devices or mammography devices. The medical devices used for X-ray imaging include at least one X-ray source. The X-ray source illuminates an examination subject and the X-ray detector positioned behind it. The X-ray beams are partially absorbed or attenuated by the examination subject. The X-ray detector is able to detect X-ray beams that pass through the examination subject.
In current-generation computed tomography systems, X-ray detectors having a scintillator material are used for converting X-ray radiation into optical signals. The optical signals are converted into electrical signals via photodiodes. The spatial resolution is limited to 15 to 20 line pairs per cm. In addition to the constraints in relation to image quality, the possibilities for deployment in clinical applications are also limited by the restricted spatial resolution.
An improvement in image quality, in particular an improved spatial resolution, would be desirable in the imaging of small structures, for example stents in the coronary arteries, in the assessment of in-stent stenoses or in imaging during interventions using needles for example. Using needles during an intervention can lead to partial volume artifacts being generated due to the inadequate spatial resolution. The partial volume artifacts are manifested as dark streak artifacts at the tip of the needle, thereby making an accurate position determination more difficult. In present-day computed tomography systems, small structures, such as, say, stents in the coronary arteries, can be examined only up to a minimum size. The partial volume artifacts produced when needles are used during interventions can only be reduced or suppressed to an inadequate extent via software-based image corrections.