Acquiring fairly large numbers of X-ray images with the aid of an X-ray angiography system requires the individual 2D image data records to be obtained at a high speed, if a 3D image data record is to be calculated from the totality of said 2D image data records (known as reconstruction). This is because the image object, usually a person (patient), naturally always moves as the image is being recorded and the longer it takes to acquire to acquire the X-ray images, the greater the blurring in the image.
The X-ray radiation detectors used in X-ray angiography systems generally have a scintillator, which converts X-ray beam quanta striking the X-ray radiation detector to light quanta. The X-ray radiation detector also has a grid or matrix of detector units, each detector unit having a light-sensitive receiver, at which a measurement value is changed by light quanta striking it. The light-sensitive receiver is typically a photodiode and the measurement value relates to a voltage that increases due to incident light quanta.
The photodiodes are typically read out in a central memory. Reading out can only take place line by line and therefore takes a relatively long time.
If two X-ray image data records are to be acquired, each with the aid of an X-ray angiography system, specifically with different spectra, and a sufficiently large number of 2D X-ray image data records in total are to be acquired in a short time, the problem arises that the photodiodes may be read out too slowly.
From other applications it is known that a buffer can be provided on detector elements, into which buffer the measurement values from the respective light-sensitive receivers can be read out so that the receivers can then be reset to zero. The buffer can be read out at a later time. CMOS technology or a related technology is particularly suitable for implementing such a buffer. CMOS stands for Complementary Metal Oxide Semiconductor.