Demands on a detector for intravenous coronary angiography—experience after 379 patients

At the Hamburger Synchrotronstrahlungslabor HASYLAB at DESY, the NIKOS system was developed for intravenous coronary angiography. To date 379 patients were examined with this system. This made it possible to exactly determine the optimal parameters of the system. The system consists of six main components. One of them, the two-line detector, is described in detail. This ionization chamber with a horizontal pixel size of 0.4 mm has a large dynamic range and low noise as well as high quantum efficiency. The fourth version of the NIKOS-detector fulfils the requirements of intravenous coronary angiography with its dynamic range of up to 300 000:1 each at four different setup modes, an equivalent photon noise of maximal 7.6, and a spatial resolution of 1.25 lp/mm in the minimum. The detective quantum efficiency reaches 85% at a readout time of 0.2 ms/line, which is faster than the necessary 0.8 ms/line. These parameters ensure that the image quality is not decreased by the detector.