NIKOS - a system for non-invasive examination of coronary arteries by means of DSA with synchrotron radiation. Pt. 2

For routine investigations a non-invasive method of coronary angiography without using a catheter is necessary. When introducing the contrast medium into a peripheral vein, due to dilution in the central circulation it is not possible to get sufficiently good images of the anatomical situation with conventional radiologic equipment. These difficulties can be overcome with digital subtraction angiography (DSA) in energy-subtraction-mode at the K-absorption-edge of iodine (33.17 keV). Today only synchrotron radiation offers enough intensity for this method. The system NIKOS was developed for DSA in energy-subtraction-mode. Main parts of the system are a two beam double crystal monochromator, a scanning device, a two line photodiode detector with large dynamic range and a computer system for data acquisition and image processing. With this arrangement in-vivo investigations of 8 dogs were carried out. The resulting images show, that it should be possible to visualize human coronary arteries down to 1 mm diameter when 10-20 ml contrast medium is rapidly injected into the brachial vein. The necessary extensions of NIKOS for these investigations are under construction. (orig.)