CORONARY ANGIOGRAPHY WITH SYNCHROTRON-RADIATION

Worldwide several systems for Digital Subtraction Angiography in energ y subtraction mode (dichromography) are developed, One of the systems which allows investigations of patients - the system NIKOS in the Hamb urger Synchrotronstrahlungslabor HASYLAB at DESY is described. The sys tem consists out of sis main parts: The 20 pole wiggler HXRWI in the b eamline W2 of the storage ring DORIS, the two beam monochromator for t he two 12.5 cm wide monochromatic X-ray beams, the safety system, the fast scanning device, the fast low-noise two-line ionization chamber a nd the computer system. Since 1990 patients were investigated with the system NIKOS, him of the work is to visualize coronary arteries down to 1 mm diameter with an iodine mass,density of 1 mg/cm(2), thus allow ing non-invasive investigations by intravenous application of the cont rast medium. The two images for subtraction are simultaneously taken w ith photon energies just below and above the iodine K-edge (33.17 keV) in a line scan mode. Intravenous angiograms from investigations with version III of the system NIKOS are presented and the next steps for g etting an increased image quality are described.