INTRAVENOUS CORONARY ANGIOGRAPHY WITH DICHROMOGRAPHY USING SYNCHROTRON-RADIATION

Dichromography represents a digital subtraction angiography mode based on energy substraction which allows imaging of fast moving subjects l ike the heart. For logarithmic subtraction 2 images with X-rays just b elow and above the iodine K-edge (33.17 keV) are simultaneously obtain ed in a line scan mode. Monochromatic X-rays of sufficient intensity t o visualize coronary arteries of 1 mm diameter with extremely low iodi ne concentrations (1 mg/cm(2)) after venous injection is only provided by synchrotron radiation. The system NIKOS (non-invasive coronary art eriography with synchrotron radiation) at the Deutsches Elektronen Syn chrotron (DESY) consists of 6 components: a wiggler, a monochromator, a safety system, a scanning device, a detector and a computer system. After experimental studies in dogs patients are imaged since 1990. Ini tial results demonstrate feasibility and safety of synchrotron radiati on coronary angiography. Large scale studies are designed to further e valuate sensitivity and specificity. When compact synchrotron radiatio n sources become available, this technique could be used for follow-up studies and for evaluation of certain high coronary risk populations.