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 like the heart. For logarithmic subtraction 2 images with X-rays just below and above the iodine K-edge (33.17 keV) are simultaneously obtained in a line scan mode. Monochromatic X-rays of sufficient intensity to visualize coronary arteries of 1 mm diameter with extremely low iodine concentrations (1 mg/cm2) after venous injection is only provided by synchrotron radiation. The system NIKOS (non-invasive coronary arteriography with synchrotron radiation) at the Deutsches Elektronen Synchrotron (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. Initial results demonstrate feasibility and safety of synchrotron radiation coronary angiography. Large scale studies are designed to further evaluate sensitivity and specificity. When compact synchrotron radiation sources become available, this technique could be used for follow-up studies and for evaluation of certain high coronary risk populations.