PROGRESS REPORT ON SYNCHROTRON RADIATION ANGIOGRAPHY ON HUMAN SUBJECTS

Overview & Synopsis

Synchrotron radiation has been used as the illuminating source for imaging the coronary artery circulation of human subjects. Iodine-containing contrast agent is introduced into the venous side of the circulation. The principle involved in the imaging procedure is that of iodine K-edge dichromography, in which two monochromatic X-ray beams, closely bracketing the K-edge of iodine (33 keV), are used to acquire a pair of line images, recorded within 0.4 msec of each other. The logarithmic subtraction of the images provides an image which enhances attenuation signals arising from iodine and virtually eliminates signals arising from attenuation by body structures. The images are recorded in line scan fashion, usually at a rate of 12 cm/sec. Photons are detected by a silicon-lithium linear detector with sensitive elements which provide spatial resolution of 0.5 mm X 0.5 mm. Typical operating parameters have been: E = 3.0 GeV, I = 50-80 mA, B = 1.8-1.9 T.