In industrial countries, coronary arterial disease is the most important etiological disease, and a safer and easily repeatable method for screening is desired. In Japan, two-dimensional K-edge energy subtraction techniques, which can demonstrate ventricular wall motion, the structure of a coronary artery as a conventional cinematic image and a quantitative regional myocardial perfusion have been developed (1-3). Oscillation of a monochromator crystal (1-5) and a filter method (6-8), now being developed, are two techniques to take precise images below and above the Kedge energy. In the iodine filter method, the energy of the beam is precisely adjusted to be both higher and lower than that of the K-edge energy (Figure 1). When the iodine filter is not inserted in the SR beam path, a mixed energy X-ray image is taken. When the filter is inserted, the higher energy component of the X-ray is blocked and a lowerenergy X-ray image is obtained. Alternatively, a high-energy X-ray image is obtained by subtracting the lower-energy X-ray image from the mixedenergy image. Su-bsequently, subtraction-of the higher-energy image from the lower-energy image generates a K-edge energy subtraction image. A cine K-edge subtraction angiographic system with an iodine filter has been constructed at the vertical superconducting wave shifter beamline BL14C at the PF. This system consists of a n iodine filter for energy exchange, a movable silicon ( 3 11) monocrystal, an image intensifier( 9 inch 11, Thomson TH9428F) and a TV (Hitachi DFA-I11 type TV), X-ray shutter, computer and a digital memory system (144 MB) (Figure 2). The filter is a quartz cell which contains a 10% sodium iodine solution corresponding to a 0.3 mm NaI crystal. This filter was inserted in the narrow SR beam path ahead of the monochromator. A 40 x 70 mm monochromatic X-ray beam is obtained using asymmetric reflection a t the silicon planes. Its energy band width is 80 eV. For digital processing, X-ray TV images are digitized in a 1024 x 1024 pixel matrix using a 12bit analog-to-digital converter. As the images with and without a filter were focused side by side, each image occupies a 512 x 512 pixel