Development of Energy Subtraction X-ray Television for diagnosis of cardiopathy

利用高速单色仪、两个CCD相机系统、两个激光光盘录像机和一个图像处理系统与同步辐射系统相结合，研制了k边减法电视系统。在注射造影剂（碘）后，受试者被单色双能x射线通量紧密包围碘的k边能量，交替照射。从每对x射线图像中得出的减法图像仅显示造影剂。造影剂在容器中的连续流动可以通过处理后的图像的串行显示来观察。为了获得清晰的冠状动脉减影图像，对系统进行了改进：1、为了使x射线能量变化与电视帧同步，引入了电子驱动单色仪。2、采用帧传送CCD相机提高垂直分辨率。为了提高图像质量，研究了图像处理算法，并将该系统与传统DSA系统的特点进行了比较。1992年9月，在日本筑波举行的BSR会议上，该系统被用于显示麻醉犬的冠状动脉，所获得的图像作为实时VCR图像显示。

A K-edge subtraction television system was developed utilizing a high speed monochromator, two CCD camera systems, two laser video disc recorders and an image processing system combined with a synchrotron radiation system. After injection of contrast medium (iodine), the subject is irradiated by monochromatized dual energy X-ray flux closely bracketing the K-edge energy of iodine, alternately. The subtraction images derived from each pair of the X-ray images visualizes contrast medium only. Continuous flow of the contrast medium in vessel can be observed by a serial display of the processed images.The system was improved to obtain clear subtraction images of coronary arteries, as follows:1, An electronic driving monochromator was introduced in order to synchronize the X-ray energy change and the TV frame.2, Frame transfer CCD cameras were utilized to improve vertical resolution.3, The image processing algorithm was investigated to improve image quality, comparing the characteristics of the system with that of a conventional DSA system.This system has been used to display a coronary artery of an anesthetized dog and the obtained images were shown as real time VCR images at the BSR Conference held in Tsukuba, Japan, at Sept. 1992.