Development of a new dual-contrast microangiographic system by using monochromatic synchrotron radiation

单色同步辐射，能级略高于或低于I、Ba或Ce的k边，其中2x2厘米的区域由高清晰度电视摄像机扫描。这种相机是一种带有非晶态硒光导靶材的摄像管，其特点是内部放大过程，利用光导电层中的雪崩现象。这些图像被存储为数字图像(1024x1024像素，帧存储器中的4096级/像素)。该系统的空间分辨率下限为25μm，对犬、兔和大鼠血管大小的检测下限为30μm。在动物体内，肝内的门静脉和胆管内充满了Ba、Ce或I标记的造影剂。肺内的肺动脉和呼吸道也充盈了造影剂。这些样品暴露在单色同步辐射下，这些元素中的每个K边只有上、下能级。通过在计算机上进行减影处理，分别拍摄直径达30μm的这些导管的图像。使用机械快门来提高时间分辨率，允许一帧图像的时间为2毫秒，这使我们能够获得心脏跳动时冠状动脉的精细图像。我们还发现，微球注射到冠状动脉中会造成狗和兔的微血管心肌缺血。

Monochromatic synchrotron radiation with an energy level of just above or below the k-edge of I, Ba, or Ce where a 2 x 2 cm area was scanned by a high-definition TV camera. This camera is an image pick-up tube with an amorphous selenium photoconductive target and is characterized by its internal amplification process, which uses the avalanche phenomenon in a photoconductive layer. The images were stored as a digital image (1024 x 1024 pixels, 4096 grades/pixel in a frame memory). The spatial resolution limit of this system was 25 μm. The detection limit of the vessel sizes are 30 μm in canine, rabbits, and rats. In the animal, the portal vein and bile duct in the liver were filled up with Ba-, Ce-, or I-labeled contrast materials. The pulmonary artery and the respiratory tract in the lung were also filled up with the contrast materials. The samples were exposed to monochromatic synchrotron radiation with just upper and lower energy levels of each K-edge in these elements. By subtraction processing on a computer, the image of these ducts up to 30 μm in diameter were taken separately. The use of a mechanical shutter to improve temporal resolution allowed 2 msec of one frame, which allowed us to obtain a fine image of the coronary artery in beating heart. We also showed that microsphere injection into the coronary artery created microvascular myocardial ischemia in dogs and rabbits.