K-edge Energy Subtraction Angiography System using Synchrotron Radiation

[目的]发展同步辐射K边缘减影血管成像技术，解决实际应用中存在的问题。[方法]L。明确影响图像质量的因素与能量移位量的关系。2.提出了消除三次谐波对相减图像影响的方法，并利用体模进行了验证。3.紧凑地安装了II和几个CCD摄像头。4.在KEK中处理的图像可以传输到崎玉医学院的计算机中。5.几种在K-边上下能量之间快速转换X射线能量的方法。[结果]a)对比度分辨率取决于光子通量、PIXL尺寸、测量系统的噪声，而空间分辨率取决于单色仪晶体的表面状态。讨论了这些因素与成像质量的关系，在考虑X射线强度、空间分辨率和对比度分辨率后，应选择晶体参数。B)弯曲磁体或摇摆器磁场的增加会导致光子通量的增加。但是，这也导致了三次谐波比例的增加。这是阻止光子通量增加的因素之一。我们提出了一种新的采集方法，该方法除了利用K边上下能量的图像外，还利用了三次谐波分量的图像。用该方法实现了对骨骼图像的消除。C)作为能量转移的方法之一，我们研究了双晶法。在这项研究中，我们证明了光谱晶体和物体之间的距离在很大程度上取决于能量的移动和膨胀的大小。

[Purpose] To develop the technique for K-edge subtraction angiography with Synchrotron Radiation and to make clear the problem for practical use.[Method] l. Relationships between factors which affect the image quality and the amount of energy shift was made clear. 2. The method to remove the effect of third harmonics on subtracted image was proposed and verified with use of phantom. 3. II and a couple of CCD camera installed compactly. 4. Images processed in KEK was made possible to be transferred to the computer in Saitama Medical School. 5. Several methods to shift the X-ray energy rapidly between the energies above and below K-edge. 6. Theory for designing the -double stationary crystal method was established.[Results] a) Contrast resolution depends on photon flux, size of pixl, noise arriving from measurment system, and spatial resolution depends on the surface state of the monochrometer crystal. The relationship between these factors and and image quality was discussed and the crystal parameters should be chosen after the X-ray intensity, spatial resolution, and contrast resolution should be taken into consideration. b) The increase of magnetic field of bending magnets or wigglers leads to the increase of photon flux. However, it also leads to the increase of the fraction of third harmonics. This is one of the factors to prevent the increase of photon flux. We proposed the new acquisition method in which the image of the component of third harmonics was utilized in addition to the images for the energies above and below K-edge. With this method cancellation of bone image was demonstrated. c) As one of the methods of energy shift, we studied the double-crystal method. In this study we demonstrated that the distance between a specrtometric crystal and a subject becomes several hundred meters largely depending on the amounts of energy shift and expansion.