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Three-Dimensional Monochromatic X-ray CT

三维单色X射线CT

基本信息

批准号：
06555116
负责人：
SAITO Tsuneo
金额：
$ 8.13万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

The development of three-dimensional (3-D) monochromatic X-ray CT has been investigated as a new generation CT.Direct reconstruction in 3-D from two-dimensional (2-D) projection data can be achieved by cone-beam CT.The following findings could be obtained through the investigation as ;1. Based on the completeness condition for mathematically exact reconstruction, an orthogonal circle-and-line orbit has been adopted as the most promissing scanning method of X-ray source in 3-D CT system configuration.2. The mathematically exact 3-D CT image reconstruction algorithm has been derived from the inversion formula of 3-D Radon transform in the practically implementable form.3. Computer simulation studies have demonstrated the validity of the proposed scanning method and the derived reconstruction algorithm.4. A proto type experimental system of 3-D monochromatic X-ray CT using fluorescent X-rays generated by synchrotron radiation was constructed in National Laboratory for High Energy Physics … More in Tsukuba. The fluorescent X-rays generated by irradiating the target material with a white X-ray produce a cone-beam geometry with large beam area and spatially uniform intensity, and its energy is tunable by changing the target materials.5. The oject is mounted on the computer controlled device which simulates the scanning of circle-and-line orbit, and 2-D projection data is acquired by the image intensifier. The complete reconstruction of 3-D structure of object could be achieved in this experimental system.6. Using the desirable characteristic of tunable X-ray source, 3-D image of specific materials (for example contrast materials) is reconstructed by taking subtraction between images above and below K-absorption edge of materials. The 3-D structure of object can be visualized by the visualization software.7. The most serious problem in the cone-beam data collection scheme is the scattering of photons in tissue which degrades the image quality. If we can resolve this problem, 3-D image with absolute CT value of tissue is available because of the absence of beam hardening. Less

作为新一代CT，三维（3-D）单色X射线CT的发展已得到研究。锥形束CT可以实现二维（2-D）投影数据的3-D直接重建。通过研究可以获得以下发现：1。基于数学上精确重建的完备性条件，正交圆线轨道被采用作为3D CT系统配置中最有前途的X射线源扫描方法。 2．从3-D Radon变换的反演公式推导出数学上精确的3-D CT图像重建算法，并具有实际可实现的形式。 3．计算机仿真研究证明了所提出的扫描方法和推导的重建算法的有效性。 4．位于筑波的高能物理国家实验室建造了使用同步加速器辐射产生的荧光 X 射线的 3D 单色 X 射线 CT 原型实验系统。白光X射线照射目标材料产生的荧光X射线产生束流面积大、强度空间均匀的锥束几何形状，其能量可通过改变目标材料进行可调。 5．将物体安装在计算机控制装置上，模拟圆线轨道扫描，通过图像增强器获取二维投影数据。该实验系统可以实现物体三维结构的完整重建。 6．利用可调谐 X 射线源的理想特性，通过材料 K 吸收边缘上方和下方的图像之间的减法来重建特定材料（例如对比材料）的 3D 图像。物体的3D结构可以通过可视化软件可视化。7．锥束数据收集方案中最严重的问题是组织中光子的散射，这会降低图像质量。如果我们能解决这个问题，由于没有束硬化，就可以获得具有组织绝对 CT 值的 3D 图像。较少的