Basic research on a 3D CT system using a CCD sensor for Oral Maxillofacial region

针对针孔CCD传感器三维CT系统开发中存在的问题，设计了仿真程序、重构程序、四步进电机控制系统和CCD控制系统。利用仿真程序(1)，得到二维数值投影数据。利用重构程序(2)计算数据的重构图像。这些结果使得评估模拟程序和重建程序的适当性成为可能。四步进电机(3)的控制系统使控制多达四轴运动成为可能。通过开发CCD控制系统，可以获得直接投影图像。利用所开发的程序和系统，可以获得中心位于CCD传感器图像上方的层析成像图像。然而，还有一个问题有待解决。x射线光子的不足使得使用针孔CCD传感器难以获得投影。我们必须在未来改善这个问题。

To investigate problems for developing a 3D CT system using a pinhole CCD sensor, 1) a simulation p program, 2) a reconstruction program, 3) a control system for four stepping motor and 4) a CCD control system were developed. By using the simulation program (1), numerical 2D projection data were obtained. The reconstruction images for the data were calculated by using the reconstruction program (2). These results made it possible to evaluate the propriety of the simulation program and the reconstruction program. The control system for four stepping motor (3) made it possible to control up to 4-axis moving. By developing the CCD control system, we could obtain direct projection images. Using all these developed programs and systems, tomographic images, the center of which was above the images obtained by a CCD sensor, could be obtained without problems. However, there is a problem to be left. The insufficient of the x-ray photons made it difficult to obtain the projection using a pinhole CCD sensor. We have to improve this problem in the future.