Development of a pseudo three dimensional display system of dental panoramic images

The purpose of this study is to develop a new dental panoramic imaging system with a tomosynthesis method. In this system we acquire many strip images of teeth and jaws, and reconstruct the standard curved plane of the image layer located at the dental arch. We used the tomosynthesis method, in which “shift and add” operations are applied to the strip images to make a dental panoramic image. To reconstruct this panoramic image accurately, we have to measure an actual geometry of the panoramic imaging system such as the movement of the x-ray source and the detector, and so on. In order to measure these parameters we developed a calibration phantom and determined the geometry. The calibration phantom consisted of 15 polymethyl methacrylate rods on which were located five brass wires. We acquired strip images of these wires and measured the positions of the wires at each projection angle. With these data we calculated several parameters defining the geometry of the dental panoramic system. If we can know these parameters accurately, we can easily change the position of the curved plane back and forth, and diagnose the condition of teeth freely. In addition, we can reconstruct a pseudo three dimensional display of teeth and jaws. In this paper we showed our method to determine several parameters needed for an accurate image reconstruction.修士(工学)法政大学 (Hosei University