[Two-dimensional Projection and Image Reconstruction].

Medical images are being recently reconstructed using several data sets. In x-ray and computed tomography (CT), 3-dimensional (3D) images are reconstructed using 2-dimensional (2D) projection data. Research regarding the image reconstruction method has been actively conducted. Further, 3D images include patient information and are used as diagnostic tools. Therefore, it is necessary to acquire a projection technique. There are several algorithms of the projection method. In this paper, we reviewed three methods. The first method is based on mathematical formulae, the second integrates pixel values at regular intervals along the x-ray track, and the third integrates pixel values multiplied by distance. We confirmed the usefulness of the projection method for reconstructing images.