A study on the three-dimensional image processing method for 3DX Multi Image Micro CT

Abstract

Objective: A clinical model of limited cone-beam X-ray CT (3DX Multi Image Micro CT) has been developed by Arai et al. [Y. Arai, E. Tammisalo, K. Iwai, K. Hashimoto, K. Shinoda, Development of ortho cubic super high resolution CT (Ortho-CT), Car '98 Computer-Assisted Radiology and Surgery, Elsevier, Amsterdam, 1998, pp. 780–785] for dental use. In this paper, a three-dimensional image processing method for 3DX Multi Image Micro CT (3DX), which is capable of obtaining clear three-dimensional images, is proposed. Method: First of all, the three-dimensional projection data are decomposed to a set of two-dimensional data. However, the obtained data contain much noise because the projection data are obtained by low-level X-ray. Therefore, we proposed the following steps for obtaining clear three-dimensional images. Firstly, contrast stretching is applied to the set of two-dimensional image data based on the contrast information of the target image for avoiding noise. Then, the edge detection with the Canny operator is performed. In our method, the loss of the target image, which is caused by noise reduction and edge detection, can be interpolated by the image obtained from different directions. Finally, the clear edge of the two-dimensional image data is reconstructed to the three-dimensional image data. Result: It is shown that clear three-dimensional images are obtained when we applied the proposed method for three-dimensional imaging of the temporomandibular joint. Conclusion: A new method for constructing three-dimensional images from the image data obtained from limited cone-beam-type X-ray CT is proposed. The effectiveness of the proposed method is shown by constructing three-dimensional images of the temporomandibular joint.