A lapse observation algorithm for lung cancer detection using 3D thoracic helical CT images

In this paper, we present a lapse observation algorithm for lung cancer detection using 3D thoracic helical CT images. Purpose of this study is to detect the interval change that exist between time different images of same patient. We employed two methods to detect the interval change. The first method is 3D local template matching method. We tried to detect the movement of blood vessel and other organs by this method. The second method is subtraction method. We tried to detect the new shadow by this method. The subtraction technique is the common method which detects the interval change. If the two images are produced in an identical manner, the subtraction image derived from a pair of thin slice CT with time difference having a uniform zero pixel value except for regions with interval changes. However, the same 3D thoracic images are not obtained. Therefore, we study the method to correct the location between 3D thoracic images with time difference.