2008 年 25 巻 4 号 p. 86-89
We have reported the usefulness of a fully automated dynamic subtraction method of hepatic CT by use of 3-D phase only correlation method for improvement of detection of hepatic tumors. However, when the liver moves greatly in breathing, subtraction of CT images fails due to mis-registration of livers in this method. So, we have developed an improved fully automated dynamic subtraction method of hepatic CT. In this method, we used segmented extracted liver regions instead of extracted bone regions. For extracting liver regions from CT images, we used a level set method. The performance of the improved method was superior to that of our previous method, especially, in the cases those livers moved greatly in breathing.