Automatic Morphological Segmentation of CT Images for Radiotherapy Treatment Planning of Hepatic Tumor

Autor: Yeh Chi-Yuan, 葉啟源
Rok vydání: 2004
Druh dokumentu: 學位論文 ; thesis
Popis: 92
Hepatocellular carcinoma (HCC) is the leading cause of cancer related death in Taiwan. Three-dimensional conformal radiotherapy (3DCRT) is gaining acceptance as an option in the treatment for HCC, partly due to improvement in medical 3D imaging capabilities of current radiotherapy treatment planning system (RTP). Tumor contour delineation is necessary for volume visualization and implementation of 3DCRT. Manual delineation of the tumor contour is time consuming and error prone. Numerous studies have been conducted in an effort to automate tumor delineation by using the different methods of image segmentation with varied success. In this study, CT image segmentation using mathematical morphology was studied with the aim of automating the delineation process and reducing operator workload and error. First, abdominal CT image in 5 mm slice were obtained from HCC patients before undergoing 3DCRT, a total of 242 CT images were collected for analysis. The DICOM 3.0 compliant images were then read using matlab image processing toolbox, the image segmentation method consisted of the several steps including averaging filter, flood fill operation, calculation of the image gradient by image dilation and erosion, and watershed transform. The Hausdorff distance, quality index, and Dice similarity index were used for validation of watershed segmentation. The study showed the mean Hausdorff distance, mean quality index and mean Dice index were 10.455 mm, 0.7478, and 0.8523 respectively. In conclusion, morphological segmentation using the watershed transform for HCC tumor contour delineation is feasible and clinically acceptable, however, more study and refinement of the algorithm is needed to improve the quality and robustness of automatic image segmentation.
Databáze: Networked Digital Library of Theses & Dissertations
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