Design Of Computer Diagnosing System For Colon Polyps

Colorectal cancer, a common gastrointestinal cancer, is ranked as one of the three most common cancers worldwide. Because most colorectal cancers are developed from preexistent polyps, the earlier detection and removal of polyps can reduce the incidence and mortality rate of colorectal cancer.Virtual colonoscopy is widely applied as a noninvasive method in clinical polyp diagnosis. However, virtual endoscopy is time-consuming with a narrow view angle, which will cause missed and erroneous diagnosis. And more and more researches propose new visualizing technology for colorectal polyp diganosis, such as virtual flattening, virtual eversion, virtual splitting, to provide wider view angle for fast and accurately locating colon polyps.The design and realization of a new computer diagnosis system for colon polyps, combined with virtual endoscopy, virtual flattening, virtual splitting, virtual eversion and other real-time diagnosing technology, were proposed to provide fast and accurate diagnosing method in clinical treatment. Three real-time virtual visualizing technology based on GPGPU acceleration was proposed to obtain more accurate result. The ray-casting algorithm and lighting computation of the virtual visualizing technology was accelerated by the high-speed parallel computing capability of graphic processing units and implemented in the proposed ray-casting model of virtual endoscopy, virtual flattening, virtual splitting to realize the real-time volume rendering. For the real-time characteristic of the virtual visualizing technology based on GPGPU, the threshold of the inner surface of colon can be modified dynamically during the procedure of diagnosis to extract the correct surface, overcoming the false surface extraction due to partial volume effect in the virtual visualizing technology based on surface rendering.Furthermore, the proposed system was integrated with the novel technology: virtual eversion and virtual rotation. Virtual eversion technology provide a wider view angle and keep the morphology of the colon by everting the inner surface to the outside so that the polyps can be directly located. Virtual rotation technology rotates the virtual eversion result along the centerline to overcome the adherence or deformation occurs at the highly curved location.With real abdominal CT volume data, the experiment result showed that the proposed system, compared with traditional virtual endoscopy system, can increase the speed of examining the colon and find out the polyps more quickly and accurately.