The Key Techniques Research For Liver Virtual Surgery

The liver is the biggest human internal organ of life activity, which is the largest digestive gland of the digestive system and important metabolic organ, but the vulnerability of the liver makes the incidence of liver disease very high. According to statistics, 10% of the country's total population is hepatitis B virus carriers, about 110 thousand people die from liver cancer each year. Liver resection and transplantation is an effective way to treat liver cancer, while the key to the success of the operation is volume estimation and the accuracy of surgical plans. Doctors generally based on three-dimensional image data experience to make judgments, and to determine surgical plan, cannot make accurate volume estimation and choice of cutting location, use computer technology to simulate and evaluate the liver imaging on virtual surgery is an important issue.Virtual liver surgery simulation system consists of image pre-processing, image segmentation, volume estimation, the virtual cutting simulation and other functions. This paper studies the functional modules key technologies of image pre-processing and virtual cutting simulation. Image pre-processing is to enhance liver tissues in CT slices. Virtual cutting simulation is to simulate the real surgical procedure, to give doctors good surgical experience.While studies the key technologies in image pre-processing, based on partial differential equations based histogram equalization method, this paper propose a method which combing global information and local gradient information. Experimental results show that the liver can be effectively enhanced in CT images, solved the difficult to distinguish problem because the contrast of liver and its surrounding tissue in the CT image is low.At present, the clinical used liver virtual surgery systems are use the mouse or a simple force feedback as an input, could not give doctors the feeling of surgery in three-dimensional space. The system use of force feedback devices is not only expensive, poor flexibility, but inaccuracy. Therefore, develop a system which according to the movement of a doctor's hand in three-dimensional space to control the movement of virtual scalpel, can increase doctor's immersion in virtual surgery.In order to track the doctor's hand movements in space, we use the Wiimote and its accessory Motion Plus which is high precision, low price, and ease to use, as a tracking device. After careful analysis of the characteristics of these devices, use Kalman filter algorithm to process data, obtained a smooth path of Wiimote follow the hand movement in three-dimensional space. Experiments show the correctness and feasibility of the algorithm design.To solve the above key technology lay a good foundation of establishment a complete virtual surgery simulation system.