脊椎是人體中最重要的結構之一，它提供支撐人體、保持平衡、保護脊髓等功能，日常生活的行為也與脊椎密切相關，如走路、運動、搬運物品等。脊椎的健康條件會隨著人體的老化、不正確或過度頻繁的使用而逐漸變差，導致骨質疏鬆、變形塌陷等問題。針對脊椎疾病或受傷，脊椎融合手術是相當普遍的治療方法。針對此項手術，醫師會藉由植入骨釘等結構把脊椎骨作融合以支撐起脊椎，藉此恢復脊椎應有的功能。由於脊椎骨牽涉到神經系統，且為人體最重要的結構，所以手術困難度很高，需要非常豐富的經驗。本論文因此建立一套骨釘植入手術模擬系統，用以提供醫師在訓練或手術評估上的需要。
論文所提議之系統可分為脊椎骨與其它軟組織的分割建模，以及輔以力回饋機制的手術模擬系統兩個部份。脊椎骨分割使用立體電腦斷層影像，以矢狀面角度針對每一張切片影像分割出脊椎骨部分。在本研究中，我們將原始電腦斷層影像以非等向性濾波器做降噪處理，再以均值偏移聚類法對影像分群，以統計方式選取出適當的初始輪廓，最後用Chan-Vese水平集方法把輪廓修正至最理想的結果，所有切面分割結果會以三維建模演算法產生出立體脊椎模型。其它軟組織分割則使用核磁共振影像，並把血管、神經等分割結果建立成三維模型。手術模擬系統針對脊椎骨及其它軟組織模型為基礎，建構出虛擬的手術場景，並藉由骨科醫師對於手術需求的建議，設計出一套擬真的手術情境。為增強手術模擬的迫真感，系統將原始電腦斷層影像資料與脊椎模型結合，計算出手術工具在使用過程中所受到的阻力並即時反饋給使用者。模擬的過程中，光源及操作角度可依需求調整。結束後，系統並提供手術評分以及不同角度觀看過程重播等功能。針對本研究主要分割方法的結果，其平均DC 值為0.92。

The spine is one of the most important parts of human body. Spine diseases owning to aging or injuries would mostly be treated by spine surgeries. However, the surgeries are highly dangerous and the surgical training can increase the success rate. In this thesis, an interactive surgical simulation system for the training of pedicle screw implantation is proposed and implemented.
An automatic and efficient method is proposed to segment the vertebra from the CT images for constructing the vertebra model. The mean shift method which can cluster the pixels having similar property into groups is used in the image data clustering. The clustered groups related to the bone region are chosen as the initial model. And then, we apply the Chan-Vese level set method which refines the vertebra contour by using the statistic concepts. After the segmentation, we then apply the marching cube algorithm to generate the 3D vertebra model. The soft tissue models like nerves, arteries and veins are also built from the MRI images by using the conventional image processing methods. All these segmented models are then merged into a virtual surgical environment. Then a haptic device is applied to interact with this model for fulfilling the surgical simulation in the virtual environment. The force feedback is calculated by the combination of CT image information and the vertebra model. A pedicle screw implantation surgical scenario is built under the opinions of the orthopedists in order to increase the simulation reality. In the surgical scene, lighting and surgical view can be adjusted. A score report and operation video replay can be checked after the simulation for a detail evaluation. The average dice coefficient of the segmentation results is 0.92.

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