椎莖螺釘手術為高風險與高難度的手術，在手術過程中醫師必須不斷拍攝C-arm影像確認手術器械不會誤傷到中樞神經，造成醫護人員與病患吸收大量輻射。本研究透過3D C-arm建立3D影像與拍攝2D影像之功能，發展一套2D/3D C-arm影像輔助導引系統，以2D影像手術導引可達到降低輻射量的目的， 3D影像手術導引可提供Axial View剖面影像，讓手術路徑規劃更精確，又2D或3D影像手術導引皆可讓手術更精確、安全、與提升手術時效。
本研究以實驗室所發展的C-arm影像輔助椎莖螺釘植入手術用導引系統為基礎，在2D C-arm影像導引部分以可以移動的X-Board取代雙層影像校正器的第二層功能，並開發自動在影像中尋找X-Board標記(鋼珠)的演算法，達到減少妨礙手術空間與提升定位精準度的目的
3D C-arm影像導引部分，將3D註冊樣板與患部一起，拍攝3D影像，透過自動化的方式完成3D影像與患部的註冊，並設計一方便的使用者介面，提供醫師可在電腦螢幕上或在患部上以定位器械進行手術路徑規劃，系統會隨者定位器械的尖點位置與角度即時切出對應的Axial 、Sagittal與 Coronal Views，讓醫師可直覺地確認手術路徑的正確性。
由2DC-arm影像導引單點定位精準度實驗結果知，X-Board在AP與LA拍攝時建議X-Board盡量遠離接收端，可達到良好的定位效果，其平均誤差值為0.49±0.2mm。在3DC-arm影像導引定位實驗得知，3D方位校準精準度誤差值會隨者目標點離3D註冊樣板越遠而越高，在離3D註冊樣板距離為11cm左右其最大定位誤差值為1.78mm已小於臨床使用導引系統的2mm誤差值。

關鍵字: 3D C-arm、C-arm手術導引、脊椎手術

Pedicle screws implantation is a high-risk surgery. During operation, the surgeon has to take a lot of C-arm X-Ray images to check if the pedicle screw is in the right path. The medical persons and patient are thus facing a risk of high radiation exposure. This study uses 3D and 2D X-ray images provided by a 3D C-arm to develop a 2D/3D C-arm image assisted surgical navigation system. The 2D system uses only two C-arm images and thus is able to reduce radiation exposure while 3D system is able to provide axial view of the spine for precise path planning. 2D or 3D system leads to more accurate, safe, and efficient surgery .
Instead of using the existing double-deck image calibrator, the 2D system applies a free-movable X-Board and a single-deck image calibrator to determine the focus point of C-arm X-ray. The approach can reduce the interference of surgical space and improves positioning accuracy of the system using double-deck image calibrator. The 3D system is able to automatically register 3D images and the patient through a registration board. The system provides a friendly user interface for the surgeon to plan surgical paths on the computer displayed axial, sagittal, and coronal views or on the patient by using a positioning tool.
As the results of positioning experiments of 2D system, it is suggested to place the X-Board far away from the C-arm image receiver to obtain precise C-arm projection model and thus to improve positioning accuracy of the system. The average positioning error of single target point is 0.49 ± 0.2mm. On the other hand, the results of the positioning experiment of the3D system show that the positioning error is proportional to the distance between the target and registration board. When the distance reaches 11 cm, the maximum positioning error of system is 1.78mm, however, it is still less the expected 2mm required for clinic application.
Key Word : 3D C-arm、surgical navigation system、spine surgery
 

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