立體定位手術是腦神經外科的核心技術，一般使用術前掃描的醫學影像操作立體定位儀，並透過頭骨上的鑽孔進行手術，立體定位手術應用之一為深腦刺激，是治療帕金森氏症和癲癇和精神疾病的方法，唯手術成效相當仰賴刺激電極放置之準確度，但由於開顱後的腦組織會因為壓力差改變而產生形變，且手術中無法確認手術器械之末端位置，此種定位方法會導致許多誤差。為了改善傳統的立體定位手術方法，本研究希望結合術中磁振造影與機器人手術兩大領域的優點，目的在於建立磁振造影相容的手術機器人，預期能藉由磁振造影導引立體定位手術，加入即時回授的影像確認電極位置並降低手術穿刺數，以提升手術之效率與安全性。
本研究提出一新型的立體定位手術機器人設計，並建立其順向和逆向運動學的模型，此機器人能夠於磁振造影系統掃描艙的有限空間中進行定位，相較於傳統的定位機構，本研究之機器人僅需要五個自由度，能降低馬達對於磁振造影影像的干擾，且為了克服磁振造影環境的強磁場導致致動器失效，本研究選擇壓電馬達作為動力來源，並進行電磁屏蔽措施以達成磁振造影相容的要求。本研究最終完成機器人上的兩個自由度，並於此兩自由度的硬體上額外設計回授控制裝置，改善原本的定位誤差，建立的手術機器人雛型也在3.0T磁振造影系統中進行相容性測試，結果顯示磁振造影系統成像時不會干擾機器人的馬達控制，且機器人的機電系統也不會影響磁振造影影像品質，符合磁振造影相容之要求。

Stereotaxy is the core technology of brain neurosurgery that involves mechanical frames and guidance using preoperative images. The surgery often performs through a small burr hole so it is hard to confirm position of distal end of a catheter and human errors and brain shift may occur. It is believed that a magnetic resonance imaging (MRI)-compatible stereotactic robot may enhance accuracy and efficiency of surgery for deep brain stimulation. The goal of this thesis is to develop a MRI-compatible robot that can perform stereotactic operation within the MRI scanning space. A stereotactic robot that has five degrees of freedom was designed and a prototype with two major degree-of-freedoms was developed and evaluated. In particular, two MRI-compatible piezoelectric motors were employed to drive an innovative remote of center mechanism. The positioning performance of each degree of freedom was measured by using an electromagnetic digitizer. After calibration the error is less than 1.38°and 1.25°for the horizontal and vertical slider, respectively. The robot also tested within the scanner of a 3T MRI machine for both safety and compatibility using a standard phantom and a healthy subject. The results show that with proper shielding the robot can be safely operated in the MRI environment. During simultaneous imaging and actuation, the average drop of signal-to-noise ratio (SNR) is only 7.5% and no significant image distortion occurred. The developed system may be operated in the scanner and used in stereotactic operation in the future.

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