摘要 電阻抗斷層攝影系統(Electrical impedance tomography, EIT)為一種應用於量測物體或人體組織橫切面阻抗變化的儀器，但重建出的影像由於受到解析度的限制，使得阻抗影像系統無法廣泛的被應用在臨床診斷上，為了能突破以往因量測資料量不足而影響解析度的問題，本論文提出旋轉式EIT系統，利用步進馬達的帶動旋轉，可使量測位置增加，因而提升量測系統的資料量，此外論文內也針對電極組態特別設計，系統內採用一複合式的電極，分別包含了電流電極與電壓電極，此一分離電極的設計可以進一步的提升系統的精確度與穩定度，藉由論文內所提出的改善方法，使EIT系統能夠達到更高的性能。 為了要確保系統的穩定度，在實驗前先對電極的效能進行評估與電流源及多工器通道測試，實驗中各別以量測到的208筆資料與1040筆資料重建影像做比較，由實驗的結果看出重建的影像若採用較多筆的資料數則可使影像解析度提高，重建的影像則可清楚的看出實際待測物的所在位置與大小。 雖然本論文提出旋轉式EIT系統可使得重建影像解析度提升，但目前仍於假體內實驗，因此未來期望系統的改良，可實際應用於人體組織量測上。 A high-performance rotary Electrical Impedance Tomography system Abstract Electrical Impedance Tomography (EIT) system is an instrumentation which measures the cross-section of material or tissues. It can not extensively apply to clinical diagnosis because the reconstructed image has poor resolution. In order to overcome the resolution limitation causing by lack of measurements, the rotary Electrical Impedance Tomography (REIT) is proposed to increase the efficiency of electrodes. The system equipped a stepping motor to drive movable electrodes. By increasing the number of measuring sites, this system can acquire more measurement data. Therefore, the image resolution can be improved further. The paper is also including the design of electrode. The configuration of electrode is a compound electrode that including current electrodes and voltage electrodes. It can make that the system perform better precision and stability. These improvements can help EIT system to achieve higher performance. To ensure reliability of the REIT system, all of the subsystem, such as electrodes, current source and multiplexer are well tested. In the experiment, we reconstructed the impedance image coming from 208 measurements and 1040 measurements respectively. From the results, we observe that the image with more measurement data has better resolution. By increasing the resolution of the image, the reconstructed image can show actual object in position and size. The proposed rotary EIT system can promote resolution of reconstruction image, but this system only tested on the phantom. Therefore we hope that the system is improved in the future, it can practically apply to biologic tissue.
