高解析度電阻抗斷層掃描系統之開發

Abstract

電阻抗斷層掃描 (Electrical Impedance Tomography)是一種非侵入式的影像技術，可以重建目標內部的阻抗分佈，此種技術的應用在醫學影像裡日益增多，但是與核磁共振和電腦斷層掃描相比，電阻抗斷層掃描所產生的影像解析度較低，因此結合了電流調控的功能，開發出新型電阻抗斷層掃描的硬體設計和影像重建演算法，使我們得到更多獨立的量測資料，進而提高電阻抗斷層掃描的影像解析度。 另外，設計了兩種不同的假體及對應的實驗環境，第一種為一般的非侵入式的EIT實驗環境，在假體表面黏貼電極並量測內部的阻抗分佈，第二種為侵入式EIT的實驗環境，設計了探棒式的電極，在圓柱狀的探棒表面上黏貼電極，量測探棒周圍的阻抗分佈，而假體實驗的結果顯示此設計明顯超越了最先進的電阻抗斷層掃描系統。

Electrical impedance tomography (EIT), which is increasing used in medical imaging application, is a non-invasive imaging technology that can generate the internal impedance distribution of the target medium. However, compared with magnetic resonance imaging and computed tomography, EIT generates images with relatively low resolution. A new EIT hardware design and image reconstruction algorithm incorporating the current steering scheme was proposed and developed, allowing us to collect more independent measurement data, thereby increasing the EIT image resolution. In addition, two experimental environments for two different phantoms were designed. The first was a general non-invasive experimental environment for EIT, with electrodes placed on the surface of the phantom system, measuring impedance distribution inside. In the second case, an EIT system was used to measure the impedance distribution surrounding a probe in an invasive experiment environment, with adhesive electrodes on the probe surface. The phantom experiments show the proposed design outperform the state of the art electrical impedance tomography system significantly.