應用呼吸流量測量於肝腫瘤高強度聚焦超音波治療的 追蹤系統設計

Design of Tracking System with Respiratory Flow Measurement in High Intensity Focused Ultrasound Liver Tumor Treatment

鄭傑方(Chieh-Fang Cheng)

指導教授 ： 陳永耀

共同指導教授 ： 林文澧

國立臺灣大學/電機資訊學院/電機工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.02806

摘要

在腫瘤的治療研究當中，高能聚焦超音波是其中一種近年來相當熱門的治療方式，但仍有許多問題需要被解決，例如會隨著呼吸移動的腫瘤。這樣的一個問題在輻射治療的領域中已經被廣泛的討論，相較於著名的即時腫瘤追蹤輻射治療系統(Real-Time Radiotherapy Tracking System, RTRT)，高能聚焦超音波領域中一直沒有一個比較好的追蹤治療系統。因此我們曾經設計了一個稱為「台大核磁造影導引高能聚焦超音波追蹤治療系統(NTU MRI Guided HIFU Tracking System)」的系統，透過核磁造影(Magnetic Resonance Imaging, MRI)的影像導引，搭配上一個 類神經網路構成的預測器，這個預測器是用來解決影響處理時所造成的時間延遲，進而控制超音波換能器能追蹤聚焦在所希望治療的區域。但是這樣的一個系統卻一直存在追蹤誤差的問題，而沒有一個較為理想的表現，因此在這篇論文中將提出一個改進的設計架構。
為了增進追蹤的效能，在這裡使用呼吸訊號的測量系統替換掉原本的核磁造影系統，並利用影像處理的肝臟定位系統換成一個將呼吸訊號轉換為肝臟位置的對應系統，再配合上一個線性外插的預測器，完成了這個新的追蹤系統「台大基於呼吸訊號的高能聚焦超音波追蹤治療系統(NTU Respiration Signal Based HIFU Tracking System)」，這個系統有著更高的取得肝臟位置的取樣頻率，以及比台大核磁造影導引高能聚焦超音波追蹤治療系統更低的追蹤誤差，系統表現也較為優良。在這篇論文中將會有一些比較來驗證這樣的設計能帶來追蹤效能上得改善。

關鍵字

高能聚焦超音波加熱系統 ； 呼吸流量 ； 肝臟腫瘤 ； 追蹤

並列摘要

In the research of treating tumors, High Intensity Focused Ultrasound (HIFU) is one of the popular treatment methods in the recent years. The treatment in the moving tumor is always a serious problem. A number of methods can solve this in the radiotherapy. Comparing Real-Time Radiotherapy Tracking System (RTRT), there is not a nicer HIFU tracking treatment system so NTU MRI Guided HIFU Tracking System was developed before. A Magnetic Resonance Imaging (MRI) system guides HIFU in this system. In order to solve the delay time produced in the liver position determination system, the neural network is a predictor. The predicted position is used to control the position of the ultrasound transducer. Some tracking errors always exist in NTU MRI Guided HIFU Tracking System and therefore the performance is not good enough. It is the reason to improve HIFU tracking system.
In order to get a better performance, a respiration signal measurement system replaced MRI system and a mapping system replaced the liver position determination system. The mapping system is used to transform the respiration signal into the liver position. The system is called NTU Respiration Signal Based HIFU Tracking System. A higher sampling rate of getting liver positions is in this system. The tracking error of this system is lower than the tracking error of NTU MRI Guided HIFU Tracking System. The performance of NTU Respiration Signal Based HIFU Tracking System is also better. Some comparisons verify the new design can bring the improvement in the performance of tracking.

並列關鍵字

HIFU ； Respiratory flow ； Liver tumor ； Tracking system

參考文獻

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