即時超音波參數化影像系統於射頻燒灼監控之驗證

Abstract

隨著醫療的進步，治療肝癌的方法不斷改進，射頻燒灼治療為近年來新興的一種局部消除治療法，也廣泛的運用在臨床治療上。為了監控射頻燒灼治療，需要一個輔助、導引的工具來評估燒灼區域，超音波影像即為臨床上最常使用評估工具，具有非侵入性、即時呈像、非游離輻射、易攜帶、價格便宜等優點。傳統的超音波影像為B-mode影像，但B-mode影像在評估熱燒灼時，很難評估燒灼區域。 因此本研究目的是利用本實驗室所開發的超音波Nakagami影像做為監控射頻燒灼治療的新工具。超音波Nakagami影像已被證實能藉由局部散射子的分布排列、濃度上的差異來辨別局部組織特性，再結合可提升靈敏度的頻率分集與複合的技術，搭配後來提到的多項式逼近影像，去發展出一個即時的超音波監控系統，並且利用離體實驗去驗證方法和系統在監控射頻燒灼上的效能和可行性。 實驗中利用離體實驗(豬肝組織)進行評估組織燒灼的面積大小，驗證出在多項式逼近影像中的-6 dB的燒灼面積與我們真實燒灼豬肝的組織切片的面積的相關係數是最高的，因此制定-6 dB為影像面積的標準。 實驗嘗試使用不同射頻燒灼的電極長度對豬肝組織進行燒灼面積的驗證，由結果顯示，使用即時參數化影像系統監控射頻燒灼，利用小電極長度(0.5、1.0公分)偵測組織的燒灼面積的評估會相較於準確。

With medical improvements , continue to improve methods of treating liver cancer, radiofrequency ablation(RFA) is an emerging therapy in recent years as , also widely used in the clinical treatment. In order to monitor RFA, requiring an auxiliary, guiding tool to evaluate ablation zone, ultrasound imaging is the most commonly used clinical evaluating tools, with a non-invasive, real-time, non-ionizing radiation, easy to carry, and inexpensive . Conventionally, ultrasound imaging is displayed as B-mode imaging, but B-mode imaging can’t identify thermal zone clearly. In this study, we investigate the use of ultrasound Nakagami developed in our laboratory imaging as a new tool for monitoring RFA therapy. Ultrasound Nakagami imaging has been shown to be capable of differentiating the characteristics of local tissues through the distribution, arrangement, and concentration differences in local scattering, combined to enhance the sensitivity of the frequency diversity and compounding technology, with later polynomial approximation imaging . We develop the real-time ultrasound monitoring system. Using in vitro to verify the effectiveness and feasibility on the RFA monitoring system. Using in vitro (liver tissue) to evaluate tissue ablation zone, we can verify imaging ablation area and true ablation area of liver tissue sections in the polynomial approximation imaging of -6 dB of the correlation coefficients is highest. Therefore we regulate -6 dB as the standard of imagnig area. In the experiments ,we try to use different electrode lengths for verifying ablation area. The results show that the use of real-time parametric imaging system monitoring radiofrequency ablation, using small electrode length (0.5, 1.0 cm) to detect ablation area of tissue assessment will be compared accurately.