扇形渦狀相位調變式超音波換能器結合機械掃描系統於超音波熱手術之探討

Investigation of a Sector-Vortex Phased Array with Mechanical Scanning for Ultrasound Thermal Surgery

楊鎮澤(Chen-Tse Yang)

指導教授 ： 林文澧

國立臺灣大學/工學院/醫學工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.02350

摘要

一般熱手術使用的超音波換能器產生的焦點小，然而治療區域大，因此需要多次的分區治療與冷卻，而造成整體的治療時間過長。文獻指出，如果能夠有效地放大焦點區域，便可以有效地縮短治療的時間。
本研究主要建立一加熱系統，此系統是結合機械式旋轉掃描系統與扇形渦狀相位調變式換能器來產生較大的治療區域。扇形渦狀相位調變式換能器能藉由調變相位來產生不同且較大的環狀焦點。我們利用機械式旋轉掃描系統來帶動換能器，以便達到擴大治療區域的效果。此掃描系統可調整的參數為：傾斜角、旋轉角、掃描半徑及加熱深度。選擇適當的系統參數，便可以達到所預期的治療效果。
我們將球形聚焦換能器切割成四片扇形，以Mode 0與Mode 1驅動，依照先前模擬的系統參數進行仿體實驗，所得到的實驗結果與之前模擬的結果相似。

關鍵字

換能器 ； 熱手術 ； 超音波 ； 腫瘤

並列摘要

The common practice in ultrasound thermal surgery for treating large tumors is to introduce a large lesion for each exposure with some proper heating strategies. The purpose of this study is to investigate the feasibility of using a sector-vortex phased array of ultrasound transducer with mechanical scanning to produce a large thermal lesion.
The proposed system is composed of a mechanical scanning system with a sector-vortex phased array. The sector-vortex phased array can produce different types of broadened focal zones by tuning the phase and the amplitude of each array element. The mechanical scanning system can control the tilt angle, rotation angle, heating depth, and scanning radius. The previous simulation results suggest that the temperature rise, heating time, and the power density are the dominating factors affecting the treatment results. The results also show that the proposed system can produce conformal thermal dose patterns for different tumors. In experiments, we use mode 0 (as a spherical transducer) and mode 1 in a sector-vortex phased array with four elements to sonicate the porcine liver. The lesion shapes in the in vitro experiments are close to those in the simulations.

並列關鍵字

phased array ； thermal surgery ； ultrasound ； tumor

參考文獻

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