利用雷射產生之漏溢聲波進行組織檢查時之針定位

Abstract

超音波影像在目前已經廣泛地被醫師們使用於手術中對於針的輔助導引，由於超音波影像的優勢，使得操作者能夠同時藉由即時影像了解組織的解剖資訊及針在組織中相對應位置。然而由於超音波在針表面的鏡面反射作用會大大限制住超音波探頭與針之間的夾角關係，進而限制手術的靈活自由度。因此本論文提出一種全新利用雷射誘發漏溢聲波的針定位方式，其主要定位原理是基於超音波導波以及其在周圍介質中所產生之漏溢聲波的物理傳播特性。我們利用雷射聚焦在針身的頂部位置以在針表面產生超音波導波，當超音波導波在傳播時同時會洩漏部分能量到周圍產生漏溢聲波，我們便能利用超音波探頭去接收漏溢聲波並去做後續定位計算。在我們的實驗中，我們將26G的不鏽鋼針分別插入塑膠仿體以及豬肉組織中去做定位測試，結果顯示我們的漏溢聲波定位方法能夠在豬肉組織中做到50 mm的定位深度，並且最大的針插入角度能夠到達40°，顯示本方法優於現有的超音波與光聲方法。

Ultrasound (US)-guided needle operations have been widely used to visualize both tissue anatomical structures and needle position in real time. However, the US transducer-needle angle is often limited due to specular reflection from the needle surface. We propose a new needle visualization method based on laser-induced leaky acoustic waves. The needle angle and position are calculated based on characteristics of guided waves and leaky acoustic waves. In our approach, the top of the needle shaft is illuminated by laser and guided acoustic waves are subsequently generated, propagating along the needle and leak to the surrounding medium that can be detected by the US transducer. This method was tested with a 26-gauge needle in both a tissue mimicking phantom and porcine muscle tissue. Results show that the detection depth is more than 50 mm and the insertion angle is up to 40°, both are superior than existing ultrasound and photoacoustic methods.