磁振造影相容之高強度聚焦型超音波熱手術系統開發

Abstract

超音波熱手術治療為一種非侵入式手術，利用機械波的震動與聚焦造成組織溫度的升高以達成腫瘤燒灼的目標；而在燒灼過程中需要溫度的監控來告訴操作人員或是醫師，且近年來，不僅許多論文探討以磁振造影引導超音波熱治療的方式觀測異常組織位置與燒灼治療時溫度變化，並且國外已經有許多研究證實影像引導式超音波熱手術治療用於子宮肌瘤，或是良性及惡性乳房腫瘤為有效的治療方法。 有鑑於此，本研究主要為開發一台與磁振造影相容的超音波熱手術系統。利用伺服馬達帶動油壓缸的方式推動移動平台，並使用Visual Basic軟體整合了二維移動平台控制機構，超音波功率放大器，CCD影像擷取，與熱手術治療規劃的使用者介面以達成軟硬體之間的整合。初步利用CCD影像觀測透明仿體的方式，暫時模擬醫學影像(磁振造影)看透物體的能力，當作此系統影像引導工具來做仿體燒灼加熱實驗。此系統經過測試運轉後，目前成功的達成二維移動的控制，移動誤差小於0.5mm；並完成了初步的仿體燒灼實驗，證實此系統能夠正確達成規劃多點加熱的動作。

High intensity focused ultrasound is a noninvasive method of tissue ablation that can be guided and monitored with magnetic resonance imaging (MRI). Magnetic resonance-guided focused ultrasound surgery (MRgFUS) has been shown clinically effective in treatment of uterine fibroids and it is being evaluated as a method of thermal ablation for other benign and malignant tumors. In this study, we develop a MRI- compatible focused ultrasound thermal surgery system with image guidance. We use hydraulic position devices driven by a computer-controlled servo motor to move the transducer holder, and integrate the automatic position devices, ultrasound power amplifier, CCD image capture into a graphical user interface. At this stage, we use two CCD cameras to capture the transparent gel phantom as an image guided tool for this system in order to simulate the future MR image system which will be employed for animal experiments and patient treatments. This system was evaluated and operated. It can do two-dimensional motion control, and the localization error is smaller than 0.5mm. Through the user interface, we can move the transducer to ablate the target region under the CCD images. The preliminary gel phantom ablation experiment demonstrated that the system can achieve reach the desired treatment plan satisfactorily.