應用於磁振造影導引聚焦式超音波 乳房腫瘤治療之三維定位系統

A Three-dimensional Positioning System Applied in MRI-guided Focused Ultrasound Thermal Therapy for Breast Tumors

陳泓年(Hung-Nien Chen)

指導教授 ： 林文澧

國立臺灣大學/文學院/歷史學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.01257

摘要

本研究的目標為研發出一套應用於磁振造影導引聚焦式超音波乳房腫瘤治療之MR相容的定位系統。利用磁振造影(Magnetic Resonance Imaging, MRI)結合高強度聚焦式超音波(High Intensity Focused Ultrasound, HIFU)做超音波熱手術，可以在診斷的同時做精準的導引與治療；其治療方式具有非侵入式的優點，並可進一步結合溫度影像及搭配其他治療方式增進其診斷治療效果。
本研究將使用超音波壓電陶瓷馬達作為致動器，以三軸滑軌疊加的形式來傳動，並以斜面來帶動Z軸，一共具有X、Y、Z三個自由度，分別各有50mm的行程。搭載乳房用環型超音波探頭時，斜面機構與超音波探頭將放置於方形水槽，所有的機構將以MR相容的材料製成。由於MRI特殊的環境條件，在受限的材料及空間下設計製造MR相容之定位機台，對於機械工程師來說是一項挑戰。
以雷射三角測距儀，對搭載探頭之原型定位平台之定位功能進行精準度測試，其誤差在經過校正後均小於500μm，經過MRI取像測試後，初步判斷其具有足夠的MR相容性，不會對人員產生安全上的危害，亦不會對MRI取像造成干擾，且能確實地將環型超音波換能器定位。
本研究針對乳房MRI造影系統，開發出適用於乳房超音波熱手術之定位移動平台系統。此系統有足夠的定位精準度及MR相容性，應可有效承載環狀陣列式超音波探頭做乳房腫瘤熱手術。

關鍵字

磁振造影 ； 定位系統 ； MR相容 ； 超音波壓電陶瓷馬達 ； 乳房腫瘤 ； 磁振造影導引聚焦式超音波

並列摘要

The main purpose of this study is to develop an MR-compatible three-dimensional positioning system applied in MRI-guided focused ultrasound thermal therapy for breast tumors. The positioning system is used to move a ring-shaped phased array ultrasound transducer to deliver sufficient acoustic power to the desired region for breast tumor treatment. The combination of MRI system and FUS (Focused Ultrasound) can supply tumor examination, treatment planning, treatment monitoring, non-invasive treatment etc. for tumor therapy.
In this study, the positioning system consists of three ultrasonic motors used as the actuators and linear three-axial guides stacked up together for a three-dimensional motion control with a ramp mechanism for the transmission of mechanical movement in the Z-dimension. The travel ranges of X-, Y-, and Z-dimension are all 50 mm. When the system drives a ring-shaped ultrasound transducer, the transducer/transducer holder and the ramp mechanism are placed in a rectangular water tank, and all components are manufactured from MR compatible materials. Under the severe MRI conditions and treatment requirements, it is a challenge for a mechanical engineer to develop an MR-compatible positioning system to meet the needs.
The developed prototype of positioning system under the driving of the ring-shaped ultrasound transducer has been examined using a laser distance device for its positioning characteristics. The results showed that the position error is less than 500 μm after system calibration. For the MRI-compatibility test, the results revealed that the positioning system owns great MR compatibility. The positioning system can drive the ultrasound transducer to the desired locations with great precision without causing significant interference to MRI.
In this study, we focused on the development of an MRI-compatible positioning system which is used to drive a ring-shaped ultrasound transducer for breast tumor thermal therapy. The system has great movement precision and MR compatibility, and owns the potential to effectively drive the ultrasound transducer for MRI-guided focused ultrasound thermal therapy.

並列關鍵字

MRI ； positioning system ； MR compatible ； ultrasonic motor ； breast tumor ； MRI guided focused ultrasound

參考文獻

[6] 何乘孝，”圓柱型相位陣列超音波換能器應用於乳癌熱手術之研究” 國立臺灣大學醫學工程學研究所 碩士論文，2006。

[7] 林伯憲，“環形相位陣列聚焦式超音波結合磁振造影系統應用於乳房腫瘤治療的研究” 國立臺灣大學醫學工程學研究所 碩士論文，2011。

[2] Osama Al-Bataineh, Jurgen Jenne, Peter Huber, “Clinical and future applications of high intensity focused ultrasound in cancer,” Cancer Treat Rev., vol. 38, Issue 5, p.p. 346-353, August 2012.

[3] Zhou YF, “High intensity focused ultrasound in clinical tumor ablation,” World J Clin Oncol. vol.2(1), p.p. 8-27, Jan 2011.

[5] Elhawary, H., Tse, Z. T. H., Hamed, A., Rea, M., Davies, B. L. and Lamperth, M. U. (2008), “The case for MR-compatible robotics: a review of the state of the art,” Int. J. Med. Robotics Comput. Assist. Surg., vol. 4, p.p. 105–113, June 2008.