【摘要】：超聲穿刺導航可以實時顯示穿刺針在組織內的運動情況,為穿刺路徑選擇提供依據,是超聲輔助治療的重要手段,具有廣闊的發(fā)展空間。然而,現(xiàn)有超聲穿刺導航系統(tǒng)存在著操作復雜、定位不精確、穿刺角度固定麻煩等問題,所以穿刺手術對醫(yī)生手法的依賴程度高,而且經常需要進行多次穿刺。針對上述情況,本文提出基于電磁定位方式的超聲自由穿刺導航方法；并針對影響穿刺精度的關鍵因素——軟組織變形,采用有限元方法進行詳細的分析；最后基于便攜式超聲成像系統(tǒng),提出自由穿刺導航的軟硬件設計方案。具體研究內容如下： 1)超聲穿刺導航算法研究。本文根據超聲穿刺導航系統(tǒng)的臨床應用,分析現(xiàn)有系統(tǒng)的不足和各種定位方式的優(yōu)缺點,得出電磁定位系統(tǒng)具有定位準確、體積小、重量輕、受環(huán)境因素影響小等特性,適合用于超聲穿刺系統(tǒng)實時定位的結論。故本文將電磁定位應用于現(xiàn)有的超聲成像系統(tǒng)中,進而設計了基于電磁定位方式的實時導航算法——建立坐標變換的數學模型,研究將磁場坐標與聲場坐標進行精確配準的手段,以便實時標示穿刺針相對于超聲圖像的位置,從而為提高穿刺準確性,縮短穿刺時間提供有效方法。 2)穿刺過程軟組織形變的有限元仿真。軟組織形變是影響穿刺精度最主要的因素,研究軟組織變形對提高穿刺的準確性具有重要的臨床意義。本文基于有限元方法,將軟組織離散化為有限個單元,并對各個離散單元進行彈性力學分析,建立軟組織的線性彈性模型。根據該理論模型,采用ANSYS有限元分析軟件進行軟組織變形仿真,根據軟組織的材料屬性、單元參數、應用邊界條件和初值條件對網格化的模型施加載荷,仿真得出穿刺過程中軟組織的形變數據。該形變模型可為穿刺導航系統(tǒng)實現(xiàn)穿刺前的路徑規(guī)劃和避障預警提供一種有效的手段。 3)軟硬件方案設計。針對現(xiàn)有數字化便攜式超聲成像系統(tǒng),本文設計了超聲穿刺導航系統(tǒng)軟硬件方案。硬件設計采用ARM+FPGA雙核處理器外加電磁定位器的方案,系統(tǒng)中ARM除負責系統(tǒng)的實時控制,如按鍵響應、字符界面的顯示、應用軟件的選擇、FPGA的信號控制等任務外,還進行定位系統(tǒng)位置信號的采集工作；而FPGA主要負責超聲圖像信息的采集和處理、探頭控制、圖像存儲、定位信息的合成顯示。系統(tǒng)軟件體系結構的設計采用消息驅動的方式,以保證代碼的運行效率。
[Abstract]:Ultrasonic puncture navigation can show the movement of puncture needle in tissue in real time, and provide the basis for puncture path selection. It is an important means of ultrasound assisted therapy and has a broad space for development. However, there are some problems in the existing ultrasonic puncture navigation system, such as complex operation, inaccurate positioning, trouble in fixing puncture angle, so puncture surgery has a high degree of dependence on doctor's manipulation, and often needs to be punctured many times. In view of the above situation, this paper proposes an ultrasonic free puncture navigation method based on electromagnetic positioning mode, and analyzes the soft tissue deformation, which is the key factor affecting the puncture accuracy, in detail by finite element method. Finally, based on the portable ultrasonic imaging system, the hardware and software design of free puncture navigation is proposed. The specific research contents are as follows: 1) the research of ultrasonic puncture navigation algorithm. According to the clinical application of ultrasonic puncture navigation system, this paper analyzes the shortcomings of the existing system and the advantages and disadvantages of various positioning methods, and concludes that the electromagnetic positioning system has the characteristics of accurate positioning, small volume, light weight and little influence by environmental factors. It is suitable for real-time positioning of ultrasound puncture system. Therefore, this paper applies electromagnetic positioning to the existing ultrasonic imaging system, and then designs a real-time navigation algorithm based on electromagnetic positioning, which is to establish the mathematical model of coordinate transformation. The method of accurate registration between magnetic field coordinates and sound field coordinates is studied in order to mark the position of puncture needle relative to ultrasonic image in real time, so as to provide an effective method for improving puncture accuracy and shortening puncture time. 2) finite element simulation of soft tissue deformation during puncture. Soft tissue deformation is the most important factor affecting puncture accuracy. It is of great clinical significance to study soft tissue deformation to improve the accuracy of puncture. In this paper, based on the finite element method, the soft tissue is discretized into finite elements, and the elastic mechanics of each discrete element is analyzed, and the linear elastic model of soft tissue is established. According to the theoretical model, the soft tissue deformation is simulated by ANSYS finite element analysis software. According to the material properties and element parameters of soft tissue, the boundary condition and initial value condition are used to apply the load to the gridded model. The deformation data of soft tissue during puncture were obtained by simulation. The deformation model can provide an effective means for puncture navigation system to realize path planning and obstacle avoidance early warning before puncture. 3) Software and hardware scheme design. Aiming at the existing digital portable ultrasonic imaging system, the software and hardware scheme of ultrasonic puncture navigation system is designed in this paper. The hardware design adopts the scheme of ARM FPGA dual-core processor plus electromagnetic locator. In the system, ARM is not only responsible for the real-time control of the system, such as keystroke response, character interface display, application software selection, FPGA signal control and so on. The position signal acquisition of the positioning system is also carried out. FPGA is mainly responsible for ultrasonic image information acquisition and processing, probe control, image storage, positioning information synthesis and display. The design of the system software architecture adopts the message-driven way to ensure the running efficiency of the code.
【學位授予單位】：浙江大學
【學位級別】：碩士
【學位授予年份】：2012
【分類號】：R318.6

【參考文獻】

相關期刊論文 前7條

1 馬志梅;梁笑坤;王桂香;;經三維超聲引導穿刺固化治療卵巢單純囊腫臨床研究[J];臨床醫(yī)藥實踐;2010年19期

2 王磊;李珊;周陶勇;;基于ANSYS的幾種建模方法的探討[J];現(xiàn)代機械;2006年03期

3 陳占斌;劉金虎;;三維超聲引導下經皮肝膽管穿刺置管引流術的臨床應用[J];西部醫(yī)學;2010年05期

4 鄭若龍;高春恒;;實時三維超聲心動圖指導心包穿刺抽液的臨床應用[J];江蘇醫(yī)藥;2009年07期

5 周玉清,張青萍;靜態(tài)結構三維超聲成像方法學進展[J];中華超聲影像學雜志;1999年01期

6 錢林學;劉婧;;介入性超聲的研究現(xiàn)狀及進展[J];中華臨床醫(yī)師雜志(電子版);2010年12期

7 陳新,林東,張慶輝,鄭惠如,杜誼,田村進一;磁場方式的內窺鏡體內三維定位與追蹤方法研究[J];中國生物醫(yī)學工程學報;2002年05期

相關碩士學位論文 前4條

1 章瑤瑛;全數字B型超聲診斷儀的測量與報告模塊設計[D];浙江大學;2006年

2 樊燕紅;全數字B型超聲診斷儀系統(tǒng)結構的研究[D];浙江大學;2006年

3 閻振梅;不同加力高度對伴有牙槽骨喪失的上頜中切牙的應力分布研究[D];大連醫(yī)科大學;2006年

4 黃立巍;醫(yī)用電磁導航實驗系統(tǒng)的研究[D];哈爾濱工業(yè)大學;2008年

，

本文編號：2476442