本文選題：微創(chuàng)虛擬血管手術(shù)　切入點(diǎn)：血管三維重建　出處：《大連理工大學(xué)》2015年碩士論文

【摘要】：微創(chuàng)虛擬血管手術(shù)仿真系統(tǒng)結(jié)合了計(jì)算機(jī)圖形學(xué)、現(xiàn)代醫(yī)學(xué)和虛擬仿真技術(shù),通過(guò)對(duì)微創(chuàng)血管手術(shù)的模擬,為很多臨床醫(yī)生和實(shí)習(xí)生再現(xiàn)出了一個(gè)真實(shí)的手術(shù)場(chǎng)景,不但提高了用戶的手術(shù)技能,同時(shí)大大減少手術(shù)誤差。在保證安全的基礎(chǔ)上,微創(chuàng)虛擬手術(shù)系統(tǒng)應(yīng)為手術(shù)過(guò)程提供足夠真實(shí)性的同時(shí),還應(yīng)使醫(yī)生能自然和本能地控制工具的運(yùn)動(dòng),充分利用其固有的感覺(jué)和反應(yīng)能力,發(fā)揮其熟練手術(shù)技能。這就要求系統(tǒng)具有高臨場(chǎng)感。為了解決仿真逼真性低、行為模型不夠完善以及實(shí)時(shí)性和準(zhǔn)確性相矛盾的問(wèn)題,本文以腹主動(dòng)脈血管為研究對(duì)象,對(duì)微創(chuàng)虛擬血管手術(shù)仿真系統(tǒng)中的三維模型重建、幾何模型的優(yōu)化、物理形變模型仿真、實(shí)時(shí)碰撞檢測(cè)等關(guān)鍵技術(shù)進(jìn)行了研究,研究主要內(nèi)容概括如下：(1)血管的三維幾何構(gòu)建是微創(chuàng)虛擬血管手術(shù)系統(tǒng)的基礎(chǔ),本文針對(duì)血管造影圖像對(duì)比度不均衡和血管邊界模糊的問(wèn)題,采用Mimics 15.0 (Materialise公司,比利時(shí))軟件對(duì)血管CT數(shù)據(jù)進(jìn)行了分割、編輯和三維重建,同時(shí)對(duì)模型進(jìn)行了相應(yīng)的優(yōu)化和檢驗(yàn)。通過(guò)Mimics軟件,采用混合自動(dòng)分割的方式將血管組織分割出來(lái),并通過(guò)空腔填充解決因造影圖像對(duì)比度不均勻造成的血管蒙版信息丟失的問(wèn)題,同時(shí),通過(guò)蒙版編輯對(duì)血管進(jìn)行邊界增強(qiáng)并去噪。(2)針對(duì)血管壁復(fù)雜的組織構(gòu)成,本文采用基于四面體網(wǎng)格的粘彈性有限元模型來(lái)模擬血管的形變。由于有限元模型在形變過(guò)程中需要進(jìn)行大量的計(jì)算,在保證腹主動(dòng)脈血管形變模型的精度的同時(shí),結(jié)合真實(shí)血管的形變數(shù)據(jù),本文將血管分為線性彈性形變部分和非線性形變部分。同時(shí),本文利用Mimics軟件對(duì)有限元的四面體網(wǎng)格進(jìn)行分析和優(yōu)化,獲得高質(zhì)量的體網(wǎng)格。(3)血管的有限元模型比較復(fù)雜,致使其碰撞檢測(cè)計(jì)算量和計(jì)算時(shí)間相對(duì)較大。為了減少相交測(cè)試時(shí)間,提高檢測(cè)精度,本文提出了基于軸向包圍盒(Aligned Axis Bounding Box, AABB)和離散方向包圍盒(Discrete Orientation Polytopes, K-DOPs)的混合雙層包圍盒碰撞檢測(cè)算法。該方法分為粗糙檢測(cè)和精確檢測(cè)兩個(gè)階段,上層(外層)采用AABB快速排出不可能發(fā)生碰撞檢測(cè)的幾何集,下層(內(nèi)層)采用K-DOPs較精確地測(cè)試可能發(fā)生碰撞的幾何集并檢測(cè)出碰撞點(diǎn)。本文通過(guò)模擬微創(chuàng)虛擬血管手術(shù)過(guò)程中血管與手術(shù)刀相接觸的場(chǎng)景,對(duì)血管的形變模型和碰撞檢測(cè)進(jìn)行了檢驗(yàn)。實(shí)驗(yàn)表明,通過(guò)Mimics進(jìn)行三維重建和模型優(yōu)化,不但提高了重建模型的精度,還極大地提高了建模的速度。改進(jìn)的血管形變模型以及用Mimics優(yōu)化后的體網(wǎng)格,不但減少了有限元形變求解計(jì)算量,同時(shí)較精確地描述了血管的形變模型。采用AABB-K-DOPs混合包圍盒有效地減少了計(jì)算量,提高了碰撞檢測(cè)速率。這為建立高臨場(chǎng)感的微創(chuàng)虛擬手術(shù)系統(tǒng)奠定了堅(jiān)實(shí)的基礎(chǔ)。
[Abstract]:The minimally invasive virtual vascular surgery simulation system combines computer graphics, modern medicine and virtual simulation technology. Through the simulation of minimally invasive vascular surgery, it reproduces a real operation scene for many clinicians and interns.Not only improve the user's surgical skills, but also greatly reduce the surgical error.While ensuring safety, the minimally invasive virtual surgery system should provide sufficient authenticity for the surgical process, while also allowing doctors to control the movement of the tool naturally and instinctively and to take full advantage of their inherent senses and responsiveness,Give play to their skilled surgical skills.This requires that the system has a high sense of presence.In order to solve the problems of low lifelike simulation, imperfect behavior model and contradiction between real-time and accuracy, the three-dimensional model reconstruction in the minimally invasive virtual vascular surgery simulation system is studied in this paper.The key technologies such as geometric model optimization, physical deformation model simulation, real-time collision detection and so on are studied. The main contents of the research are summarized as follows: Three-dimensional geometry construction of blood vessel is the foundation of minimally invasive virtual vascular surgery system.In this paper, aiming at the problems of uneven contrast and blurred boundary of angiography images, Mimics 15.0 Materialise Corporation (Belgium) is used to segment, edit and reconstruct the CT data of blood vessels.At the same time, the model is optimized and tested.By using Mimics software, the vascular tissue is segmented by mixed automatic segmentation, and the problem of missing information of vascular mask caused by uneven contrast of angiography image is solved by cavity filling. At the same time,Aiming at the complex tissue structure of vascular wall, a viscoelastic finite element model based on tetrahedron mesh is used to simulate the deformation of blood vessel.Since the finite element model needs a lot of calculation in the process of deformation, the accuracy of the model is guaranteed, and the deformation data of the real blood vessel are combined.In this paper, blood vessels are divided into linear elastic deformation and nonlinear deformation.At the same time, using Mimics software to analyze and optimize the finite element tetrahedron mesh, the finite element model of high quality volume mesh.In order to reduce the intersecting test time and improve the detection accuracy, a hybrid double-layer bounding box collision detection algorithm based on axial bounding Axis Bounding box (AABB) and discrete bounding box concrete Orientation polytopes (K-DOPs) is proposed.The method can be divided into two stages: rough detection and accurate detection. The upper layer (outer layer) uses AABB to quickly remove the geometric sets which cannot be detected by collision.The lower layer (inner layer) uses K-DOPs to accurately test the geometric set of possible collisions and to detect collision points.In this paper, the deformation model and collision detection of blood vessels were tested by simulating the contact scene between blood vessels and scalpel during minimally invasive virtual vascular surgery.Experimental results show that 3D reconstruction and model optimization through Mimics not only improve the accuracy of the reconstruction model, but also greatly improve the speed of modeling.The improved vascular deformation model and the volume mesh optimized by Mimics not only reduce the computational complexity of finite element deformation solution, but also accurately describe the vascular deformation model.The AABB-K-DOPs hybrid bounding box can effectively reduce the computation and improve the collision detection rate.This has laid a solid foundation for the establishment of a high-sense minimally invasive virtual surgery system.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：R654;TP391.9

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 王晨;基于物理的柔性管形變建模實(shí)時(shí)仿真[D];浙江大學(xué);2008年

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本文編號(hào)：1730625