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Diffuse domain method for needle insertion simulations.
International Journal for Numerical Methods in Biomedical Engineering ( IF 2.1 ) Pub Date : 2020-08-03 , DOI: 10.1002/cnm.3377
Katharina I Jerg 1 , René Phillip Austermühl 1 , Karsten Roth 2 , Jonas Große Sundrup 3 , Guido Kanschat 4 , Jürgen W Hesser 1 , Lisa Wittmayer 1
Affiliation  

We present a new strategy for needle insertion simulations without the necessity of meshing. A diffuse domain approach on a regular grid is applied to overcome the need for an explicit representation of organ boundaries. A phase field function captures the transition of tissue parameters and boundary conditions are imposed implicitly. Uncertainties of a volume segmentation are translated in the width of the phase field, an approach that is novel and overcomes the problem of defining an accurate segmentation boundary. We perform a convergence analysis of the diffuse elastic equation for decreasing phase field width, compare our results to deformation fields received from conforming mesh simulations and analyze the diffuse linear elastic equation for different widths of material interfaces. Then, the approach is applied to computed tomography data of a patient with liver tumors. A three‐class U‐Net is used to automatically generate tissue probability maps serving as phase field functions for the transition of elastic parameters between different tissues. The needle tissue interaction forces are approximated by the absolute gradient of a phase field function, which eliminates the need for explicit boundary parameterization and collision detection at the needle‐tissue interface. The results show that the deformation field of the diffuse domain approach is comparable to the deformation of a conforming mesh simulation. Uncertainties of tissue boundaries are included in the model and the simulation can be directly performed on the automatically generated voxel‐based probability maps. Thus, it is possible to perform easily implementable patient‐specific elastomechanical simulations directly on voxel data.

中文翻译:

用于针插入模拟的漫域方法。

我们提出了一种无需网格划分的针插入模拟新策略。应用规则网格上的扩散域方法来克服对器官边界的显式表示的需要。相场函数捕捉组织参数的转变,并且隐含地施加边界条件。体积分割的不确定性转化为相位场的宽度,这是一种新颖的方法,克服了定义准确分割边界的问题。我们对减小相场宽度的扩散弹性方程进行收敛分析,将我们的结果与从符合网格模拟中接收到的变形场进行比较,并分析不同宽度材料界面的扩散线性弹性方程。然后,该方法应用于肝脏肿瘤患者的计算机断层扫描数据。三类 U-Net 用于自动生成组织概率图,作为不同组织之间弹性参数转换的相场函数。针组织相互作用力由相场函数的绝对梯度近似,这消除了在针-组织界面进行显式边界参数化和碰撞检测的需要。结果表明,漫射域方法的变形场与符合网格模拟的变形相当。模型中包含组织边界的不确定性,可以直接在自动生成的基于体素的概率图上进行模拟。因此,
更新日期:2020-08-03
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