Soft tissue deformation for surgical simulation: a position-based dynamics approach.
Soft tissue deformation for surgical simulation: a position-based dynamics approach.
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DOI：
10.1007/s11548-016-1373-8
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发表时间：
2016-06
影响因子：
3
通讯作者：
Pratt P
中科院分区：
文献类型：
--
作者：
Camara M;Mayer E;Darzi A;Pratt P
为了协助机器人辅助肾部分切除术的演练和规划，提出了一个实时模拟平台，使外科医生能够可视化快速构建的感兴趣解剖区域的患者特异性生物力学模型并与之交互。与体积变形框架相结合，该平台还使用术前成像作为数据源来模拟体内二维超声图像采集。这不仅有助于规划最佳传感器轨迹和视点，而且还可以作为手动操作徒手 3D 采集和重建的验证环境。该仿真平台是在 GPU 加速的 NVIDIA FleX 基于位置的动态框架内实现的。为了验证模型并确定材料特性和其他模拟参数值，对嵌入基准珠的猪肾脏进行 CT 扫描和分割。收集了静止位置和三个不同水平的探针引起的变形的数据。针对一系列不同粒子半径确定簇刚度系数的最佳值，其中目标函数包括变形序列上真实基准位置和模拟基准位置之间的平均距离误差。发现每个变形阶段的平均基准误差与临床实践中通常观察到的超声探头校准误差水平相一致。此外，由于使用了集群形状匹配约束，模拟表现出无条件稳定性。一种新颖的基于位置的软组织变形动态实现已被证明可以促进几个理想的模拟特性：实时性能、无条件稳定性、快速模型构建，实现患者特定的行为以及相对于参考 CT 图像的准确性。本文的在线版本 (doi:10.1007/s11548-016-1373-8) 包含补充材料，可供授权用户使用。
To assist the rehearsal and planning of robot-assisted partial nephrectomy, a real-time simulation platform is presented that allows surgeons to visualise and interact with rapidly constructed patient-specific biomechanical models of the anatomical regions of interest. Coupled to a framework for volumetric deformation, the platform furthermore simulates intracorporeal 2D ultrasound image acquisition, using preoperative imaging as the data source. This not only facilitates the planning of optimal transducer trajectories and viewpoints, but can also act as a validation context for manually operated freehand 3D acquisitions and reconstructions. The simulation platform was implemented within the GPU-accelerated NVIDIA FleX position-based dynamics framework. In order to validate the model and determine material properties and other simulation parameter values, a porcine kidney with embedded fiducial beads was CT-scanned and segmented. Acquisitions for the rest position and three different levels of probe-induced deformation were collected. Optimal values of the cluster stiffness coefficients were determined for a range of different particle radii, where the objective function comprised the mean distance error between real and simulated fiducial positions over the sequence of deformations. The mean fiducial error at each deformation stage was found to be compatible with the level of ultrasound probe calibration error typically observed in clinical practice. Furthermore, the simulation exhibited unconditional stability on account of its use of clustered shape-matching constraints. A novel position-based dynamics implementation of soft tissue deformation has been shown to facilitate several desirable simulation characteristics: real-time performance, unconditional stability, rapid model construction enabling patient-specific behaviour and accuracy with respect to reference CT images. The online version of this article (doi:10.1007/s11548-016-1373-8) contains supplementary material, which is available to authorized users.