Patient-specific 4D Virtual Reality Simulation of Punctures and Radiofrequency Ablations in Breathing Virtual Body Models

在这个项目中，逼真的视觉触觉虚拟现实模拟呼吸运动的虚拟患者模型的方法。应用领域是针对患者的穿刺和射频消融（RFA）呼吸运动下的规划和培训。对于新患者的静态3D图像数据，传输个体以及平均4D运动模型，其已经从4D图像数据中提取并且用作真实的呼吸运动的体素相关描述。通过使用基于代理的4D运动模型，在不同的呼吸周期中逼真地模拟呼吸的变化。通过非线性配准方法补偿模型的解剖结构和患者之间的解剖结构差异，并且将器官的4D运动转移到静态3D患者图像数据上以用于动画。4D运动模型被集成到视觉-触觉框架中，这使得能够实现穿刺或消融针与呼吸虚拟患者模型的视觉-触觉交互。为了实现3D动画图像数据的实时4D可视化，开发了特殊的基于体的4D渲染技术，并在GPU上高度并行化。此外，对于针刺和RFA，将呼吸运动对RFA的4D路径规划和生物物理模拟的影响与使用静态3D图像数据进行规划和模拟进行比较。除了对单独的方法和组件进行评价外，还对射频消融（包括呼吸运动）的整个VR培训模拟器进行了用户评价。

In this project, methods for realistic visuo-haptic virtual reality simulation of respiratory motion in virtual patient models are developed. Areas of application are patient-specific planning and training of punctures and radiofrequency ablations (RFA) under respiratory motion. For static 3D image data of a new patient, individual as well as mean 4D motion models are transferred, which have been extracted from 4D image data and serve as voxel-related descriptions of real respiratory motion. By using surrogate-based 4D motion models, the variability of respiration is simulated realistically in different respiratory cycles. The anatomical differences between the anatomy of the model and the patient are compensated and the 4D motion of organs is transferred for animation onto the static 3D patient image data by means of non-linear registration methods. The 4D motion models are integrated into a visuo-haptic framework, which enables the visuo-haptic interaction of the puncture or ablation needle with the breathing virtual patient model. For the real-time 4D visualization of animated 3D image data, special volume-based 4D rendering techniques are developed and highly parallelized on the GPU. Additionally, for needle punctures and RFA, the effects on 4D path planning and biophysical simulation of RFA caused by respiratory motion are compared to planning and simulating by using static 3D image data. Apart from evaluation of the separate methods and components, a user evaluation of the whole VR training simulator for RF ablations including respiratory motion is carried out.