Santhanam A, Low D, Kupelian P
UCLA, Los Angeles, CA.
Med Phys. 2012 Jun;39(6Part7):3675. doi: 10.1118/1.4734934.
On-board optical 3D imaging enables measuring daily setup patient uncertainties without involving any additional imaging-induced radiation dose to critical structures. We hypothesize that the tumor and normal organ deformation caused by routine patient head and neck misalignments can be determined by coupling a quantitative patient-specific biomechanical model with quantitative skin surface 3D imaging.
A set of 3D cameras are used to track the patient anatomy externally. One of the cameras employed a marker less face recognition and tracking for delineating the region of the patient's face. The location of the face was then shared among the camera controllers in real-time and the anatomical contour that closely matches the face region is selected and integrated to form a single 3D anatomical representation. Patient surface aligning was performed between the patient's external surface obtained from a reference 3D anatomy (simulation CT, MRI, patient surface map from previous fraction) and the above-mentioned camera system to quantify the daily patient setup variations. For each of the 3D patient surface, a point feature histogram (PFH) was first generated. Once the PFH descriptors were generated, a non-rigid iterative closest point registration algorithm that minimizes the difference in the PFH descriptor aligns the patient surface to the reference 3D anatomy.
The proposed tracking system was able to track both the patient surface setup uncertainty and the internal anatomy when coupledwith a patient specific biomechanical head and neck model.
A 3D head and neck tracking system that monitors the interfraction patient setup uncertainties in the head and neck cancer patient is presented. The aligning process was shown to perform for cases with and without the head immobilization system. The external patient surface manifold and the motion vectors will be coupled to align the biomechanical model using model-guided techniques.
机载光学三维成像能够测量每日患者摆位的不确定性，而不会给关键结构带来任何额外的成像诱导辐射剂量。我们假设，通过将定量的患者特异性生物力学模型与定量的皮肤表面三维成像相结合，可以确定由常规患者头颈部错位引起的肿瘤和正常器官变形。
使用一组三维相机从外部跟踪患者的解剖结构。其中一台相机采用无标记人脸识别和跟踪技术来描绘患者面部区域。然后，面部位置实时在相机控制器之间共享，并选择与面部区域紧密匹配的解剖轮廓并整合，以形成单一的三维解剖表示。在从参考三维解剖结构（模拟CT、MRI、先前分次的患者表面地图）获得的患者外表面与上述相机系统之间进行患者表面对齐，以量化每日患者摆位变化。对于每个三维患者表面，首先生成点特征直方图（PFH）。一旦生成PFH描述符，一种使PFH描述符差异最小化的非刚性迭代最近点配准算法将患者表面与参考三维解剖结构对齐。
当与患者特异性生物力学头颈部模型结合时，所提出的跟踪系统能够跟踪患者表面摆位不确定性和内部解剖结构。
提出了一种三维头颈部跟踪系统，用于监测头颈癌患者分次间的摆位不确定性。结果表明，该对齐过程在有无头部固定系统的情况下均能执行。将使用模型引导技术将外部患者表面流形和运动向量耦合起来，以对齐生物力学模型。
