Kaus Michael R, Brock Kristy K, Pekar Vladimir, Dawson Laura A, Nichol Alan M, Jaffray David A
Philips Radiation Oncology Systems, Fitchburg, WI 53705, USA.
Int J Radiat Oncol Biol Phys. 2007 Jun 1;68(2):572-80. doi: 10.1016/j.ijrobp.2007.01.056.
The aim of this study is to develop a surface-based deformable image registration strategy and to assess the accuracy of the system for the integration of multimodality imaging, image-guided radiation therapy, and assessment of geometrical change during and after therapy.
A surface-model-based deformable image registration system has been developed that enables quantitative description of geometrical change in multimodal images with high computational efficiency. Based on the deformation of organ surfaces, a volumetric deformation field is derived using different volumetric elasticity models as alternatives to finite-element modeling.
The accuracy of the system was assessed both visually and quantitatively by tracking naturally occurring landmarks (bronchial bifurcations in the lung, vessel bifurcations in the liver, implanted gold markers in the prostate). The maximum displacements for lung, liver and prostate were 5.3 cm, 3.2 cm, and 0.6 cm respectively. The largest registration error (direction, mean +/- SD) for lung, liver and prostate were (inferior-superior, -0.21 +/- 0.38 cm), (anterior-posterior, -0.09 +/- 0.34 cm), and (left-right, 0.04 +/- 0.38 cm) respectively, which was within the image resolution regardless of the deformation model. The computation time (2.7 GHz Intel Xeon) was on the order of seconds (e.g., 10 s for 2 prostate datasets), and deformed axial images could be viewed at interactive speed (less than 1 s for 512 x 512 voxels).
Surface-based deformable image registration enables the quantification of geometrical change in normal tissue and tumor with acceptable accuracy and speed.
本研究旨在开发一种基于表面的可变形图像配准策略，并评估该系统在多模态成像整合、图像引导放射治疗以及治疗期间和治疗后几何变化评估方面的准确性。
已开发出一种基于表面模型的可变形图像配准系统，该系统能够以高计算效率对多模态图像中的几何变化进行定量描述。基于器官表面的变形，使用不同的体积弹性模型替代有限元建模来推导体积变形场。
通过跟踪自然存在的地标（肺部支气管分叉、肝脏血管分叉、前列腺植入的金标记）对系统的准确性进行了视觉和定量评估。肺部、肝脏和前列腺的最大位移分别为5.3厘米、3.2厘米和0.6厘米。肺部、肝脏和前列腺的最大配准误差（方向，平均值±标准差）分别为（下 - 上，-0.21±0.38厘米）、（前 - 后，-0.09±0.34厘米）和（左 - 右，0.04±0.38厘米），无论变形模型如何，均在图像分辨率范围内。计算时间（2.7 GHz英特尔至强处理器）为秒级（例如，2个前列腺数据集为10秒），并且可以以交互速度查看变形的轴向图像（对于512×512体素，小于1秒）。
基于表面的可变形图像配准能够以可接受的准确性和速度对正常组织和肿瘤中的几何变化进行量化。
