Three-dimensional finite-element based deformable image registration for evaluation of pleural cavity irradiation during photodynamic therapy
Three-dimensional finite-element based deformable image registration for evaluation of pleural cavity irradiation during photodynamic therapy
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DOI：
10.1002/mp.12284
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发表时间：
2017-07-01
期刊：
影响因子：
3.8
通讯作者：
Zhu, Timothy C.
中科院分区：
文献类型：
--
作者：
Penjweini, Rozhin;Kim, Michele M.;Zhu, Timothy C.
目的：应用光动力疗法（PDT）治疗恶性胸膜间皮瘤术后显微病变，提高生存率。由于准确的光传递对PDT的疗效至关重要，因此我们研究了术中胸膜体积的变形对传递光的影响。本研究提出了一种基于三维有限元（3D FEM）的可变形图像配准方法，将肺的体积与PDT期间获得的胸膜腔体积直接匹配，以准确表征治疗期间肺、心、肝（危险器官）积累的光能。方法：一根由改良的管内充脂管和管内光纤组成的魔杖用于传递治疗光。使用光学跟踪系统跟踪处理的位置，该系统由9个反射被动标记组成，由基于红外摄像机的导航系统看到。该信息用于获得所述复数空腔的表面轮廓和所述正在处理的空腔表面每一点上的累积光影响。通过对同一患者手术前后获得的器官进行一系列计算机断层扫描（CT），重建肺、心和肝的几何形状。将光学跟踪系统和ct获得的轮廓导入到COMSOL Multiphysics中，获得基于三维有限元的可变形图像配准。传递的通量值分配给光学跟踪轮廓上的相应位置（x、y和z）。以光学跟踪轮廓为参考，以CT轮廓为目标，目标将发生变形。来自三个病人的数据构成了这项研究的基础。结果：利用基于三维有限元的图像形变配准，建立了不同成像设备在不同时间拍摄的CT与光学跟踪几何形状之间的物理对应关系。肺的体积与胸膜腔的体积匹配，得到心、肝和变形肺体积表面的光通量分布。结论：所使用的方法适用于分析复杂域上的问题，例如当域发生变化时（如在具有移动边界的固态反应中），当所需的精度在整个域上变化时，或者当解决方案缺乏平滑性时。在临床应用中实时实施这种方法，并在PDT期间对光照不足或过度暴露的区域进行原位监测，可以显着改善间皮瘤的治疗。(C) 2017年美国医学物理学家协会
Purpose: Photodynamic therapy (PDT) is used after surgical resection to treat the microscopic disease for malignant pleural mesothelioma and to increase survival rates. As accurate light delivery is imperative to PDT efficacy, the deformation of the pleural volume during the surgery is studied on its impact on the delivered light fluence. In this study, a three-dimensional finite element-based (3D FEM) deformable image registration is proposed to directly match the volume of lung to the volume of pleural cavity obtained during PDT to have accurate representation of the light fluence accumulated in the lung, heart and liver (organs-at-risk) during treatment.Methods: A wand, comprised of a modified endotrachial tube filled with Intralipid and an optical fiber inside the tube, is used to deliver the treatment light. The position of the treatment is tracked using an optical tracking system with an attachment comprised of nine reflective passive markers that are seen by an infrared camera-based navigation system. This information is used to obtain the surface contours of the plural cavity and the cumulative light fluence on every point of the cavity surface that is being treated. The lung, heart, and liver geometry are also reconstructed from a series of computed tomography (CT) scans of the organs acquired in the same patient before and after the surgery. The contours obtained with the optical tracking system and CTs are imported into COMSOL Multiphysics, where the 3D FEM-based deformable image registration is obtained. The delivered fluence values are assigned to the respective positions (x, y, and z) on the optical tracking contour. The optical tracking contour is considered as the reference, and the CT contours are used as the target, which will be deformed. The data from three patients formed the basis for this study.Results: The physical correspondence between the CT and optical tracking geometries, taken at different times, from different imaging devices was established using the 3D FEM-based image deformable registration. The volume of lung was matched to the volume of pleural cavity and the distribution of light fluence on the surface of the heart, liver and deformed lung volumes was obtained.Conclusion: The method used is appropriate for analyzing problems over complicated domains, such as when the domain changes (as in a solid-state reaction with a moving boundary), when the desired precision varies over the entire domain, or when the solution lacks smoothness. Implementing this method in real-time for clinical applications and in situ monitoring of the under- or over- exposed regions to light during PDT can significantly improve the treatment for mesothelioma. (C) 2017 American Association of Physicists in Medicine