Lin Qinyong, Yang Rongqian, Cai Ken, Guan Peifeng, Xiao Weihu, Wu Xiaoming
Department of Biomedical Engineering, South China University of Technology, Guangzhou, Guangdong, China.
School of Information Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, China.
Biomed Opt Express. 2015 Aug 7;6(9):3287-302. doi: 10.1364/BOE.6.003287. eCollection 2015 Sep 1.
Image-guided navigation for radiofrequency ablation of liver tumors requires the accurate guidance of needle insertion into a tumor target. The main challenge of image-guided navigation for radiofrequency ablation of liver tumors is the occurrence of liver deformations caused by respiratory motion. This study reports a strategy of real-time automatic registration to track custom fiducial markers glued onto the surface of a patient's abdomen to find the respiratory phase, in which the static preoperative CT is performed. Custom fiducial markers are designed. Real-time automatic registration method consists of the automatic localization of custom fiducial markers in the patient and image spaces. The fiducial registration error is calculated in real time and indicates if the current respiratory phase corresponds to the phase of the static preoperative CT. To demonstrate the feasibility of the proposed strategy, a liver simulator is constructed and two volunteers are involved in the preliminary experiments. An ex-vivo porcine liver model is employed to further verify the strategy for liver intervention. Experimental results demonstrate that real-time automatic registration method is rapid, accurate, and feasible for capturing the respiratory phase from which the static preoperative CT anatomical model is generated by tracking the movement of the skin-adhered custom fiducial markers.
用于肝脏肿瘤射频消融的图像引导导航需要将针准确插入肿瘤靶点。肝脏肿瘤射频消融图像引导导航的主要挑战是呼吸运动引起的肝脏变形。本研究报告了一种实时自动配准策略，用于跟踪粘贴在患者腹部表面的定制基准标记以找到呼吸相位，在此相位下进行术前静态CT扫描。设计了定制基准标记。实时自动配准方法包括在患者空间和图像空间中自动定位定制基准标记。实时计算基准配准误差，以指示当前呼吸相位是否与术前静态CT的相位相对应。为了证明所提出策略的可行性，构建了一个肝脏模拟器，并让两名志愿者参与初步实验。采用离体猪肝模型进一步验证肝脏介入策略。实验结果表明，实时自动配准方法通过跟踪粘贴在皮肤上的定制基准标记的运动来捕获呼吸相位是快速、准确且可行的，术前静态CT解剖模型即由该呼吸相位生成。
