肝肿瘤热消融机器人定位导航系统的研究

Research on robot positioning and navigation system for thermal ablation of liver tumors

目的设计一种结合计算机辅助手术路径规划、电磁定位和机器人技术的肝肿瘤热消融机器人定位导航系统,利用机械臂将消融针精准定位在规划的进针路径上。方法将介入热消融治疗的临床需求量化为多项约束条件,使用加权求和方法求解多目标优化问题,实现计算机辅助手术路径规划。导航定位系统中存在多个坐标系,使用基于成对点集配准的奇异值分解算法完成空间坐标转换,将规划的手术路径映射到机器人坐标系下。构建机械臂目标位置和姿态矩阵,利用运动学方法求解各关节角度,从而将机械臂定位在规划的进针路径上。最后以本文设计的导航系统作为穿刺实验组,常规穿刺方法作为对照组,利用腹部体模进行系统精度验证。结果使用本系统进行穿刺的平均进针误差(1.11 mm)、平均进针次数(1次)、平均进针时间(11.4 s)都明显优于常规的穿刺方法(5.38 mm、4.6次、62.2 s)。结论基于图像处理、电磁定位和机器人技术构建的热消融机器人定位导航系统能够降低手术穿刺难度,提高消融治疗效率。

Objective The purpose of this study is to design a robotic system combined with the computer-aided surgical path planning,electromagnetic positioning and the robot technology to accurately guide the needle to the designed ablation path.Methods The clinical requirements of ablation are quantified as constraints,and we use weighted sum method to solve multi-objective optimization problem.Then we program the surgical plan assisted by computer.There are several coordinate systems in the navigation and positioning system,and we use pairing point based on SVD matrix decomposition to complete spatial coordinate transformation.Then we complete the transformation from the image coordinate system to robot coordinate system.We calculate the position and posture of the robot,and inverse kinematics is used to calculate the angle value of each joint.Then we control the robot to the planned position.Finally,the accuracy of the system is verified by the phantom.The system designed in this paper is used as the experimental group,and the conventional method is used as the control group.Results The average needle error of puncture by using this system(1.11 mm),average operation times(just once)and average time of the system(11.4 s)are both better than the conventional puncture method(5.38 mm,4.6 times,62.2 s).Conclusions The robotic system which integrates the image processing and electromagnetic positioning can decrease the difficulty of treatment and improve the treatment efficiency.