Volumetric characterization of the Aurora magnetic tracker system for image-guided transorbital endoscopic procedures
Volumetric characterization of the Aurora magnetic tracker system for image-guided transorbital endoscopic procedures
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DOI：
10.1088/0031-9155/53/16/009
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发表时间：
2008-08-21
影响因子：
3.5
通讯作者：
Galloway, R. L.
中科院分区：
文献类型：
--
作者：
Atuegwu, N. C.;Galloway, R. L.
在一些医疗程序中，很难或不可能保持导航系统的视线。对于这样的应用，人们已经开始使用电磁跟踪器。在定位器可以有效地用于图像引导过程之前，需要定位器的特征。这项工作的目的是通过使用层析网格对磁场进行采样来对极光磁跟踪器工作体积中的基准定位误差(FLE)进行体积表征。由于极光磁性跟踪器将用于图像引导的跨眼眶手术，我们选择了接近人头平均大小的工作体积。构建了有机玻璃栅格体模，并将其用于极光磁跟踪器的表征。通过将平坦的有机玻璃体模从9.6 mm向上移动38.4mm到201.6 mm来执行磁性空间的体积图。然后计算相对空间分布和随机分布。由于我们的内窥镜引导的目标是视神经后面的眼眶空间，所以场发生器与传感器之间的最大距离是根据场发生器与颅骨的位置来计算的。对于不同的场发生器位置，我们发现6D探头的平均随机FLE小于0.06 mm，5D探头的平均随机FLE小于0.2 mm。我们还观察到6D探头的平均相对空间FLE小于0.7 mm，5D探头的平均相对空间FLE小于1.3 mm。我们观察到，误差随场发生器与传感器之间距离的增加而增大。我们还观察到距离跟踪器底座48 mm到86 mm之间的最小误差。
In some medical procedures, it is difficult or impossible to maintain a line of sight for a guidance system. For such applications, people have begun to use electromagnetic trackers. Before a localizer can be effectively used for an image-guided procedure, a characterization of the localizer is required. The purpose of this work is to perform a volumetric characterization of the fiducial localization error (FLE) in the working volume of the Aurora magnetic tracker by sampling the magnetic field using a tomographic grid. Since the Aurora magnetic tracker will be used for image- guided transorbital procedures we chose a working volume that was close to the average size of the human head. A Plexiglass grid phantom was constructed and used for the characterization of the Aurora magnetic tracker. A volumetric map of the magnetic space was performed by moving the flat Plexiglass phantom up in increments of 38.4 mm from 9.6 mm to 201.6 mm. The relative spatial and the random FLE were then calculated. Since the target of our endoscopic guidance is the orbital space behind the optic nerve, the maximum distance between the field generator and the sensor was calculated depending on the placement of the field generator from the skull. For the different field generator placements we found the average random FLE to be less than 0.06 mm for the 6D probe and 0.2 mm for the 5D probe. We also observed an average relative spatial FLE of less than 0.7 mm for the 6D probe and 1.3 mm for the 5D probe. We observed that the error increased as the distance between the field generator and the sensor increased. We also observed a minimum error occurring between 48 mm and 86 mm from the base of the tracker.