De Silva Tharindu, Punnoose Joshua, Uneri Ali, Mahesh Mahadevappa, Goerres Joseph, Jacobson Matthew, Ketcha Michael D, Manbachi Amir, Vogt Sebastian, Kleinszig Gerhard, Khanna Akhil Jay, Wolinksy Jean-Paul, Siewerdsen Jeffrey H, Osgood Greg
Johns Hopkins University, Department of Biomedical Engineering, Baltimore, Maryland, United States.
Johns Hopkins University, Russell H. Morgan Department of Radiology, Baltimore, Maryland, United States.
J Med Imaging (Bellingham). 2018 Jan;5(1):015005. doi: 10.1117/1.JMI.5.1.015005. Epub 2018 Feb 13.
Positioning of an intraoperative C-arm to achieve clear visualization of a particular anatomical feature often involves repeated fluoroscopic views, which cost time and radiation exposure to both the patient and surgical staff. A system for virtual fluoroscopy (called FluoroSim) that could dramatically reduce time- and dose-spent "fluoro-hunting" by leveraging preoperative computed tomography (CT), encoded readout of C-arm gantry position, and automatic 3D-2D image registration has been developed. The method is consistent with existing surgical workflow and does not require additional tracking equipment. Real-time virtual fluoroscopy was achieved via mechanical encoding of the C-arm motion, C-arm geometric calibration, and patient registration using a single radiograph. The accuracy, time, and radiation dose associated with C-arm positioning were measured for FluoroSim in comparison with conventional methods. Five radiology technologists were tasked with acquiring six standard pelvic views pertinent to sacro-illiac, anterior-inferior iliac spine, and superior-ramus screw placement in an anthropomorphic pelvis phantom using conventional and FluoroSim approaches. The positioning accuracy, exposure time, number of exposures, and total time for each trial were recorded, and radiation dose was characterized in terms of entrance skin dose and in-room scatter. The geometric accuracy of FluoroSim was measured to be [Formula: see text]. There was no significant difference ([Formula: see text]) observed in the accuracy or total elapsed time for C-arm positioning. However, the total fluoroscopy time required to achieve the desired view decreased by 4.1 s ([Formula: see text] for conventional, compared with [Formula: see text] for FluoroSim, [Formula: see text]), and the total number of exposures reduced by 4.0 ([Formula: see text] for conventional, compared with [Formula: see text] for FluoroSim, [Formula: see text]). These reductions amounted to a 50% to 78% decrease in patient entrance skin dose and a 55% to 70% reduction in in-room scatter. FluoroSim was found to reduce the radiation exposure required in C-arm positioning without diminishing positioning time or accuracy, providing a potentially valuable tool to assist technologists and surgeons.
术中C形臂的定位以实现对特定解剖特征的清晰可视化通常需要反复进行荧光透视，这既耗费时间，又会使患者和手术人员受到辐射暴露。一种虚拟荧光透视系统（称为FluoroSim）已经开发出来，它可以通过利用术前计算机断层扫描（CT）、C形臂机架位置的编码读出以及自动3D-2D图像配准，显著减少“荧光搜索”所花费的时间和剂量。该方法与现有的手术流程一致，不需要额外的跟踪设备。通过C形臂运动的机械编码、C形臂几何校准以及使用单张X线片进行患者配准，实现了实时虚拟荧光透视。与传统方法相比，测量了FluoroSim与C形臂定位相关的准确性、时间和辐射剂量。五名放射技术人员的任务是使用传统方法和FluoroSim方法，在一个拟人化骨盆模型中获取与骶髂关节、髂前下棘和耻骨上支螺钉置入相关的六个标准骨盆视图。记录每次试验的定位准确性、曝光时间、曝光次数和总时间，并根据皮肤入口剂量和室内散射来表征辐射剂量。测量得出FluoroSim的几何准确性为[公式：见原文]。在C形臂定位的准确性或总耗时方面未观察到显著差异（[公式：见原文]）。然而，获得所需视图所需的总荧光透视时间减少了4.1秒（传统方法为[公式：见原文]，而FluoroSim为[公式：见原文]，[公式：见原文]），曝光总数减少了4.0次（传统方法为[公式：见原文]，而FluoroSim为[公式：见原文]，[公式：见原文]）。这些减少相当于患者皮肤入口剂量降低了50%至78%，室内散射降低了55%至70%。研究发现，FluoroSim在不减少定位时间或准确性的情况下，减少了C形臂定位所需的辐射暴露，为协助技术人员和外科医生提供了一个潜在有价值的工具。
