An interactive 3D user interface for guided bronchoscopy

Recent studies have shown that more than 5 million bronchoscopy procedures are performed each year worldwide. The procedure usually involves biopsy of possible cancerous tissues from the lung. Standard bronchoscopes are too large to reach into the peripheral lung, where cancerous nodules are often found. The University of Washington has developed an ultrathin and flexible scanning fiber endoscope that is able to advance into the periphery of the human lungs without sacrificing image quality. To accompany the novel endoscope, we have developed a user interface that serves as a navigation guide for doctors when performing a bronchoscopy. The navigation system consists of a virtual surface mesh of the airways extracted from compute d-tomography (CT) scan and an electromagnetic tracking system (EMTS). The complete system can be viewed as a global positioning system for the lung that provides pre-procedural planning functionalities, virtual bronchoscopy navigation, and real time tracking of the endoscope inside the lung. The real time virtual navigation is complemented by a particle filter algorithm to compensate for registration errors and outliers, and to prevent going through surfaces of the virtual lung model. The particle filter method tracks the endoscope tip based on real time tracking data and attaches the virtual endoscopic view to the skeleton that runs inside the virtual airway surface. Experiment results on a dried sheep lung show that the particle filter method converges and is able to accurately track the endoscope tip in real time when the endoscope is inserted both at slow and fast insertion speeds.