CustusX: an open-source research platform for image-guided therapy.

PURPOSE: CustusX is an image-guided therapy (IGT) research platform dedicated to intraoperative navigation and ultrasound imaging. In this paper, we present CustusX as a robust, accurate, and extensible platform with full access to data and algorithms and show examples of application in technological and clinical IGT research. METHODS: CustusX has been developed continuously for more than 15 years based on requirements from clinical and technological researchers within the framework of a well-defined software quality process. The platform was designed as a layered architecture with plugins based on the CTK/OSGi framework, a superbuild that manages dependencies and features supporting the IGT workflow. We describe the use of the system in several different clinical settings and characterize major aspects of the system such as accuracy, frame rate, and latency. RESULTS: The validation experiments show a navigation system accuracy of [Formula: see text]1.1 mm, a frame rate of 20 fps, and latency of 285 ms for a typical setup. The current platform is extensible, user-friendly and has a streamlined architecture and quality process. CustusX has successfully been used for IGT research in neurosurgery, laparoscopic surgery, vascular surgery, and bronchoscopy. CONCLUSIONS: CustusX is now a mature research platform for intraoperative navigation and ultrasound imaging and is ready for use by the IGT research community. CustusX is open-source and freely available at http://www.custusx.org.

Navigated bronchoscopy with electromagnetic tracking-cone beam computed tomography influence on tracking and registration accuracy.

Current image guidance systems for bronchoscopy are limited to the diagnosis of small tumors and placing fiducials for radiation therapy and surgery. Ideally, a navigation system should be useable for the range of bronchoscopic procedures, including therapy with concurrent radiology imaging for control. As most guidance systems rely on electromagnetic (EM) fields, it is advised to leave the C-arm mounted fluoroscopy unit outside the operating field during navigation. We have assessed the accuracy of our research navigation platform, containing an EM field generator and a C-arm fluoroscopy unit. We have simulated a regular bronchoscopy session with an initial image-to-patient registration procedure, and a subsequent bronchoscopy with the C-arm inside the EM field. The registration accuracy was significantly influenced, introducing an error that may be carried through to the bronchoscopy procedure. During the bronchoscopy session, the C-arm caused a wave drift in the tracking positions and distorted the EM field, causing a translation error up to 22 mm. Even by averaging out the drift, there was a systematic shift in the x, y, and z positions. The errors were more evident in some C-arm positions and seem to be linked more to the electrical current in the fluoroscopy unit than the metallic C-arm itself. A fluoroscopy unit may be used during a navigation procedure, but care must be taken. To enable real-time navigation, the C-arm could be removed sufficiently from the EM tracking field or correction schemes must be implemented to compensate for the distortions.