Fabrication and shape detection of a catheter using fiber Bragg grating

Considering the spatial position and shape detection properties of the fiber Bragg grating (FBG) curve sensor used in the human body, the positioning accuracy of the FBG curve sensor plays a major role in the pre-diagnosis and treatment of diseases. We present a new type of shape-sensing catheter (diameter of 2.0 mm and length of 810 mm) that is integrated with an array of four optical fibers, where each contains five nodes, to track the shape. Firstly, the distribution of the four orthogonal fiber gratings is wound around a nitinol wire using novel packaging technology, and the spatial curve shape is rebuilt based on the positioning of discrete points in space. An experimental platform is built, and then a reconstruction algorithm for coordinate point fitting of the Frenet frame is used to perform the reconstruction experiment on millimeter paper. The results show that, compared with those in previous studies, in 2D test, the maximum relative error for the end position is reduced to 2.74%, and in 3D reconstruction experiment, the maximum shape error is 3.43%, which verifies both the applicability of the sensor and the feasibility of the proposed method. The results reported here will provide an academic foundation and the key technologies required for navigation and positioning of non-invasive and minimally invasive surgical robots, intelligent structural health detection, and search and rescue operations in debris.