Key technique research and system realization for C-arm based spinal surgical navigation / 生物医学工程学杂志

C-arm based surgical navigation system is a kind of computer assisted surgery (CAS) system. In this paper, key techniques concerning this kind of system are presented. The key techniques mainly include XRII image distortion correction and C-arm imaging system calibration. On this basis, we designed relevant tools and made them fabricated, and developed a software system. Experimental results of human fresh spine sample showed that with the surgical navigation system, screw insertion accuracy was much higher than that without the surgical navigation system.

XRII image distortion correction for C-arm-based surgical navigation system / 生物医学工程学杂志

XRII image distortion correction is a key technique in a C-arm-based surgical navigation system. In this paper, we present a new correction method, which integrates the method of moving least squares(MLS) and the method of multilevel B-spline approximation (MBA). Experiments show that the proposed method leads to good outcome of image correction and it is more accurate than the exsiting correction methods.

A surgical navigation system based on C-arm fluoroscopy images / 生物医学工程学杂志

A surgical navigation system based on X-rays of C-arm with a calibration target has been studied and developed. Extracting images of markers in the two templates on the calibration target, the system is able to establish the relationship between different markers coordinates in different coordinate systems using the algorithm based on the layout of specific markers. The correction of X-ray image distortion and C-arm camera calibration are performed using the images of calibration target as bases. After the parameters of the C-arm projection model being determined, an X-ray image of surgical site will be acquired preoperatively; the surgical instruments will be tracked by the optical position system, and then virtual projections of instruments can be formed on preoperative images. Surgeons will perform operations with the guidance of the system. The C-arm can be used less frequently and the X-ray radiation can be reduced. Cadaveric spine specimen experiments and error analysis have underpinned the clinical feasibility of the system.

A method for extracting landmark geometric data from X-ray images / 生物医学工程学杂志

Extracting landmark geometric data in C-arm X-ray images is a key technique of camera calibration process in a fluoroscopic-image-based surgical navigation system. The geometric data is the basis of X-ray image distortion correction and C-arm camera calibration. In this paper we present an integrated clustering algorithm for landmark geometric data extraction. This proposed alorithm, with the advantages of an adaptive thresholding method as well as of a fast quasi connected-component labeling method, needs only one pass to extract the needed geometric data in a gray scale image. It is of high executive efficiency and good robustness as well.

An improved design of calibration target used in C-arm-based surgical navigation system / 生物医学工程学杂志

Seeing that there are several defects in the calibration target currently used in C-arm-based surgical navigation system, we propose an improved design of calibration target based on the theory of generalized mapping. The method of design is introduced, the analysis is made, and the results are reported. The newly designed calibration target is of low manufacturing difficulty and cost; with the new calibration target, the running efficiency and the image quality of the whole navigation system could be improved. The new calibration target is found to be of several advantages over the currently used ones; it is feasible and is under manufacturing already.