碩士 / 國立中央大學 / 機械工程研究所 / 100 / C-arm image assisted surgical navigation system has been broadly applied to orthopedic surgery. For spinal surgery, accurate path planning on the C-arm AP image is difficult. Therefore, the applicability of the system is restricted. This research develops a 2D C-arm/3D CT image registration method to obtain the transformation matrix between C-arm and CT image coordinate frames. Through the transformation matrix, the preplanned surgical path or implant model on preoperative CT images can be transformed and displayed on the C-arm images for surgical guidance. During operation, the locations of surgical instruments will also be displayed on both CT and C-arm images to help the surgeon to precisely and safely position surgical instruments.
First, the C-arm images are calibrated and the focus point of X-ray is determined. Then, select three identical characteristic points from C-arm images and CT images to obtain the initial registration between the C-arm and CT image frames. After that, the ray-casting algorithm is applied to generate digital reconstructed radiographs (DRR) from CT images. To speed up the generation of DRR, an Nvida’s CUDA graphics processing unit (GPU) is used for parallel computing of linear integration of X-ray absorptivity. Five similarity measures of 2D-3D registration including Normalized Cross-Correlation, Gradient Correlation, Pattern Intensity, Gradient Difference Correlation, and Mutual Information combined with three optimization methods including Powell, Downhill Simplex, and Genetic Algorithm are applied to evaluate the performance of converge range, efficiency and accuracy. The results show that the combination of Normalized Cross-Correlation measure with Downhill Simplex optimization algorithm has maximum correlation and similarity in C-arm and DRR images.
Saw bone models are used in the experiment to evaluate registration accuracy. The initial convergence range is set within ±10mm and ±10 degree. The average errors in displacement and orientation of forty experiment sets are 0.22mm and 0.25° respectively. The success rate is approximately 90% and average registration time takes 16 seconds.
| Identifer | oai:union.ndltd.org:TW/100NCU05489011 |
| Date | January 2012 |
| Creators | Geng-Li Lin, 林耿立 |
| Contributors | Ching-Shiow Tseng, 曾清秀 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 144 |
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