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| Autor: | ZHE-WEI ZHANG, 張哲維 |
|---|---|
| Rok vydání: | 2015 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 Currently intramedullary nailing is a common operation for long bone fracture reconstruction. Distal locking of intramedullary nails is difficult due to the nail deformation after implantation. Therefore, orthopedic surgeons take tens C-arm images to verify the correction of drilling procedure. The accumulation of mass radiation dosage is harmful to the health of the patient and medical persons. Thus, development of a low-cost and low-radiation navigation system for intramedullary nailing is expected. In this research, the integration of C-arm images with efficient perspective-n- point camera pose estimation (EPnP) method is applied to calculate the spatial position and orientation of the positioning plate relative to the C-arm image frame. Two C-arm images taken in different positions are used to determine the axial direction of the intramedullary nail and the center position of fixation holes by Bi-plane algorithm. Then, according to the real C-arm X-ray projection model, an identical computer model is created to simulate the C-arm X-ray projection. The intramedullary nail is rotated about its axis sequentially and the images of fixation holes are projected simultaneously. Similarity measures of the projection images of fixation holes generated by computer simulation and the real C-arm system are calculated. The axial directions of fixation holes of the simulated intramedullary nail with largest similarity measure value are those of the real intramedullary nail. Then, the guide slot of the drill guide device will be adjusted to have identical directions as the fixation holes. In the experiment, 3 and 4 C-arm images are taken from both sides of the fixation holes respectively. They are grouped to generate 12 experimental cases. The experimental results show that there are 10 cases which the drill bit can be guided to pass through the fixation holes. The other 2 cases are failed to do it because of image processing and segmentation of steel balls of the positioning plate and fixation holes of the intramedullary nail are not good enough. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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