On June 3rd, 2 o’clock P.M, Master Chaoqiang Tao passed the Master Thesis Defense in the conference room on 10th floor of Automation Building. His thesis topic is ”Study On 2D/3D Image Registration And Application  On Pedicle Screw Implantation”.

Here is the abstract:

With the continuous development and progress of modern medical technology, surgical operation is moving increasingly precise and sophisticated. Because of many restrictions on technology, the traditional surgical approach is often difficult to meet the current demand for high-precision surgery. Image-guided surgery is an emerging biomedical engineering research in the past 20 years, and it has developed very rapidly. In this study, by studying 2D/3D image registration technology in imaged-guided surgery field based on pedicle screw fixation, unified image space between preoperative CT image and intraoperative X-ray image will be created.

In the study of 2D/3D image registration techniques, this study do a series of experiments on the three-dimensional image CT using digitally reconstructed radiographs and combing with the searching method Powell optimization algorithm. The experiments includes those comparison between similarity measures such as mean square, gradient difference and mutual information, 2D/3D registration based Shepp-Logan model, 2D/3D image registration and registration based real intraoperative x-ray images. Through these experiments, it’s conclusive that the 2D/3D image registration in this study is rather accurate and precise.

Then, in this study, according the fact that traditional intensity-based rigid 2D/3D image registration is not so fast, a new method is presented. Combing with preoperative DRR sets which is generated by maximum intensity projection of CT and approximate geometric transformation, the method converts the traditional six degrees of freedom to four taking considering the fact that the real intraoperative registration error attributes mainly to the patient’s rotation. This method will greatly improve the efficiency of registration, and ensure the accuracy.

Finally, according to the existing registration scheme, combing with the open source medical image processing algorithm library MITK (Medical Imaging Interaction Toolkit), this study developed the registration software which has manual transform and customizable 2D/3D registration functions. And in accordance with the registration results and pedicle screw fixation operation, a spine navigation framework is proposed. This framework will play a very good reference for clinical application.