Publication Date



Open access

Embargo Period


Degree Name

Master of Science (MS)


Biomedical Engineering (Engineering)

Date of Defense


First Committee Member

Weizhao Zhao

Second Committee Member

Xiaodong Wu

Third Committee Member

Jorge Bohorquez


Stereotactic radiosurgery (SRS) is a kind of method of radiation therapy that uses three-dimensional computerized imaging to precisely guide a high-powered X-ray beam to deliver a concentrated dose of radiation to the abnormal area of the body. This therapy can efficiently and successfully treat many different types of tumors, either benign or malignant. Commonly used radiosurgery treatments are applied by CyberKnife or Gamma Knife through Stereotactic mechanism. Stereotactic radiosurgery can be assisted by two and three dimensional imaging during a course of radiation treatment. This is usually called Image-guided radiation therapy (IGRT), which utilizes the imaging coordinates to direct radiation beams to follow the actual radiation treatment plan. The image-guided system is the essential item to enable superior accuracies in the dose delivery by locating the patient’s instantaneous position during radiation treatments. In CyberKnife system current setup, two X-ray imaging sources and cameras are orthogonally mounted around the patient allowing instantaneous X-ray images to be obtained. This thesis presents a method that uses the technique of computed tomography, called partial CT, to guide the stereotactic surgery and significantly simplifies the image registration procedure by one set of X-ray sources and radiation detectors. The image processing for the partial CT is based on mutual information algorithm, a technically successful method, which ensures the accuracy of the image guidance system. All the experiments are demonstrated with respect to the CyberKnife system.


stereotactic radiosurgery; image-registration; partial CT; mutual information; CyberKnife; X-ray stereotactic imager