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Title: Image guidance in telemanipulator assisted urology surgery
Author: Thompson, Stephen Alexander
Awarding Body: University College London
Current Institution: University College London (University of London)
Date of Award: 2011
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This thesis describes an image guided surgery system for use during telemanipulator assisted radical prostatectomy. The thesis is primarily concerned with determining the system accuracy. We first defined a method to present the component errors as an on-screen projection error in pixels. This allowed the error due to each component to be compared and then summed to give a system error. An MRI image of the patient is transformed into the intraoperative coordinate system, defined by the coordinate system of an optical tracking system. The endoscope is calibrated and tracked during surgery, defining a transformation to the endoscope screen. This transform is used to project the MRI image onto the endoscope video display. A novel algorithm for registering MRI to ultrasound images of pelvic bone was used to transform the MRI image to the intraoperative coordinate system. This algorithm localises the prostate to within 7 mm, giving an on-screen error of 28 pixels. The on-screen error due to endoscope tracking was found to be 65 pixels. The high tracking error is caused by a non-normally distributed marker tracking error, highlighting an important shortcoming in the bulk of the image guided surgery literature. Due to the high tracking errors we implemented a limited image guidance system that does not use endoscope tracking. The final part of the thesis details our experience in implementing this system on 5 patients. The main contributions of this thesis are: • A robust error analysis of an image guided endoscopic surgery system. • A novel algorithm for fitting inter patient CT data to an MRI image. The algorithm compares well in with the state of the art for segmenting pelvic bone from MRI images. • A method to analyse the endoscope tracking error that does not depend on the assumption of normally distributed, homogeneous marker tracking error.
Supervisor: Hawkes, D. ; Penney, G. ; Dasgupta, P. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available