University of Twente Student Theses


Ultrasound-guided control of a minimally-invasive surgical instrument

Ellenbroek, T.T.M. (2013) Ultrasound-guided control of a minimally-invasive surgical instrument.

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Abstract:Development in Minimally Invasive Surgery (MIS) aims at minimizing patient trauma. A major improvement in cardiac surgery with respect to minimizing patient trauma would be omitting the need to perform a sternotomy. Working around the sternum, the surgeon needs instruments that perform a task inside the body while the controls are outside the body. Images should also be recorded inside the body, but shown to the surgeon outside the body. Amongst others, ultrasound, Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) are imaging modalities that would fit in an MIS environment. MRI has the disadvantage that not many instruments are suited for the applied magnetic fields, and CT has the disadvantage of radiation. Both MRI and CT are also expensive imaging modalities. Therefore, ultrasound is chosen to provide images in this project. Instruments allowing the surgeon to operate from outside the body are generalized in the family of MIS instruments. These instruments allow the surgeon to operate through small incisions, while the instrument performs the task at the target location inside the body. The MIS instrument used in this project is a cylinder-shaped device, of the family of continuum robots, that has a exible tip. The tip is actuated by pulling on two sets of tendons that emerge from the rear of the instrument. The MIS instrument is mounted in an experimental setup, where two motors operate the instrument's tendons. The instrument is mounted on a linear stage, allowing for movement along its longitudinal axis. A 2D ultrasound probe is positioned above the tip to visualize it. Image processing is used to find the tip location from the ultrasound images and the measured position is used for closed-loop control. The setup and instrument are characterized and a number of (model-based) controllers are designed and evaluated.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:53 electrotechnology
Programme:Electrical Engineering MSc (60353)
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