Research Proposal


Taking endoscopy to a higher dimension: With MUSTOF to NOTES

With a novel approach abdominal surgery can be performed without skin incisions. The natural orifices may provide the entry point with a following incision in stomach or colon. "Natural Orifice Translumenal Endoscopic Surgery" (NOTES) is assumed to offer significant benefits to patients such as less pain, faster recovery, and better cosmesis than current laparoscopic techniques. Even particular improvement can be reached for obesity and burn injury patients and children. Several barriers identified for the clinical practicability in flexible intra-abdominal endoscopy can be solved with computer-assisted surgical systems, but additional 3-D information is fundamentally required. Our approach to face this challenge is the acquisition of 3-D information directly via the endoscope with a hybrid imaging system. Parallel to the CCD camera a Time-Of-Flight (TOF) system is integrated. Accordingly, the name Multisensor-Time-Of-Flight endoscope (MUSTOF endoscope) was chosen. TOF cameras illuminate the scene actively with an optical reference signal. For each TOF pixel a distance value depending on the phase shift of the reflected optical wave and electrical reference signal is estimated. To compensate the high optical attenuation of endoscopic systems, we designed a much more efficient illumination unit with laser diodes. Currently, TOF chips with lateral resolutions of up to 140x170 pixels and z-resolutions of 1 mm are achievable.

Online 3-D information registered with preoperative CT or MR data may provide real-time information on position and orientation of the endoscope, show hidden organs by augmented reality while finding the entry point, extend and virtually rotate the field of view and enable efficient collision prevention. Therefore sensor calibration, image reconstruction, feature extraction and volume registration are required. Since MUSTOF endoscopy gives a third dimension to endoscopic images in real-time, those algorithms can be processed fast enough by now. With such an enhanced endoscopic system, NOTES will be able to be performed in a fundamentally safer manner.