Enabling Technologies for Natural Orifice Transluminal Endoscopic Surgery (NOTES) using Robotically Guided Elasticity Imaging

Natural orifice transluminal endoscopic surgery (N.O.T.E.S) is a minimally invasive surgical technique that could benefit greatly from additional methods for intraoperative detection of tissue malignancies (using elastography) along with more precise control of surgical tools. Ultrasound elastography has proven itself as an invaluable imaging modality. However, elasticity images typically suffer from low contrast when imaging organs from the surface of the body. In addition, the palpation motions needed to generate elastography images useful for identifying clinically significant changes in tissue properties are difficult to produce because they require precise axial displacements along the imaging plane. Improvements in elasticity imaging necessitate an approach that simultaneously removes the need for imaging from the body surface while providing more precise palpation motions. As a first step toward performing N.O.T.E.S in-vivo, we integrated a phased ultrasonic micro-array with a flexible snake-like robot. The integrated system is used to create elastography images of a spherical isoechoic lesion (approximately 5mm in cross-section) in a tissue-mimicking phantom. Images are obtained by performing robotic palpation of the phantom at the location of the lesion.