All Publications

2009
L. Maier-Hein, et al., “Human vs. Robot Operator Error in a Needle-Based Navigation System for Percutaneous Liver Interventions,” in Proc. SPIE, Lake Buena Vista, FL, 2009, vol. 7261, pp. 72610Y-72610Y-12. Publisher's VersionAbstract

Computed tomography (CT) guided percutaneous punctures of the liver for cancer diagnosis and therapy (e.g. tumor biopsy, radiofrequency ablation) are well-established procedures in clinical routine. One of the main challenges related to these interventions is the accurate placement of the needle within the lesion. Several navigation concepts have been introduced to compensate for organ shift and deformation in real-time, yet, the operator error remains an important factor influencing the overall accuracy of the developed systems. The aim of this study was to investigate whether the operator error and, thus, the overall insertion error of an existing navigation system could be further reduced by replacing the user with the medical robot Robopsy. For this purpose, we performed navigated needle insertions in a static abdominal phantom as well as in a respiratory liver motion simulator and compared the human operator error with the targeting error performed by the robot. According to the results, the Robopsy driven needle insertion system is able to more accurately align the needle and insert it along its axis compared to a human operator. Integration of the robot into the current navigation system could thus improve targeting accuracy in clinical use.

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2008
C. J. Walsh, J. T. Heaton, J. B. Kobler, T. L. Szabo, and S. M. Zeitels, “Imaging of the Calf Vocal Fold with High Frequency Ultrasound,” The Laryngoscope, vol. 118, no. Oct. pp. 1894-1899, 2008. PDF
C. J. Walsh and C. K. Kearney, “Engineering, Science and Medicine: Transforming Healthcare,” Royal College of Surgeons in Ireland Student Medical Journal, vol. 1, no. 1, pp. 56-59, 2008. PDF
C. J. Walsh, N. C. Hanumara, A. H. Slocum, J. - A. Shepard, and R. Gupta, “A Patient-Mounted, Telerobotic Tool for CT-Guided Percutaneous Interventions,” ASME Journal of Medical Devices, vol. 2, no. 1, 2008. PDF
2007
C. J. Walsh, K. Endo, and H. Herr, “Quasi-Passive Leg Exoskeleton for Load Carrying Augmentation,” International Journal of Humanoid Robotics, Special Issue: Active Exoskeletons, vol. 4, no. 3, pp. 487-506, 2007.Abstract

A quasi-passive leg exoskeleton is presented for load-carrying augmentation during walking. The exoskeleton has no actuators, only ankle and hip springs and a knee variable damper. Without a payload, the exoskeleton weighs 11.7kg and requires only 2 Watts of electrical power during loaded walking. For a 36kg payload, we demonstrate that the quasi-passive exoskeleton transfers on average 80% of the load to the ground during the single support phase of walking. By measuring the rate of oxygen consumption on a study participant walking at a self-selected speed, we find that the exoskeleton slightly increases the walking metabolic cost of transport (COT) as compared to a standard loaded backpack (10% increase). However, a similar exoskeleton without joint springs or damping control (zero-impedance exoskeleton) is found to increase COT by 23% compared to the loaded backpack, highlighting the benefits of passive and quasi-passive joint mechanisms in the design of efficient, low-mass leg exoskeletons.

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N. C. Hanumara, C. J. Walsh, R. Gupta, J. - A. Shepard, and A. H. Slocum, “Human Factors Design for Intuitive Operation of a Low-cost, Image-Guided, Tele-Robotic Biopsy Assistant,” in Proceedings of the IEEE Engineering in Medicine and Biology Conference, Lyon, France, 2007, pp. 1257-1260. PDF
2006
C. J. Walsh, K. Pasch, and H. Herr, “An Autonomous, Underactuated Exoskeleton for Load Carrying Augmentation,” in Proc. Inter. Conf. on IROS, Beijing, China, 2006, pp. 1410-1415. PDF
C. J. Walsh, D. Paluska, K. Pasch, W. Grand, A. Valiente, and H. Herr, “Development of a Lightweight, Under-actuated Exoskeleton to Assist in Load Carrying in Walking,” in Proceedings of the IEEE International Conference on Robotics and Automation, Orlando, Florida, 2006, pp. 3485-3491. PDF
2005
S. R. H. Barrett, R. Gupta, N. C. Hanumara, A. H. Slocum, and C. J. Walsh, “Remote Needle Guidance System for Percutaneous Image Guided Biopsies,” in Proc. American Society of Mechanical Engineers International Design Engineering and Technical Conferences, Long Beach, California, 2005. PDF

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