Date: June 10, 2014
Venue: University of Verona, Strada le Grazie 15 – 37134 Verona ITALY
Robotic technologies for medicine and healthcare applications are receiving more and more attention in clinical practice. This workshop will cover three specific topics in the areas of computer aided surgical intervention and assistive and rehabilitation robotics. Surgery related topics are image-guided interventions, medical image processing, image registration, navigation systems and devices for minimal invasive procedures. Rehabilitation-related topics address physical human-robot interaction in active orthoses and prostheses, patient-specific rehabilitation, compliant actuation systems and compliant control algorithms.
The workshop will be half-day and free of charge. Registration is mandatory and should be confirmed by email to firstname.lastname@example.org. Registration deadline is on 3rd June.
9.00 – 9.30 Welcome and Introduction
9.30 – 10.30 Registration of medical images for applications in minimally invasive procedures
10.30 – 11.30 Navigation for percutaneous surgical interventions: ultrasound data processing, feature extraction and 3D organ reconstruction
11.30 – 12.30 Compliant control of elastic actuators for human robot interaction
12.30 – 13.30 Lunch Break
Paolo Fiorini, Marta Capiluppi
University of Verona
Registration of medical images for applications in minimally invasive procedures
The registration of medical images is necessary to establish spatial correspondences across two or more images. Registration is rarely the end-goal, but instead, the results of image registration are used in other tasks.
The starting point of this presentation is to analyze which methods at the state of the art of image registration are suitable to be used in assisting a physician during a minimally invasive procedure, such as a percutaneous procedure performed manually or a teleoperated intervention performed by the means of a robot. The first conclusion is that, even if much previous work has been devoted to develop registration algorithms to be applied in the medical context, most of them are not designed to be used in the operating room scenario (OR) because, compared to other applications, the OR requires also a strong validation, real-time performance and the presence of other instruments. Almost all of these algorithms are based on a three phase iteration: optimize-transform-evaluate similarity. In this work, we study the feasibility of this three steps approach in the OR, showing the limits that such approach encounter in the applications we are considering. We investigate how could a simple method be realizable and what are the assumptions for such a method to work. We then develop a theory that is suitable to register large sets of unstructured data extracted from medical images keeping into account the constraints of the OR. The use of the whole radiologic information is not feasible in the OR context, therefore the method we are introducing registers processed dataset extracted from the original medical images. The framework we propose is designed to find the spatial correspondence in closed form keeping into account the type of the data, the real-time constraint and the presence of noise and/or small deformations. The theory and algorithms we have developed are in the framework of the shape theory proposed by Kendall (Kendall’s shapes) and uses a global descriptor of the shape to compute the correspondences and the distance between shapes. Since the registration is only a component of a medical application, the last part of the presentation is dedicated to some practical applications in the OR that can benefit from the registration procedure.
Navigation for percutaneous surgical interventions: ultrasound data processing, feature extraction and 3D organ reconstruction
In this presentation we describe different methods able to improve the current ultrasound based navigation systems, with specific attention to cryoablation percutaneous procedures.
The first part of this presentation presents a feature detector and descriptor able to localize and match salient points from ultrasound image. These methods have been designed and tested with specific attention to ultrasound images, where the intensity information are not stable. The detector is based a local energy model in place of the widely adopted gradient methods, where feature points are localized based on the phase congruency of Fourier components. The detector is based on Local Binary Pattern operator computed over a local angle and direction of the phase congruency. These choices enable the robust localization of feature point in ultrasound image in presence of intensity and geometrical transformation. The second part is dedicated to a compact navigation device that integrate a small display directly onto the ablation tool to provide indication on how to move the needle in the proper way and to guarantee the correct insertion along the planned trajectory. The last part present a method that overcomes the unfeasible monitoring of the ablation area with ultrasound image during cryoablation procedures, and it is based on ultrasound elastography. Ultrasound elastography is used for the measurement of tissue elasticity; since the freezing produce cellular structural damage we measure the tissue elastic properties before and after the complete thawing of the tissue. We believe that the presented contributions, if integrated in an ultrasound guided navigation system, will improve the characteristics of these advanced systems with specific attention to real clinical requirements.
Compliant control of elastic actuators for human robot interaction
This presentation focuses on the control of interaction between a soft robot and a human being. It proposes a novel approach to physical human-robot interaction (pHRI) by explicitly accounting for human dynamics. In fact existing interaction control solutions guarantees stability by regarding the human to a passive system without accounting for its dynamics. Unfortunately such unmodeled dynamics is actually in the loop and influences the interaction unpredictably. As a result the closed loop dynamics is stable but not well defined. This is in general not desired especially if we aim to guarantee a certain control performance as in the case of robotic orthoses and prostheses. Also unpredictable interaction dynamics can be harmful when closing an higher level control loop as the stability region is in turn not well defined.
This presentation proposes a novel control approach to the problem. We start from the analysis of existing design and control principles of soft interaction. We outline that physical compliance has the fundamental role of stabilizing force control. Then we propose a novel approach that, taking advantages of compliance, explicitly accounts for the human dynamics in the loop. In particular we propose two kind of control solutions. The first is based on the on-line estimation of human dynamics and on-line adaptation of control law. The second considers certain unmeasurable parts of human dynamics as a disturbance and provides to be insensitive to it. Stability and performance of both solutions are theoretically guaranteed under realistic hypotheses. Experimental validation in a physical human-robot interaction task shows evident advantages of the proposed approaches with respect to existing solutions.