Elisa Buselli

A magnetic internal mechanism for precise orientation of the camera in wireless endoluminal applications

BACKGROUND AND STUDY AIMS The use of magnetic fields to control operative devices has been recently described in endoluminal and transluminal surgical applications. The exponential decrease of magnetic field strength with distance has major implications for precision of the remote control. We aimed to assess the feasibility and functionality of a novel wireless miniaturized mechanism, based on magnetic forces, for precise orientation of the camera. MATERIALS AND METHODS A remotely controllable endoscopic capsule was developed as proof of concept. Two intracapsular moveable permanent magnets allow fine positioning, and an externally applied magnetic field permits gross movement and stabilization. Performance was assessed in ex vivo and in vivo bench tests, using porcine upper and lower gastrointestinal tracts. RESULTS Fine control of capsule navigation and rotation was achieved in all tests with an external magnet held steadily about 15 cm from the capsule. The camera could be rotated in steps of 1.8 degrees . This was confirmed by ex vivo tests; the mechanism could adjust the capsule view at 40 different locations in a gastrointestinal tract phantom model. Full 360 degrees viewing was possible in the gastric cavity, while the maximal steering in the colon was 45 degrees in total. In vivo, a similar performance was verified, where the mechanism was successfully operated every 5 cm for 40 cm in the colon, visually sweeping from side to side of the lumen; 360 degrees views were obtained in the gastric fundus and body, while antrally the luminal walls prevented full rotation. CONCLUSIONS We report the feasibility and effectiveness of the combined use of external static magnetic fields and internal actuation to move small permanent intracapsular magnets to achieve wirelessly controllable and precise camera steering. The concept is applicable to capsule endoscopy as to other instrumentation for laparoscopic, endoluminal, or transluminal procedures.

Evaluation of friction enhancement through soft polymer micro-patterns in active capsule endoscopy

Capsule endoscopy is an emerging field in medical technology. Despite very promising innovations, some critical issues are yet to be addressed, such as the management and possible exploitation of the friction in the gastrointestinal environment in order to control capsule locomotion more actively. This paper presents the fabrication and testing of bio-inspired polymeric micro-patterns, which are arrays of cylindrical pillars fabricated via soft lithography. The aim of the work is to develop structures that enhance the grip between an artificial device and the intestinal tissue, without injuring the mucosa. In fact, the patterns are intended to be mounted on microfabricated legs of a capsule robot that is able to move actively in the gastrointestinal tract, thus improving the robots traction ability. The effect of micro-patterned surfaces on the leg-slipping behaviour on colon walls was investigated by considering both different pillar dimensions and the influence of tissue morphology. Several in vitro tests on biological samples demonstrated that micro-patterns of pillars made from a soft polymer with an aspect ratio close to 1 enhanced friction by 41.7% with regard to flat surfaces. This work presents preliminary modelling of the friction and adhesion forces in the gastrointestinal environment and some design guidelines for endoscopic devices.

Wireless steering mechanism with magnetic actuation for an endoscopic capsule

This paper illustrates the design, development and testing of a miniature mechanism to be integrated in endoscopic capsules for precise steering capabilities (Magnetic Internal Mechanism, MIM). The mechanism consists of an electromagnetic motor connected to a couple of small permanent magnets and immersed in a static magnetic field produced by an external permanent magnet or a by an electromagnetic coil. The overall steering capsule, integrating the magnetic steering mechanism and the vision system is 15.6 mm in diameter, 48 mm in length, 14.4 g in weight and can be oriented with an accuracy of 0.01°. As regards system scalability, the capsule size could be reduced down to 11 mm in diameter by optimizing some mechanical components. On the other hand, the magnets size cannot be reduced because the magnetic link between internal and external magnets at typical operation distances (about 15 mm) would be weak.

Superelastic leg design optimization for an endoscopic capsule with active locomotion

Nowadays Nitinol structures are accepted and highly exploited in the medical field. Therefore, studying the mechanical properties of this material—which is not trivial by considering the thermal behaviour of the alloy—is very important in order to get quantitative data for a reliable design of novel Nitinol components. In particular, this study focuses on the design optimization of superelastic Nitinol legs to be integrated into an endoscopic capsule for biomedical applications. The leg is provided with an elastic knee that adds a passive degree of freedom to the structure; this solution allows us to achieve a good locomotion adaptability in the unstructured environment of the gastrointestinal tract, characterized by different diameters. First, the mechanical behaviour of Nitinol was analysed. Tensile tests were carried on in order to extract the peculiar stress–strain curve of the material. The hysteretic behaviour was observed through 100 loading–unloading cycles. The acquired data were used to model the leg design by finite element methods (FEM) and to estimate the stress–strain internal state during the operative work. These data were used to optimize the leg, which was finally fabricated and tested, demonstrating an improvement of five times regarding the number of cycles before leg failure.

Design and Impact of a Teacher Training Course, and Attitude Change Concerning Educational Robotics

Current initiatives and laboratories concerning Educational Robotics (ER) are often not based on strong pedagogical backgrounds. Additionally, they are carried out by inadequately trained teachers, and are not evaluated properly in terms of effectiveness. Moreover, according to teachers, ER usability is often neglected. The main goal of the present article is to present a training course on ER (Edu.Ro.Co.), grounded in pedagogical insights, and to discuss the results of the course and teacher’s opinion about ER in terms of: (i) teachers’ attitudes and perceptions of using ER; (ii) the potential impact of ER on students’ key competences for lifelong learning; and (iii) strengths and weaknesses of ER. These aspects were analysed by means of questionnaires specifically designed by the authors, and administered before and after the training course. A total of 339 teachers attended the training course and 254 completed the questionnaires. The article describes the methodology utilised in the realisation of the course and analyses the questionnaire’s results. In particular, the number of teachers that considered themselves prepared to apply ER significantly improved after the training course. ER is considered by teachers an important tool for the improvement of students’ motivation, planning skills, team working, problem solving and creativity development. Finally, the results from questionnaires indicate that teachers consider ER, a method that improves team-working abilities and motivation in the students. In contrast, the main disadvantage is the cost of the robotic kits. Based on these results, new directions for future research in ER are discussed.