IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, VOL. 58, NO. 2, FEBRUARY 2011 231 Magnetically Controllable Gastrointestinal Steering of Video Capsules Federico Carpi*, Nathan Kastelein, Michael Talcott, and Carlo Pappone Abstract—Wireless capsule endoscopy (WCE) allows for com- fortable video explorations of the gastrointestinal (GI) tract, with special indication for the small bowel. In the other segments of the GI tract also accessible to probe gastroscopy and colonscopy, WCE still exhibits poorer diagnostic efficacy. Its main drawback is the impossibility of controlling the capsule movement, which is randomly driven by peristalsis and gravity. To solve this prob- lem, magnetic maneuvering has recently become a thrust research area. Here, we report the first demonstration of accurate robotic steering and noninvasive 3-D localization of a magnetically enabled sample of the most common video capsule (PillCam, Given Imag- ing Ltd, Israel) within each of the main regions of the GI tract (esophagus, stomach, small bowel, and colon) in vivo, in a domestic pig model. Moreover, we demonstrate how this is readily achiev- able with a robotic magnetic navigation system (Niobe, Stereotaxis, Inc, USA) already used for cardiovascular clinical procedures. The capsule was freely and safely moved with omnidirectional steering accuracy of 1 ◦ , and was tracked in real time through fluoroscopic imaging, which also allowed for 3-D localization with an error of 1 mm. The accuracy of steering and localization enabled by the Stereotaxis system and its clinical accessibility world wide may al- low for immediate and broad usage in this new application. This anticipates magnetically steerable WCE as a near-term reality. The instrumentation should be used with the next generations of video capsules, intrinsically magnetic and capable of real-time optical- image visualization, which are expected to reach the market soon. Index Terms—Capsule, control, endoscopy, gastrointestinal (GI), in vivo, magnetic, motion, navigation, robotic, video, wireless. I. INTRODUCTION T EN years ago, the introduction of wireless capsule en- doscopy (WCE) [1] marked a revolution for gastrointesti- nal (GI) diagnostics, opening the era of comfortable video explorations of the GI tract. Today, it has been well docu- mented that WCE is especially indicated for examinations of Manuscript received July 9, 2010; revised August 31, 2010; accepted October 5, 2010. Date of publication October 14, 2010; date of current version January 21, 2011. Asterisk indicates corresponding author. *F. Carpi is with the Interdepartmental Research Centre “E. Piaggio”, University of Pisa, School of Engineering, Pisa 56100, Italy (e-mail: f.carpi@centropiaggio.unipi.it). N. Kastelein is with Stereotaxis, Inc., St Louis, MO 63108 USA (e-mail: nathan.kastelein@stereotaxis.com). M. Talcott is with the Veterinary Surgical Services, Division of Comparative Medicine, Washington University School of Medicine, St. Louis, MO 63110 USA (e-mail: mtalcott@wustl.edu). C. Pappone is with the Department of Arrhythmology, Villa Maria Cecilia Hospital, Ravenna 48010, Italy (e-mail: cpappone@gvm-vmc.it). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TBME.2010.2087332 the small bowel [2], [3]. However, in the rest of the GI tract (esophagus, stomach, and colon) accessible also to probe gas- troscopy and colonscopy, WCE still exhibits poorer diagnostic efficacy [2]–[4]. Its main drawback is the impossibility of con- trolling the capsule movement, which is randomly driven by peristalsis and gravity. To solve this problem, magnetic control of magnetically en- abled standard video capsules was proposed a few years ago [5]. At present, magnetic maneuvering has become an area of in- tense research in the field [2], [3], [6]–[9]. Capsule motions can readily be induced with hand-held/hand-guided magnets, as demonstrated even in the esophagus and stomach of a volun- teer [7]. Despite this, precise field control for reliable and re- peatable maneuvers is challenged by the characteristic instabil- ity of permanent-magnet configurations (Earnshaw’s theorem). Thus, to improve maneuvering performance, the development of robotic systems, as opposed to manual procedures, is the focus of significant efforts [6], [8], [9]. Here, we report the first demonstration of accurate robotic steering and noninvasive 3-D localization of a magnetically en- abled sample of the most common video capsule (PillCam, Given Imaging Ltd, Israel) within each main region of the entire GI tract (esophagus, stomach, small bowel, and colon) in vivo, in a domestic pig model. Moreover, we show that this is readily achievable with a magnetic navigation system (Niobe, Stereotaxis, Inc, USA) already used for cardiovascular clinical procedures [10]. II. MATERIALS AND METHODS As no magnetic capsule is commercially available yet, the technique was validated by equipping the PillCam device with a custom-made coaxial magnetic shell, glued to its external surface. The analytical design and implementation of the shell have been described previously [6]. The shell was based on neodymium and had a cylindrical shape, with a length of 13 mm, an external diameter of 13 mm, an internal diameter of 11 mm, a mass of 3.59 g, and a uniform diametral magneti- zation of 9.71 × 10 5 A/m. Motion control tests were performed in vivo, on four domestic pigs, having an average weight of 110 kg. The studies were done in accordance with the authors’ institutional guidelines for animal care and use, and according to a research protocol approved by the Washington University School of Medicine, St Louis. Magnetic steering inside the different regions of the GI tract was investigated during separate test sessions, with different an- imals on different days. Each session required a specific prepa- ration of the animal, so as to allow the capsule to be properly 0018-9294/$26.00 © 2010 IEEE