Capsular endoscopy of the GI tract has its advantages, but since the swallowed capsule moves randomly through the intestines, there’s absolutely no control of where the eye of the device is pointing at. Now researchers from Tel Aviv University and Brigham and Women’s Hospital are using a 3T MRI machine to both power and propel a new capsule they invented. The tail of the device that provides the motive force is made of copper and a flexible polymer.
So far the technology has been tested in a water tank and the researchers believe the power produced is sufficient to navigate the capsule inside the stomach. This technology is reminiscent of the magnetically guided capsule project between Siemens and Olympus (see flashbacks below), but that one was different in that the capsule doesn’t use a propeller of any sort but is directly moved around by the magnetic field.
From the study abstract in Biomedical Microdevices:
We have found that an approximately 20 mm long, 5 mm wide swimming tail is capable of producing 0.21 mN propulsive force in water when driven by a 20 Hz signal providing 0.85 mW power and the tail located within the homogeneous field of a 3 T MRI scanner. We also analyze the parallel operation of the swimming mechanism and the scanner imaging. We characterize the size of artifacts caused by the propulsion system. We show that while the magnetic micro swimmer is propelling the capsule endoscope, the operator can locate the capsule on the image of an interventional scene without being obscured by significant artifacts. Although this swimming method does not scale down favorably, the high magnetic field of the MRI allows self propulsion speed on the order of several millimeter per second and can propel an endoscopic capsule in the stomach.
Abstract in Biomedical Microdevices: MRI driven magnetic microswimmers
Flashbacks: Mermaid, the Swimming Capsule Endoscope; Externally Navigated Capsule Scope from Siemens/Olympus “Feasible and Sufficiently Accurate for Gastric Examination”; Siemens and Olympus Attempt to Improve GI Imaging With New Magnetically Guided Capsule Endoscope; Capsule Endoscope by Olympus;