Tadpole-like endoscope swims through gastrointestinal tract in search of cancer

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The Tadpole Endoscope can be swallowed like a large pill and then remotely guided around inside the patient's stomach by a doctor

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Endoscopes are essential tools for the medical examination of many organs of the human body, and are best known for their use in examining the gastrointestinal tract. Generally consisting of a flexible tube with a light source and an arrangement of lenses – or small cameras in more modern devices – the endoscope is a vital, but unwieldy tool that takes a great deal of skill to operate and maneuver around in tight areas. Now engineers have created a new device dubbed the Tadpole Endoscope, that literally swims around inside the organ of a patient and wirelessly transmits video of what it sees.

With cancers of the gastrointestinal (GI) tract, such as esophageal cancer, stomach cancer, and colon cancer, being some of the most commmon of all cancers in the world, a range of procedures are necessary to physically examine all parts of the GI for maximum diagnostic effect. Of these, gastroscopy is used to help diagnose esophageal and stomach cancer, whilst intestinal and coleorectal cancers can be determined with the use of capsule endoscopy and colonoscopy, respectively. Unfortunately, all of these procedures are costly to perform and can place a great deal of stress on someone who may already be quite ill.

The new Tadpole Endoscope (TE), on the other hand, is a relatively non-invasive device that is simply swallowed like a large pill and then remotely guided around inside the patient's stomach by a doctor. Created by engineers from the Institute of Precision Engineering at the Chinese University of Hong Kong, the device has a soft-tail that it uses to maneuver about, a 3D printed shell that contains the control electronics, and a placeholder for a wireless video camera.

Not the first stomach-inspecting device ever to be created to wirelessly transmit video from within a patient, nor even the first to use external magnetic propulsion – the Olympus/Siemens ingestible device being one notable example – the TE is, however, potentially much more maneuverable, particularly with its driven tail.

The drive unit for the TE is constructed with two permanent magnets, a magnetic coil and a tail. As the polarity of the two magnets is opposing, when the coil is energized, a repulsive and an attractive force is generated. With the tail of the device attached to the coil, it then flaps in harmony to the current applied and propels the TE along. Magnetic field generation with coils located outside the body supply the electrical current wirelessly to the coil located within the TE, much like that suggested for use in certain shape-shifting nanoprobes.

After the TE has been used in the initial diagnosis of the stomach, natural peristaltic action (the "squeezing" motion of muscles that ordinarily move food down the GI) will push it into the lower GI tract. The patient under observation may then be discharged and, over the following days, a sensor pad attached to the person can continue to capture and record subsequent images which a medical professional can then download and add to the complete diagnostic data set.

In testing thus far, the TE has been deployed in both an artificial stomach model and a pig stomach. Whilst the image system has yet to be fitted to the device, the researchers believe that the feasibility of the propulsion model will move their creation toward the next set of experiments and onward to eventual deployment in working medical applications.

The results of this research were published in the journal HKIE Transactions.

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