Magnetic Tentacle Robot

‘Tentacle robot’ powered by magnets can delve into narrow tubes of human lungs

Image credit: University of Leeds

A robot that can reach some of the smallest bronchial tubes in the lungs using magnets to take tissue samples or deliver cancer therapy has been developed by University of Leeds researchers.

Known as a magnetic tentacle robot, it measures just 2mm in diameter - approximately twice the size of the tip of a ballpoint pen. Magnets on the outside of the patient will be used to guide it into place.

A proof-of-concept device has already been made based on laboratory tests involving a 3D replica of a bronchial tree modelled from anatomical data. The next phase of the research will investigate the effectiveness of the device in navigating lungs taken from a cadaver.

Currently, doctors use an instrument called a bronchoscope to carry out an examination of the lungs and air passages. The procedure involves passing a flexible tube-like instrument, about 3.5-4mm in diameter, through the nose or mouth and into the bronchial passages.

Due to its size, the bronchoscope can only travel as far as the upper levels of the bronchial tree.

To delve deeper into the lungs, a catheter or fine tube - measuring about 2mm in diameter - is passed through the bronchoscope and then into the smaller tubes of the lungs. 

Doctors are limited in how they can move a bronchoscope, making it difficult to navigate the instrument and the catheter to where they are needed.

The magnetic tentacle robot has been developed to be much more manoeuvrable and uses a robotic guidance system that is personalised for each procedure.

Professor Pietro Valdastri, who supervised the research, said: “A magnetic tentacle robot or catheter that measures 2mm and whose shape can be magnetically controlled to conform to the bronchial tree anatomy can reach most areas of the lung and would be an important clinical tool in the investigation and treatment of possible lung cancer and other lung diseases.

“Our system uses an autonomous magnetic guidance system which does away for the need for patients to be X-rayed while the procedure is carried out.”

To reduce the size of the robot while retaining controllability of motion, the researchers manufactured it from a series of interlinked cylindrical segments, each 2mm in diameter and around 80mm in length. The segments were made of a soft elastomeric or rubber-like material which had been impregnated with tiny magnetic particles.

Because of the presence of the magnetic particles, the interlinked segments can move somewhat independently under the effect of an external magnetic field. The result is a magnetic tentacle robot which is highly flexible, able to shape shift and small enough to avoid snagging on anatomical structures in the lungs.

Magnets mounted on robotic arms on the outside of the patient would be used to guide the device into the lungs in a process that would be tailor-made for each procedure.

The route through the bronchial tree is planned from pre-operative scans of a patient’s lungs and programmed into the robotic system.

As the magnets outside of the patient move, they develop forces on the magnetic particles in the segments of the catheter, causing them to change shape or direction - enabling the robot to be manoeuvred through the lungs and to a site of a suspicious lesion.

Once at the target location, the robot is used to take a tissue sample or deliver treatment.

However, it may still be several years before “magnetic tentacle” technology is available in a hospital setting, the researchers said.

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