Thin and cleverly controllable: Researchers have developed a probe system that can penetrate into fine ramifications of the lungs. The “tentacle” is only two millimeters wide and is automatically controlled from the outside by magnetic forces that emanate from movable robotic arms. The system, which is now being tested further, could make it possible to reach even deeper areas of the lungs than before in order to take tissue samples or carry out treatments, the scientists say.
Endoscopes and catheters, probe systems that are inserted into the body from the outside have greatly advanced the possibilities for diagnosing and treating various diseases in recent decades. In the case of the lungs, the procedure currently used is called bronchoscopy. A flexible, tubular instrument with a diameter of about 3.5 to 4 millimeters is inserted through the nose or mouth into the bronchi of the sedated patient. Due to its size, however, the bronchoscope can only penetrate to the upper levels of the bronchial tree. To get even deeper, a catheter or fine tube is then inserted through the bronchoscope and eventually into the finer tubes of the lungs.
Target finer areas
These probes only have a diameter of about two millimeters. But with previous manual control techniques, they can only be guided to a limited extent through the branched bronchial system, which means that certain areas remain inaccessible. In addition, x-rays are often required during the procedure, which can pose another technical challenge for the medical staff. There is therefore potential for optimization in endoscope and catheter technology. The scientists led by Pietro Valdastri from the University of Leeds are dedicating themselves to this field of research. Specifically, they are working on the development of more manoeuvrable and more precisely controllable systems that require less effort.
This is how the catheter concept, which they call “magnetic tentacles”, came about. This structure is made up of interconnected, cylindrical segments, each with a diameter of two millimeters. The material is a soft elastomeric plastic that gives the tentacle enormous flexibility in addition to segmentation. In order to be able to remotely control its movements, magnetic particles are integrated into the material. The segments can thus be influenced independently of one another by external magnetic fields. The result is a highly flexible structure that bends like a tentacle and is small enough not to catch on anatomical structures in the lungs, writes the University of Leeds.
Remote maneuverability
The tentacle is under the spell of magnetic fields that emanate from two robotic arms that move with fine motor control over the patient. They cause the catheter to change direction, allowing the probe to be maneuvered as it slowly advances to the site of a suspicious spot in the lungs. However, this does not happen manually, but fully automatically: The path through the bronchial tree is planned based on previous scans of the patient’s lungs and then programmed into the robot system. “Thanks to our autonomous magnetic guidance system, the patient does not have to be x-rayed during the procedure,” says Valdastri.
So far, however, the researchers have only provided the “proof of concept”: They have demonstrated the basic functionality of their concept through laboratory tests: they successfully steered the tentacle through a 3D replica of a bronchial tree that was modeled using anatomical data. Development work is therefore still required before it can be used in clinical practice. In the next phase, the team now plans to investigate the system’s performance in navigating a cadaver’s lungs. The University of Leeds writes that, after further trials, the “magnetic tentacle” technology could start benefiting patients for the first time in a few years.
This could then represent an important advance, emphasizes Valdastri: “A magnetic catheter that is only two millimeters wide and whose shape can be magnetically controlled to adapt to the anatomy of the bronchial tree can reach most areas of the lung and would be an important one clinical tool for examining and treating possible lung cancer and other lung diseases,” the scientist sums up.
Source: University of Leeds