In the clinic, the phenomenon of robots being used as an adjunctive therapeutic tool for disease detection or treatment is becoming more and more common.
In December 2020, the team of Professor Pietro Valdastri of the Storm Lab, University of Leeds developed a robotic-assisted colonoscopy that can be guided by external tools to precisely reach diseased areas in the human body. This provides doctors with a new way of thinking about testing inside the human body, while also helping patients alleviate the pain caused by traditional testing.
Figure | robotic magnetic flexible endoscope (MFE) system (Source: Nature Machine Intelligence)
Recently, Pietro Valdastri's latest research results, similar to the research results mentioned above, are also the application of robot-assisted technology to the clinic, with the difference that the test site for patients is different.
Petro Valdastri's team has developed a "magnetic tentacle robot" with a diameter of only 2 millimeters (mm), if described by visual objects, the size of the robot is only about 2 times the size of the ballpoint pen tip, and robots of this size can be easily delivered to some narrow bronchial trees in the human lungs to help doctors collect tissue samples or assist in the treatment of diseases such as cancer.
On March 21, the paper was published in Soft Robotics under the title "Patient-Specific Magnetic Catheters for Atraumatic Autonomous Endoscopy," by Professor Pietro S. Thompson of the Storm Lab, University of Leeds. Pietro Valdastri serves as the corresponding author.
Figure | related papers (Source: Soft Robotics)
The findings state that "in the field of minimally invasive surgery, the relationship between flexible endoscopes and catheters remains elusive"
In addition, following the path of least resistance in the delicate and tortuous tracheal environment of the human body, without relying on the interaction of surrounding anatomical structures, requires more control over the degree of freedom of the analyte, in which case large-diameter instruments are often required.
Without increasing the size of the conduit, a viable solution is to transfer through the length of the multi-point magnetic drive conduit. The team developed and designed a fully formed soft magnetic conduit with a length of 80mm and a diameter of 2mm that could be transmitted in a specific direction during human anatomy.
Figure | Magnetic Tentacle Robot (Source: Soft Robotics)
Not only that, but the magnetic tentacle robot can also perform specific preoperative scans according to the actual situation of the patient. At the same time, the team also optimized the magnetization profile and shape drive field of the catheter.
Development of new robotic systems to address the limitations of existing technologies
At present, most doctors in the clinic use a bronchoscopic instrument to examine the lungs and airways, and flexible tubular instruments with a diameter of about 3.5 mm to 4 mm enter the bronchial passage through the nose or mouth. Due to the size limitations of this flexible filling instrument, it can only reach the upper layer of the bronchial bundle.
To develop a robotic system that is better suited for clinical testing, the team had to address two main challenges: first, the team needed to develop a bronchial tree detection device that was the right size to use and controllable; second, they needed to design an autonomous system to guide the magnetic tentacle robot into place, thereby reducing the process by which doctors manually maneuvered the instrument into place during surgery.
Because the second condition usually requires patient exposure to X-rays, it makes safety control challenging for medical staff.
To change the size of the traditional robot while ensuring controllability during delivery, the research team fabricated the new robot from a series of interconnected cylindrical materials. To generate the desired transient magnetic field, they also employed a two-arm system, which is made of a soft elastomer or rubber-like material impregnated with tiny magnetic particles.
Figure | experimental diagram of the two-arm magnetic tentacle robot (Source: Soft Robotics)
Due to the presence of magnetic particles, under the action of the external magnetic field, the connected parts of the robot can move independently to a certain extent, and the three independent robot prototypes made by the team can be demonstrated under pre-set conditions, and then minimal contact navigation through the three-dimensional bronchial tree model.
This magnetic tentacle robot is not only highly flexible, but also deformable, small enough in size, and its biggest highlight is that it can avoid being hindered by the anatomy of the lungs.
Patient-specific, lesion sampling machine guidance system
To debug the performance of the magnetic tentacle robot, the team compared four individually designed catheters and mechanical devices.
They found that the catheters, which had only an axial magnetization curve at the top of the vertical direction, demonstrated a 50 percent higher accuracy tracking, reduced obstacle contact time by 50 percent during state-of-the-art navigation, and increased aiming errors by 90 percent.
It is worth noting that the group pair can tailor a machine guidance system for patients, so that the magnetic tentacle robot guides the device into the human body under the action of a magnet on the external robotic arm of the human body. Magnetic particles in human catheters can change the direction of motion guided by in vitro magnets, and when the magnetic tentacle robot reaches the diseased area from the patient's lungs, it can be sampled or assisted in treatment.
Figure | from preoperative CT images to optimized magnetic catheter characterization (Source: Soft Robotics)
Arguably, the technology creates a prototype of a low-cost endoscope that can study the upper gastrointestinal tract of the human body, benefiting low- and middle-income countries that cannot afford expensive screening equipment.
However, the clinical application of this magnetic tentacle robot technology in hospitals may take several more years. The University of Leeds Storm Lab is working to change the techniques used in endoscopic and catheter research.
-End-
reference:
https://www.liebertpub.com/doi/10.1089/soro.2021.0090
https://techxplore.com/news/2022-03-magnetic-tentacle-robot-narrow-tubes.html