Lecture Review: Robot and Intelligent System for Intra-operative MRI-guided Interventions
On 20th of May, AIRS invited Prof. Ka-Wai Kwok from the Department of Mechanical Engineering in the University of Hong Kong, to give an online public lecture on “Robot and Intelligent System for Intra-operative MRI-guided Interventions”. The lecture is hosted by Prof. Zhenglong Sun from the School of Science and Engineering in the Chinese University of Hong Kong, Shenzhen. Prof. Kwok was also an alumnus of the CUHK, and obtained Ph.D. in the Imperial College London where he continued his research on surgical robotics as a postdoctoral fellow before he joined HKU as Assistant Professor in 2014.
Prof. Kwok first gave thanks for the invitation from AIRS. He mentioned that the very first robotics class in his life was actually taught by President Yangsheng Xu, inspiring him till today to pursue a research career in the robotics field. He also expressed great appreciation of the words “for Society” in the name of AIRS (Shenzhen Institute of Artificial and Intelligence and Robotics for Society), showing that technology we develop should be used for the society.
In the lecture, Prof. Kwok firstly gave a brief introduction about Minimally Invasive Surgery, MIS. Taking the most successful commercial product, the da Vinci surgical robotic system as an example, he explained the advantage and benefits of the robotic surgery. Talking about the historical process of surgical robots, Prof. Kwok took the evolution of mobile phones as an example. He believes that this field is in the ascendant and has very broad development prospects.
Then Prof. Kwok introduced the advantages of MRI, the magnetic resonance imaging technology, which can accurately visualize the anatomy of organs and tissues, even brain details. However, traditional motor-driven and other optical or electromagnetic navigation methods cannot be used in strong magnetic field of MRI scanner. Therefore, realization of intra-operative navigation and manipulation in an extreme environment like MRI, poses a huge challenge to the surgical robotic technology.
Prof. Kwok mentioned about the definition of robot, just as what President Xu mentioned in his first robot class: the difference between robot and machine requires driving, perception, and decision-making. Then Prof. Kwok introduced the limitations and challenges in development of MRI-compatible surgical robots, by showcasing a few systems developed by some internationally renowned research teams in this regard. After that, Prof. Kwok showed his planning for MRI intra-operative surgical robots in four aspects: MRI-safe compact robot design and actuation, sensing under MRI, fast imaging processing and continuum robot control, which were explained in detail in the following of the lecture.
Regarding MRI-safe actuation development, Prof. Kwok first introduced the pneumatic-driven stepper motor developed by the team in 2014. Results were published on the top journal in the biomedical engineering field. However, performance of the pneumatic actuation is insufficient to fulfil the requirement of precision and response time in surgery. Prof. Kwok shared an interesting conversation between his wife and him: his wife was saying why not use a hamster to run in a paper wheel as the actuation unit, so that it could be fully compatible with MRI and bio-inspired. Although it seemed to be tease, Prof. Kwok was inspired and consolidated a full list of design criteria for developing an MRI-compatible actuation unit.
Following these design criteria, Prof. Kwok and his team started to try different methods. They tried to use the hydraulic actuation with innovative design to minimize the friction by using rolling diaphragms cylinders. Step by step, based on this concept, the hydraulic continuous motor was developed in 2017 with improved dynamic performance.
Based on this, a system was developed targeting the deep brain stimulation surgery. In order to realize intra-operative tracking, the team also invented miniature wireless RF tracking markers. By embedding multiple markers in the surgical tool, the system could achieve accurate real-time localization and tracking during MRI scanning. The robotic system went through cadaver trials in 2018, achieving an accuracy level within 2mm. The research conferred the Best Paper Award in the top conference in the robotics field, ICRA (International Conference on Robotics and Automation) 2018. The first author of the paper, Dr. Guo Ziyan, first Ph.D graduate of Prof. Kwok, was also elected as Innovators under 35 for the Asia Pacific Region by MIT Technology Review.
Lastly, Prof. Kwok also mentioned several robotic prototypes designed for MRI compatible intervention in other applications, such as the MRI-guided cardiovascular catheterization, and MRI-guided transoral laser microsurgery. Prof. Kwok expressed his passion in developing MRI-compatible robotic systems, for his lifelong R&D exercise in his career. He also thanked his research team and students as well as his collaborators worldwide for their contribution. In the end, Prof. Kwok had an interactive Q&A session with the audience.