Project Goals
Nasopharynx cancer, or nasopharyngeal carcinoma (NPC), is a tumor that originates in the nasopharynx, the uppermost region of the pharynx where the nasal passage and the throat join. It is a common disease occurring to ethnic Chinese people living in or emigrating from southern China; it is also the eighth most frequently occurred cancer among Singaporean men. Traditional posterior nasopharyngeal biopsy using a flexible nasal endoscope has the risks of abrasion and injury to the nasal mucosa and thus causing trauma to the patient. Therefore, the goal of this project is to develop a compact continuum tubular robotic system to achieve collision free nasopharyngeal biopsy.
![illustration](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/illustration-300x189.jpg)
Fig.1 Illustration of the proposed CTR for nasopharyngeal biopsy.
Approaches
We developed a compact CTR which is 35 cm in total length, 10 cm in diameter, 2.15 kg in weight, and easy to be integrated with a robotic arm to perform more complicated operations.
![2](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/2-300x188.jpg)
Fig.2 The proposed continuum tubular robot
![3](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/3-300x169.jpg)
Fig.3 Compact and light weight CTR integrated with a positioning arm for
better conducting surgery
We also developed a 3D printed biopsy needle to equip our robot for transnasal biopsy procedure.
![5](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/5-300x116.jpg)
Fig.4 3D printed biopsy needle for transnasal biopsy
The workspace of the robot was analyzed to determine optimized tube parameters.
![workspace](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/workspace-178x300.jpg)
Fig.5 Workspace comparison for 3-DOF CTR with three initial configurations.
Top: all the outstretched part of the inner tube exposes; Middle: the outstretched part of the inner tube is partially covered by the outer tube; Bottom: the outstretched part of the inner tube is totally covered by the outer tube.
Further more, by using an electromagnetic tracking system, we are able to build a navigation system with shape reconstruction for the tubes.
![7](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/7-300x207.jpg)
Fig.6 Shape reconstruction using 3-order Bézier curve fitting
![8](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/8-300x200.jpg)
Fig.7 Sensing by EM tracker
![10](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/10-300x221.jpg)
Fig.8 Navigation interface
Results
Three groups of experiments were carried out. The first group is to tele-operate the robot to follow a linear path and a circular path. We found that the path following accuracy was about 2 mm.
![11](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/11-300x190.png)
Fig.9 Tele-operating the robot to follow a linear path and a circular path
![12](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/12-300x151.jpg)
Fig.10 Accuracy of the robot following the predefined paths
The second group is to validate the shape reconstruction algorithm. The accuracy of the results is about 1 mm.
![13](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/13-300x151.png)
Fig.11 Reconstruction setup
![13](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/13-300x120.jpg)
Fig.12 Reconstruction error
In the last group of experiments, the robot was tested in a biopsy procedure on a cadaver. The feasibility of the proposed robotic system was validated.
![14](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/14-272x300.jpg)
Fig.13 Cadaver experiment setup
![15](http://bioeng.nus.edu.sg/mm/wp-content/uploads/2015/07/15-300x206.jpg)
Fig.14 Cadaver experiment process
People Involved
Research Fellow: Liao Wu
PhD Student: Keyu Wu
FYP Student: Li Ting Lynette Teo
Intern Student: Jan Feiling and Xin Liu
Project Investigator: Hongliang Ren
Publications
[1] Liao Wu, Shuang Song, Keyu Wu, Chwee Ming Lim, Hongliang Ren. Development of a compact continuum tubular robotic system for nasopharyngeal biopsy. Medical & Biological Engineering & Computing. 2016.
[2] Keyu Wu, Liao Wu, Hongliang Ren. Motion planning of continuum tubular robots based on features extracted from statistical atlas. In: Proceedings of 2015 IEEE International Conference on Intelligent Robots and Systems (IROS 2015).
[3] Keyu Wu, Liao Wu, Chwee Ming Lim, Hongliang Ren. Model-free image guidance for intelligent tubular robots with pre-clinical feasibility study: towards minimally invasive trans-orifice surgery. In: Proceedings of 2015 IEEE International Conference on Information and Automation (ICIA 2015). ( best paper finalist)
[4] Benedict Tan, Liao Wu, Hongliang Ren. Prototype development of a handheld tubular curvilinear robot for minimally invasive surgery. In: The 11th Asian Conference on Computer Aided Surgery (ACCAS 2015).
[5] Keyu Wu†, Liao Wu†, Hongliang Ren. An image based targeting method to guide a curvilinear concentric tube robot. In: Proceedings of 2014 IEEE International Conference on Robotics and Biomimetics (ROBIO 2014). Bali, Indonesia, 2014: 386-391 († equally contributed author).