RoboMed Lab
Advisor: Dr. Jaydev P. Desai, Ph.D.
Collaborator: Dr. Joshua J. Chern, M.D., Ph.D.
Georgia Institute of Technology
2019 Petit Scholar, PURA Scholar, Tech Temp Research Support
May 2018 - June 2022
Preclinical Evaluation of Robotic Pediatric Neuroendoscope Tool
May 2019 - November 2023
Published! Will add content here soon!
Meso-scale Steerable Grasper for Robotic Pediatric Neurondoscopy
Jan. 2021 - June 2022
The 1.93-mm grasper is a tendon-acuated steerable design that can be implemented onto the Robotic Pediatric Neuroendoscopic Tool. Machined using a 5-axis CNC micro-mill (grasping links) and a femtosecond laser (transmission links), we were able to assemble the tendon-actuated grasper and test its grasping force.
Featured in:
- T.A. Brumfiel, K.K. Yamamoto, A. Rashid, A. Shigematsu, C. Chapman, S.N. Melkote, J.J. Chern, J.P. Desai, “Design of a Meso- Scale Grasper for Robotic Pediatric Neuroendoscope Tool”,
Hamlyn Symposium on Medical Robotics, 2022 Jun, London, UK (Link, Abstract)
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1.93-mm OD Grasper
Grasping Force Testing
Multi-Composition Hydrogel Phantom Model of Pancreas with Cyst
June 2020 - May 2021
Using an MRI-derived mold of the human pancreas, I developed a hydrogel phantom model of the pancreas with embedded cysts (colored in red). The molding process was two-fold: first, casting the overall geometry of the pancreas (~1.4 KPa) with spherical positive molds to create negative spaces for the cysts. After curing, a different hydrogel composition (more stiff, ~1.81 KPa) was injected into the negative spaces and cured. The result was a hydrogel phantom model of the human pancreas with harder hydrogel, representing the cysts, embedded within the pancreas
Hydrogel Pancreas (Front)
Hydrogel Pancreas w/ Visible Cyst
Featured in:
N. J. Deaton T. A. Brumfiel, M. Sheft, K. K. Yamamoto, D. Elliott, P. Patel, J.P. Desai, ”Towards Steering a High-Dose Rate Brachytherapy Needle with a Robotic Steerable Stylet," in IEEE Transactions on Medical Robotics and Bionics, doi: 10.1109/ TMRB.2023.3237861. (Link)
Meso-scale Steerable Bipolar Electrocautery Tip
Aug. 2019 - March 2020
I designed, manufactured, and integrated a bipolar electrocautery tip on a steerable surgical robot for neuroendoscopic procedures. The cauterizing tips are soldered to 50-micron insulated wires, which traverse through the body of the nitinol robot. The distal joint tendon for actuation is also attached to the cauterizing tip. The two wires are then attached to the Bovie Electrosurgical Generator, commonly used in today's surgeries, to supply the cauterizing electricity. One wire is grounded, while the other supplies the current.
The video on the right demonstrates the steerable bipolar cauterizing tip on a hydrogel phantom. The user controls the robot to a target location, then steps on a pedal to actuate the cauterization. You can see the vapors that arise due to the burning hydrogel!
Bipolar Cautery Tip on PedNeuro Robot
Video of Cauterizing Hydrogel Phantom
Featured in:
K.K. Yamamoto, J. P. Desai, “Pediatric Phantom Model and Cauterizing Tool Design for Novel Neuroendoscopic Surgical Robot Evaluation,” Georgia Tech Undergraduate Research Spring Symposium, 2021 Apr, Atlanta, GA (Link, Presentation PDF).
Y. Chitalia, S. Jeong (co-first author), K. K. Yamamoto, J. J. Chern, J.P. Desai, “Modeling and Control of a Meso-scale Multi-Joint Continuum Robot for Pediatric Neurosurgery,” in IEEE Transactions on Robotics, 2021 Apr, DOI: 10.1109/TRO.2020.3031270 (Link).
Hydrogel Phantom Model Design of Pediatric Skull and Brain
Jan. 2019 - March 2020
The goal of this independent project was to create a realistic model of the human brain to conduct phantom model testing of the Pediatric Neuroendoscope Robotic tool. I segmented deidentified patient CT and MRI scans using medical image processing skills to obtain the geometries of the human skull, and brain. I then converted the 3D surfaces into 3D volumes, then designed 3D printable molds of the organs for material casting. After experimenting with silicone to mimic the mechanical properties of the brain, I found that Polyvinyl hydrogels can be tuned to reach desired mechanical properties.
After conducting tensile and indentation testing on various hydrogel compositions, I tuned the parameters of the hydrogel and reached a composition with a Young’s Modulus similar to that of grey matter found in literature.
Phantom Model Design Workflow
Final Hydrogel Phantom of the Brain
Virtual Pre-operative Planning Interface for Pediatric Hydrocephalus
May 2019 - Jan. 2020
The objective of this project was to incorporate both a model of the PedNeuro Robot with a software phantom model of a pediatric brain. I used the PedNeuro forward kinematics transformation to model the robot as depicted in the video to the left. The joint values were then mapped to inputs on an X-box controller, allowing the user to bend both proximal and distal joints and insert/retract the robot into the brain. The virtual phantom model was a point-cloud derived from MRI segmentation of a hydrocephalic pediatric brain. The segmented volume was then modeled into a 3D-printable STL file, which was then imported into MATLAB as a point-cloud.
Pre-operative Planning Demo
Pediatric Neuroendoscope (PedNeuro) Robot Workspace Analysis
Jan. 2019 - Aug. 2019
The Pediatric Neuroendoscope Robotic Tool is a 2-DoF, tendon-actuated robot body that maneuvers within the ventricles of the brain. To assess whether the robot can reach certain target points in the brain for the endoscopic third ventriculostomy (ETV) procedure, we designed and executed a workspace analysis experiment.
I attached three 6-DoF Aurora Systems Electromagnetic (EM) trackers on the (1) tip of the distal end (end-effector space), (2) near the proximal joint, and (3) at the base of the robot. EM Tracker 3 was used as a reference, and trackers 1 and 2 monitored the bending angle of both the proximal and distal joints. The Euler angles were then measured and plotted in MATLAB in 3D space.
This was a guided project, assisting Yash Chitalia Ph.D. with his paper for “Design and Kinematics Analysis of a Robotic Pediatric Neuroendoscope Tool Body,” in IEEE/ASME Transactions on Mechatronics.
Workspace Analysis of 2-DoF PedNeuro Robot
Workspace Superimposed in Virtual Phantom
Automated System for Femoral Artery Phantom Model Production
May 2018 - Dec. 2018
As my first project in the RoboMed Lab, I investigated the design of a system that automates the process of creating silicone phantom models around a 3D-printed positive mold of the femoral artery. The “dip-and-spin” RPR apparatus linearly submerged the mold into a vat of silicone, retracted, then spun about two axes of rotation two planes to remove excess silicone while curing. This project required me to learn computer aided design (CAD) software (SolidWorks, AutoCAD), rapid prototyping/machining skills (resin 3D printing, laser-cutting, CNC milling), and circuitry and controls using stepper motors, motor controllers, and the Arduino microcontroller.
"Dip-and-Spin" Apparatus
Femoral Artery Positive Mold
Femoral Artery Silicone Mold