This research is motivated by the high incidence of atrial fibrillation (AF)  in US (1 in 100 people), and the suboptimal treatment outcome of traditional approaches (~30-50% recurrence rate). Recurrence of AF occurs when there are gaps between ablation lesions, which can be caused by multiple reasons, including limited ability to manipulate the catheter in a manner that reaches all desired ablation targets while also maintaining proper catheter-tissue contact force (CTCF) for effective ablation energy delivery.  In addition, there is 3) lack of effective navigation methods that accurately identify sites of incomplete ablation and guide the catheter to complete ablation. In this project, we aim to create a multi-modal feedback-based navigation system and MR-compatible robotic platform that enables precise, continuous, and permanent lesion creation during MR-guided radiofrequency ablation (RFA) for AF treatment. 

Collaborators: Aravindan Kolandaivelu, Ehud Schmidt, JHU; Junichi Tokuda, BWH

About 1 in 50 people suffer from Intracerebral Hemorrhage (ICH) in their lifetime. ICH occurs when blood leaked from a ruptured vessel accumulates and forms a blood clot (hematoma) in the cerebrum. The 30-day mortality for ICH is about 40% with half of all deaths occurring in the acute phase, especially in the first 48 hours. Blood spilled outside of the intracranial vessels is toxic to surrounding neurons, causing inflammation and perihematomal edema seen as early as 12-24 hours after hemorrhage. These deleterious effects motivate emergent treatment to save at-risk brain tissue.  The objective of this proposal is to create and validate a minimally-invasive Magnetic Resonance (MR) - compatible concentric tube robot for ICH evacuation. We will develop dexterous robot hardware, enable accurate real-time image guidance, and perform system-level evaluations in live animals. 

Collaborators: Kevin Cleary, Children's National Hospital

Brachytherapy is a radiation treatment method used for gynecological cancers which involves placing radioactive sources into, or next to, the tumor with needle guided catheters. However, due to the limited degrees of freedom of the needles currently used (1 DOF: insertion), and the anisotropic elastic properties of the tissue, multiple insertion and retraction trials at different locations in the grid of a plastic template sutured to the patients perineal skin must be conducted until the target location is reached. Hereinto, we present a novel approach for actively controlling the needle by implementing two additional degrees of freedom through planar bending and rotation of a custom made nitinol tube, and active MR tracking using micro-coils. Increased dexterity of the tube is permitted due to cutouts made in the distal end of the tube, where tension force initiated by the tendon in the inner diameter of the tube results in buckling of the machined region. With the aid of a dial indicator, the active tracking of the needle tip, and the tendon input force, trajectory planning can be conducted to the target.

Collaborators: Ehud Schmidt, Akila N. Viswanathan, JHU

Needle artifacts have been a long unsolved challenge in the field of Interventional MRI. The large difference in magnetic susceptibilities between an MR compatible metallic needle or stylet and the surrounding water containing tissue induces significant field perturbations in the vicinity of the needle, which results in signal loss due intra-voxel dephasing, image distortions and signal pileups due to voxel mismapping. These artifacts limit to various extents almost every interventional MRI procedure by obscuring and distorting targets and preventing accurate imaging of the region of interest. This results in reduced targeting accuracies, increased procedure times, inability to monitor therapy and ultimately, reduction in the efficacy of MRI guided procedures. The goal of this proposal is to therefore introduce a proof-of-concept solution for this problem that is inspired by degaussing coil technology used in ships and submarines for defense against magnetic field sensitive sea mines. We propose to develop an active degaussing or shim insert for compensation of needle induced B0 and demonstrate correction of susceptibility artifacts in ex-vivo tissue experiments at 3 Tesla.

Collaborators: Saikat Sengupta, Vanderbilt University

Minimally invasive surgeries and treatments are of keen interest to researchers. One such minimally invasive cancer treatment involves the implementation of High Intensity Focused Ultrasound (HIFU) for ablation of tumors. This treatment aims to kill cancer cells by delivering high intensity ultra sounds waves at a focused located directly onto the cancerous tumor, which it turn heats up the cells and kills them. This treatment is used in situations where a single tumor, or part of a large tumor must be eliminated. Here, we propose to incorporate robot assistance in the procedure, where, after determining the locations of the tumors in the human body using an image modality such as MRI, a planned trajectory can be developed for a robot arm to follow and in turn administer the HIFU waves to the tumor. In this case, a Franka Emika 7DOF robot arm will be used to orient and position the HIFU probe at the desired locations. By using the robot arm in conjunction with the HIFU probe not only eliminates hospitalization for outpatient procedures, it also increase efficiency, accuracy, and reduces surgeon bodily strain.

Collaborators: Ashish Ranjan, OSU

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death in the world with a five-year survival rate as low as 4%. Laser ablation has been shown to be an effective method of treating HCC. However, with current clinical practices it is rather difficult to place the ablation needle within the target volume due to the respiratory-induced dynamic movement of the liver. We propose a novel robotic platform that will enable accurate needle deployment under intraoperative CT image guidance. The robot consists of upper and lower XY-carriages that allow for 4-DOF in aiming the needle and this is coupled with a 3D printed flexible fluidic actuator that creates a step-like grasp-insert-release method of actuation.

Collaborators: Kevin Cleary, Children's National Hospital; David A. Woodrum, Aiming Lu, Mayo.

Soft robots can undergo large elastic deformations and adapt to complex shapes. However, they lack the structural strength to withstand external loads due to the intrinsic compliance of fabrication materials. We present a novel stiffness modulation approach to a tendon-actuated soft bending robot that controls the robot stiffness on-demand without permanently affecting the intrinsic compliance of the elastomeric body. The mechanics modeling of the variable-stiffness soft robot was developed using the Cosserat rod theory. The experimental results show that the model is capable of estimating the shape of the soft robot with internal pull force and external load. The results indicate that robot stiffness can be increased up to 613% via the proposed method.

Collaborators: Isuru Godage, TAMU

Berries in the US have reached a market value of $1.4 billion in 2015. Fresh-market berries typically are manually harvested either for pick-your-own operations or retail markets. The cost of manual picking represents a significant percentage of the total cost of berry production. With the projected trend of labor shortage, there is an urgent need to create alternative methods for cheap and efficient berry harvesting. Machine harvesting, such as shaking, has not been a successful approach due to the consequences of sizable reduction of the amount of sellable fruit compared to the hand-picking approach. This reduction is not only caused by damage to the fruit but also the reduced postharvest quality from fruit decay, rot, and leakage. We propose to implement a tendon actuated soft robotic gripper on a multi-degree of freedom robot arm to provide an automated harvesting method for blackberries. The University of Arkansas is one of the largest public fresh-market blackberry breeding programs in the world and has released over 60 blackberry cultivars in the past 30 years. The berries will be harvested using force control for the gripper to provide the optimal contact force, image processing for berry location, and an off-road chassis for navigating the assembly along the floricane rows.

Collaborators: Ye Zhao, GT; Ai-Ping Hu, GTRI; Renee Terrell, UARK