Autonomous Medical Needle Steering In Vivo

The use of needles to access sites within organs is fundamental to many interventional medical procedures both for diagnosis and treatment. Safe and accurate navigation of a needle through living tissue to an intra-tissue target is currently often challenging or infeasible due to the presence of anatomical obstacles in the tissue, high levels of uncertainty, and natural tissue motion (e.g., due to breathing). Medical robots capable of automating needle-based procedures in vivo have the potential to overcome these challenges and enable an enhanced level of patient care and safety. In this paper, we show the first medical robot that autonomously navigates a needle inside living tissue around anatomical obstacles to an intra-tissue target. Our system leverages an aiming device and a laser-patterned highly flexible steerable needle, a type of needle capable of maneuvering along curvilinear trajectories to avoid obstacles. The autonomous robot accounts for anatomical obstacles and uncertainty in living tissue/needle interaction with replanning and control and accounts for respiratory motion by defining safe insertion time windows during the breathing cycle. We apply the system to lung biopsy, which is critical in the diagnosis of lung cancer, the leading cause of cancer-related death in the United States. We demonstrate successful performance of our system in multiple in vivo porcine studies and also demonstrate that our approach leveraging autonomous needle steering outperforms a standard manual clinical technique for lung nodule access.Comment: 22 pages, 6 figure

Akışkan ortamların rehabilitasyon amacı ile robotik yürüyüş sistemi üzerinde gerçeklenmesi.

Patients with disorders such as spinal cord injury, cerebral palsy and stroke can perform full gait when assisted, which progressively helps them regain the ability to walk. A very common way to create assistive effects is aquatic therapy. Aquatic environment also creates resistive effects desired for increasing muscle activity. Simulating the fluid environment using a robotic system would enable therapists to adjust various fluid parameters so that the therapy is tailored to each patient’s unique state. In this study, realization of a virtual fluid environment on a robotic gait trainer for rehabilitation purposes is presented. A model is created to determine torques and forces exerted on a partially submerged human body by the fluid environment. Then, the fluid model is used to create a control scheme which is implemented on a robotic gait trainer. A compensation algorithm is developed so that weight and friction of robotic links are countered. Smooth transition between stance and swing phases of gait is ensured with a developed algorithm that only uses kinematic data. Experiments with healthy subjects were done to verify the stance-swing algorithm, the changes in gait characteristics between land and water conditions, and to assess effects of changes in fluid model parameters to gait characteristics. It is shown that realization of virtual fluid environment on robotic gait trainer is achieved. The torque measurements showed that the controller was able to make the orthosis transparent to the patient. Significant changes in gait characteristic were observed by modifying fluid model parameters.   M.S. - Master of Scienc

SIMULATION OF FLUID ENVIRONMENTS ON ROBOTIC ORTHOSES FOR REHABİLİTATİON PURPOSES

SIMULATION OF FLUID ENVIRONMENTS ON ROBOTIC ORTHOSES FOR REHABİLİTATİON PURPOSE

Realization of human gait in virtual fluid environment on a robotic gait trainer for therapeutic purposes

Patients with disorders such as spinal cord injury, cerebral palsy and stroke can perform full gait when assisted, which progressively helps them regain the ability to walk. A very common way to create assistive effects is aquatic therapy. Aquatic environment also creates resistive effects desired for strength building. In this study, realization of a virtual fluid environment on a robotic gait trainer is presented as an alternative method. A model was created to determine torques and forces acting on the human body while performing gait in a fluid environment. The developed model was implemented on a robotic gait trainer. By adjusting the virtual fluid model parameters, precise control over assistive and resistive effects during gait was achieved without enforcing any pre-defined gait pattern. The real-time gait phase information required by the fluid model to determine torques was provided with a developed algorithm which only uses kinematic gait data. Experiments with healthy subjects were done using the robotic gait trainer to verify the gait phase algorithm, and to compare gait characteristics obtained in virtual land and water environments with the literature. Additional experiments were performed with the robotic system to assess effects of changing fluid model parameters to healthy subject gait characteristics. The results show that force and torque effects of virtual fluid environment on robotic gait trainer were achieved. The gait phase algorithm was shown to provide smooth transition between phases. Also, significant changes in gait characteristics were observed by modifying fluid model parameters

Simulation of Fluid Environment using a Robotic Orthosis on Human Lower Extremity for Therapeutic Purposes

Rehabilitation under water is a viable physical rehabilitation option, but it has some limitations in terms of adapting to needs of each patient. In addition, its facility requirements are relatively high. Simulating the fluid environment using a robotic system would enable therapists adjust various parameters so that the therapy is tailored to the patient's unique state. Also, using a robotic system instead might be less costly and easily reachable. In this study, human lower extremity movement in fluids is modeled. This model is verified by comparing computer simulations with the results of previous experimental studies. Then, the model is used to create a control scheme which is implemented on a robotic gait trainer. Output torques are measured to check the effectiveness of the controller in simulating the fluid environment while compensating for weight and friction of the robotic system. Measurements showed that the desired joint torques were achieved and the controller was able to make the orthosis transparent to the patient. A hip extension exercise used in aquatic therapy was performed with the robotic system while varying drag coefficient, fluid density and flow velocity, and the data collected is presented