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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 3 - ROBOTAR (Robot-Assisted Flexible Needle Steering for Targeted Delivery of Magnetic Agents)

Teaser

Summary

Problem/issue being addressed:
Diagnostic agents are currently injected into the body in an uncontrolled way and visualized using non-real-time imaging modalities. Delivering agents close to the organ and magnetically guiding them to the target would permit a myriad of novel diagnostic and therapeutic options, including on-site pathology and targeted drug delivery. Such an advance would truly revolutionize minimally invasive surgery (MIS). Presently MIS often involves manual percutaneous insertion of rigid needles and catheters. These instruments deviate from their intended paths due to tissue deformation and physiological processes. Inaccurate needle placement may result in misdiagnosis or ineffective treatment. Thus, the goal of ROBOTAR is to design a robotic system to accurately steer flexible needles/catheters through tissue, and enable precise delivery of agents by magnetically guiding them to a designated target.

Important for society:
Despite many advances in minimally invasive surgery (MIS) and drug availability, cancer is still one of the leading causes of mortality worldwide. Early diagnosis and effective treatment of the diseased tissue can greatly improve patient care. However, diseased tissue is often deep-seated within the body, and the sizes of cancer cells and lesions are small (from 10 Î¼m to 10 mm). Therefore, it is a challenge to perform precise diagnosis and localized therapy without affecting neighboring healthy tissue, and toxicity of healthy tissue often results in side effects. Motivated by this challenge, researchers have proposed the use of biodegradable and biocompatible diagnostic agents. However, these agents are currently injected into the circulatory system in an uncontrolled manner, and visualized using non-real-time imaging modalities (e.g., magnetic resonance (MR) or molecular imaging techniques). If these agents could be delivered closer to the organ of interest, and then magnetically guided precisely to the target - this would open up a gamut of diagnosis and treatment options ranging from rapid on-site pathological tests and localized chemotherapy to targeted drug delivery via nanocapsules. Such an advance would truly revolutionize MIS; also for clinical applications beyond cancer.

Overall objective:
The overall aim of ROBOTAR is to develop an integrated robotic needle steering system that enables targeted delivery of a wide range of diagnostic and therapeutic magnetic micro- and nano-sized agents, thereby making MIS more effective and improving patient care.

Work performed

* The use of a pseudo-rigid-body model for real-time control of magnetic catheter is a novel and promising methodology, displaying advantages in terms of precision at higher tip movement speeds.
* A simplified kinematics based model is used to estimate the tip position of the magnetic catheter in 2D by fusing ultrasound and FBG measurements.
* ROBOTAR has produced a state-of-the-art equipment for magnetic actuation of flexible devices, called BigMag. BigMag can be used to actuate catheters, needles and millirobots.
* GPU-accelerated model-based approach to track online the full pose and articulations of submillimeter grippers.
* New techniques that are developed in the fields of nonlinear control theory and numerical optimization have been investigated in the field of micro-robotics. The prescribed performance technique is applied to control the microagents to follow desired motion trajectories

Final results

* Progress have been made beyond the state of the art, including relevant improvements in the dexterity of microrobots, development of advanced techniques for robustness to noise in unpredictable micromazes, and introduction of intuitive interfaces for control of microrobots.
* Achieving multi-point actuation of catheters using the new pseudo-rigid-body model is a significant contribution.
* The framework for intra-operative position control and visual servoing of a flexible catheter is also novel, with significant advantages over pre-existing approaches in terms of computational speed, and accuracy, even at large deflection of the flexible device.