Optically Actuated Needles for Oncological Applications

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DESCRIPTION (provided by applicant): In this FastTrack Phase I/II SBIR application, IFOS, in collaboration with the Stanford Center for Design Research (CDR) proposes to develop and validate an actively steered, photo-actuated, small-caliber needle for precise imaging-assisted percutaneous procedures. This innovation specifically addresses the need for precise needle placement in procedures targeting deep tissue, where routes of entry are restricted due to anatomical obstructions and the need to avoid vital organs. The proposed active steering can compensate for the deflection encountered during needle insertion into soft tissue, which becomes increasingly significant as the path to the target lengthens. Such deviations from the planned path can result in multiple reinsertions, adding to patient discomfort and procedure time, and compromising the effectiveness of minimally invasive procedures. The active steering concept is based on optical activation of a shape memory alloy (SMA) embedded within a flexible stylet. Design features compatible with standard needle tips and outer cannula sheaths will be employed. Unlike other techniques based on electrical or magnetic actuation, the proposed approach is compatible with all major imaging techniques, including MRI. By using fiber-optic connections, the stand-off distance from the laser power source to the needle can be greater than that for actuation motors required for tendon approaches. The technique requires minimal power input and can be implemented in a user-friendly hand-held biopsy needle system. While the basic needle concept does not rely on complex algorithms and robotic needle insertion systems, the basic design includes a streamlined back-end that affords a ready connection to more complex instrumentation, including advanced online-imaging interface capabilities. In prior work, bending rates of over 2� per second have been repeatably achieved in phantoms that mimic the properties of human prostate tissue. Also, the collateral temperature rise in surrounding tissue was shown to be minimal, effectively eliminating thermal damage as a concern. The Phase I effort is designed to demonstrate still greater deflection efficiency using various needle insertion strategies in ex vivo prostate tissue, using a novel approach involving low-transition-temperature SMAs and optimized superelastic biopsy needle structures and control. This work will lead to further development activities in Phase II, including thinner needl designs, a console design, and a closed-loop control system that enables real-time needle curvature and in situ tissue reaction force measurements. In Phase II, we also will investigate steering protocols that would take advantage of axial rotation and other known passive control strategies, thereby adding bending degrees-of freedom and dexterity to the needle system. These studies will culminate in a series of in vivo experiments, targeting prostate biopsy and brachytherapy procedures under imaging modalities such as ultrasound and MRI, to establish key clinical efficacy and safety parameters, and validate practical/clinical aspects for facilitatig FDA approval and the successful introduction of the new active needle to end users.