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In a minimally invasive percutaneous procedure like biopsy, brachytherapy, and tissue ablation, the inner soft tissue is accessed through surgical needle-puncture of the skin. This process reduces tissue damage and risk of infection and improves patient recovery time. However, its effectiveness depends on the needle’s ability to travel on a curved path, avoid obstacles, and maintain high targeting accuracy. Conventional needles are passive and have limited steerability and trajectory correction capability. This has motivated researchers to develop actuation mechanisms to create active needles. In this study, an innovative active steerable needle with a single shape memory alloy (SMA) wire actuator is designed, fabricated, and tested for maneuver. A closed-loop Proportional Integral Derivative (PID) controller with position feedback is developed to control needle tip deflection in air and tissue-mimicking gels. The needle tip is deflected up to 5.75 mm in the air medium. In tissue-mimicking gel, it is deflected up to 15 mm in a predefined trajectory during a 100 mm insertion depth. Our results show that needle tip deflection control has an average root mean square error (RMSE) of 0.72 mm in the air and 1.26 mm in the tissue-mimicking gel. The trajectory tracking performance of the designed SMA actuated needle and its control system show the effectiveness of the active needle in the percutaneous procedures. Future work includes testing the needle’s performance in the biological tissues.
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Design and evaluation of shape memory alloy‐actuated active needle using finite element analysis and deflection tracking control in soft tissues
Abstract BackgroundConventional needles lack active mechanisms for large tip deflection to bypass obstacles or guide through a desired trajectory in needle‐based procedures, compromising accuracy and effectiveness. MethodsAn active needle with a shape memory alloy (SMA) actuator was designed and evaluated by demonstrating deflections in tissue‐mimicking gels. Finite element simulation and real‐time needle tip deflection tracking in tissue‐mimicking gels were performed. ResultsThe active needle deflected 50 and 39 mm at 150 mm insertion depth in the liver and prostate mimicking gels, respectively. Reasonable simulation errors of 16.42% and 12.62% in needle deflections and small root mean squared errors of 1.42 and 1.47 mm in deflection tracking were obtained. ConclusionsThe proposed needle produced desirable large tip deflections capable of bypassing obstacles in the insertion path and tracked a preplanned trajectory with minor errors. The finite element study would help optimise needle designs and predict deflections in soft tissues.
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- Award ID(s):
- 1917711
- PAR ID:
- 10441598
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- The International Journal of Medical Robotics and Computer Assisted Surgery
- Volume:
- 19
- Issue:
- 5
- ISSN:
- 1478-5951
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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