Department of Mechanical Engineering, University of Hawaii at Manoa, United States.
Department of Mechanical Engineering, University of Hawaii at Manoa, United States.
Med Eng Phys. 2022 Sep;107:103846. doi: 10.1016/j.medengphy.2022.103846. Epub 2022 Jul 10.
Percutaneous needle-based procedures such as prostate brachytherapy demands for accurate placement of the needle tip at target locations. Recently, robotic needle insertion systems have been made available to help physicians in needle guidance and control inside tissue. It is often challenging to obtain an accurate and real-time position of the needle tip in clinical practice using medical imaging techniques. However, this information is vital for closed-loop control of the needles inside tissue. This work presents an SMA-actuated active flexible needle that is controlled inside a phantom without a need for a position sensor or a medical imaging device. The needle tip position feedback is found using shape sensing capabilities of the embedded SMA-wire actuators and a force sensor at the needle base. Three models were characterized and used to estimate needle tip position in real time. The control scheme was then tested on the active flexible needle to track a desired triangular trajectory in a phantom. It was shown that the control scheme presented in this work was able to manipulate the needle in this path with a reasonable accuracy.
经皮针引导程序，如前列腺近距离治疗，需要将针尖精确地放置在目标位置。最近，机器人针引导系统已经可以帮助医生在组织内进行针引导和控制。在临床实践中，使用医学成像技术往往难以获得准确和实时的针尖位置。然而，这对于组织内针的闭环控制至关重要。本工作提出了一种 SMA 驱动的主动式柔性针，在没有位置传感器或医学成像设备的情况下在体模内进行控制。使用嵌入式 SMA 线驱动器的形状感应能力和针基部的力传感器来找到针尖位置反馈。对三个模型进行了特征描述，并用于实时估计针尖位置。然后，该控制方案在主动式柔性针上进行了测试，以在体模中跟踪期望的三角形轨迹。结果表明，本文提出的控制方案能够以合理的精度在该路径上操纵针。
