During the process of percutaneous puncture, a medical needle with a beveled tip is usually inserted into a multilayered soft tissue, which contains a muscle layer, before it reaches the target. The robot-assisted needle insertion technology will help brachytherapists to perform high-accuracy seed implantation. To guide the automatic needle insertion, a mechanics-based model to simulate needle deflection caused by the asymmetric cutting force during insertion in the muscle-contained double-layered tissue is developed. The model is driven by the anisotropic and inhomogeneous interaction forces, which are updated off-line according to the tip’s position and pose and are independent of the real-time data feedback. The parameterized insertion orientation angle and 180° axial rotation are introduced in the simulating process as the control inputs of the needle to adjust the needle deflection. Simulations and experiments confirm that the cooperative control of the insertion orientation angle and 180° axial rotation can steer the needle towards to any desired target in the reachable region of the tip. The results show that the proposed approach can successfully predict the needle deflection in the muscle-contained double-layered tissue. This work will be useful for a needle automatic control strategy design.

Graphical abstract

在经皮穿刺过程中，通常将带有斜面尖端的医用针插入到达目标的包含肌肉层的多层软组织中。机器人辅助的针头插入技术将帮助近距离放射治疗师进行高精度的种子植入。为了指导自动针的插入，开发了一种基于力学的模型来模拟在插入包含肌肉的双层组织过程中由于不对称切削力而引起的针偏斜。该模型由各向异性和不均匀的相互作用力驱动，这些相互作用力根据尖端的位置和姿势离线更新，并且独立于实时数据反馈。在模拟过程中，将参数化的插入方位角和180°轴向旋转作为针的控制输入，以调整针的偏转。仿真和实验证实，插入方向角和180°轴向旋转的协同控制可以将针引导到笔尖可到达区域中的任何所需目标。结果表明，所提出的方法可以成功地预测包含肌肉的双层组织中的针头偏转。这项工作将对针头自动控制策略设计有用。结果表明，所提出的方法可以成功地预测包含肌肉的双层组织中的针头偏转。这项工作将对针头自动控制策略设计有用。结果表明，所提出的方法可以成功地预测包含肌肉的双层组织中的针头偏转。这项工作将对针头自动控制策略设计有用。

图形概要