Lee Hyosang, Kim Jung
Division of Mechanical Engineering, School of Mechanical, Aerospace and Systems Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea,
Med Biol Eng Comput. 2014 Sep;52(9):729-40. doi: 10.1007/s11517-014-1173-7. Epub 2014 Jul 10.
The estimation of needle deflection when the needle interacts with biological tissue is challenging in needle steering. Most previous studies have used homogeneous tissue models to estimate the deflection of a needle. However, biological tissue typically has a layered structure with variable mechanical properties and geometric features. In this study, we propose a needle deflection model with a double-layered elastic medium. Each layer possesses distinct mechanical properties, which result in inconsistent degrees of friction force on the needle surface, needle-cutting force, and forces caused by the stiffness of the elastic medium. The model uses the Rayleigh-Ritz method to analytically estimate the needle deflection. To validate the model, needle steering experiments were performed using double-layered tissue phantoms and porcine tissues. The experimental results revealed that changes in reaction force at the needle base occurred when the needle passed through the boundary between the two layers. The mean absolute error between the estimated and measured needle tip trajectory was 0.88 ± 0.30 mm for the double-layered tissue phantom and 1.85 ± 0.73 mm for the porcine tissue. These results are comparable with previous studies of homogeneous tissue. The proposed model could improve needle steering in biological tissues, which consist of multiple layers.
在针引导过程中，当针与生物组织相互作用时，估计针的偏转具有挑战性。大多数先前的研究使用均匀组织模型来估计针的偏转。然而，生物组织通常具有分层结构，其机械性能和几何特征各不相同。在本研究中，我们提出了一种具有双层弹性介质的针偏转模型。每层都具有独特的机械性能，这导致针表面的摩擦力、针切割力以及由弹性介质刚度引起的力的程度不一致。该模型使用瑞利 - 里兹法来分析估计针的偏转。为了验证该模型，使用双层组织模型和猪组织进行了针引导实验。实验结果表明，当针穿过两层之间的边界时，针基部的反作用力会发生变化。对于双层组织模型，估计的和测量的针尖轨迹之间的平均绝对误差为0.88±0.30毫米，对于猪组织为1.85±0.73毫米。这些结果与先前关于均匀组织的研究结果相当。所提出的模型可以改善在由多层组成的生物组织中的针引导。
