This study investigates the effect of needle tip geometry on the needle deflection and tissue sampling length in biopsy. Advances in medical imaging have allowed the identification of suspicious cancerous lesions which then require needle biopsy for tissue sampling and subsequent confirmatory pathological analysis. Precise needle insertion and adequate tissue sampling are essential for accurate cancer diagnosis and individualized treatment decisions. However, the single-bevel needles in current hand-held biopsy devices often deflect significantly during needle insertion, causing variance in the targeted and actual locations of the sampled tissue. This variance can lead to inaccurate sampling and false-negative results. There is also a limited understanding of factors affecting the tissue sampling length which is a critical component of accurate cancer diagnosis. This study compares the needle deflection and tissue sampling length between the existing single-bevel and exploratory multi-bevel needle tip geometries. A coupled Eulerian-Lagrangian finite element analysis was applied to understand the needle-tissue interaction during needle insertion. The needle deflection and tissue sampling length were experimentally studied using tissue-mimicking phantoms and ex-vivo tissue, respectively. This study reveals that the tissue separation location at the needle tip affects both needle deflection and tissue sampling length. By varying the tissue separation location and creating a multi-bevel needle tip geometry, the bending moments induced by the insertion forces can be altered to reduce the needle deflection. However, the tissue separation location also affects the tissue contact inside the needle groove, potentially reducing the tissue sampling length. A multi-bevel needle tip geometry with the tissue separation point below the needle groove face may reduce the needle deflection while maintaining a long tissue sampling length. Results from this study can guide needle tip design to enable the precise needle deployment and adequate tissue sampling for the needle biopsy procedures.

本研究调查了活检中针尖几何形状对针头偏转和组织采样长度的影响。医学影像学的进步使得能够识别可疑的癌性病变，然后需要进行穿刺活检以进行组织采样和随后的确认性病理分析。准确的针头插入和足够的组织采样对于准确的癌症诊断和个性化的治疗决策至关重要。但是，当前的手持式活检设备中的单斜角针在插入针头时通常会明显偏斜，从而导致采样组织的目标位置和实际位置发生变化。这种差异可能导致不正确的采样和假阴性结果。对影响组织采样长度的因素的理解还很有限，而这是精确癌症诊断的关键组成部分。这项研究比较了现有的单斜角和探索性多斜角针尖几何形状之间的针头偏转和组织采样长度。应用耦合的欧拉-拉格朗日有限元分析来了解针头插入过程中针头与组织之间的相互作用。分别使用模仿组织的体模和离体组织对针的偏转和组织采样长度进行了实验研究。这项研究表明，针尖处的组织分离位置会影响针头偏转和组织采样长度。通过改变组织分离位置并创建多斜角针尖几何形状，可以改变由插入力引起的弯矩，以减少针头偏斜。但是，组织分离的位置也会影响针槽内的组织接触，可能会缩短组织采样的时间。组织分离点在针槽表面下方的多斜角针尖几何形状可以减少针头偏斜，同时保持较长的组织采样长度。这项研究的结果可以指导针尖设计，以实现针头活检程序的精确针头部署和足够的组织采样。组织分离点在针槽表面下方的多斜角针尖几何形状可以减少针头偏斜，同时保持较长的组织采样长度。这项研究的结果可以指导针尖设计，以实现针头活检程序的精确针头部署和足够的组织采样。组织分离点在针槽表面下方的多斜角针尖几何形状可以减少针头偏斜，同时保持较长的组织采样长度。这项研究的结果可以指导针尖设计，以实现针头活检程序的精确针头部署和足够的组织采样。