Manual palpation to update the position of subsurface tumor(s) is a normal practice in open surgery, but is not possible through the small incisions of minimally invasive surgery (MIS). This paper proposes a method that has the potential to use a simple constant-force indenter and the existing laparoscopic camera for tumor location refinement in MIS. The indenter floats with organ movement to generate a static surface deformation on the soft tissue, resolving problems of previous studies that require complicated measurement of force and displacement during indentation. By analyzing the deformation profile, we can intraoperatively update the tumor’s location in real-time. Indentation experiments were conducted on healthy and “diseased” porcine liver specimens to obtain the deformation surrounding the indenter site. An inverse finite element (FE) algorithm was developed to determine the optimal material parameters of the healthy liver tissue. With these parameters, a computational model of tumorous tissue was constructed to quantitatively evaluate the effects of the tumor location on the induced deformation. By relating the experimental data from the “diseased” liver specimen to the computational results, we estimated the radial distance between the tumor and the indenter, as well as the angular position of the tumor relative to the indenter.

手动触诊来更新表面下肿瘤的位置是开放手术中的常规做法，但无法通过微创手术 (MIS) 的小切口进行。本文提出了一种方法，该方法有可能使用简单的恒力压头和现有的腹腔镜摄像头在 MIS 中进行肿瘤位置细化。压头随器官运动而浮动，在软组织上产生静态表面变形，解决了以往研究压痕过程中需要复杂测量力和位移的问题。通过分析变形轮廓，我们可以在术中实时更新肿瘤的位置。对健康和“患病”猪肝脏标本进行压痕实验，以获得压头部位周围的变形。开发了逆有限元 (FE) 算法来确定健康肝脏组织的最佳材料参数。利用这些参数，构建了肿瘤组织的计算模型，以定量评估肿瘤位置对诱导变形的影响。通过将“患病”肝脏标本的实验数据与计算结果联系起来，我们估计了肿瘤与压头之间的径向距离，以及肿瘤相对于压头的角位置。