Crouch Jessica R, Schneider Chad M, Wainer Josh, Okamura Allison M
Computer Science Dept., Old Dominion University, VA, USA.
Med Image Comput Comput Assist Interv. 2005;8(Pt 2):624-32. doi: 10.1007/11566489_77.
Models that predict the soft tissue deformation caused by needle insertion could improve the accuracy of procedures such as brachytherapy and needle biopsy. Prior work on needle insertion modeling has focused on static deformation; the experiments presented here show that dynamic effects such as relaxation are important. An experimental setup is described for recording and measuring the deformation that occurs with needle insertion into a soft tissue phantom. Analysis of the collected data demonstrates the time- and velocity-dependent nature of the deformation. Deformation during insertion is shown to be well represented using a velocity-dependent force function with a linear elastic finite element model. The model's accuracy is limited to the period during needle motion, indicating that a viscoelastic tissue model may be required to capture tissue relaxation after the needle stops.
能够预测针插入引起的软组织变形的模型可以提高近距离放射治疗和针活检等程序的准确性。先前关于针插入建模的工作主要集中在静态变形上；此处展示的实验表明，诸如松弛等动态效应也很重要。本文描述了一种用于记录和测量针插入软组织模型时发生的变形的实验装置。对收集到的数据进行分析，证明了变形具有时间和速度依赖性。使用具有线性弹性有限元模型的速度依赖性力函数，可以很好地表示插入过程中的变形。该模型的准确性仅限于针运动期间，这表明可能需要一个粘弹性组织模型来捕捉针停止后组织的松弛情况。
