Model based stabilization of soft tissue targets in needle insertion procedures

This paper presents a soft tissue target stabilization method during needle insertion procedures. The object considered in this study may have fixed boundary sections and limited surface exposed to external manipulation. The target must be stabilized along the needle path during the needle insertion. It is assumed that a paddle with fixed geometry is available for deformable object manipulation. Two approaches were considered for the target stabilization problem. The first approach uses a static paddle placed on the available boundary, at a strategic location, such that the target motion orthogonal to the needle axis is minimized during the needle insertion. The second approach uses a dynamic paddle attached to the available boundary for the active compensation of the target deflection. In this paper we analyze the optimal paddle placement for the two proposed approaches and present initial numerical results for the case of homogeneous and nonhomogeneous deformable objects. The results show that the first approach is sensitive to possible non-homogeneities in the object, therefore it is not robust to modeling errors. The results also show that optimal placement for the second approach is less sensitive to modeling errors, making it more desirable for physical applications.