The University of British Columbia

A methodology for estimating the force distribution that occurs along a needle shaft during insertion is described. To validate the approach, an experimental system for measuring planar tissue deformation during needle insertions has been developed and is presented. The planar motion of a soft tissue phantom is measured during needle penetration and used in conjunction with a two dimensional linear elastostatic material model, discretised using the finite element method, to derive contact force information that is not directly measurable. This approach provides a method for quantifying the needle forces and soft tissue deformations that occur during general needle trajectories in multiple dimensions. A simulation algorithm that is based upon these results is also described.