3D Trajectory Planning Based on FEM with Application of Brachytherapy

Brachytherapy is a validate treatment for certain stage,prostate cancer.Large deformation characteristic of soft tissue and force loaded on the tip of insertion needle will cause some unexpectable results, such as imprecise implant of radioactive seeds and extra injury to other tissues. Apparently, improved implant accuracy can not only improve the local control but also reduce global toxicity. As a part of on going efforts to develop robot assisted brachytherapy, the current investigation focuses on dynamic trajectory planning of the brachytherapy needle. Toward that goal, a 3D planning algorithm based on artificial potential field, non-linear material model and dynamic finite element method is proposed. The whole insertion process has been discretized into several time steps. Using compartment trajectory planning in each time step constantly, the dynamic trajectory planning can be conducted smoothly. A numerical simulation has been done to prove the algorithm validity. The result shows that the needle can reach the target without touching the obstacle.