Interior point-based method for surgical planning and risk analysis of robot-assisted liver tumor coagulation therapy system

Due to the lack of surgical planning, the needle-insertion path planning still depends on the surgeon's operation experience and the reconstructed 3D operation environment in the robot-assisted liver tumor coagulation therapy system. So, the study of the surgical planning strategy is an important task to reduce the surgeon workload and improve the therapy efficiency and quality. To this end, according to the operation characteristics, the surgical planning is divided into two parts: pre-operative surgical planning and intra-operative risk analysis in this paper. In the pre-operative stage, the interior point method is used to obtain the constraint equations which prohibit the needle-insertion path from damaging important organs or tissues, e.g., ribs or primary blood vessels. In the intra-operative stage, a rapid risk analysis of previous planning is performed to assist surgeons in determining the final needle-insertion path. In this paper, the needle's collision-free reachable workspace is successfully solved. The simulation results indicated that the needle-insertion path selected in the needle's collision-free reachable workspace can avoid the collision with important organs or tissues. The risk analysis algorithm can quickly calculate the nearest distance between the pre-planned insertion path and the important organs, which could assist surgeons in evaluating the pre-planned needle-insertion path. The proposed surgical planning strategy can significantly reduce the surgeon workload and improve the efficiency and safety of operation.