Physical Properties of the Liver and the Development of an Intelligent Manipulator for Needle Insertion

Medical procedures such as RFA and cryosurgery require the insertion of a needle into the target area within the body. Needle insertion is difficult because it can easily result in organs being deformed and displaced. This research aims to produce an intelligent robot for needle insertion, incorporating the following three techniques, A: visual feedback B: organ-model base control C: force control. This research uses a robot model and a liver for the target object to evaluate organ-model base control. For the purpose of organ-model base control, three experiments were conducted to evaluate the physical properties of the liver for robot control. A dynamic viscoelastic test was then carried out to show the dynamic properties of the liver in the form of a differential equation. The nonlinearity of the liver was supported by the creep test while an axial needle insertion test was also carried out to model the force and the extent of deformation experienced during needle insertion. In addition, an intelligent needle insertion robot was developed for the purpose of the experimentation concerning intelligent control of the needle. The experimental result displayed the margin error between the needle tip and target marker when the needle reaches the target position was around 1[mm] and a result led to positive findings.