Research On The Active Catheter And Operating System Assisted In Brain Surgery

At the present time, due to the lack in the necessary instruction methods of cerebral vascular minimally invasive surgery, surgical techniques are very hard to master to the degree that few surgeons in few hospitals across the world can conduct this operation. With the fast development of technology, mechanism and integrated electronics, applying the current technical means to minimally invasive surgery has become central issue of present researchers. This research can improve not only the quality of the operation, but also the security, precision and efficiency of the operation etc.Setting in the application of vascular interventional operation, this paper carries research on the smart catheter and its operating system assisted in brain surgery. Once the study of the system succeeds, it can reduce operating error rate and. raise the application. This paper summarizes several current bottlenecks encountered in this field; for instance, the surgeons cannot feel the tactile force between blood vessel and catheter when the they operate the robot, whether the active catheter can precisely enter into the anticipant embranchment of the blood vessel when the catheter in arterial bifurcation conditions, the feedback of tactile force information and the reliability of transporting machine for the catheter. All the problems above are carried thorough analysis and research in this paper, and it mainly includes the following aspects:The tactile sensor is researched in this paper, combining its application in angiocarpy, we chose piezoelectric material Polyvinylidene Fluoride (PVDF) with good dynamic performance as sensitive material of sensors, analyzed piezoelectric characteristics of this material and designed the corresponding charge amplifier circuit, established electrical and mechanical models. Eventually the mathematical model of the tactile force sensor is established and tactile sensor clusters consisting of three PVDF tactile sensors are designed and tested. Besides, the finite element analysis on PVDF array is carried on, cluster analysis and genetic algorithms are also used to optimize the design of tactile sensor array, and then a 3 X 3 PVDF sensor array is designed and corresponding experiments are carried on. Furthermore, in the research of actuator which control the motion of the catheter, two types of material for actuator are analyzed separately, one is the design and research on shape memory alloy (SMA) actuator, the electrothermal driving principle of SMA actuator is analyzed, the model of temperature kinetics is established, and a simulation experiment is carried on this model, the SMA actuator of active catheter is developed; the other one is the research on currently popular Ionic conducting polymer film (ICPF) integrated sensory actuator, the characteristic of bending output and tip output are analyzed, a actuator model and a force sensor model of the end actuator is built, the robustness of senor is analysed and a experimental verification is carried on, it overcomes the influence of feedthrough coupling and enviromental noises, and so on. Finally, operating system of catheter for neurosurgery is researched, first we introduced a master-slave remote catheter operating system which utilizes a handle to control the slave-side to complete the propulsion manipulate of catheter, but this device can not constitute the entire catheter force feedback, therefore we propose a new catheter operating system design based on linear stepping mechanism (LSM), the catheter operating system is designed mainly based on the reality of a doctor operating system on the catheter, and the complete force feedback system is constituted. The structure of a new type linear step mechanism can prevent slip and easy for operate and antisepsis, and it is easy for remote control in the system, it can give the surgeon a strong sense of the operation, it has more advantages than old systems and is more convenient for the doctor.The active catheter operating system assisted in brain surgery can help surgeon to perform catheter insertion, it can realize the forward, backward and rotation of the catheter by the computer control equipment, and it can inspect the kinetic resistance of the catheter in the course of motion. The manipulator adjust the motion of the catheter according to the feedback of the tactile force information, and then give the relevant response operate in order to avoid damage to the blood vessel.The system can also be used as an experimental teaching system of the surgeon, after finishing the improvement of the future work, we can have a good solution to the high difficulty in insertion and the big danger problems, which can largely reduce the working strength of the surgeon and improve the success rate of the operation.