Research On Key Technology Of Puncture Robot System For Brachytherapy

Radiation therapy is often used to treat tumors,including external irradiation and radioactive particle implantation.External radiation therapy with high radiation dose tends to damage the healthy tissues of patients.Since brachytherapy with radioactive particles has many advantages,such as low radiation dose,long acting time,little damage to healthy tissues,and low price,its application in the field of treatment has gradually increased in recent years.At present,most puncture operations are performed manually by doctors,with problems such as low accuracy and poor stability.The use of surgical robot system can assist doctors in surgical planning,assist in surgical process safety monitoring,improve surgical accuracy,operation efficiency and ensure surgical safety.In this paper,the related system architecture,space registration,needle entry strategy and other key technologies of the puncture robot system of brachytherapy were studied.The research group cooperated with Peking University stemmatological hospital to draw on the clinical experience of doctors,analyze the requirements of puncture surgery of brachytherapy,extract the commonness of preoperative biopsy and radioactive particle implantation,and construct the architecture of puncture robot system.According to the requirements,the overall scheme of the robot system is designed,and a robot surgery system with visual navigation function is constructed.The system includes a seven-degree-of-freedom collaborative robotic arm,end tool,optical positioning system,three-dimensional surgical monitoring system,upper computer control software and preoperative planning system.Meanwhile,in order to perform surgical actions flexibly,accurately and efficiently,kinematics analysis is carried out on the robotic arm,forward and inverse kinematics solutions are derived,intraoperative movement trajectory of the robotic arm is planned,surgical planning needle entry path is realized,and the operation is completed.To unified operation system space,build robots,optical positioning system and the spatial coordinate transformation relation between the patients,proposed to improve the automatic registration method of straight line rotation method and application of the theory of lie groups with manual registration method are compared,and the experimental results show that the algorithm improve the efficiency and precision of the registration,so as to improve the veracity and reliability of piercing operation.Aiming at the problem of puncture needle deformation and puncture error in the process of puncture,the interaction between puncture needle and tissues of human body is analyzed,and the interaction model is established.A calculation model of needle tip deviation based on information of six-dimensional force sensor is established.Under the guidance of this model,a stepping Angle adjustment needle insertion strategy is proposed to reduce the impact of puncture needle deviation and deformation on puncture accuracy in the process of puncture.The experimental platform of surgical robot system was built to verify the navigation accuracy and system stability of the system.In addition,puncture force collection and precision verification experiments were carried out on the skull model and cadaver head respectively to verify the system functions and surgical procedures,meeting the requirements of doctors on the safety,operability and precision of the surgical system.