Research On Puncture Path Planning And Spatial Registration Of Robotic Brachytherapy

Cervical cancer has been endangering the health of women,but also a major problem in the field of modern medical treatment.At present,the mainstream treatment is to use chemotherapy and radiotherapy,and radiotherapy is generally divided into external and internal radiation.Cervical cancer is located in the cervix.It extremely harms other normal tissue cells to using external radiation,which could produce large quantity of dose and wide range of external radiation from the outside to the inside of the irradiation.Therefore,brachytherapy has been generally used in clinical practice.At present,for it has the advantages of low dose,radiation range only for the tumor area and particle radiation from the inside to the outside,which can not only kill the tumor region,but also reduce the damage of normal cells.The first problem to be solved in brachytherapy is the implantation of radioactive particles in the tumor area.At present,the method of catheterization after manual puncture depends on the clinical experience of doctors,and the effect of radiation directly depends on the precision of puncture.A robotic brachytherapy system is used to help doctors plan the puncture path and the particle radiation plan in advance.The robot system then carries out the puncture and radiation according to the planned plan,which effectively improves the puncture precision,reduces the complexity of the operation process,enhances the effect of radiotherapy and ensures the safety of the operation.In this paper,the puncture path planning and spatial registration in the robot puncture module are studied.The team has been collaborating with the hospital to analyze the brachytherapy procedure of cervical cancer.Based on the doctors’ clinical experience during the operation,those key points in the process of puncturing were sorted out.Combined with the characteristics of the surgical robot,the puncture operation process applied to the robot was proposed.For the puncture path planning module and spatial registration module in robot puncture,the functional requirements were analyzed respectively,meanwhile the puncture procedure applied to robot was constructed in the system.In this paper,the positioning technology was combed.The robot calibration method has been used to obtain the position information of the marked point in the robot coordinate system,and the coordinate information of the point in the system can be obtained through Spatial Registration Module.The main spatial registration algorithm had been studied in this paper,and the unit quaternion registration algorithm is chosen and integrated into the software system.In the spatial registration module,the position information of known mark points in two different space coordinates is calculated by the registration algorithm,and then the space conversion relationship between them is established.Puncture path planning and spatial registration are both special functional requirements in the subject,which need to be developed independently.Based on the full understanding of the business requirements,the corresponding process and implementation plan were proposed.The system infrastructure is built based on the open source framework 3D Slicer,and the system function requirements are developed in the form of extension modules under the Windows platform.The puncture path model is generated by VTK,then integrate with Modules in Slicer,and the monitoring of Markups is carried out to realize the function of real-time adjustment of puncture path.The interface design and interaction can be realized by using Qt,and the data storage and reading can be realized by establishing a connection with My SQL database.The Numpy Computing Library in Python is used to write the space registration logic code,and the mapping relationship between the software system and the robot system is established.