Study On Soft Tissue Deformation Model During Breast Interventional Surgery

The detection and treatment of breast cancer involves the surgical form of cutting breast soft tissue with a large number of needles.Therefore,the study of the interaction mechanism of needle puncture soft tissue,especially the bending of needle and the deformation of soft tissue in the process of puncture,is of great significance to the research of breast intervention robot-assisted puncture system.Based on this,the research of this paper is as follows:Based on the rheological properties of biological soft tissue,the stress and deformation of soft tissue is analyzed from two aspects of elasticity and viscosity,and a three-parameter viscoelastic model of soft tissue is established.On this basis,the needle puncture soft tissue is regarded as the local damage of the soft tissue caused by the needle.Based on the fracture characteristics of different failure types in fracture mechanics,the changes of the displacement and force of the crack tip during the interaction between needle and tissue are analyzed,and the viscoelastic fracture model of needle puncture soft tissue is established.As for the destructive deformation of soft tissue in the process of oblique needle puncture,the problems of stress singularity and high complexity of data structure are often encountered when using computational models.In this paper,a complex variable meshless method is proposed to deal with the soft tissue deformation model.Based on the above analysis,the weak form of Galerkin integral of viscoelastic mechanics is adopted,and the constitutive relation of viscoelastic fracture of soft tissue is expressed by the displacement calculated by complex variable meshless method through Newton-Raphson time integral time integral,and the deformation calculation of needle and tissue is realized.The simulation program of needle and soft tissue deformation is compiled by using MATLAB software.the simulation results show that the calculation results of the model meet the experimental requirements.Based on the physical properties of breast tissue under pressure,the hydrogel with similar physical properties was selected as biomaterial,and the oblique tip puncture needle made of non-magnetic stainless steel was used.The puncture force,the bending of the needle and the deformation of soft tissue were measured by puncture experiment.In this paper,the mechanical model of soft tissue interaction of oblique needle puncture is established,programmed and simulated by MATLAB,and the experimental platform of needle puncture is built for experimental verification.The study of this paper is helpful to understand the mechanism of needle puncture soft tissue interaction and provide a theoretical basis for the establishment of breast intervention robot-assisted puncture system.