Study On Experimentation And Mechanics Modeling For Needle Insertion Into Soft Tissue

Needle insertion into soft tissue has been an important aspect of modern clinical.It is applied more and more in medical diagnoses and treatments. This paper focuseson the need of needle insertion into soft tissue experiments. The preparation ofartificial non-creatural material, tissue properties measurement and needle insertioninto soft tissue experiments are main content in this paper.The polyvinyl alcohol hydrogel is prepared to simulate the material of soft tissue,and its properties verification are introduced in detail. Based on a large number ofexperiments, the proportion of polyvinyl alcohol hydrogel with better transparence isobtained and materials properties are transformed following the method offreeze-thaw cycles. The Young’s modulus and Poisson’s ratio of polyvinyl alcoholhydrogel in different proportion and cycles have been received with groups ofcompression test. A reasonable proportion of ingredient and freeze-thaw cyclesissought out by test and in this condition, the properties of the polyvinyl alcoholhydrogel implant material is close to liver tissue material.An experimental platform for needle insertion is established on preparing thesoft tissue material. The experimental platform hardware used the high-precisionmobile platforms produced by Germany PI as the power of needle insertion andNano17, six-axis force/torque measuring system, produced by ATI as the measuringdevice for needle insertion force. A program that contains the experimental platformcontrol and needle insertion force collection is written on LabVIEW.The experiments of needle insertion into soft tissue (porcine liver and PVAhydrogel) were conducted on the platform. Analysis of the dynamic process of needleinsertion into porcine liver is performed and the insertion force model is fittedthrough the experimental graphs. Besides, the influence of insertion force mutationson the stability of needle is proposed.