Research On Multi-tined Electrode Based On Needle Steering For Conformal Radio-frequency Ablation

As a typical minimally invasive procedure,radiofrequency ablation(RFA)has been widely reckoned as a promising therapy for the treatment of malignant tumors.In an RFA surgery,one or more radiofrequency ablation electrodes are used to apply the radiofrequency energy to the target tumor and generate heat inside tumor tissues.Further,heat diffusion results in an RFA lesion,which covers the tumor tissues,achieving in-situ inactivation of tumor cells.However,the-state-of-art commercial RFA electrode fails to control the geometry of RFA lesion,thus geometric mismatch between RFA lesion and tumor ends up generating a much larger unnecessary lesion.Conformal ablation as a new clinical demand arises therefrom.This paper proposed a needle steering technology based conformal ablation scheme,where the shape of naked electrode was controlled by needle steering technology so as to control the geometry of RFA lesion.Based on this idea,a conformal ablation system prototype,consisting of a multi-tined electrode with multi-level nested structure and a compatible driving system,was designed and fabricated.Through theoretical analysis and experimental observation,a mathematical model of the in-vitro trajectory of the electrode was established.Test results showed that the prediction error of this model was within0.15 mm.Furthermore,the error of position runout of the outer puncture sheath’s tip was less than 1mm during electrode actuation,exhibiting nice position stability.The effectiveness of the multi-tined conformal RFA electrode was verified by multiphysics simulation and in-vitro tissue experiments,which laid a solid foundation for the animal experiments and clinical surgical efficacy evaluation in the future.The multi-tined conformal radiofrequency ablation electrode based on needle steering technology proposed in this paper can tune the geometry of RFA lesion in the process of single puncture and single ablation,thereby improve the matching degree of RFA lesion and tumor without sacrificing its low invasiveness,which is of great significance for RFA to move towards the era of conformal ablation.