Finite element analysis of radiofrequency ablation process in soft tissue sarcomas

Soft tissue sarcomas which are serious hazard to human are aggressive and difficult to control. Traditional ways of treatment can bring great pain to the patients. Radiofrequency(RF) ablation has become a feasible and minimally invasive treatment for soft tissue sarcomas. However, there are few literatures to study the energy and temperature distributions in the sarcomas. In this paper, sarcomas simulation model was established based on the prototype of gastrointestinal stromal sarcoma. Parameters of electric and thermal properties of the sarcomas were set appropriately by considering its thermal sensitivity. Temperature of 323.15K is chosen as a border edge to evaluate the efficacy of RF ablation. Results indicate that the maximum temperature point occurs at the apex of RF probe. Growth of temperature at the probe apex decreases with the increment of ablation time. In addition, a local maximum temperature point is presented at the interface of the sarcoma and muscle tissue, which is meaningful for RF ablation to keep the normal tissue undamaged. Effects of electrode insertion depth on the RF ablation were studied in this paper. Results indicate that area of tumor cell necrosis is expanded gradually with the increase of insertion depth and RF power radiated. However, the temperature of the apex of probe drops with the increasing of the depth inserted. As a result, probe insertion depth and RF ablation power must be cooperated to achieve desired RF ablation effect.