脑组织射频消融的有限元仿真与分析

Finite element simulation analysis of radiofrequency ablation in brain

目的运用有限元方法(finite element method,FEM)模拟颅内病灶射频消融过程中的温度场分布,以合理有效利用热疗方案,提高射频消融对颅内病灶的治疗效果。方法建立电导率不变和电导率随温度变化的两种有限元模型,并对两种模型的中心温度、电场强度、热生成率、比吸收率(specificabsorption rate,SAR),以及热损伤区域进行对比分析。结果对比电导率不变的有限元模型,在电导率随温度变化的情况下,电场强度减小,电流密度增大,中心温度升高,热损伤范围增大;当消融温度接近100℃时电导率变化明显,其对消融效果影响较大。结论射频热疗手术中考虑随温度变化的组织参数有较高的临床参考价值。

Objective To simulate the temperature distribution during radiofrequency ablation（RFA）of intracranial lesion by the finite element method （FEM）. This thermotherapy might improve the treatment effectiveness of the RFA in intracranial nidus. Methods Two finite element models including the constant electrical conductivity model and the temperature-dependent conductivity model were built, and the key parameters including central temperature, electric field intensity, heat flux, specific absorption rate （ SAR ） and lesion size were compared. Results In the ease of the temperature-dependent conductivity, the lower electric field intensity, the higher electric current density, the higher central temperature, and the bigger lesion size were obtained. The impact of the temperature-dependent conductivity on the radiofrequency ablation operation was great,especially when the central temperature was near to 100℃. Conclusions The temperature-dependent parameters provided important clinical reference values in the intracranial radiofrequency ablation operation.