Cosman Eric R, Cosman Eric R
Department of Electrical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
Pain Med. 2005 Nov-Dec;6(6):405-24. doi: 10.1111/j.1526-4637.2005.00076.x.
A study is carried out of the spatial distribution and time dependence of electric and thermal fields in the tissue around a radiofrequency (RF) electrode used in pain therapy. Finite-element calculation of the fields is performed, and results are compared with ex vivo tissue data. Field predictions are made for continuous and for pulsed RF applications.
A special RF cannula electrode is constructed with both macro and micro thermocouple sensors to measure both average and rapid, transitory temperature effects. Temperatures and impedances are recorded in liver and egg-white models using signal outputs from a commercially available RF lesion generator. These data are compared with the results of finite-element calculations using electric field equations and the bio-heat equation.
Average and pulsatory temperatures at the RF electrode are measured. Rapid temperature spikes during pulsed RF bursts are observed. These data compared well with theoretical calculations using known electrical and thermal tissue parameters.
Continuous RF lesioning causes heat destruction of neurons. Pulsed RF lesioning (PRFL) produces heat bursts with temperatures in the range associated with destructive heat lesions. PRFL also produces very high electric fields that may be capable of disrupting neuronal membranes and function. Finite-element calculations agree substantially with the measured data, giving confidence to their predictions of fields around the RF electrode.
对用于疼痛治疗的射频（RF）电极周围组织中的电场和热场的空间分布及时间依赖性进行研究。对这些场进行有限元计算，并将结果与离体组织数据进行比较。对连续和脉冲射频应用进行场预测。
构建一种特殊的射频套管电极，其带有宏观和微观热电偶传感器，以测量平均及快速的瞬态温度效应。利用市售射频损伤发生器的信号输出，记录肝脏和蛋清模型中的温度及阻抗。将这些数据与使用电场方程和生物热方程的有限元计算结果进行比较。
测量了射频电极处的平均温度和脉动温度。观察到脉冲射频爆发期间的快速温度峰值。这些数据与使用已知电和热组织参数的理论计算结果吻合良好。
连续射频损伤会导致神经元的热破坏。脉冲射频损伤（PRFL）产生的热脉冲温度处于与破坏性热损伤相关的范围内。PRFL还会产生非常高的电场，可能能够破坏神经元膜及其功能。有限元计算结果与实测数据基本一致，这使其对射频电极周围场的预测具有可信度。
