Cavagnaro M, Pinto R, Lopresto V
Department of Information Engineering, Electronics and Telecommunications, Sapienza University, Rome, Italy.
Phys Med Biol. 2015 Apr 21;60(8):3287-311. doi: 10.1088/0031-9155/60/8/3287. Epub 2015 Mar 31.
Microwave thermal ablation (MTA) therapies exploit the local absorption of an electromagnetic field at microwave (MW) frequencies to destroy unhealthy tissue, by way of a very high temperature increase (about 60 °C or higher). To develop reliable interventional protocols, numerical tools able to correctly foresee the temperature increase obtained in the tissue would be very useful. In this work, different numerical models of the dielectric and thermal property changes with temperature were investigated, looking at the simulated temperature increments and at the size of the achievable zone of ablation. To assess the numerical data, measurement of the temperature increases close to a MTA antenna were performed in correspondence with the antenna feed-point and the antenna cooling system, for increasing values of the radiated power. Results show that models not including the changes of the dielectric and thermal properties can be used only for very low values of the power radiated by the antenna, whereas a good agreement with the experimental values can be obtained up to 20 W if water vaporization is included in the numerical model. Finally, for higher power values, a simulation that dynamically includes the tissue's dielectric and thermal property changes with the temperature should be performed.
微波热消融（MTA）疗法利用微波（MW）频率下电磁场的局部吸收，通过非常高的温度升高（约60°C或更高）来破坏不健康组织。为了制定可靠的介入治疗方案，能够正确预测组织中温度升高的数值工具将非常有用。在这项工作中，研究了随温度变化的介电和热特性的不同数值模型，观察模拟的温度增量和可实现的消融区域大小。为了评估数值数据，在与天线馈电点和天线冷却系统相对应的位置，针对辐射功率的增加值，测量了靠近MTA天线处的温度升高。结果表明，不包括介电和热特性变化的模型仅适用于天线辐射功率非常低的值，而如果在数值模型中包括水汽化，则在高达20W的情况下可以获得与实验值的良好一致性。最后，对于更高的功率值，应进行动态包括组织介电和热特性随温度变化的模拟。
