Department of Mechanical Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA.
Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Int J Hyperthermia. 2021;38(1):611-622. doi: 10.1080/02656736.2021.1913244.
Alternating magnetic field (AMF) tissue interaction models are generally not validated. Our aim was to develop and validate a coupled electromagnetic and thermal model for estimating temperatures in large organs during magnetic nanoparticle hyperthermia (MNH).
Coupled finite element electromagnetic and thermal model validation was performed by comparing the results to experimental data obtained from temperatures measured in homogeneous agar gel phantoms exposed to an AMF at fixed frequency (155 ± 10 kHz). The validated model was applied to a three-dimensional (3D) rabbit liver built from computed tomography (CT) images to investigate the contribution of nanoparticle heating and nonspecific eddy current heating as a function of AMF amplitude.
Computed temperatures from the model were in excellent agreement with temperatures calculated using the analytical method (error < 1%) and temperatures measured in phantoms (maximum absolute error <2% at each probe location). The 3D rabbit liver model for a fixed concentration of 5 mg Fe/cm of tumor revealed a maximum temperature ∼44 °C in tumor and ∼40 °C in liver at AMF amplitude of ∼12 kA/m (peak).
A validated coupled electromagnetic and thermal model was developed to estimate temperatures due to eddy current heating in homogeneous tissue phantoms. The validated model was successfully used to analyze temperature distribution in complex rabbit liver tumor geometry during MNH. In future, model validation should be extended to heterogeneous tissue phantoms, and include heat sink effects from major blood vessels.
交变磁场（AMF）组织相互作用模型通常未经验证。我们的目的是开发和验证一个用于估计磁纳米粒子热疗（MNH）期间大器官中温度的耦合电磁和热模型。
通过将结果与在固定频率（155±10 kHz）下暴露于 AMF 的均匀琼脂凝胶模型中测量得到的实验数据进行比较，对耦合有限元电磁和热模型进行了验证。验证后的模型应用于从 CT 图像构建的三维（3D）兔肝，以研究 AMF 幅度下纳米粒子加热和非特异性涡流加热的贡献。
模型计算出的温度与使用解析方法计算出的温度（误差<1%）和在模型中测量出的温度（在每个探头位置的最大绝对误差<2%）非常吻合。对于固定浓度为 5mg Fe/cm 的肿瘤的 3D 兔肝模型，在 AMF 幅度约为 12 kA/m（峰值）时，肿瘤中的最大温度约为 44°C，肝脏中的最大温度约为 40°C。
开发了一个经过验证的耦合电磁和热模型，用于估计均匀组织模型中的涡流加热引起的温度。验证后的模型成功地用于分析 MNH 期间复杂兔肝肿瘤几何形状中的温度分布。在未来，模型验证应扩展到不均匀组织模型，并包括主要血管的热汇效应。
