Numerical Investigation of Blood Flow Effects on Temperature Distribution in Pulmonary Tumors during Magnetic Induction Hyperthermia

Xiao LiuMai Lu^*

• Key Laboratory of Extreme Environmental Microbial Resources and Engineering, School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, China

Magnetic Induction Hyperthermia (MIH), as an emerging physical approach for tumor treatment, has attracted widespread attention in clinical research. However, most existing studies focus on optimizing magnetic nanoparticle properties and magnetic field parameters, while relatively few have investigated the heat sink effects caused by blood flow in the treatment region. In this study, based on multiphysics coupling theory, a three-dimensional lung tumor model incorporating vascular structures and laminar blood flow was developed. The coupled effects of magnetic, electric, flow, and thermal fields during MIH treatment were simulated using the COMSOL Multiphysics finite element platform. Results show that, in the absence of blood flow, the tumor center temperature can rapidly increase to 47.7 °C within 300 seconds, with the peripheral temperature stably maintained above 42 °C, indicating effective thermal treatment. However, once blood flow is introduced, the resulting heat sink effect significantly reduces the therapeutic temperature: the tumor center drops to 44.5 °C, and the minimum peripheral temperature to 39.4 °C. Further analysis reveals that both blood flow velocity and vessel diameter significantly affect the heat sink intensity. When flow velocity decreases or vessel diameter is reduced, the heat sink effect is notably weakened. To address temperature inhomogeneity, this study suggests increasing the number of Helmholtz coil turns, enhancing excitation current, or optimizing magnetic fluid distribution within the tumor region to improve overall thermal control performance. This work provides theoretical insights into the influence of blood flow in MIH and offers important guidance for clinical individualized treatment planning and magnetic field parameter optimization.