[Paper Review] Simulation of magnetic hyperthermia cancer treatment near a blood vessel

Qian Jiang, Renhai Feng+7 more|arXiv (Cornell University)|Aug 27, 2023

Characterization and Applications of Magnetic NanoparticlesEngineering3 citations

TL;DR

This study develops a comprehensive computational framework to simulate magnetic hyperthermia cancer treatment near a blood vessel, integrating heat transfer, mass transfer of magnetic nanoparticles (MNPs), interstitial fluid flow, and blood rheology. The model reveals that a nearby blood vessel significantly cools the tumor, reducing ablation efficacy—yet optimal positioning (e.g., downward gravity with a lower horizontal vessel at 4 mm distance) achieves 97.77% tumor ablation and only 0.87% healthy tissue injury.

ABSTRACT

In this study, we conduct a study on magnetic hyperthermia treatment when a vessel is located near the tumor. The holistic framework is established to solve the process of tumor treatment. The interstitial tissue fluid, MNP distribution, temperature profile, and nanofluids are involved in the simulation. The study evaluates the cancer treatment efficacy by cumulative-equivalent-minutes-at-43 centigrade (CEM43), a widely accepted thermal dose. The influence of the nearby blood vessel is investigated, and parameter studies about the distance to the tumor, the width of the blood vessel, and the vessel direction are also conducted. After that, the effects of the fluid-structure interaction of moving vessel boundaries and blood rheology are discussed. The results demonstrate the cooling effect of a nearby blood vessel, and such effect reduces with the augment of the distance between the tumor and blood vessel. The combination of downward gravity and the cool effect from the lower horizontal vessel leads to the best performance with 97.77% ablation in the tumor and 0.87% injury in healthy tissue at distance d = 4 mm, but the cases of the vertical vessel are relatively poor. The vessel width and blood rheology affect the treatment by velocity gradient near the vessel wall. Additionally, the moving boundary almost has no impact on treatment efficacy. The simulation tool has been well-validated and the outcomes can provide a useful reference to magnetic hyperthermia treatment.

Motivation & Objective

• To develop a holistic simulation framework for magnetic hyperthermia that integrates heat, mass, and fluid dynamics in tumor regions near blood vessels.
• To quantify the impact of nearby blood vessels on thermal dose distribution and treatment efficacy using CEM43 as a metric.
• To investigate the influence of vessel distance, width, orientation, blood rheology, and moving vessel boundaries on treatment outcomes.
• To validate the numerical model using benchmark cases for immersed boundary and non-Newtonian blood flow.

Proposed method

• Uses the immersed boundary method (IBM) to simulate fluid-structure interaction, modeling moving vessel walls with Lagrangian markers and Eulerian grids.
• Applies the Navier-Stokes equations to model interstitial and blood flow fields, with non-Newtonian blood rheology described by the Carreau-Yasuwa model.
• Solves the Pennes bioheat transfer equation (PBHTE) with MNP-induced heat generation to predict temperature fields.
• Models MNP mass transfer using a convection-diffusion equation to track nanoparticle distribution in tissue.
• Employs the CEM43 thermal dose metric to evaluate treatment efficacy, accounting for spatial and temporal non-uniformity.
• Validates the IBM and non-Newtonian flow models against established benchmarks (flow past cylinder and lid-driven cavity).

Experimental results

Research questions

• RQ1 How does the presence of a nearby blood vessel affect the thermal dose distribution and tumor ablation efficiency in magnetic hyperthermia?
• RQ2 What is the influence of the distance between the tumor and the blood vessel on treatment efficacy and healthy tissue damage?
• RQ3 How do vessel width and orientation (horizontal vs. vertical) affect heat dissipation and ablation performance?
• RQ4 What role does blood rheology (non-Newtonian behavior) play in altering velocity gradients and heat transfer near the vessel wall?
• RQ5 How significant is the impact of moving vessel boundaries (due to pulsation and deformation) on overall treatment outcome?

Key findings

• A nearby blood vessel exerts a strong cooling effect on the tumor, reducing the thermal dose and decreasing ablation efficiency.
• The cooling effect diminishes with increasing distance between the tumor and the vessel, with optimal results observed at 4 mm separation.
• The configuration with downward gravity and a lower horizontal vessel achieves 97.77% tumor ablation and only 0.87% healthy tissue injury at d = 4 mm.
• Vertical vessels yield poorer treatment outcomes compared to horizontal vessels due to less favorable thermal convection patterns.
• Vessel width and blood rheology influence treatment by altering the velocity gradient near the vessel wall, which affects heat transfer efficiency.
• The moving boundary of the vessel has negligible impact on treatment efficacy, indicating that rigid wall assumptions are acceptable for this simulation.