| Author: | Jiang, Qian |
| Title: | Study of magnetic hyperthermia based cancer treatment using a holistic simulation framework |
| Advisors: | Tang, Hui (ME) Liu, Yang (ME) |
| Degree: | Ph.D. |
| Year: | 2024 |
| Subject: | Cancer -- Thermotherapy Tumors -- Treatment Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Mechanical Engineering |
| Pages: | xxxviii, 205 pages : color illustrations |
| Language: | English |
| Abstract: | Cancer, a predominant cause of mortality globally, was responsible for the diagnosis of 19.98 million individuals and the demise of 9.74 million in 2022, spanning various types. Hyperthermia is a newly developed cancer treatment procedure. With the potential of locally ablating the tumor cell but not injuring surrounding healthy tissue, hyperthermia can effectively reduce the side effects induced by traditional methods. As one of the hyperthermia modalities, magnetic hyperthermia treatment utilizes magnetic nanoparticles (MNPs), which are firstly injected into the tumor and subsequently subjected to an external high-frequency alternating magnetic field (AMF), to generate the requisite heat at target regions. The ultimate goal is to inflict lethal thermal damage to cancerous tissues while sparing surrounding healthy tissues. Despite its demonstrated efficacy in diverse clinical scenarios, however, the precise control of local heat spots exerted by MNPs remains a challenge to optimize therapeutic outcomes. To address this great challenge, this study aims to develop a holistic simulation tool that incorporates almost all related physics, by using this tool, exploring the strategies for optimizing the magnetic hyperthermia treatment process, and from physics perspective providing valuable insights for clinicians. We develop a holistic simulation framework for magnetic hyperthermia treatment. The simulation tool incorporates porous media fluid flow, heat and mass transfer, fluid-structure interaction (FSI), and blood rheology, etc. The flow within the tissue interstitial space is governed by the Navier-Stocks equation, while heat and MNP transfer are governed by the energy and concentration equations, respectively. The governing equations are solved by the multiple-relaxation-time lattice Boltzmann method (MRT-LBM) schemes. The immersed boundary method (IBM) is applied to deal with FSI. Using the developed simulation framework, we first conduct a study on searching optimal MNP injection strategies, in which the particle swarm optimization (PSO) algorithm is adopted. Two representative tumor models, i.e., a circular tumor model and an elliptical tumor model are considered. The results converge rapidly in both cases, albeit requiring more generation iterations for the elliptical tumor. It is found that the more injection sites, the better the treatment performance. Next, the interstitial flow and MNP transport are involved. We investigate the influence of the gravity effect and several key parameters, including the Lewis number and the heat source number in the no-gravity scenario, while the Darcy ratio and the buoyancy ratio in the with-gravity scenario. It is found that, compared to the no-gravity cases, the with-gravity cases require much more time to complete tumor ablation but a deteriorated treatment efficacy. Some useful power laws on the optimal treatment time and the investigated parameters are also revealed. Then, we incorporate the blood rheology and FSI, considering scenarios where the tumor is near a large blood vessel. It is observed that the nearby blood vessel exerts a significant cooling effect. The distance between the tumor and the blood vessel considerably impacts the temperature profile and treatment efficacy. The combination of the gravity effect and the blood vessel’s cooling effect also affects the efficacy. The velocity gradient at the vessel wall also influences the tumor ablation pace. Last, the optimization study is extended into 3D space, targeting at a more realistic situation. We consider three representative tumor models, i.e., a spherical tumor, a simple and a complex irregular tumor. For the spherical tumor, generally, multi-site injection strategies are beneficial to treatment, but the one-site injection strategy achieves an almost perfect efficacy if time permits. For the irregular tumor models, the optimal number of injections and the corresponding injection sites are determined by the shape of the tumor. This research enhances our comprehension of magnetic hyperthermia treatment, offering valuable insights that serve as beneficial references for clinicians in the field. |
| Rights: | All rights reserved |
| Access: | open access |
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