Pearce John, Giustini Andrew, Stigliano Robert, Jack Hoopes P
Department of Electrical and Computer Engineering, The University of Texas at Austin , Austin, TX 78712 e-mail:
J Nanotechnol Eng Med. 2013 Feb;4(1):110071-1100714. doi: 10.1115/1.4024904. Epub 2013 Jul 16.
Hyperthermia therapy for cancer treatment seeks to destroy tumors through heating alone or combined with other therapies at elevated temperatures between 41.8 and 48 °C. Various forms of cell death including apoptosis and necrosis occur depending on temperature and heating time. Effective tumoricidal effects can also be produced by inducing damage to the tissue vasculature and stroma; however, surrounding normal tissue must be spared to a large extent. Magnetic nanoparticles have been under experimental investigation in recent years as a means to provide a favorable therapeutic ratio for local hyperthermia; however, practical numerical models that can be used to study the underlying mechanisms in realistic geometries have not previously appeared to our knowledge. Useful numerical modeling of these experiments is made extremely difficult by the many orders of magnitude in the geometries: from nanometers to centimeters. What has been missing is a practical numerical modeling approach that can be used to more deeply understand the experiments. We develop and present numerical models that reveal the extent and dominance of the local heat transfer boundary conditions, and provide a new approach that may simplify the numerical problem sufficiently to make ordinary computing machinery capable of generating useful predictions. The objectives of this paper are to place the discussion in a convenient interchangeable classical electromagnetic formulation, and to develop useful engineering approximations to the larger multiscale numerical modeling problem that can potentially be used in experiment evaluation; and eventually, may prove useful in treatment planning. We cast the basic heating mechanisms in the framework of classical electromagnetic field theory and provide calibrating analytical calculations and preliminary experimental results on BNF-Starch nanoparticles in a mouse tumor model for perspective.
用于癌症治疗的热疗旨在通过单独加热或与其他疗法联合，在41.8至48°C的高温下破坏肿瘤。根据温度和加热时间的不同，会发生包括凋亡和坏死在内的各种形式的细胞死亡。通过诱导对组织脉管系统和基质的损伤，也可以产生有效的杀肿瘤作用；然而，必须在很大程度上避免周围正常组织受到损伤。近年来，磁性纳米颗粒一直在进行实验研究，作为一种为局部热疗提供良好治疗比率的手段；然而，据我们所知，此前尚未出现可用于研究实际几何形状中潜在机制的实用数值模型。由于几何形状存在多个数量级的差异：从纳米到厘米，对这些实验进行有用的数值建模变得极其困难。一直缺少的是一种实用的数值建模方法，可用于更深入地理解实验。我们开发并提出了数值模型，这些模型揭示了局部传热边界条件的程度和主导地位，并提供了一种新方法，该方法可能会充分简化数值问题，使普通计算机能够生成有用的预测。本文的目的是将讨论置于一种方便的可互换经典电磁公式中，并针对更大的多尺度数值建模问题开发有用的工程近似方法，这些方法可能用于实验评估；最终，可能在治疗规划中证明有用。我们将基本加热机制置于经典电磁场理论的框架内，并提供校准分析计算以及在小鼠肿瘤模型中对BNF-淀粉纳米颗粒的初步实验结果以供参考。
