Sefidgar Mostafa, Bashooki Ehsan, Shojaee Pejman
Department of Mechanical Engineering, Pardis Branch, Islamic Azad University, Pardis, Iran.
Department of Mechanical Engineering,West-Tehran Branch, Islamic Azad University, Tehran, Iran.
J Therm Biol. 2020 Dec;94:102742. doi: 10.1016/j.jtherbio.2020.102742. Epub 2020 Oct 7.
In a magnetic hyperthermia treatment, malignant cancerous cells are ablated by the heat production of magnetic nanoparticles (MNP) under an external magnetic field. This novel approach is a promising tool to eliminate the tumor cells by a higher temperature inside the tumor microenvironment. MNPs are needed inside the tumor microenvironment to increase the heat, and this could be possible with intravenous drug injection. However, tumors with necrosis regions are more resistant to drug penetration, and this can cause inadequate and non-homogeneous temperature distribution in the tumor. Hence, in this study, we used numerical methods to investigate the Spatio-temporal temperature field distribution in the necrotic tumor and its surrounding tissue. To this end, an intravenous bolus injection is used to simulate the effect of systemic drug delivery in tumors with necrosis region. Results show that the temperature field with the necrosis region with 10% of the tumor radius is more prone to higher temperature values. The hypoxia region is affected by the high temperature despite the necrosis region in the tumor. However, a broader necrosis region impedes drug penetration inside the inner layers of tumors, which leads to a lower heat generation by the MNPs. Results also demonstrate that only 15.5% of MNP concentration distributed to the necrosis with 50% of tumor radius, leading a temperature of 42C in the necrosis region, which is not sufficient for the tumor ablation. Therefore, the temperature distribution is dependant on the sizes of necrosis regions in tumors, and tumors with a larger necrotic region (over 20% of tumor radius) are challenging to treat with hyperthermia treatment. This study could help the future in vitro and in vivo studies of hyperthermia treatment in necrotic tumors.
在磁热疗中，恶性癌细胞在外部磁场作用下因磁性纳米颗粒（MNP）产热而被消融。这种新方法是通过肿瘤微环境内更高温度消除肿瘤细胞的一种有前景的工具。肿瘤微环境内需要MNP来增加热量，通过静脉注射药物可能实现这一点。然而，有坏死区域的肿瘤对药物渗透更具抗性，这会导致肿瘤内温度分布不足且不均匀。因此，在本研究中，我们使用数值方法研究坏死肿瘤及其周围组织中的时空温度场分布。为此，采用静脉推注来模拟在有坏死区域的肿瘤中全身给药的效果。结果表明，坏死区域半径占肿瘤半径10%的温度场更容易出现较高温度值。尽管肿瘤中有坏死区域，但缺氧区域仍受高温影响。然而，更宽的坏死区域会阻碍药物渗透到肿瘤内层，这导致MNP产生的热量更低。结果还表明，只有15.5%的MNP浓度分布到半径占肿瘤半径50%的坏死区域，使得坏死区域温度达到42℃，这不足以进行肿瘤消融。因此，温度分布取决于肿瘤中坏死区域的大小，坏死区域较大（超过肿瘤半径20%）的肿瘤用热疗治疗具有挑战性。本研究有助于未来对坏死肿瘤热疗的体外和体内研究。
