Boroon Mostafa Pasandi, Ayani Mohammad-Bagher, Bazaz Sajad Razavi
Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran.
Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran.
J Therm Biol. 2018 Feb;72:127-136. doi: 10.1016/j.jtherbio.2018.01.010. Epub 2018 Jan 31.
Hyperthermia is one of the most appealing methods of cancer treatment in which the temperature of tumor is elevated to reach a desired temperature. One of the methods of increasing tissue temperature is injection of nanoparticle fluids to tumor and applying alternative magnetic field, which is called magnetic nanoparticle hyperthermia method. The total number of injection points, as well as the their location within a tissue play a significant role in this method. Furthermore, the power of heating of a magnetic material per gram or specific loss power (SLP) is another important factor which needs to be investigated. As the uniform temperature of 43 °C is effective enough for a tumor regression in certain specific tissues, the inverse method is applied to find out both the number of injection points and their location. Furthermore, the effective amount of heat generated by nanoparticles is investigated by this technique. Two-dimensional cancerous brain tissue was considered, zero gradients on boundary conditions were assumed, and diffusion equation and Pennes equation, which is regarded as energy equation, were solved, respectively. Conjugate gradient technique as a one way of inverse methods is applied, and unknowns are investigated. The results illustrate that three-point injection with the best injection sites cannot induce a uniform temperate distribution of 43 °C, and although four-point injection can create a uniform temperature elevation, the amount of it cannot reach the 43 °C. Finally, the optimum locations of five-point injection which are ((0.80,3.24), (0.80,0.84), (2.00,2.00), (3.20,3.24), (3.32,0.84)) (all dimensions are in mm) in the studied domain with special loss power of 420 W/g, all of which are obtained after 36 iterations, demonstrate that these conditions can meet the requirements of the magnetic fluid hyperthermia and can be considered for the future usage of researchers and investigators.
热疗是最具吸引力的癌症治疗方法之一，即提高肿瘤温度以达到预期温度。增加组织温度的一种方法是向肿瘤注射纳米颗粒流体并施加交变磁场，这被称为磁性纳米颗粒热疗方法。注射点的总数及其在组织内的位置在该方法中起着重要作用。此外，每克磁性材料的加热功率或比损耗功率（SLP）是另一个需要研究的重要因素。由于43°C的均匀温度对某些特定组织中的肿瘤消退足够有效，因此采用逆方法来确定注射点的数量及其位置。此外，通过该技术研究纳米颗粒产生的有效热量。考虑二维癌性脑组织，假设边界条件为零梯度，分别求解扩散方程和被视为能量方程的佩恩斯方程。应用共轭梯度技术作为逆方法之一，并对未知数进行研究。结果表明，三点注射且注射位点最佳时也无法诱导出43°C的均匀温度分布，虽然四点注射可以产生均匀的温度升高，但其升高量无法达到43°C。最后，在比损耗功率为420W/g的研究区域中，五点注射的最佳位置为（(0.80,3.24),(0.80,0.84),(2.00,2.00),(3.20,3.24),(3.32,0.84)）（所有尺寸单位均为mm），所有这些都是在36次迭代后获得的，表明这些条件可以满足磁流体热疗的要求，可供研究人员和调查人员未来使用时参考。
