Department of Mechanical Engineering, University of Maryland Baltimore County , Baltimore, MD 21250, USA.
Int J Hyperthermia. 2011;27(5):491-502. doi: 10.3109/02656736.2011.584856.
Among a variety of hyperthermia methods, magnetic nanoparticle hyperthermia is a highly promising approach for its confined heating within the tumour. In this study we perform in vivo animal experiments on implanted prostatic tumours in mice to measure temperature distribution in the tumour during magnetic nanoparticle hyperthermia. Temperature elevations are induced by a commercially available ferrofluid injected via a single injection to the centre of the tumour, when the tumour is subject to an alternating magnetic field. Temperature mapping in the tumours during magnetic nanoparticle hyperthermia has demonstrated the feasibility of elevating tumour temperatures higher than 50°C using only 0.1 cm(3) ferrofluid injected in the tumour under a relatively low magnetic field (3 kA/m). Detailed 3-D nanoparticle concentration distribution is quantified using a high-resolution microCT imaging system. The calculated nanoparticle distribution volume based on the microCT scans is useful to analyse nanoparticle deposition in the tumours. Slower ferrofluid infusion rates result in smaller nanoparticle distribution volumes in the tumours. Nanoparticles are more confined in the vicinity of the injection site with slower infusion rates, causing higher temperature elevations in the tumours. The increase in the nanoparticle distribution volume in the tumour group after the heating from that in the tumour group without heating suggests possible nanoparticle re-distribution in the tumours during the heating.
在各种热疗方法中，磁纳米粒子热疗因其在肿瘤内的局限加热而极具应用前景。本研究在植入的小鼠前列腺肿瘤的体内动物实验中，测量了磁纳米粒子热疗过程中肿瘤内的温度分布。当肿瘤处于交变磁场中时，通过向肿瘤中心单次注射市售的铁磁流体来产生温度升高。在相对较低的磁场（3kA/m）下，仅向肿瘤内注射 0.1cm3 的铁磁流体，即可实现将肿瘤温度升高到 50°C 以上，这证明了磁纳米粒子热疗升高肿瘤温度的可行性。使用高分辨率 microCT 成像系统定量分析了详细的 3D 纳米颗粒浓度分布。基于 microCT 扫描计算出的纳米颗粒分布体积可用于分析肿瘤内的纳米颗粒沉积。较慢的铁磁流体输注速率会导致肿瘤内的纳米颗粒分布体积减小。输注速率较慢时，纳米颗粒在注射部位附近更为局限，导致肿瘤内的温度升高更高。加热后肿瘤组的纳米颗粒分布体积比未加热组的增加，表明加热过程中肿瘤内的纳米颗粒可能发生了重新分布。
