Radiology Department, School of Allied Medical Sciences, Students Research Committee, Shahid Beheshti University of Medical Science, Tehran, Iran.
Skull Base Research Center, The Five Senses Institute, Iran University of Medical Sciences (IUMS), Tehran, Iran; ENT and Head & Neck Research Center and Department, The Five Senses Institute, Iran University of Medical Sciences (IUMS), Tehran, Iran; Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran.
Photodiagnosis Photodyn Ther. 2019 Mar;25:66-73. doi: 10.1016/j.pdpdt.2018.11.010. Epub 2018 Nov 14.
Gold nanoparticles (AuNPs) have shown potential strength in photothermal therapy of cancer. Several techniques have been developed to investigate local heat generation by AuNPs. However, a sensitive thermal imaging technology with high temporal resolution, minimum invasiveness and high spatial resolution is still lacking. In this research study, by using magnetic resonance thermal imaging (MRTI), we reported a technique for monitoring of heat generation and distribution in an AuNPs loaded agar phantom irradiated by laser. Three different agar phantoms with various AuNPs concentrations (0, 8 and 16 μg/ml) were produced and studied. The phantoms were exposed to an external laser [532 nm; 4 min] under MRTI. For real-time temperature monitoring, we employed the theory of proton resonance frequency (PRF) shift. Infrared (IR) camera was employed to measure the actual temperature of each point on the surface of irradiated agar gel. Finally, the correlation between the temperatures obtained by IR camera and MRTI was evaluated. We observed that temperature of the gels loaded by AuNPs at concentration of 0, 8 and 16 μg/ml reached 27.2, 37.8, 45 °C with a total area of heat distribution of 94.98, 452.16, and 907.34 mm (from the point of irradiation). During the process of laser irradiation, we observed: (i) a significant rise in temperature, (ii) a dependency between the rate of temperature rise and concentration of AuNPs, and (iii) a direct correlation between temperature change and MR image phase. In addition, statistical analysis showed that the variation of temperatures measured by IR camera and temperatures computed by MRTI had acceptable correlation (R > 0.9). In conclusion, MRTI has a good sensitivity and precision that can be employed for nano-photothermal therapy planning and may be considered for real-time mapping of heat generation and distribution in a laser irradiated tissue loaded by AuNPs.
金纳米粒子（AuNPs）在癌症的光热治疗中显示出了强大的潜力。已经开发了几种技术来研究 AuNPs 的局部热产生。然而，仍然缺乏一种具有高时间分辨率、最小侵入性和高空间分辨率的敏感热成像技术。在这项研究中，我们通过使用磁共振热成像（MRTI），报道了一种监测激光辐照下负载 AuNPs 的琼脂体中热产生和分布的技术。制备并研究了三种不同 AuNPs 浓度（0、8 和 16μg/ml）的琼脂体。将这些体模暴露在 MRTI 下的外部激光[532nm；4min]中。为了实时温度监测，我们采用了质子共振频率（PRF）偏移的理论。使用红外（IR）相机测量辐照琼脂凝胶表面各点的实际温度。最后，评估了通过 IR 相机和 MRTI 获得的温度之间的相关性。我们观察到，浓度为 0、8 和 16μg/ml 的 AuNPs 负载的凝胶温度分别达到 27.2、37.8 和 45°C，其热分布总面积分别为 94.98、452.16 和 907.34mm（从辐照点开始）。在激光照射过程中，我们观察到：（i）温度显著升高，（ii）温度升高率与 AuNPs 浓度之间的依赖性，以及（iii）温度变化与 MR 图像相位之间的直接相关性。此外，统计分析表明，IR 相机测量的温度和 MRTI 计算的温度之间的变化具有可接受的相关性（R＞0.9）。总之，MRTI 具有良好的灵敏度和精度，可用于纳米光热治疗计划，并可考虑用于实时绘制 AuNPs 负载的激光辐照组织中的热产生和分布。
