Karunamuni Roshan, Naha Pratap C, Lau Kristen C, Al-Zaki Ajlan, Popov Anatoliy V, Delikatny Edward J, Tsourkas Andrew, Cormode David P, Maidment Andrew D A
Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
Department of Radiology, University of Pennsylvania, 1 Silverstein, 3400 Spruce Street, Philadelphia, PA, 19104, USA.
Eur Radiol. 2016 Sep;26(9):3301-9. doi: 10.1007/s00330-015-4152-y. Epub 2016 Feb 24.
Dual-energy (DE) mammography has recently entered the clinic. Previous theoretical and phantom studies demonstrated that silver provides greater contrast than iodine for this technique. Our objective was to characterize and evaluate in vivo a prototype silver contrast agent ultimately intended for DE mammography.
The prototype silver contrast agent was synthesized using a three-step process: synthesis of a silver core, silica encapsulation and PEG coating. The nanoparticles were then injected into mice to determine their accumulation in various organs, blood half-life and dual-energy contrast. All animal procedures were approved by the institutional animal care and use committee.
The final diameter of the nanoparticles was measured to be 102 (±9) nm. The particles were removed from the vascular circulation with a half-life of 15 min, and accumulated in macrophage-rich organs such as the liver, spleen and lymph nodes. Dual-energy subtraction techniques increased the signal difference-to-noise ratio of the particles by as much as a factor of 15.2 compared to the single-energy images. These nanoparticles produced no adverse effects in mice.
Silver nanoparticles are an effective contrast agent for dual-energy x-ray imaging. With further design improvements, silver nanoparticles may prove valuable in breast cancer screening and diagnosis.
• Silver has potential as a contrast agent for DE mammography. • Silica-coated silver nanoparticles are biocompatible and suited for in vivo use. • Silver nanoparticles produce strong contrast in vivo using DE mammography imaging systems.
双能乳腺摄影术最近已进入临床应用。先前的理论和模型研究表明，对于该技术，银比碘能提供更高的对比度。我们的目的是对一种最终用于双能乳腺摄影术的银造影剂原型进行体内特性表征和评估。
采用三步法合成银造影剂原型：银核合成、二氧化硅包封和聚乙二醇涂层。然后将纳米颗粒注射到小鼠体内，以确定它们在各个器官中的蓄积情况、血液半衰期和双能对比度。所有动物实验程序均经机构动物护理和使用委员会批准。
纳米颗粒的最终直径测量为102（±9）nm。这些颗粒从血管循环中清除的半衰期为15分钟，并在富含巨噬细胞的器官如肝脏、脾脏和淋巴结中蓄积。与单能图像相比，双能减影技术使颗粒的信号差异噪声比提高了多达15.2倍。这些纳米颗粒在小鼠中未产生不良反应。
银纳米颗粒是双能X线成像的有效造影剂。随着进一步的设计改进，银纳米颗粒可能在乳腺癌筛查和诊断中证明具有价值。
• 银有潜力作为双能乳腺摄影术的造影剂。• 二氧化硅包被的银纳米颗粒具有生物相容性，适合体内使用。• 使用双能乳腺摄影成像系统时，银纳米颗粒在体内产生强烈的对比度。
