Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA.
J Biomater Appl. 2013 Jul;28(1):100-11. doi: 10.1177/0885328212437883.
The ability to reliably detect sentinel lymph nodes for sentinel lymph node biopsy and lymphadenectomy is important in clinical management of patients with metastatic cancers. However, the traditional sentinel lymph node mapping with visible dyes is limited by the penetration depth of light and fast clearance of the dyes. On the other hand, sentinel lymph node mapping with radionucleotide technique has intrinsically low spatial resolution and does not provide anatomic details in the sentinel lymph node mapping procedure. This work reports the development of a dual modality imaging probe with magnetic resonance and near infrared imaging capabilities for sentinel lymph node mapping using magnetic iron oxide nanoparticles (10 nm core size) conjugated with a near infrared molecule with emission at 830 nm. Accumulation of magnetic iron oxide nanoparticles in sentinel lymph nodes leads to strong T2 weighted magnetic resonance imaging contrast that can be potentially used for preoperative localization of sentinel lymph nodes, while conjugated near infrared molecules provide optical imaging tracking of lymph nodes with a high signal to background ratio. The new magnetic nanoparticle based dual imaging probe exhibits a significant longer lymph node retention time. Near infrared signals from nanoparticle conjugated near infrared dyes last up to 60 min in sentinel lymph node compared to that of 25 min for the free near infrared dyes in a mouse model. Furthermore, axillary lymph nodes, in addition to sentinel lymph nodes, can be also visualized with this probe, given its slow clearance and sufficient sensitivity. Therefore, this new dual modality imaging probe with the tissue penetration and sensitive detection of sentinel lymph nodes can be applied for preoperative survey of lymph nodes with magnetic resonance imaging and allows intraoperative sentinel lymph node mapping using near infrared optical devices.
可靠地检测前哨淋巴结进行前哨淋巴结活检和淋巴结切除术，这对于转移性癌症患者的临床管理非常重要。然而，传统的使用可见染料的前哨淋巴结定位受到光的穿透深度和染料快速清除的限制。另一方面，放射性核素技术的前哨淋巴结定位具有固有的低空间分辨率，并且在进行前哨淋巴结定位时无法提供前哨淋巴结的解剖细节。本研究报告了一种具有磁共振和近红外成像功能的双模式成像探针的开发，该探针使用与近红外分子（发射波长为 830nm）缀合的 10nm 核大小的磁性氧化铁纳米颗粒（magnetic iron oxide nanoparticles，IONPs）进行前哨淋巴结定位。前哨淋巴结中磁性氧化铁纳米颗粒的积累导致强烈的 T2 加权磁共振成像对比，这可能用于前哨淋巴结的术前定位，而共轭的近红外分子提供具有高信号背景比的淋巴结光学成像跟踪。新型基于磁性纳米颗粒的双成像探针表现出显著更长的淋巴结保留时间。与游离近红外染料在小鼠模型中 25 分钟相比，纳米颗粒共轭近红外染料的近红外信号在前哨淋巴结中持续时间长达 60 分钟。此外，由于其缓慢清除和足够的灵敏度，该探针还可以可视化腋窝淋巴结，除了前哨淋巴结之外。因此，这种具有组织穿透性和灵敏检测前哨淋巴结的新型双模式成像探针可用于磁共振成像对淋巴结进行术前检查，并允许使用近红外光学设备进行术中前哨淋巴结定位。
