Magnetically-coated silica nanospheres for dual-mode imaging at low ultrasound frequency
磁包覆二氧化硅纳米球的双模成像在低超声频率作者机构：Consiglio Nazionale delle Ricerche Istituto di Fisiologia Clinica (CNR-IFC) c/oCampus Ecotekne via per Monteroni National Research Council Istituto di Nanoscienze National Research Council Institute of Clinical Physiology
出 版 物：《World Journal of Radiology》 (世界放射学杂志（英文版）（电子版）)
年 卷 期：2013年第5卷第11期
页 面：411-420页
学科分类：1001[医学-基础医学(可授医学、理学学位)] 10[医学]
基 金：Supported by Italian Ministry of Instruction and Research,No.DM18604-Bando Laboratori-DD MIUR 14.5.2005 n.602/Ric/2005 FESR PO Apulia Region 2007-2013-Action 1.2.4,No.3Q5AX31 the Progetto Bandiera NANOMAX ENCODER
主 题：Ultrasound Magnetic resonance Nanocomposite Dual-mode Imaging Contrast agent Diagnostic imaging
摘 要：AIM: To experimentally investigate the acoustical behavior of different dual-mode nanosized contrast agents(NPCAs) for echographic medical imaging at low ultrasound(US) frequency. METHODS: We synthesized three different nanosized structures:(1) Pure silica nanospheres(SiNSs);(2) FePt-iron oxide(FePt-IO)-coated SiNSs; and(3) IOcoated SiNSs, employing three different diameter of SiNS-core(160, 330 and 660 nm). Tissue mimicking phantoms made of agarose gel solution containing 5 mg of different NPCAs in 2 mL-Eppendorf tubes, were insonified by a commercial echographic system at three different low US pulse values(2.5, 3.5 and 4.5 MHz). The raw radiofrequency signal, backscattered from each considered NPCA containing sample, has been processed in order to calculate the US average backscatter intensity and compare the acoustic behavior of the different NPCA types. RESULTS: The highest US contrast was exhibited by pure SiNSs; FePt-IO-coated SiNSs acoustical behavior followed a similar trend of pure SiNSs with a slight difference in terms of brightness values. The acoustic response of the examined NPCAs resulted function of both SiNS diameter and US frequency. Specifically, higher US frequencies determined higher value of the backscatter for a given SiNS diameter. Frequencydependent enhancement was marked for pure SiNSs and became less remarkable for FePt-IO-coated SiNSs, whereas IO-coated SiNSs resulted almost unaffected by such frequency variations. Pure and FePt-IO-coated SiNSs evidenced an image backscatter increasing with the diameter up to 330 nm. Conversely, among the types of NPCA tested, IO-coated SiNSs showed the lowest acoustical response for each synthesized diameter and employed US frequency, although a diameter-dependent raising trend was evidenced. CONCLUSION: The US characterization of magnetically covered SiNS shows that FePt-IO, rather than IO, was the best magnetic coating for realizing NPCAs suitable for dual mode imaging of deep organs, combining US and
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