Tomographic imaging using the nonlinear response of magnetic particles
Tomographic imaging using the nonlinear response of magnetic particles
复制标题
DOI：
10.1038/nature03808
复制
发表时间：
2005-06-30
期刊：
影响因子：
64.8
通讯作者：
Weizenecker, R
中科院分区：
文献类型：
--
作者：
Gleich, B;Weizenecker, R
造影剂和示踪剂在医学成像中的使用具有悠久的历史（1-7）。它们为诊断和治疗提供了重要的信息，但对于某些期望的应用，需要比使用当前可用的医学成像技术可以获得的分辨率更高的分辨率。例如，考虑在磁共振成像中使用磁示踪剂：体外（8）和体内（9）成像的检测阈值是这样的，来自宿主组织的背景信号是一个关键的限制因素。直接检测磁性粒子的灵敏方法是使用弛豫测量法测量它们的磁场;但是这种方法的缺点是逆问题（与将数据转换为空间图像相关联）是不适定的，因此产生低空间分辨率。在这里，我们提出了一种方法，用于获得这样的示踪剂，利用小磁性颗粒的非线性磁化曲线的高分辨率图像。初步的“幻影”实验报告，证明成像方法的可行性。我们实现的分辨率已经远低于1毫米。我们评估的前景进一步改善，并表明，该方法有可能被开发成一种成像方法，其特征在于高空间分辨率以及高灵敏度。
The use of contrast agents and tracers in medical imaging has a long history(1-7). They provide important information for diagnosis and therapy, but for some desired applications, a higher resolution is required than can be obtained using the currently available medical imaging techniques. Consider, for example, the use of magnetic tracers in magnetic resonance imaging: detection thresholds for in vitro(8) and in vivo(9) imaging are such that the background signal from the host tissue is a crucial limiting factor. A sensitive method for detecting the magnetic particles directly is to measure their magnetic fields using relaxometry(10); but this approach has the drawback that the inverse problem ( associated with transforming the data into a spatial image) is ill posed and therefore yields low spatial resolution. Here we present a method for obtaining a high-resolution image of such tracers that takes advantage of the nonlinear magnetization curve of small magnetic particles. Initial 'phantom' experiments are reported that demonstrate the feasibility of the imaging method. The resolution that we achieve is already well below 1 mm. We evaluate the prospects for further improvement, and show that the method has the potential to be developed into an imaging method characterized by both high spatial resolution as well as high sensitivity.