A Single-Sided Magnetic Particle Imaging Scanner for In Vivo Breast Cancer Imaging

磁粒子成像(MPI)是一种新兴的非侵入性断层成像方式；与CT或MRI一样，它 可以作为一种安全的诊断技术应用于临床和研究环境中，但不会产生电离辐射 或者有毒的示踪剂。MPI对临床翻译的主要挑战之一是能够扩大 环绕人体的线圈，同时能够产生和驱动足够强的磁场 高空间分辨率所需的渐变。然而，这些要求需要令人望而却步的高功率 在具有圆柱形几何图形的设备中的消耗；因此，替代拓扑，如开放几何图形 扫描仪，将是非常可取的。该方案的目标是开发一种新型单面mpi成像器。 并在啮齿类动物身上展示了体内癌症成像。单面设备将所有硬件都放在一面 成像体积；因此，这种设备可以同样好地用于小动物和人类 多维诊断成像和作为MPI光谱仪(MPS)。在我们独特的方法中，我们将 开发一种具有更有前景的场拓扑结构的单面MPI成像器，即无场线(FFL)AS 相对于更常见且相对更容易实现的无场点(FFP)几何，对于势场 信噪比提高10倍，图像重建更稳健，视场更大。 到目前为止，我们已经建立了第一个单面线圈组件的原型，其FFL几何结构包括 所有所需线圈均为单边配置。测量的磁场显示出与 这些模拟。我们通过演示磁粉信号检测来进一步验证我们的设备 点源体模。基于单面几何的全功能多维扫描仪的研制 在乳腺癌成像中具有直接的临床意义。我们追求两个具体目标：1)开发一种 多维成像技术，可以在我们的单面设备上实现。主 这一目标的目的是显著提高设备的灵敏度并识别成像序列 它结合了选择线圈和激励线圈，并与我们独特的表面线圈接收器协同工作 接近。我们将实施所需的硬件改造和信号自动化。2)验证 通过获取MPI图像的成像方法。MPI扫描仪的性能将使用以下方法进行分析 带有氧化铁纳米颗粒的幻影。最后，我们将在活体成像中验证扫描仪的性能 荷瘤小鼠。 拟议研究的总体优势在于开发了有史以来第一台MPI扫描仪，它可以 有可能被转化到临床环境中。具体地说，我们希望提供一种更敏感和非侵入性的 对妇女健康有直接影响的乳腺癌筛查工具。

Magnetic Particle Imaging (MPI) is an emerging non-invasive tomographic imaging modality; like CT or MRI, it could be applied in clinical and research settings as a safe diagnostic technique, but without ionizing radiation or toxic tracers. One of the major MPI challenges toward clinical translation has been the ability to scale up the coils to surround a human body while being able to generate and drive the sufficiently strong magnetic field gradient required for high spatial resolution. These requirements, however, demand prohibitively high power consumption in a device with cylindrical geometry; therefore, alternative topologies, such as an open geometry scanner, would be highly desirable. The goal of this proposal is to develop a novel single-sided MPI imager and demonstrate in vivo cancer imaging in rodents. The single-sided device has all the hardware on one side of the imaging volume; therefore, such a device can be used equally well on small animals and humans for multidimensional diagnostic imaging and as an MPI spectrometer (MPS). In our unique approach, we will develop a single-sided MPI imager with much more promising field topology, namely, field-free line (FFL) as opposed to the more common and relatively easier to implement field-free point (FFP) geometry, for a potential 10-fold increase of SNR, more robust image reconstruction, and larger field of view. To date, we have built a first prototype of a single-sided coils assembly with the FFL geometry that consists of all the required coils in a unilateral configuration. The measured magnetic field showed perfect agreement with the simulations. We further validated our device by demonstrating magnetic particle signal detection using a point-source phantom. Developing a fully capable multidimensional scanner based on single-sided geometry has direct clinical relevance in breast cancer imaging. We pursue two specific aims: 1) Develop a multidimensional imaging technique, which can be implemented in our single-sided device. The main objectives of this aim are to drastically increase the sensitivity of the device and identify an imaging sequence that combines both selection and excitation coils and works in tandem with our unique surface-coil receive approach. We will implement the required hardware modification and signal automation. 2) Validate the imaging method by obtaining the MPI images. The performance of the MPI scanner will be analyzed using phantoms with iron oxide nanoparticles. Finally, we will validate the scanner performance in in vivo imaging of breast tumor-bearing mice. The overall strength of the proposed research lies in developing the first ever MPI scanner that could potentially be translated to clinical settings. Specifically, we hope to deliver a more sensitive and non-invasive tool for breast cancer screening that has a direct impact on women health.