Establishment of quantitative Magnetic Particle Imaging (MPI) application oriented phantoms for preclinical investigations

在最近的一次电话会议上，DFG资助了磁粒子成像（MPI）扫描仪，以便为研究人员提供探索这种成像方法潜力的机会。这需要阐明新成像模式的基本原理，例如，MPI扫描仪的检测极限和图像分辨率。进一步的特殊问题将出现在由MPI跟踪器的特定局部配置引起的特定医学应用中，例如，该项目旨在建立一个可控制和验证的实验条件的基础设施，这将作为定量MPI的良好基础。为此，应开发和提供专用的体模，通过该体模可以对MPI扫描仪的单个成像特性进行计量学监测。特别是分辨率，以及在现实的医疗环境中的示踪剂的量和分布的量化将得到解决。此外，应研究MRT-MPI配准时解剖结构和示踪剂分布的一致性。除了MRT之外，我们还将使用磁弛豫测量作为一种独立的空间分辨参考技术来评估MPI结果。为了真实地检查MPI扫描仪的性能，体模必须以受控的方式反映预期医学MPI应用的基本属性。这包括MPI示踪剂的浓度变化、流动性和粘度，以及生理介质（血液）的速度、温度、粘度和直径。通过这种方法，将增加MPI测量在体内环境中的有效性，并将临床前研究的设计置于可靠、合理的基础上，从而增加这些项目成功的前景。因此，可以减少动物试验的数量。由此产生的长期稳定的幻影将提供给医生和物理学家谁的工作与两个DFG资助的MPI扫描仪网站探索这种有前途的技术的潜力。

In a recent call DFG has funded Magnetic Particle Imaging (MPI) scanners in order to provide researchers the opportunity to explore the potential of this imaging method. This requires clarifying the fundamentals of the novel imaging modality, such as, e.g., detection limits and image resolution of the MPI-scanners. Further peculiar questions will emerge from particular medical applications resulting from the specific local configuration of the MPI-tracer, e.g., in a vascular system or in a tumor.This project aims to establish a metrological infrastructure to accomplish controlled and validated experimental conditions, which will serve as a sound basis for a quantitative MPI.To this end, dedicated phantoms shall be developed and provided, by which individual imaging properties of an MPI scanner can be metrologically monitored. In particular the resolution as well as quantification of tracer amount and distribution in realistic medical environments will be addressed. Further, the congruence of anatomy and tracer distribution at a MRT-MPI coregistration shall be investigated. In addition to MRT we will employ magnetorelaxometry as an independent, spatially resolving reference technique to assess MPI results.For realistic examination of the MPI scanner performance the phantoms have to reflect the essential properties of the intended medical MPI application in a controlled manner. This comprises concentration variations, mobility and viscosity of the MPI tracer, as well as velocity, temperature, viscosity, and diameter of the physiological medium (blood).By this approach the validity of the MPI measurements in an in-vivo setting will be increased and the design of preclinical studies will be put on a reliable, sound basis increasing the prospects of success of these projects. As a consequence the number of animal testing can be reduced. The resulting long-term stable phantoms will be made available to physicians and physicists who work with the two DFG-funded MPI scanner sites for exploring the potential of this promising technique.