Mathieu Jean-Baptiste, Martel Sylvain
Department of Computer Engineering and Institute of Biomedical Engineering, NanoRobotics Laboratory, Ecole Polytechnique de Montréal, Montréal, Québec, Canada.
Biomed Microdevices. 2007 Dec;9(6):801-8. doi: 10.1007/s10544-007-9092-0.
This paper presents a magnetic microparticle steering approach that relies on improved gradient coils for Magnetic Resonance Imaging (MRI) systems. A literature review exposes the motivation and advantages of this approach and leads to a description of the requirements for a set of dedicated steering gradient coils in comparison to standard imaging coils. An experimental set-up was developed to validate the mathematical models and the hypotheses arising from this targeting modality. Magnetite Fe(3)O(4) microparticles (dia. 10.9 microm) were steered in a Y-shaped 100 microm diameter microchannel between a Maxwell pair (dB/dz = 443 mT/m) located in the center of an MRI bore with 0.525 m/s mean fluid velocity (ten times faster than in arterioles with same diameter). Experimental results based on the percentage of particles retrieved at the targeted outlet show that the mathematical models developed provide an order of magnitude estimate of the magnetic gradient strengths required. Furthermore, these results establish a proof of concept of microparticle steering using magnetic gradients within an MRI bore for applications in the human cardiovascular system.
本文提出了一种用于磁共振成像（MRI）系统的磁微粒操控方法，该方法依赖于改进的梯度线圈。文献综述揭示了这种方法的动机和优势，并引出了与标准成像线圈相比，一组专用操控梯度线圈的要求描述。开发了一个实验装置来验证由此种靶向方式产生的数学模型和假设。在位于MRI孔径中心的麦克斯韦对（dB/dz = 443 mT/m）之间，直径为100微米的Y形微通道中操控磁铁矿Fe(3)O(4)微粒（直径10.9微米），平均流体速度为0.525 m/s（比相同直径的小动脉快十倍）。基于在目标出口处回收的颗粒百分比的实验结果表明，所开发的数学模型提供了所需磁梯度强度的数量级估计。此外，这些结果为在MRI孔径内使用磁梯度进行微粒操控以应用于人体心血管系统建立了概念验证。
