title: Magnetic microparticle steering within the constraints of an MRI system: proof of concept of a novel targeting approach.
abstract: 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.
authors.affiliation: Department of Computer Engineering and Institute of Biomedical Engineering, NanoRobotics Laboratory, Ecole Polytechnique de Montréal, Montréal, Québec, Canada. jean-baptiste.mathieu@polymtl.ca
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Mathieu
authors.forename: Sylvain
authors.initials: S
authors.lastname: Martel
mesh_terms: D016503:Drug Delivery Systems / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D018189:Immunomagnetic Separation / Q000295:instrumentation* / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity