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MAGNETIC WELL GRADIENT COIL: ELECTROMAGNET ARRANGEMENT FOR MAGNETIC STEERING AND SPATIAL CONFINEMENT OF MAGNETIC OBJECTS

IP.com Disclosure Number: IPCOM000237618D
Publication Date: 2014-Jun-27
Document File: 9 page(s) / 204K

Publishing Venue

The IP.com Prior Art Database

Abstract

The invention proposes a technique to generate a nonlinear magnetic force well to attract magnetic particles in a region of interest towards a desired location. The technique includes a magnetic well gradient coil (MWGC) configuration to generate a nonlinear magnetic force well that attracts magnetic particle present in the region of interest towards a maximum magnetic field point (MMFP) in a magnetic resonance (MR) system. Configurations of the gradient coils are able to generate the MMFP whose position is varied in three dimensions to steer magnetic particles to a desired location by energizing the sub-coil of the MWGC appropriately. This new configuration provides a stable actuation technique to reduce refresh rate required from a software controller, tracking technique and power supplies. This allows higher magnetic force amplitudes through high inductance gradient coil.

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MAGNETIC WELL GRADIENT COIL: ELECTROMAGNET ARRANGEMENT FOR MAGNETIC STEERING AND SPATIAL CONFINEMENT OF MAGNETIC OBJECTS

 

BRIEF ABSTRACT

The invention proposes a technique to generate a nonlinear magnetic force well to attract magnetic particles in a region of interest towards a desired location. The technique includes a magnetic well gradient coil (MWGC) configuration to generate a nonlinear magnetic force well that attracts magnetic particle present in the region of interest towards a maximum magnetic field point (MMFP) in a magnetic resonance (MR) system. Configurations of the gradient coils are able to generate the MMFP whose position is varied in three dimensions to steer magnetic particles to a desired location by energizing the sub-coil of the MWGC appropriately. This new configuration provides a stable actuation technique to reduce refresh rate required from a software controller, tracking technique and power supplies. This allows higher magnetic force amplitudes through high inductance gradient coil.

KEYWORDS

MWGC, MMFP, MRI Scanner, Gradient coil.


DETAILED DESCRIPTION

Magnetic field is modulated to guide cells or polymeric carriers which are tagged with a magnetic agent to the desired location. These cells or polymeric carriers are a magnetic dipole. Force acting on the magnetic dipole is given by equation 1 as given below.

The equation is a function of magnetization M and volume V of the magnetic material in the cell or carrier, strength of the magnetic field B and of the amplitude and direction of the dipole’s magnetic moment. Penetration depth and geometric control of the magnetic field and gradient limits utilization of external permanent magnet for in vivo human scale cell patterning to superficial organ. Utilization of an electromagnet resolves this limitation, which are large enough to contain volume of interest of sample or patient. MRI technologies demonstrate every day in hospital settings that such electromagnets are reliably and cost effectively manufactured. They provide region of homogeneities large enough to be compatible with human anatomy while generating field strength of several Tesla (T) and homogeneity in order of parts per million. In addition to offering high strength and homogeneity static magnetic field, MRI scanners contain pulsed electromagnets (gradient coils) that are switched to modulate the magnetic field in three dimensions with frequencies up to several kHz. For offering high strength and homogeneity static magnetic field, M term is delivered by magnetizing magnetic material as well as directional bias field in Equation 1 by aligning the M and B vectors. The gradient coils, typically, utilized for slice selection and spatial encoding of the image are also used to generate a controllable magnetic force on magnetized materials by providing the gradient term in Equation 1.

The force is modulated in direction and amplitude independently in each dimension of space by appropriately energizing orthogonal e...